From Scope F70076

Revision as of 22:03, 8 October 2008

76mm reflector telescope F70076

I'm a complete beginner what concerns telescopes and astronomy, so I thought that my experience about telescopes might be useful for other beginners. Therefore also, a lot what I write here is about what I think, I just discover all these things for myself, only for entertainment.

Telescope F70076

This telescope was made by the German company Telescope-Sevice, the parts of it were though likely made by the Chinese company Wuhan Siwei, except perhaps the focuser and the eyepieces, because Wuhan Siwei only produces a 0.96 inch focuser, but this telescope has a 1 1/4 inch focuser. I think though that the companies which order such telescopes have some quality control, the telescope has quite high quality for such class of telescopes. F70076 is also the name of the telescope produced by Wuhan Siwei, based on which likely all the similar telescopes are made, so it can be said that the PowerSeeker 76 AZ, the Orion SpaceProbe 3 Altaz and the other such 76mm Newton reflectors, are also F70076.

Many ask a question, what telescope should they buy. But there is no single answer to that question, there are different types of telescopes and the only way to find out whether these telescopes are good for your needs, is to know more about these telescopes. This is a description of one type of telescope. This telescope is not a kind of one which should be recommended definitely not to buy, but you should know more about this type of telescopes to decide whether they satisfy your needs, or you should rather consider buying a more expensive telescope, such as the 8 inch dobsonian.

What is important about such cheap telescopes though is that almost everyone can afford them. Thus a telescope is not a matter of money, telescope is a matter of knowledge, and everyone who knows how to use a telescope, can have a telescope.

Price

This is one of these less than $100 telescopes, it is very similar to the Celestron PowerSeeker 76 AZ, which at least in Amazon.com costs $64, and to the Orion SpaceProbe 3 Altaz, which costs $99.95 at the Orion site, Bushnell, Tasco, Bresser, Sky-Watcher and the other companies also produce a similar telescope. Of these, I find the Orion SpaceProbe still to be better, because it has a 10mm eyepiece. In spite that my eyepieces are Huygens, this telescope has a good selection of eyepieces, and I found the 12.5mm eyepiece to be very useful, and the 4mm practically useless. The Celestron PowerSeeker selection of 20mm and 4mm eyepieces and the 3x Barlow lens (a quality of so powerful plastic Barlow lens is questionnable) is a very bad set at least for deep sky objects, and therefore if you buy the Celestron PowerSeeker 76 AZ or any similar telescope, certainly also buy an eyepiece around 10mm, you can still get a telescope for less than $100, but this additional eyepiece is absolutely necessary. This telescope did cost 64 EUR plus shipping costs, which also is less than $100, depending on the exchange rate. But there often is no choice for one who lives in Europe, other than to buy goods from countries like Germany, as shipping them from America is first expensive, and there would be troubles with customs formalities. So it can be said, that this is the European version of this family of 76mm reflector telescopes.

How is it useful

After a little time of using it with the light polluted skies, I found that this telescope has the following values for me:

• It is good to get to know and learn to use a reflector telescope.
• It can show you the stars even with the light polluted skies, seeing the stars itself is a kind of nice experience. Stars are also not located randomly, there are many double and multiple stars, but I also have seen many straight lines of stars and another quite regular patterns.
• It has a mount which at least enables to see the objects standing absolutely still, any wobbling image is by far not as impressive.
• It is small, carrying and setting it up doesn't take no time at all.
• It is decorative, a telescope symbolizes some great things, and is even better in the corner of the living room than a crystal ball, star globe or such.

As a conclusion, I would say that I'm satisfied with that telescope. And I'm sure that once, when the skies are clearer, it would show me some nice deep sky objects as well :) When you have not much money to waste, get yourself a cheap telescope, it's worth of it. But when you have more money to waste, then you should think about buying some bigger one, though not too big, my favorite would be the SkyWatcher 8 inch dobsonian, which is also white, I think white telescopes are the most beautiful :), and it is also a pure Newton reflector.

What I describe in this wiki, is my odyssey with my telescope. I didn't clearly see any deep sky objects, I'm sure that I can see them better once the skies are very clear, then the light pollution also shouldn't be very intense. The most important is perhaps, that when I have a telescope, then I still have a chance to see these things, this is much more than a zero chance when you have no telescope. But the most important I think is whether you want to mess around with the telescope and astronomy, or not. Who wants to do that, has some joy also using this telescope, but who doesn't, would not find an 8 inch telescope much useful either. What concerns the nice pictures, one can look at the Hubble images, telescope is not necessary for this. Also perhaps, who only wants to do some astrophotography, may better buy a good digital camera with a 4.5 inch aperture, though this would likely cost three times more than this telescope. Telescope is for looking at the night sky objects directly, so that the light of the distant objects would go directly into your eyes, and it can only be useful for people who can appreciate and enjoy that.

But I feel that for me, the main value of this telescope is knowing that I can look at the night sky with a telescope, whenever I want. Sometimes I certainly do, but I don't think that I would do that too often in the future, this is not at all because my telescope is bad, but simply because there are many other things which I would like to do, and I don't want to spend so much time for astronomy. I described here my experience of starting to use a telescope, in a hope that it would give you some idea of what it is about. I haven't seen some objects yet, but you can find out some more about what you can do with this telescope, especially when your visial magnitude limit is more than 3.5 (see whether you can see all stars in Big Dipper), which is very probable, you may well see much more than I can see.

I also found that the star hopping needs some practice. At first, you should very exactly identify the places what you see through the finder scope, later there would be more skill, so that moving somewhere finder scope's three fields of view away, would not be a trouble at all, and so one can find many objects almost instantly.

Comparison with other cheap telescopes

It is the rule, that a reflector with the same aperture, always costs less than a refractor. This is true also concerning the cheapest telescopes. A 60mm refractor costs almost as much as this telescope, all 70mm refractors are much more expensive. So it is likely the best choice for the cheapest telescope. Refractor is not better than reflector, except some expensive apochromatic refractors, there is no reason for the light going through the lenses to necessarily have a higher quality, and in a reflector with the same aperture less light would be lost. The secondary mirror obstruction for this telescope is only 7% by area, which means that this telescope has a 70mm "clear aperture". The biggest advantage of refractors seems to be that they almost don't need any maintenance, and they are also almost eternal, while the reflector's mirror would corrode after 30 or so years. But the maintenance like collimation of the reflector telescope is not difficult at all, and is some fun also, so being maintenance-free may be important only for these who know nothing about any technical things, I would not agree to have more than 10mm less aperture for that reason, and it is not so extremely important for me that a cheap telescope would be inherited by my grandson. If you can waste more than $100 for a telescope, consider more powerful pure Newton reflectors, such as the 6 inch Orion SkyQuest XT6 [1]. The XT6 weighs already 16 kg, maybe you may also consider a 8 inch telescope, but carrying a telescope bigger than that would be more like carrying furniture, a big undertaking, which you would not do just to quickly check something, and therefore such telescope would be much less useful. I have found only one similar telescope which should be available in Europe, the 6 inch Sky-Watcher Dobsonian [2], there is also a similar 8 inch telescope. An 8 inch telescope would enable you to see some 2 magnitudes more than this telescope, in all conditions, and 2 magnitudes more makes a lot of difference. Thus if you have to decide what telescope to buy, maybe start from determining the visual magnitude limit in your location, ie determine what is the magnitude of the faintest stars which you see with the naked eye. As much as I can tell, this telescope in the location with good visibility should be almost equivalent to 8 inch telescope in my location, and thus would likely show clearly most of the Messier objects. So the visibility in your location is the most important in deciding what telescope to buy.

Newton reflector

Newton reflector is the best and cleanest optical system for a reflector that an ordinary person can afford. The others, like Maksutov-Cassegrain and Newton reflectors with an extended focal length, all have some additional lens or glass where the light should go through. Also the almost 1/10 focal ratio (focal length 700mm) is good, as it enables eyepieces with greater focal length for high power, which gives higher quality images, and also all possible aberrations are almost not noticeable at that focal length. It gives also a reasonably wide view at lower magnifications. Well, the Newton reflector was first made in 1672 by Isaac Newton, and this was a 2 inch telescope, and had an inferior quality metal mirror, so our 3 inch telescope with a glass mirror is much more powerful. To these who don't know what is Newton reflector, Newton reflector is the simplest mirror telescope design where the primary mirror is in the bottom of the tube, and the image is reflected to the focuser at the front of the tube by a flat diagonal (secondary) mirror. The construct called spider holds the secondary mirror in place, the spider is the first thing which you see when you look into the telescope tube. This spider also causes a little trouble, as it causes spikes in the form of the spider at the brightest objects. This is though not that bad, the spikes can be seen only at the brightest objects which are surrounded by complete darkness, like the brightest stars, and these are considered normal on the astronomical images. The limiting magnitude of this telescope supposed to be 12 but in my conditions it seems to be 9. This suggests that the visual magnitude limit in my conditions is 2.5 and it is indeed close to that. This means that I can normally see almost 100 stars in the whole sky with the naked eye. The biggest visual magnitude limit with dark skies in a rural environment is considered to be 6, and in the center of the big cities this limit is often 2.

What was inside the box

All the parts seemed to be high quality, all the screws were also nicely tightened, the mirrors and accessories were not damaged anyhow. The assembly of the telescope was extremely simple and took almost no time at all. There were 2 Huygens eyepieces, 20mm and 12.5mm, and one Super Ramsden eyepiece 4mm. The eyepieces all looked decent, the lower part of them is made of metal, and the lenses are all glass (different from some other similar telescopes like these made by Bresser, where the lenses are plastic). There were also a Barlow lens 2x, and an erecting lens 1.5x. These both are made of plastic and the lenses are also plastic, but the image through them doesn't in spite of that seem anyhow bad or darker. The Barlow lens is quite small, but the erecting lens is a long tube, the telescope looks nice though with that in. The images through all the eyepieces were crystal clear, somewhat the eye has to be in the right position to see the whole field, but there is no problem when one gets used to. The image through the 4mm eyepiece together with the Barlow lens (350x magnification) was already too pale, but through the 4mm eyepiece alone (175x magnification) it was nice and sharp, and there was no difficulty in looking through that eyepiece at all. There also was a moon filter and a metal triangle to use as a screwdriver. The scope has a nice cap to close the front of it, and especially good that there is another cap in the center of that cap -- opening that cap makes collimation somewhat easier, as there are less reflections then. The focuser was good, entirely made of metal, and standard 1 1/4 inch in diameter, so all standard eyepieces can be used. The telescope had a nice smell of rubber inside its tube. The inside of the tube made of sheet metal was painted with a black non-reflective paint. This is also in a way an exceptional cheap telescope in that nowhere on the box were no advertisements that this telescope has 350x power or such. Also, it is said in the Telescope-Service site that using the 2x Barlow lens and the 4mm eyepiece together is useless. 350x is indeed a useless magnification, it is considered that the maximum useful magnification of a telescope is two times its aperture in millimetres, for this telescope therefore 152x. But the best magnification for a telescope is considered to be 20 times its aperture in inches, which is 60 times for this telescope, and the magnification with the 12.5mm eyepiece is quite close to this.

Huygens eyepieces

Huygens eyepieces are the oldest design, and up to the middle of the 19. century all good telescopes had Huygens eyepieces. Some say that these are bad, and recommend not to buy telescopes which have Huygens eyepieces because these eyepieces have always a low quality. Of course, more expensive eyepieces are always better, but Huygens eyepieces are not necessarily bad when the focal ratio is small (like the almost 1/10 focal ratio which this scope has). It seems that in spite that the eyepieces are Huygens, they are quality Huygens, the daytime images were very clear and sharp, and I never noticed any chromatic, spherical or other aberration at all. I'm very satisfied with these eyepieces. There might be some truth about the advice that Huygens eyepieces may have a low quality, so one should be careful while buying a telescope when it is known that the eyepieces are Huygens, as I have seen some cheap telescopes like these made by Bresser, where the eyepieces are whole plastic together with lenses. There is only one problem which I noticed concerning the Huygens eyepieces -- the image tends to easily disappear when the eye is not in the correct position. It is completely possible to hold an eye in the right position by holding the eyebrow against the edge of the eyepiece. It needs to get used to, but I can now look through the eyepiece so that the image never disappears. So this is not exactly a problem, but rather a matter of convenience -- with better eyepieces one can take less care to look through the eyepiece in the right way, and this would certainly feel better. But I have read that there is such problem also with some other small telescopes, the eyepieces of which are said to be Kellner. So you should consider that the eyepieces of a cheap telescope could be inconvenient, no matter what type they are said to be, therefore the only thing which may guarantee you something, is that they are not made of plastic, then you see that some care has been taken at least to make them more durable with higher quality. It is also not exactly certain that some low quality Kellner eyepieces with defective coating are necessarily better. Consider that a single good eyepiece costs much more than this telescope, so most certainly some bargain has been made to make the eyepieces cheaper, so it is not so bad when the only such thing is that the eyepieces have the Huygens design -- for some purposes there are Huygens eyepieces in some professional equipment even today. The eyepieces consist of two lenses, but in more expensive eyepieces like Kellner and Plössi, these lenses consist of two or more lenses glued together, like achromatic objectives in refractors. In Huygens eyepieces, and also in Super Ramsden eyepieces, both lenses are simple, and the lenses also didn't seem to be coated.

Moon filter

The moon filter made the image of the Moon kind of green and ugly, and I didn't see more details with it than without it. It is likely that with some 10 inch telescopes the Moon would be too bright and a filter would be necessary, but with this telescope it seems to be just useless.

Finder scope

The finder scope is a simple 5x24 (5x magnification, one inch aperture, helix focuser) all-plastic scope. The limiting magnitude of such scope supposed to be 8 but in my conditions it seems to be 5. The finder scope is very useful, you should move the telescope so that the object is in the center of the crosshair, and the object would then be visible in the eyepiece. I have been able to see the crosshair even against the darkest sky, though it is difficult, you can though certainly always see the edges of the field of view. Some more expensive finder scopes have the crosshair or a dot in the center lightened, but this appears to be not so good, as seeing a lightened object may make you not been able to see the fainter stars and objects. The field of view of most finder scopes is 5 degrees, so likely also this finder scope has that field of view. Such field of view is enough for some combination of fainter stars, but not enough for having even two stars in the same constellation in the same field of view. I couldn't find any objects without the finder scope. There is also some additional use for the finder scope -- you can just look over the edge of the finder scope to see where your telescope is pointed, for that you should look at the finder scope so that your eye is on its axis, which means that you don't see the sides of it, and move the telescope so that the outer circle of the finder scope is around the area which you want to see. That way you can also see whole constellations. When you move the telescope that way, you would see the star which you want your telescope to point to, appearing in the finder scope, then move until that star is in the center of the crosshair. I found that the best way to move the telescope is by holding it with the left hand from the two lower thumb knobs of the screws which fasten the spider. The finder scope should be aligned first, it has three adjustment screws, but it isn't so precise instrument as it looks like. When you cannot fix it properly, open all the adjustment screws, remove the finder scope, then wrap the film inside the fastening ring around the finder scope, and put the finder scope back into the ring, making sure that the film isn't below the adjustment screws. At a daytime, move the telescope so that some well-determined object such as the corner of a house, is in the center of the eyepiece. Open the upper adjustment screw, with two lower adjustment screws move the object as close to the center of the crosshair as you can, and then tighten slightly all the adjustment screws. Then bend the scope to align it even more exactly, and finally tighten the adjustment screws even more. That way you can align the finder scope very exactly, and it only goes slightly out of the alignment when you strongly knock it with hand.

The mount

The tripod is sturdy when the legs are kept short, and almost no wobbling from the tripod is noticeable then. The telescope can be nicely used that way, sitting near it. Whenever the legs would be made longer, the wobbling caused by the tripod would be noticeable -- that wobbling is especially nasty in that it ends only in 15 seconds or so after touching the telescope, therefore making the legs longer should be avoided whenever possible. The telescope has a fork mount, all the cheapest telescopes have such mount -- likely it is more expensive to make any other joint, so there is no choice anyway what concerns the mount. Such mount causes wobbling after moving the scope or focusing, but this wobbling ends in one second and the telescope would be completely stable after that. This time is short enough so that it enables the normal use of the telescope, a slight wobbling while moving or focusing is not that important, important is that you can observe objects while they are completely still. The wobbling is caused by twisting the base of the fork and cannot be avoided anyhow, for no wobbling a very massive or wooden fork would be necessary. The movements of the telescope are smooth, and it can be moved very exactly. The fine adjustment rod is completely unnecessary and causes uneven altitude movement even when the tightening screw is completely open, so I use the telescope without that rod. The azimuth movements are smooth also, but I first had to oil the azimuth joint. Concerning the mount, there was a warning on the box not to tighten the srews too much. Likely, at least the screws screwed into the aluminium would become loose when screwed in too much, and would then fall out. Therefore, when the screws are well tightened, there is no need to touch them any more and then they would stay permanently in. One more thing to say about the mounts: you may regret that the mount is not equatorial, but it is said that the cheap equatorial mounts are by far not precise enough to use them to position the telescope to a star, and such mounts are mostly even more unstable, only causing an additional wobbling, thus it is not good to buy a cheap telescope with an equatorial mount.

Star hopping

A few words about star hopping, as much I can tell from my little experience so far. Star hopping is not so simple as it may seem, finding a new object may take quite a lot of time. Always start moving from a visible star, never from some points between some stars or such, because you cannot point the telescope quite exactly in between some stars, even if you see these stars in the finder scope. From that visible star move to the star which is closest to your object, with the finder scope. Always verify that the star from which you would move further, really is the right star, then you will be certain where you are, and you will remove by that so many uncertainties. For that you should look at the patterns which must be around that star -- there may be a double star near that star, or whatever combination of stars of equal brightness. You should verify that such patterns really are at the right distance and to the right direction from the star which you see, sometimes even a single star in the right location near the star which you observe can be enough to identify that star. When the finder scope cannot show any more stars closer to your object, then you should move forward with the eyepiece. You should find some distinguished patterns of stars and remember their location, to be able to go forward towards your object. This may take quite a lot of time, as you should learn the area. All these patterns or combinations of them should be such that there is no other similar pattern nearby -- for example the constellations are good examples of such patterns, they are in a way carefully thought through to be unique and distinguishable. Try to find patterns of stars that show you the direction, as when you search a lot, you may easily lose orientation. Finally you should find some pattern around or near your object, so that you can verify that you indeed reached the location where your object should be, and when your object is not visible, you can establish that too beyond doubt. Moving to some new object may sometimes take hours. Such search certainly cannot be done with a scope without a mount, and the mount should also be sturdy enough so that the image stands still, only then you can really properly observe what you see. You can occasionally find objects even with a scope without a mount, but you cannot properly search for objects, and especially this is not a solution for beginners who at first have no idea where the objects supposed to be. But in spite that all this may sound complicated, and one may think that using an equatorial mount and setting circles would make finding objects much easier, it is not necessarily so. Such way you would be too dependent on all the additional equipment, and setting up the equatorial mount would take quite a lot of time every time you observe. But when you use star hopping, you would be ready to go every time when you would happen to be under a clear night sky with your telescope. And also, setting circles with a cheap equatorial mount would not provide you much precision. Consider the great precision which you have when you use star hopping -- every star which you can identify would provide you an almost precise location in the sky, and by finding out near what stars is the object which you see, it would be possible to determine the location of that object very exactly.

The size and weight

By the shipping information, the whole package of the telescope weighs 6.2 kg, the telescope together with the mount therefore likely less than 6 kg. The telescope feels to be very light and it is no problem to carry it, holding from the fork. The telescope is so light that it is possible to hold it even with one hand. It is the best to keep the telescope mounted, it doesn't take much room even so, and it also looks nice, so you don't exactly have to hide it behind the corner. The telescopes bigger than that are much bigger and heavier, much more difficult to carry and therefore also less useful, as most of the time one would use a telescope which is easiest to carry. There are some smaller "table telescopes", but the problem with these is that they almost always need something with a proper height to put them on, some made some special stools for that purpose, and they still have to carry the telescope together with that stool, which is not easier at all than carrying this telescope. Preparing this telescope for use takes only a few seconds. I used to keep the 20mm eyepiece always in the focuser, but to protect it from dust, I put the cover of its case on it, which stays there nicely. It's also better to keep the front end of the finder scope covered with the focuser cap, which also fits there well. Thus, all that is necessary to prepare the telescope for use is to remove all the caps, and put them in a place where they would not be lost. Also, carrying the telescope is easy when the legs are kept short, it's small enough so that it can be lifted over the objects like tables and chairs, thus it would not be necessary to move anything to make way for the telescope.

Cleaning mirrors

I don't know much about cleaning the mirrors, and I have only cleaned the secondary mirror. It was easy and fast, really, though I cannot assure you that I did it in the most correct way, but taking care of such telescope cannot be too complicated, so we should use easy solutions. I rinsed the mirror, took a piece of medical cotton, made it wet, and added to it a bit of soap. Soap is not necessarily the best though, many soaps contain different ingredients such as color, which cannot be removed from the surface. Better than soap is certainly some substance intended for cleaning the optics, but at least it should be a simple soap with no additional ingedients added. Spirit may be better than soap, but again it must be clean, spirit is a strong solvent and thus may contain many kind of ingredients, also it might be dificult to obtain a pure spirit. Then I wiped the mirror slightly, one cannot use any pressure at all. Then I rinsed the mirror thoroughly, and just let it dry. I found that this way there was much less residue than when trying to remove the water droplets anyhow. The best is to rinse the mirror with distilled water immediately after rinsing it with ordinary water, so that there would be no residue. When I cleaned the secondary mirror, I didn't have distilled water, thus there remained some residue which one can barely see only in a strong light, but that has not caused any problems when looking through the telescope. For cleaning the primary mirror, a distilled water would still be a must I think. I bought distilled water from the drug store, distilled water is extremely cheap. The most important is not to touch the surface of the mirror never. Also the mirrors should be cleaned as rarely as ever possible, or never if there is no serious reason. Optics surface is a very subtle thing, it must be exact to the degree close to the wave length of light, thus any residue on that surface is a great impurity.

Collimating

There are several methods of collimating, it can be done using a laser, or by the diffraction rings around a star when the telescope is slightly out of focus. I though satisfy with only the easiest collimation, as I think that taking care of such telescope shouldn't take too much time. Collimating is aligning the primary and secondary mirror. The mechanism which enables collimation is really the most simple, I would even say primitive, and this mechanism is the same both for the primary and secondary mirror. There is a plate with three screws on it, which are called the collimation screws. These screws go against some support, which is the bottom of the telescope tube in case of the primary mirror. This simply means that by adjusting these screws by a few turns, the tilt of the mirror can be changed. And there are the other screws called locking screws, which simply fasten the plate to the support. There are three locking screws for the primary mirror and one locking screw for the secondary mirror. Naturally, for adjusting the tilt of a mirror the locking screws must be loosened. For the primary mirror you should loosen all screws first only slightly, and then all almost by the same amount, as doing that unevenly would cause one screw to become too tight. The collimation screws are in a triangle, which means that for tilting towards one screw, the two opposite screws must be evenly screwed in. Collimate the secondary mirror only when the telescobe tube is in the horizontal position, to avoid anything from falling into the tube, which may damage the primary mirror. The first thing which you likely should do for collimating, is to look through the focuser (in the lowest position and without any eyepiece in) whether you can see the whole primary mirror. If you cannot, you should either adjust the tube axis position of the secondary mirror, or the spider (with which the secondary mirror is fastened to the tube) so that the mirror would be closer to the focuser. For that you may need to remove the spider, and adjust the length of its vanes, all are also screwed into the center, so they can be adjusted that way too. It seems to be a problem with these telescopes that the secondary mirror is only then close enough to the focuser, when the center of the spider is not exactly in the center, or the secondary mirror seems to be a bit too small. Then collimate the secondary mirror so that you can see the whole primary mirror. Then collimate the primary mirror so that the spider is in exactly the same shape as you see it when you look into the tube (unfortunately we cannot say in the center). There is also a thing called collimation cap, which for example can be made of a 35mm photo canister by making a small hole in its center, putting it into the focuser and looking through that hole. The only purpose of the collimation cap is to ensure that your eye is in the center. But we can satisfy with less precision, and therefore not to use even this additional tool.

What can I see through it

I don't really have much idea what can I see through that telescope, but Charles Messier who made the catalog of 110 deep sky objects (galaxies, nebulae and star clusters) in 1780, had a telescope which may be equivalent to today's 3 inch telescope, so I should see all these objects at least somewhat. But of course the skies of Paris were not so light polluted at that time, when there were no electric lights yet, than the skies of the cities today. Indeed I have found that I cannot see as much as Messier did, in addition having by far not such experience of observing as Messier had. Hodierna [3] found 19 deep sky objects already in 1654, using only a Galileo telescope with 1 inch aperture, of which 12 were Messier objects and 7 of these (M31, M36, M37, M38, M42, M44 and M45) were in the northern constellations.

There is a review in Cloudy Nights of the Orion SpaceProbe 3 EQ [4] which has an equatorial mount, but is otherwise optically similar to this telescope. At least it shows that one is able to see with this telescope the colors of the Orion nebula. I though didn't succeed the see colors of the Orion Nebula in my conditions, but considering how bright the nebulosity is, it seems believable that one can see some colors even with the visibility one magnitude better than mine, which is even not so good visibility, and you don't even have to be in a rural area. So don't be discouraged, your visibility is most probably better than mine.

First light

April 15, 2008. Tonight, my telescope saw first light. But the sky is still not clear enough, so I could only observe the Moon. The Moon was an almost full moon, I saw clearly the craters and the edges of the craters were kind of rough, so I was able to see even more details. I saw the Moon with all eyepieces, with the 12.5mm eyepiece the Moon covered almost all the field of view, which means that the field of view with that eyepiece is almost 0.5 degrees, with the 20mm eyepiece it should be almost 1 degree. I saw craters through the 4mm eyepiece as well, but I was not able to focus properly, because I observed the moon through the window, where I had not enough room to move properly, and the 4mm eyepiece needs a very fine focusing. The 4mm eyepiece can be used for observing the Moon, as the Moon is very bright so that the aperture of the telescope is not that important while observing it, all that matters is the magnification. But the problem is that the mount of this telescope makes the 4mm eyepiece useless even for the Moon, as the fork wobbles too much, making any observing impossible with such high magnification -- a wobbling image with high magnification doesn't give a better resolution than an image with lower magnification with no noticeable wobbling. The vertical adjustment rod may decrease the wobbling somewhat, but the telescope cannot be normally used with that rod always in, and inserting the rod every time when using higher magnification is too frustrating, and would not improve the view that much either.

Ring Nebula

April 23, 2008. Tonight I saw my first deep sky object, the Ring Nebula or M57 in Lyra. The sky was cloudless, but visibility was still not good, with only a few brightest stars visible. The location where I am is also likely heavily light polluted, on light pollution map it is in the red pollution zone and is also near the sea, so that there is mostly a lot of moisture in the air. But it is still possible to find objects even in such light polluted skies. First I noticed four stars in a pattern which resembled the tail of Cygnus. I looked from Linux Stellarium that Cygnus exactly supposed to be there where I saw it. Cygnus is also called the Northern Cross. Likely everyone can find the Big Dipper, a part of the Ursa Major, but at the opposite side of Polaris likely the most significant constellation is Cygnus, so one should be able to find it when looking at the direction where the Big Dipper is not visible. These four stars are like in the shape of a arrow head, with two more stars forming the tail of an arrow or the longer branch of the cross. Of these two stars only the farthest was faintly visible. Cygnus is an important constellation also because it is on the Milky Way, and indeed when I looked at that constellation with the 20mm eyepiece, a huge number of stars were visible, it is really beautiful to see so many stars through the telescope, these are only stars but it is really impressive to see them. At the top of the Northen Cross there is a bright star called Deneb, Deneb is one of the three brightest stars in the Northern hemisphere, which are mostly high in the sky, these are Arcturus, Vega and Deneb. Arcturus is the brightest, and Vega is the next brightest. All these three stars were visible. I found Vega by the Stellarium map, near the constellation Cygnus, and thought that I should look at that star to check whether the stars which I saw are really what they supposed to be. Vega is a part of the constellation Lyra, which is a small constellation, and good in that most pairs of stars there are visible in the same field of view in the finder scope. There is a double star near Vega (Epsilon Lyrae), two stars with equal brightness, which should be visible in the finder scope together with Vega in the same field of view. The finder scope did show two stars near Vega, the other was more hazy one, so I thought that it should be the double star, but the finder scope couldn't resolve it. Then I moved that star into the center of the crosshair, and looked through the 20mm eyepiece, I clearly saw two stars with equal brightness, and then I knew that the bright star which I saw was indeed Vega. So I moved ahead with the finder scope from Vega to Zeta Lyrae, and from there to Delta Lyrae. In the 20mm eyepiece I saw that this was indeed a double double star, so it was verified that it was Delta Lyrae. From Delta Lyrae I moved to Gamma Lyrae, and cleary saw the other side of the Lyra trapezium, Gamma Lyrae and Beta Lyrae, in the same field of view. Almost exactly in the middle of these two stars, slightly outside the trapezium, is the Ring Nebula. I moved the point where the Ring Nebula supposed to be into the center of the crosshair, it even seemed to me that I noticed some hint of some object there in the finder scope, but nothing was clearly visible there. Then I looked into the 20mm eyepiece, and after some slight moving around I saw a hazy patch, which was hazy in spite that small stars around it were focused to almost a point. The brighter stars never focus to a point and are like sparkles with the light polluted skies, ideally they should be round with diffraction rings around them. I looked into the same area with the 12.5mm eyepiece with and without the 2x Barlow lens, and with the 4mm eyepiece, focusing the stars every time. The 4mm eyepiece didn't give much, looking through it seemed like looking through a keyhole, it may be good for looking at some bright objects like planets, but it cannot show anyhow better the hazy patches like nebulae and galaxies. The 2x Barlow lens couldn't make anything better either. The object looked the best through the 12.5mm eyepiece (56x magnification). It was quite small, but clearly hazy, or nebulous. I saw that it was a round hazy patch, but I really couldn't see that it had a round shape, maybe at some moments I noticed some hint of it, but didn't really see that at all. This is likely what one can see with the light polluted skies and bad visibility, what the condition is unfortunately most of the time. It is said that one can see more after some more practice of seeing the deep sky objects, because the brain would learn to obtain more from what you see. I think that at least somewhat this should be true, but I describe here the experience of a beginner, and a beginner certainly has no experience of looking at the deep sky objects for hundrieds of hours. A telescope with a larger aperture and therefore with greater light gathering power would certainly show more, but with clear skies this telescope would certainly show the Ring Nebula quite nicely. Did I see any color? Well, I didn't really see what I could call color on any stars, neither on the Ring Nebula, they are all a kind of blue, but the light of different objects certainly has a different character, one can see this but it cannot be exactly called color. This light is though still very impressive, and faint differences of it are beautiful as well. I would finally say that there really is a kind of magic in what you see by looking at the night sky through telescope, in spite that I didn't see that much this time, I would like to do that more. And the other thing which I found was that with these light polluted skies, any smaller telescope than this 76mm one does not have enough power to show anything, as even this telescope had barely enough power to show a hardly visible faint patch of light where the Ring Nebula is, so faint that it is certain that nothing were visible there through a 50mm scope, in the conditions of that visibility and light pollution which likely is the condition most of the time. Well and, a 60mm telescope and a wobbly tripod would have been as bad. Don't even try to use any smaller telescope with the light polluted skies, this is nothing bout a waste of time, because these are not good enough instruments to find anything in these conditions. This is clearly a minimal telescope which makes sense to buy, I have no doubt in this now, but it is a useful instrument still. The Ring Nebula was discovered by Antoine Darquier de Pellepoix in 1779, who described it as a "dull nebula, but perfectly outlined; as large as Jupiter and looks like a fading planet".

The Great Cluster in Hercules

April 26, 2008. Tonight I found another deep sky object, the Great Cluster in Hercules, or M13. The visibility was bad, there were even some small clouds in the sky. So I had to move ahead from Vega again, because this was the only star nearby which I saw, no stars in Hercules were visible. The star hopping guides often instruct to "move in the direction" of some star. This means that you should know in what direction from your starting point is the star towards which you should move, you should find out what this direction is in your location at the time when you do your observation. I use Linux Stellarium to find that out, it can also be derived from the star maps, though it is a bit more difficult. You though have to move only approximately into some direction, because you always have to move until you reach something very distinguished, mostly a bright star, which you easily see when it would appear into your field of view. So, using the finder scope, I moved ahead from Vega in the direction of Theta Herculis, which is the closest star to Vega in the constellation Hercules, until I reached Theta Herculis, or more exactly, the first bright star which I saw. From Theta Herculis I moved in the direction of Pi Herculis, which is almost the same direction as before. Pi Herculis is one of the stars of the keystone of Hercules, four stars of almost equal brightness which form a well distinguished tetragon in the sky. I moved into that direction until I saw three bright stars quite close together, these stars are Rho Herculis, e Herculis and Pi Herculis. I moved the first of these stars in my direction, Rho Herculis, into the center of the crosshair, and looked at it through the eyepiece (I always use the 20mm eyepiece with 35x magnification when I search the objects). This star should have a double star close to it, and indeed there was a double star, made of two stars whith equal brightness, near that star. From that I knew, that these three stars which I saw, were really Rho, e and Pi Herculis. From these three stars I moved towards Eta Herculis, another star of the Hercules keystone, until I reached Eta Herculis. This direction was again almost the same as before. But from that star I couldn't move ahead with the finder scope, as finder scope did show a complete darkness, no stars whatsoever, between Eta Herculis and Zeta Herculis, where the Great Cluster in Hercules is located. So I looked at Eta Herculis through the eyepiece. Close to that star there should be an almost equilateral triangle made of small stars of equal brightness, but with the conditions of bad visibility I were not able to see even these stars. But in the same direction a little further from that equilateral triangle there should be an isosceles triangle of brighter stars with equal brightness, with its shortest side towards the Eta Herculis. I indeed saw that triangle. The shortest side of that isosceles triangle is a part of seven stars in a row in almost a straight line. I saw this line of stars, and from that I knew that the bright star which I looked at was indeed Eta Herculis. Then I moved in the direction of that line of stars, until I reached three stars of almost equal brightness in almost a straight line. Look at the brightest star nearby, which you should see in the same field of view together with these three stars. These three stars together with that brighter star form an almost isosceles triangle, the base of which is formed from these three stars, and in the center of that isosceles triangle is the Great Cluster in Hercules. Though if you followed that track, you most likely did notice that object already earlier. I observed the Great Cluster in Hercules through the 12.5mm eyepiece (56x magnification). I saw a dim hazy patch, which was cleary round, and was brighter in the center. The patch which I saw was quite big, some 1/8 of the field of view of my 12.5mm eyepiece. I saw though no stars in it or anything brighter. Several times during my jouney to that object, looking through the eyepiece, I saw satellites, and once I saw a meteorite. The Great Cluster in Hercules is quite far from Vega, so I proved with that, that with star hopping using only a finder scope, and sometimes eyepiece of course, it is possible to find most of the deep sky objects, proceeding from a visible bright star which is closest to them, even when only a few stars are visible in the whole sky. I should say that I did like the process of finding that object, sitting near the telescope in the darkness of the night sky, and all the observation during that, seeing so many stars during all that time. It is somehow relaxing, just to see the stars, and once you saw them through the telescope, you need to see them again. That the objects which I saw looked bad, is not the fault of the telescope, but it was because of visibility -- when you see only a few brighter stars in the sky, then the visibility is likely below the magnitude 2. The Great Cluster in Hercules was discovered by Edmond Halley in 1714.

Saturn

May 3, 2008. The night was cloudless, but I still didn't see more than ten stars in the sky. This time I looked to the other side, to the west, and I saw there two bright stars close to each other. From the Stellarium map I later found out that these were Saturn and Regulus in the constellation Leo. Regulus is another bright star, which is though usually not very high in the sky. I looked at these two objects through the finder scope and one, which appeared to be Saturn, had an elongated shape even through the finder scope, so that a small 1 inch finder scope appears to be as efficient as the Galileo telescope in spite that it has only 5x magnification. I looked at Saturn through the 20mm and 12.5mm eyepieces. Through the 20mm eyepiece I first saw that this object is clearly something bigger than a star. But after more focusing I clearly saw the disk and the ring of Saturn, and saw that the ring is separated from the planet, but couldn't see any belts. Through the 12.5mm eyepiece I saw the same, only somewhat bigger, it was quite small object there. I also looked at it through the 20mm eyepiece and through the 2x Barlow lens, it was bigger but I did not see any more details. With great difficulties I was able to see it through the 4mm eyepiece. Centering it in the 20mm eyepiece and then changing the eyepieces, was at that not a successful method at all. I saw no more detail, it was only just a bit more hazy. The finder scope is not exact enough for using the 4mm eyepiece, and the telescope cannot be moved exactly enough to use the 4mm eyepiece without much trouble. I'm sorry but, in spite of all respect towards the PowerSeeker 76 AZ, in many ways such telescope is not good enough for the 4mm eyepiece, and the 12.5mm eypiece is good enough for almost anything. The function of the telescope is light gathering, and therefore the magnification doesn't matter that much.

Mars

May 4, 2008. The visibility was almost as in the previous night. Mars was in the constellation Gemini, to the left of the two brightest stars in Gemini, which were the only stars which I saw in Gemini. Mars and these two stars formed almost a straight line with equal intervals. Mars was very small through the 12.5mm eyepiece, I saw that it was a disk and I saw its reddish yellow color, but that was all, it was much too small to see any surface details or icecaps. Mars is a beautiful object though, and its color is really nice and impressive. BTW, what concerns a color, one can see the color of some brightest red and yellow stars. The only star which I so far have seen to have some color, is Gamma Sagittae, the brightest star in the constellation Sagitta, which supposed to be a red giant, its color was clearly yellow. I don't know what the color of this star supposed to be, but the color of some red giants can also be yellow orange. So it is not completely true that one cannot see colors at all with this telescope, but in the light polluted skies only a few objects have a clear color.

Praesepe cluster

May 10, 2008. There were only some slights clouds in the sky near the horizon, but still I think that not more than twenty stars were visible in the whole sky. In fact I found the Praesepe cluster (the Messier object M44) easily because the Moon was near it, but it should also be possible to find it by moving from Pollux, one of the two brightest stars in Gemini, towards Delta Cancri. Praesepe cluster is in the constellation Cancer near the stars Delta and Gamma Cancri. It filled all the field of view of the 20mm eyepiece, but what I saw was really nothing than maybe twenty stars, not closer together than the stars usually are for example in the constellation Cygnus on the milky way. I didn't really see anything more through the 12.5mm eyepiece, except that it seemed to me that I saw some very faint nebulosity near some groups of three and more stars, but I couldn't be sure in that. The Praesepe cluster was first mentioned by Aratos in 260 B.C.

The Pleiades

Sep 20, 2008 This was the first night this year when the sky was dark and clear enough after the light nights in summer. There were still some clouds in the sky. Again it was quite easy to find the Pleiades (the Messier object M45) because the Moon was quite near it, and because the Pleiades is a quite big object so that when moving from Moon in the approximately right angle, it was easy to see that object in the finder scope. To find it otherwise, the Pleiades is in the constellation Taurus, and Aldebaran (Alpha Tauri) is the brightest star in Taurus. Aldebaran is a very bright, less than magnitude 1 yellow star, so one most likely can find it, but the Pleiades itself is also quite bright, so with clearer skies one may also see it with the naked eye. The Pleiades filled all the field of view of my 20mm eyepiece. There were the seven bright stars, and many smaller ones. I saw something which resembled nebulosity, but it was likely rather a large number of small stars which my telescope couldn't resolve. Later I also saw Pleiades with the naked eye. It was a glow in the sky bigger than the Moon, but it was very faint so that it was barely visible, it is possible to see it though when you know where to look. The Pleiades cluster was mentioned by Homer in 750 B.C.

Andromeda Galaxy

Sep 23, 2008 There was some slight cloud cover in the lower part of the sky, maybe 20 stars were visible in the eastern part of the sky. I saw Cassiopeia, except a star in the one end of it. The five brightest stars in Cassiopeia form a W shape in the sky. In fact, four of them are brighter, and of almost equal brightness, thus what I actually saw was not the W shape but a triangle with the fourth star as an extension of its base, something like a triangular-shape dipper. The bigger triangle in that W points to Mirach, one of the brightest stars in the constellation Andromeda. Mirach or Beta Andromedae is the first bright (magnitude 2) star in that direction. Mirach is a red giant, which looks like a bright yellow star. Near it (some 0.1 degrees from it) is a magnitute 8 star. As there are not many stars in that area, it was possible to identify Mirach by that nearby star, which located at almost the same distance from Mirach at almost the same angle as on the Stellarium map. Stellarium caused some confusion though, as it showed some red 5.6 magnitude star near Mirach, which I didn't see through the telescope. I found that this star is also missing in Your Sky map. Your Sky is a public domain star map, which is good to use when you would doubt in something in Stellarium, also it can be used to print star maps for different times of observation, when you would use telescope somewhere where you cannot use a computer. Using the finder scope, I moved from Mirach to Mu Andromedae, and from there in the same direction to the next bright star, Nu Andromedae. These stars form what is called the girdle of Andromeda. Nu Andromedae has two brigter yellow stars near it, of equal brightness, I saw these two yellow stars and thus verified the location. Andromeda Galaxy (the Messier object M31) is quite near to that star, so I moved in the direction of Andromeda Galaxy and indeed saw it. It was the best to observe the Andromeda Galaxy with the 12.5mm eyepiece. I saw a faint glow, this glow covered almost 1/4 of the field of view. There seemed to be a bright spot in the center, and the glow became fainter smoothly further from the center. The glow didn't seem to have a completely round shape, it was brighter in some directions. It had no color, the most it seemed to be white. It looked like something deep, and left a feeling that this object is something special. It seems that such telescope in my conditions doesn't show colors of the Messier objects, it may be that it would show some colors in Orion Nebula, which is the brightest nebula, but in my conditions of light pollution there most likely would not be much colors. Andromeda Galaxy was likely the most interesting deep sky object which I have ever seen with my telescope. It was the first deep sky object which I have seen that was not just many stars or a gray batch, but was indeed a nebulous glow of light, and of course this was the first galaxy which I have seen through the telescope. The Andromeda Galaxy was first mentioned by Al-Sufi in 905, who described it as a "little cloud".

Orion Nebula

Oct 4, 2008 There were some clouds on the horizon. It was not very difficult to find the Orion Nebula (the Messier object M42). I saw the Orion belt that was quite low on the horizon, but not so low that I couldn't reach it with my telescope. The Orion belt consists of three stars of equal brightness in a row with equal intervals, a pattern in the sky which is very easy to recognize. I saw all the three stars of the Orion belt in the finder scope. Then I moved from the central star of the Orion belt, Epsilon Orionis, also called Alnilam, in the direction of the Orion Nebula, until I saw some bright objects in the finder scope. Then I looked through the 12.5mm eyepiece, and with some slight moving around I saw the Orion Nebula. What I saw was a bright star and a double star near it, surrounded by nebulosity. The bright star was likely Theta1 Orionis and the double star was Theta2 Orionis. It seems that what I saw was almost exactly what Hodierna saw [5], thus it seems that in my conditions I can see through my 3 inch telescope exactly the same what Hodierna saw through his 1 inch telescope. The nebulosity seemed to be more on one side of these stars. The nebulosity was very clear and became fainter further from these stars, it covered almost 1/4 of the field of view (when I say field of view, I mean the diameter of the field of view). But I didn't see any color, the color was not blue though, the most it seemed to be white. I couldn't observe the Orion Nebula for a long time, because the clouds covered it soon. This was the second object on which I have seen a clear nebulosity. I also saw the Orion Nebula through a 2 inch spotting scope, but this was only a good luck that I happened to spot it. The spotting scope could barely resolve Theta2 Orionis, but I saw some nebulosity around these stars, somewhat less though than with this telescope. The Orion Nebula was discovered by Johann Baptist Cysatus in 1619.

Astrophotography

Astrophotography can be done using an ordinary digital camera which almost everyone has in their pocket, I for example use Canon Powershot A430. I use the normal exposure, though all these cameras enable to increase the exposure. This method of astrophotography is called afocal astrophotography, which simply means putting the camera objective against the eyepiece of the telescope, tuning it until the picture looks nice on the LCD display, and then taking the picture. First of all, the physical zoom of the camera must be increased a bit, until all the field you see in the eyepiece covers the LCD screen. Then you have to focus the telescope, so that the image is the sharpest. In general, it is very difficult to take photos that way, because you have to adjust many things at the same time. I found that it is the best to hold the camera with the left hand in the correct position against the eyepiece, and focus with the right hand. It is completely possible to take photos that way, though not easy, and certainly needs to get used to.

April 16, 2008. I tried to photograph the Moon first, to test the astrophotography with my telescope. You see though, that the image is out of focus. It took some time to focus the image properly, and when I then tried to take the next photo, the batteries became empty, and as a result I have nothing better to present as the result of my first night of testing the astrophotography, than this image.

May 4, 2008. I tried to photograph Saturn, but all I got was just a hazy patch. It seems that focusing for your eye is also good enough for focusing for the camera. I even once saw a clear shape of Saturn on the LCD screen, but with hand I was not able to hold the camera stable enough. I think though that it can be done with a little more practice.

External links

• Telescope-Service F70076 page.
• AstroShop F70076 page
• Celestron PowerSeeker 76 AZ
• Orion SpaceProbe 3 Altaz
• Stellarium download
• Your Sky