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Stargazing Telescope Question

  1. Aug 12, 2004 #1

    I am looking to buy a Schmidt-Cassegrain Scope for 1,999 euros.
    But I am unaware of the quality of this scope. Can anybody tell me what the image quality/details are like. Can you see for eg M42 clearly or Andromeda.
    Can you see details on Jupitar like the Giant red spot or the equitorial bands?
    And the rings of saturn, or mars? Or is Mars just like a small red speck?
  2. jcsd
  3. Aug 12, 2004 #2
    Would you tell us the aperture of the scope you are considering? From this we can estimate the limit to which you can clearly magnify (resolve) an image.

    The type of scope you are considering should be good for the planetary viewing and with a large enough aperture, should work fairly well for viewing galaxies.

    The rings of Saturn and equatorial bands on Jupiter are visible in even some of the cheapest small aperture scopes.

    A good quality scope of at least 4.5" aperture will allow you to see the Cassini division in Saturn's rings, Jupiter's redspot, some of the detail in the Andromeda Galaxy, Ice caps on Mars (when it is close enough), all of the Messier Objects can at least be seen. With a decent quality 6" or 8" aperture scope you will able to see more detail on good seeing days.

    Hope this helps.
  4. Aug 12, 2004 #3


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    Artman is right - with specific info on the scope, you can get pretty specific about its capabilities. But I can tell you that with an el cheapo pair of binoculars you can see Jupiter's moons, a good pair of binoculars, you can see Saturn's rings, a toy-store refractor telescope, you can see the Great Red Spot and bands on Jupiter, and with a decent reflector, you can see the gap in Saturn's rings.
  5. Aug 12, 2004 #4
    Karl, judging just by the price of the scope, I would suspect you have about a 203 mm scope. And, I'll bet it's probably a Meade or a Celestron. Making these assumptions, you're limiting theoretical magnitude is about 14. This puts all the planets, all the Messier objects, and many other even fainter objects such as distant galaxies within your reach. Further, Meade and Celestron both produce quality scopes.

    Some words of caution however. The limiting magnitude I quoted above is strictly a theoretical limit. Under good actual sky conditions, you will find in a 203mm scope you will probably be limited to about 12th magnitude. Also, be prepared, what you will see in the eyepiece won't look like the pictures in the magazines. The difference is that cameras integrate the light coming into them and your eye does not. However, it is still a thrill to see that sharp little needle of a galaxy, or the dim fuzzy cloud of a distant planetary nebula for the first time in your eyepiece.
  6. Aug 12, 2004 #5


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    The most important concern for purchasing this scope is its field of view. All SCTs are high focal-ratio scopes, most being f/10. They will not show you much more than a degree of the sky even with the best widefield eyepieces. A lot of well-known objects (Andromeda, for example) have very large areas, and this telescope will not be able to show you all of these objects at once -- only the roughly circular core will be visible. A pair of binoculars is really better suited for looking at Andromeda.

    - Warren
  7. Aug 12, 2004 #6
    This is very true, but you should find it to be a good planetary performer. They are also so short in length because of their folded light path, that they are easy to store and transport, so you are more likely to use it.
  8. Aug 12, 2004 #7


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    Too true, and often overlooked. I have a 6" f:8 apo refractor (2" focusser) with a 3" f:5.6 apo finderscope (2" focusser) and a decent pair of Nikon 7X50 binoculars. They ALL get used, depending on the object, and give nice bright views with great contrast. I might use the finderscope as the guidescope for the 6" when photographing a small faint object, or vice-versa when photographing a more extended object, like a comet. The binoculars get used a lot, too. I had a Questar about 20 years ago, but after getting used to Newtonians, using a small long-focal length scope like that was like peering through a soda straw. f:10 SC scopes are better in that respect, and they are still portable and quite affordable, but I find that their contrast leaves something to be desired, the field of view can be claustrophobic, and the mirror shift at higher magnifications is a pain in the butt. If I were to start over again and had a limited budget and no interest in astrophotography, I would buy a sturdy tripod and a decent pair of 100mm or larger binoculars. There is a lot of stuff to see with such an instrument. Two eyes integrate a lot better than one, making fainter extended objects like the Veil Nebula, for instance, really pop out at you. Plus, it's a great way to search for comets.
    Last edited: Aug 12, 2004
  9. Aug 12, 2004 #8
    Yea Celestron or Meade is the only type in which I would think about purchasing. This is the scope here that I have my eye on.
    I wanna do my degree in physics with astrophysics or physics & astronomy so will a telescope like this be like a perfect tool in studying the course like.
    And I was also thinking is it possible to find the composition of gases from astronomical clouds by focusing the light through a diffraction grating and onto a plate for the spectral lines (atomic emission spectra).
    Ive never seen through a telescope before except my cheap 80 euro telescope, though i cud, if i looked hard enough, see saturn as a speck with its ring, and jupitar v. bright with its moons. But thats about all.

    Here are the specifications of the telescope:

    Celestron's famous Schmidt-Cassegrain optics on a HD mount

    Schmidt-Cassegrain Scope With German Equatorial Mount
    203mm (8") Diameter Schmidt-Cassegrain
    2032mm Focal Length (f/10)
    6x30 Finderscope
    25mm (80x) SMA Eyepieces
    1-1/4" Star Diagonal
    1-1/4" Visual Back

    Attached Files:

    • g8.jpg
      File size:
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  10. Aug 12, 2004 #9


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    Definitely... serious astronomers will likely end up with more than one instrument, since no single type can deliver everything.
    I own a Celestron 11" SCT, and purchased an aftermarket motorized crayford focuser for it. I've owned it for years, and love it.
    This is, in fact, wonderful advice that is often overlooked in "aperture fever." :smile:

    - Warren
  11. Aug 12, 2004 #10


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    These are very cost-effective telescopes, and they are popular. If you would like to mount instruments on it, though, you should expect to pay at least as much for a decent mount as you paid for the main tube (to properly counterbalance and support the weight of the instruments). Also, you will need a separate guidescope, or an off-axis guider (more weight).

    As Warren pointed out, you can beef up the focusers of these off-the-shelf SCs to reduce image shift, but that also costs money. With a short SC main tube, your guide scope's mounts will be close together and may result in flexure - a real pain for photography or spectrography. There are a lot of factors to consider. If your best scope to date has been a cheap refractor, you owe it to yourself to look into a nice pair of large-aperture binoculars (which you will treasure forever, regardless of how many other instuments you buy) or perhaps a nice small aperture (4" or so) apochromatic refractor. These small telescopes are great for planetary views, splitting double stars, etc, and due to their superior contrast (as opposed to mirror or mirror-and-corrector systems) they work very well on the brighter deep-sky objects too.

    The 4" APO can be your main scope for years, and later when you decide to buy a larger refractor or perhaps a nice Newtonian, it can do double-duty as your "finder/guidescope". My 3" Vernonscope is my 6" Astro-Physics' finder (with a 50mm 2" ocular) and is also the guidescope (with a barlow and a high-power illuminated-reticle eyepiece). It is also a pretty darned nice scope for birdwatching, comet hunting, or just plain star-gazing. The Vernonscope is one of the nicest little refractors ever made. Of course they made Questar's oculars, so they are no strangers to quality.

    Look at your options. I'm not trying to tell you that an 8" SC is a poor choice, but it is limiting, and you will probably outgrow it pretty soon if you are serious. Try to spend your money on equipment that will engage your mind and your interest. A modest-aperture but high-quality scope and a good set of charts is the best way to become familiar with the sky, IMO. If you have a great dark-sky site where you can store your scope, invest in a larger Dob and a good set of charts (and a Tel-rad finder). If you can only get in your car every once in a while and get to a really dark site, buy a pair of 100mm or larger binoculars and a good tripod (AND the decent charts) and have at it.
    Last edited: Aug 12, 2004
  12. Aug 12, 2004 #11


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    :surprise: You must have a money tree growing near your house. :biggrin:

    - Warren
  13. Aug 12, 2004 #12


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    No, I just saved my money until I got enough to buy the scopes I wanted, and added incrementally to the equipment. Even though I live in Maine where such things are commonplace, I don't buy snowmobiles, 4-wheelers, motorboats, or new cars (they all depreciate quickly and leave you with liabilities) and I try to live within my means. Anybody who can afford to buy a house and maintain it can afford to buy a decent telescope if they will budget accordingly. Luckily, I bought my AP before Roland got so busy that he had to institute 3-5 year lead-times and raise his prices to keep the demand limited to match his projected output. :smile:

    I have yet to look through a 10" Newtonian that can match the views through my 6" AP on deep-sky objects. Of course, I'd love to have a 20" RC system, but I'd have to start buying lottery tickets to have a shot at that!
  14. Aug 13, 2004 #13
    I like the view through binoculars, but they become hard to hold and keep steady without a decent mount. Also, the angle at which you need to keep your head to use them is difficult (you need to recline to be comfortable, and then you have the problem of holding them again).

    I really like the 4" APO suggestion. I have an 80mm (3.2") f5 Celestron refractor and the views through it are not bad for the cost (it's not an APO, but the images are pretty sharp and clear at lower magnifications.

    Orion has some decent prices on their APO scopes. Their quality has been pretty good on the stuff I have bought from them in the past.

    Orion Telescope
  15. Aug 13, 2004 #14


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    A friend has an 8" Celestron. Wouldn't trade it for anything. He is a photo freak and has pics of everything from galaxies to hummingbirds. The picture quality is amazing. If you have your own personal observatory, I would go aperature crazy and all. But, if you have to share a patio with the barbecue grill or head out to the wilderness to find a decent night sky, the Celestron is a no brainer. They are extremely portable, compact and a breeze to set up.

    I would definitely want a computer assisted target finder. Locating deep sky objects with star maps will have you talking to yourself [trust me]. You might want to look at the Celestron NexStar 8i. It is a nice instrument and well within your budget [more accessories!].
  16. Aug 13, 2004 #15


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    The angle can be a problem sometimes, but this can be overcome. I found a 1'x1' front-surface silvered mirror at a salvage business, mounted in a nice wooden frame with wingnut adjustments for angling the mirror. I built a binocular mount with some sturdy brackets attached to that wood frame, so I could sit at a table and look DOWN through the binoculars to see the reflection of stuff at very high elevations. Where do you find these nice framed front-surface-silvered mirrors? The are used in every optometrist's and ophthalmologists' exam rooms to bounce the Snellen chart images to your eye. The exam room may be fairly small, but bouncing the Snellen chart image a couple of times gives them a virtual "long" examination lane so they can check your visual acuity. These mirrors are all front-silvered and are very flat and accurate.

    If you're not a DIY'er, simply take a nice reclining lawn chair to your observing site, lie back and gaze away.
  17. Aug 13, 2004 #16


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    I would advise against the computer-drive for several reasons, not the least of which is that being able to star-hop with charts is one of the most rewarding skills you can acquire. When you wish to visit a faint fuzzy object, it can be pretty unsatisfying to punch in some coordinates into your scope's computer and have it slew to a patch of blank sky, or even worse, to a patch of sky that has numerous faint fuzzies, and you have no idea which is which. I have watched people do this, and the technology may be somewhat better now, but I'd bet against it being really usable. That technology sounds like a great thing, but your money is better spent on 1) better mount, 2) good charts, 3) a large aperture, fast finder scope, 4) good oculars, 5) better mount (see a pattern?). A nice instrument on a really solid mount is a joy to use, especially if you learn to polar-align it efficiently and accurately.

    I'm not trying to poo-poo the high-tech commercial scopes - they have their place, but good, solid basic equipment (that won't blow a computer chip 5 years down the road) is a far better investment. Let's face it - if someone says they'd like to look at double stars and you can swing the scope over to Alberio or Epsilon Lyra (a bonus there!), you've gained some really valuable knowledge. If you have to punch the star names into the computer and hope the 'scope acquires them, you're at the mercy of the guys who programmed the 'scope. Blah! :yuck: I would not venture out without my Tirion Sky Atlas 2000 and Uranometria 2000.0.
    Last edited: Aug 13, 2004
  18. Aug 13, 2004 #17
  19. Aug 14, 2004 #18


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    The LX200 has all the bells and whistles, and comes in at about $20,000 street price with basic necessities only. For that money, I would buy an RC optical tube assembly and a very simple but solid mount without all the electronics. In a school situation, where you have many students using the scope (many with no working familiarity with the night sky) the computerized point+go system might be a good idea - I don't know. But for anybody thinking of buying a personal 'scope, I would strongly advise you to get the best optics you can afford on the most solid mount you can afford, and learn to point the 'scope yourself. My old Astro-Physics' mount doesn't even have setting circles. Good charts and a decent finder will get you there. Eventually, when that Celestron/Meade, etc, computer dies, you will own a mediocre optical tube assembly on a manual-only mount. The standard fork mounts that come with those mass-produced scopes are adequate at best, and should be avoided, if you think you might want to add heavy accessories later (like a camera and off-axis guider). I've had my 6" APO and mount for over 15 years now, and I fully expect it to last my lifetime. It has seen heavy use, often in -20F temperatures and it is as solid as a rock. Keep it simple and sturdy and avoid the high-tech features - they are the weak spot in what seems to be an attractive package.
  20. Aug 14, 2004 #19
    I have a computerized telescope and several non-computerized ones including a few that I built myself. The computerized one rarely gets used anymore. Charging the batteries is a hassle, slewing is slow if you know where to find the object manually and you first have to align it, which may or may not work, depending on the visibility of bright stars in your area to use as alignment stars.

    However, if you're hosting a star party and you are the only one who knows anything about telescopes, you can align the scope, set it on an object and it will track it until everyone can get an opportunity to see it (mine does not track well enough for photography, but does pretty good for observation). Otherwise, I have had to run from scope to scope adjusting the position, etc. Another nice thing is that this scope helped me get back into astronomy, by helping me to find some objects I may not have been able to put the time into locating.

    All in all, I would also recommend not getting a computerized model. A good solid mount, and good optics are what you should start with.
  21. Aug 14, 2004 #20
    Ritchey-Chretien's are nice....the astronomy org. i belong to is getting a $100k setup in a state park (mmmmmmmmmmmmm :) ) but RC's are more for imaging and research. Meade starts there SCT's at about $1,300 (no comp).....i think Celestron SCT's are find unless u get the Nexstar series, they are the devil (no setting circles....comp only) the link i had above in my last post was for a Meade 8" LX200 GPS-SMT for about $2,100..........if u use it in ur backyard just get an AC adapter or if ur at star parties there are cig-adapters for ur car and/or "power tanks" to power ur scope.

    and i like the 16" LX200 i use!!!!!!!!!!!!!! (yes i'd like a RC since i'm starting up a research program with the new SBIG camera :) )....turbo-1 is right about APO's they are some quality scopes.....images u get in them are razor sharp and they are buit rock solid....and they better be for the damn price!!!!!
    Last edited: Aug 14, 2004
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