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| - | * [[Telescope F70076]]
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| - | * [[Price]]
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| - | * [[How is it useful]]
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| - | * [[Comparison with other cheap telescopes]]
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| - | * [[Newton reflector]]
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| - | * [[What was inside the box]]
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| - | * [[Huygens eyepieces]]
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| - | * [[Moon filter]]
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| - | * [[Finder scope]]
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| - | * [[The mount]]
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| - | * [[Star hopping]]
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| - | * [[The size and weight]]
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| - | * [[Cleaning mirrors]]
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| - | * [[Collimating]]
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| - | * [[What can I see through it]]
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| - | o [[First light]]
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| - | o [[Ring Nebula]]
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| - | o [[The Great Cluster in Hercules]]
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| - | o [[Saturn]]
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| - | o [[Mars]]
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| - | o [[Praesepe cluster]]
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| - | o [[The Pleiades]]
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| - | o [[Andromeda Galaxy]]
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| - | o [[Orion Nebula]]
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| - | * [[Astrophotography]]
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| - | = 76mm reflector telescope F70076 =
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| | __TOC__ | | __TOC__ |
| | + | 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 am writing here is about what I think, I am just discovering all these things for myself, only for entertainment. |
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| - | 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 == |
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| | + | This telescope was made by the German company Teleskop-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 is only producing a 0.96 inch focuser, but this telescope has a 1 1/4 inch focuser. I think though that the companies which are ordering 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. |
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| | + | Most importantly in my opinion, as i have found out now, is that this telescope is not a useful item, this is an amusement item. It certainly has a value as an amusement item. If you want it cheap, buy the cheapest 10x50 binoculars instead, but all binoculars will do, except theater binoculars. The only thing this telescope enables to view that cheap binoculars don't, are the planets, because it is a reflector telescope, and maybe the Hercules cluster. You may also consider buying the sunwatch verlag kit newton reflector telescope from astroshop instead, this one has almost as big mirror, you may get it for only 24 euros with shipping, it is very difficult to assemble though and not sure about the quality of the mirror. The other option of trying to see the planets is to put a diaphragm (a cover with a hole at the center) in front of the objective lens. The planets are too tiny even through this telescope though. If you want a useful telescope with which you can really see something more than with binoculars, buy an 8 inch skywatcher dobson, depending on where you are, you can get it for 400 euros with shipping. This is good for everyone for starting, even if you have tons of money, because why we need a telescope is to see the objects in the night sky with our own eyes, photography is not the primary importance. |
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| | + | 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. |
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| - | | + | * [[Price]] |
| - | | + | * [[How is it useful]] |
| - | | + | * [[Comparison with other cheap telescopes]] |
| - | | + | * [[Newton reflector]] |
| - | | + | * [[What was inside the box]] |
| - | | + | * [[Huygens eyepieces]] |
| - | | + | [[Image:f70076_3s.jpg]] |
| - | | + | * [[Moon filter]] |
| - | | + | * [[Finder scope]] |
| - | | + | * [[The mount]] |
| - | | + | * [[Star hopping]] |
| - | | + | * [[The size and weight]] |
| - | | + | * [[Cleaning mirrors]] |
| - | | + | * [[Collimating]] |
| - | | + | * [[King Jordan] |
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| - | == The size and weight ==
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| - | 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.
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| - | == Cleaning mirrors ==
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| - | 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.
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| - | == Collimating ==
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| - | 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.
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| | == What can I see through it == | | == What can I see through it == |
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| - | 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 [http://seds.lpl.arizona.edu/messier/xtra/similar/hodierna.html] 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.
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| - | There is a review in Cloudy Nights of the Orion SpaceProbe 3 EQ [http://www.cloudynights.com/item.php?item_id=249] 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.
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| - | === First light ===
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| - | ''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.
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| - | === Ring Nebula ===
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| | [[Image:Cygnus.jpg]] | | [[Image:Cygnus.jpg]] |
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| - | ''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". | + | 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 can see by far not as much as Messier did, in addition having by far not such experience of observing as Messier had. Hodierna [http://seds.lpl.arizona.edu/messier/xtra/similar/hodierna.html] 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. |
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| - | === The Great Cluster in Hercules ===
| + | There is a review in Cloudy Nights on the Orion SpaceProbe 3 EQ [http://www.cloudynights.com/item.php?item_id=249] which has an equatorial mount, but is otherwise optically similar to this telescope. It says that one would be able to see with this telescope the colors of the Orion nebula, which is very questionable, or then one had to have an extraordinarily good visibility. |
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| - | ''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.
| + | * [[First light]] |
| | + | * [[Ring Nebula]] |
| | + | * [[The Great Cluster in Hercules]] |
| | + | * [[Saturn]] |
| | + | * [[Mars]] |
| | + | * [[Praesepe cluster]] |
| | + | * [[The Pleiades]] |
| | + | * [[Andromeda Galaxy]] |
| | + | * [[Orion Nebula]] |
| | + | * [[k̲̱̠̞̖ͧ̔͊̇̽̿̑ͯͅi̞̟̫̺ͭ̒ͭͣn͉̠̙͉̗̺̋̋̔ͧ̊g͎͚̥͎͔͕ͥ̿ j͇̗̲̞̪̹̝̫̞ͬ͐̀ͧ̿o͎̜̓̇ͫ̉͊ͨ͊r̼̯̤̈ͭ̃ͨ̆d̥̝̮͙͈͂̐̇ͮ̏̔̀̚ͅa̘̫͈̭͌͛͌̇̇̍n͉̠̙͉̗̺̋̋̔ͧ̊ i̞̟̫̺ͭ̒ͭͣs̪̭̱̼̼̉̈́ͪ͋̽̚ c͔ͣͦ́́͂ͅo͎̜̓̇ͫ̉͊ͨ͊o͎̜̓̇ͫ̉͊ͨ͊l͕͖͉̭̰ͬ̍ͤ͆̊ͨ]] |
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| - | === Saturn ===
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| - | ''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.
| + | * [[ᏦᎥᏁᎶ jᎾᏒᎠᎪᏁ]] |
| - | | + | * [[Triangulum Galaxy]] |
| - | === Mars ===
| + | * [[Venus]] |
| - | | + | * [[Jupiter]] |
| - | ''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.
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| - | === Praesepe cluster ===
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| - | ''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.
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| - | === The Pleiades ===
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| - | ''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.
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| - | === Andromeda Galaxy ===
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| - | ''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".
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| - | === Orion Nebula ===
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| - | ''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 [http://seds.org/messier/more/m042_hodierna.html], 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.
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| | == Astrophotography == | | == Astrophotography == |
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| - | 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.
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| | [[Image:Moon1.jpg]] | | [[Image:Moon1.jpg]] |
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| | + | Astrophotography can be done using an ordinary digital camera which almost everyone has in their pocket, I for example am using Canon Powershot A430. Why it might be a good idea to take photos through the telescope, is that such small camera alone cannot gather enough light, like I have never managed to take photos of the stars such way even with the biggest optical zoom. I mostly 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 screen, 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 would be the sharpest. In general, it is very difficult to take photos that way, because you would have to adjust many things at the same time. I have 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. |
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| | ''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. | | ''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. |
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| | == External links == | | == External links == |
| | | | |
| - | * [http://www.telescope-service.com/newtonians/start/newtoniansstart.html#n76mm Telescope-Service F70076 page]. | + | * [http://www.teleskop-express.de/shop/product_info.php/info/p683_TS-Optics-Newtonian-76-700mm-telescope-with-mount--tripod-and-much-accessories.html Teleskop-Service F70076 page]. |
| - | * [http://www.astroshop.de/en/telescopes/telescope-service/ts-newton-reflector-76-700 AstroShop F70076 page] | + | * [http://www.astroshop.eu/ts-optics-telescope-n-76-700-az-1/p,4966 AstroShop F70076 page] |
| | * [http://www.celestron.com/c2/product.php?CatID=5&ProdID=521 Celestron PowerSeeker 76 AZ] | | * [http://www.celestron.com/c2/product.php?CatID=5&ProdID=521 Celestron PowerSeeker 76 AZ] |
| | * [http://www.telescope.com/control/product/~category_id=reflectors/~pcategory=telescopes/~product_id=09883 Orion SpaceProbe 3 Altaz] | | * [http://www.telescope.com/control/product/~category_id=reflectors/~pcategory=telescopes/~product_id=09883 Orion SpaceProbe 3 Altaz] |
| | + | *[http://www.skywatchertelescope.net/swtinc/product.php?id=39&class1=1&class2=104 Sky-Watcher BK767AZ1] |
| | + | *[http://www.cfa.harvard.edu/iau/Ephemerides/Comets Comets ephemerides] |
| | *[http://www.stellarium.org Stellarium download] | | *[http://www.stellarium.org Stellarium download] |
| | *[http://www.fourmilab.ch/yoursky Your Sky] | | *[http://www.fourmilab.ch/yoursky Your Sky] |
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 am writing here is about what I think, I am just discovering all these things for myself, only for entertainment.
This telescope was made by the German company Teleskop-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 is only producing a 0.96 inch focuser, but this telescope has a 1 1/4 inch focuser. I think though that the companies which are ordering 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.
Most importantly in my opinion, as i have found out now, is that this telescope is not a useful item, this is an amusement item. It certainly has a value as an amusement item. If you want it cheap, buy the cheapest 10x50 binoculars instead, but all binoculars will do, except theater binoculars. The only thing this telescope enables to view that cheap binoculars don't, are the planets, because it is a reflector telescope, and maybe the Hercules cluster. You may also consider buying the sunwatch verlag kit newton reflector telescope from astroshop instead, this one has almost as big mirror, you may get it for only 24 euros with shipping, it is very difficult to assemble though and not sure about the quality of the mirror. The other option of trying to see the planets is to put a diaphragm (a cover with a hole at the center) in front of the objective lens. The planets are too tiny even through this telescope though. If you want a useful telescope with which you can really see something more than with binoculars, buy an 8 inch skywatcher dobson, depending on where you are, you can get it for 400 euros with shipping. This is good for everyone for starting, even if you have tons of money, because why we need a telescope is to see the objects in the night sky with our own eyes, photography is not the primary importance.
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.
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 can see by far not as much as Messier did, in addition having by far not such experience of observing as Messier had. Hodierna [1] 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.
Astrophotography can be done using an ordinary digital camera which almost everyone has in their pocket, I for example am using Canon Powershot A430. Why it might be a good idea to take photos through the telescope, is that such small camera alone cannot gather enough light, like I have never managed to take photos of the stars such way even with the biggest optical zoom. I mostly 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 screen, 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 would be the sharpest. In general, it is very difficult to take photos that way, because you would have to adjust many things at the same time. I have 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.
