Good consumer telescope?

Discussion in 'Digital Photography' started by CalPoly10, Jan 22, 2008.

  1. CalPoly10 macrumors regular

    Joined:
    Sep 5, 2006
    #1
    Hello all, I have a great interest in the stars, planets, galexies, etc. I also love photography, so here is my question.

    What telescope would you recommend to a beginner (but not novice) telescope buyer? I am thinking something in the price range of $300-$500, and it would be fine if it's used.

    I really want the features like auto-tracking, optional camera mounts, somewhat portable.

    I have been looking at a Meade ETX-90 (used). Any opinions?
     
  2. arogge macrumors 65816

    arogge

    Joined:
    Feb 15, 2002
    Location:
    Tatooine
  3. Airforce macrumors 6502a

    Airforce

    Joined:
    Jan 12, 2006
    #3
    I'd like to see if you get anyone knowledgable in the field of telescopes to answer you! I've been thinking about this and wondering if I could hook up my Olympus E410 to one to get some shots of the stars, moon, and planets.

    What kind of costs are associated with a telescope that can view Jupiter, mars, ect?
     
  4. arogge macrumors 65816

    arogge

    Joined:
    Feb 15, 2002
    Location:
    Tatooine
    #4
    A T-mount adapter is usually required to mount a camera to the eyepiece tube of a telescope.
     
  5. astrostu macrumors 6502

    Joined:
    Feb 15, 2007
    #5
    What a Telescope Does

    A telescope is just like a camera lens. Therefore, its most basic components are a focal length and an aperture. The larger the aperture, the more light it will collect, and the brighter the object viewed will be.

    The longer the focal length, the smaller the field-of-view (FOV) will be. This can be changed by changing eyepieces where the smaller the eyepiece, the narrower the FOV. This means that any telescope can have any magnification or "power," but it'll be as dark as pitch if the aperture is too small. A rule of thumb is that you can get about 40x practical "power" per 1" of aperture.


    What to Avoid

    Department-store telescopes. They are over-priced and under-built.

    Anything with an aperture smaller than 3" (7.5 cm). Especially when they advertise stuff like "400x magnification power!!!!"


    What to Look For

    Buy the largest aperture you can afford. 4" or larger.

    A sturdy tripod and a sturdy mount between the telescope and the tripod.

    While Dobsonian telescopes are cheaper than equatorial and alt/az (altitude/azimuth), it's the equatorial ones that will have a clock-drive to compensate for Earth's motion. This is necessary for astrophotography of anything other than the moon, sun, star trails, artificial satellites, or meteor showers. So you should look for an equatorial mount with a clock-drive.

    If you can't find objects yourself, you'll want one of those Go-To things, but they're expensive so you're better-off learning to use RA/DEC to find objects yourself, or to starhop.


    To Mount a Camera

    You need both a T-mount and a T-ring. The T-mount is specific to the type of eyepiece the telescope takes, either 1.25" or 2" usually. It will be a tube, much like an eyepiece, but it will end in a threaded region.

    The threads fit into one end of the T-ring which is specifically made to fit your camera body. One end of the T-ring is universal and screws into the T-mount, the other end goes on your camera body like a normal lens ... which is what the telescope technically is, just a really long lens with a relatively large aperture. Obviously any auto-focus will not work, and usually the auto-exposure won't work.


    The Meade ETX-90 looks to be a tad slow at f/13.8, but that's expected given its aperture of 3.5". A focal length of 1250 mm will give you a field of view (with a 35 mm eyepiece) of about 1.6°, which is 3x the size of the full moon. Stick a 9 mm eyepiece in there (the very smallest I recommend or you'll go blind trying to stare through that tiny hole) and you have 0.4°, or 24 arcmin. Planets are usually measured on the scale of arcsec, which are 1/60 of an arcmin.
     
  6. mac-slap-happy macrumors member

    Joined:
    Jul 25, 2007
    #6
    I'm a relative amateur to amateur astronomy (ha!), but have read enough to know a few things. I've only been in this for a few years on and off, but I suggest you start doing LOTS of reading over at Cloudy Nights (http://cloudynights.com). The forums are great, and the beginners forum will be especially helpful to you.

    Astrophotography is one of the hardest things to master, and also one of the most expensive. Shooting the moon and the planets is fairly easy, and could be done nicely with the ETX-90 as you suggested. Getting any sort of photograph of a DSO (deep space object) such as galaxies and nebula will take a much more expensive system, IMHO. The problem is two-fold -- you have a light issue where you will need to do long exposure to get enough photons for a good photograph, and add to that the fact that you'll need to accurately track the sky to get that long exposure photograph. Things start to get complicated at this point with wedges, polar alignment, and autoguiders, so I'll leave that to the experts over at Cloudy Nights.

    If you're just wanting a telescope to get started with, a good dob is recommended by most that have been in this hobby for a while. If you're like me and want the Go-To functionality right off the bat, I'd say the ETX-90 will get you going just fine. I'm currently running an Orion 4.5" reflector in a Celestron GT mount, and have had exceptional luck with this setup so far. I suspect you'll have the same luck w/ the ETX series.

    Be warned - this is both an addictive and expensive hobby. The paltry amount of money I spent on my setup currently has me scanning the net for a Meade LX200 or Celestron CPC setup. It seems in astronomy that aperture rules, and aperture is expensive! Explaining a $2500 Macbook Pro to your significant other is one thing, but just wait until you try to explain a $2500 tube full of glass. ;)
     
  7. David G. macrumors 6502a

    Joined:
    Apr 10, 2007
    Location:
    Alaska
    #7
    Can I use that in my sig, mac-slap-happy?
     
  8. scotthayes macrumors 68000

    scotthayes

    Joined:
    Jun 6, 2007
    Location:
    Birmingham, England
    #8
    I had a Meade ETX-80 for Christmas and love it (well will do when we finally get a clear night).

    Very light, very easy to set up and the one I bought came with tri-pod and two eye pieces

    The Meade ETX-80 (and I believe ETX-90) come with a port on the back for fitting a dSLR camera, you just need the t-mount and adaptor (I paid £30 for mine).
     
  9. mac-slap-happy macrumors member

    Joined:
    Jul 25, 2007
    #9
    LOL ... sure thing. The funny thing is how true it is, at least in my situation. :)

    CalPoly10: I forgot one of the most important pieces of advice: visit a local astronomy group and arrange to go to a star party with them. This will give you the opportunity to look through various scopes, and discuss the ins and outs of each with the experienced folks around you.
     
  10. ChrisA macrumors G4

    Joined:
    Jan 5, 2006
    Location:
    Redondo Beach, California
    #10
    This is very hard to answer without more information. First question is where will the telescope be used? At home? Is this in a city? how dark is the sky. What stars can you see with the un-aided eye? Next question is the types of things you might want to look at.

    Hopefully your answers are not "bright city location" and "low contract extended objects"

    The single most important feature of any telescope is the diameter. Bigger is always better up to the point where the scope is just to big to store, move and set up for use.

    Here is a very good on-line resource to help you select a telescope. But first you need to define your needs
    http://www.skyandtelescope.com/equipment/basics

    After reading this you can then make some more specific, informed questions.
     
  11. kcross macrumors member

    Joined:
    Jun 8, 2007
    #11
    a few of the other guys have mentioned that you need to provide more information as to where and what you want to observe. thats a good place to start.

    furthermore, i would personally suggest buying used, but only after you have had a chance (as was mentioned) to go to an amateur meeting (star party) and got a feel for what all the different equipment is (theres a ton!). astronomers are like photographers. their equipment is generally in very good condition second hand. i buy from www.astromart.com myself.

    if you are interested in photographing the sky i would suggest a refracting telescope (looks like a telephoto lens). a good low cost option is a william optics 80mm. refractors like that are very compact as well.

    however, to be completely honest, don't expect much performance for $500. i would recommend that if you do have a genuine interest in the long (LONG) term hobby that is astrophotography that you save $1000-$1500 to get set up good and well right out of the gate. remember, a telescope will let you see objects, and photograph a few (the moon and a select number or other objects). however if you want to make long exposures (to see the cool stuff) you need a tracking mount. now a cheap goto mount will point you to objects and follow them, but it is unsuitable for quality long exposures. even high quality mounts need to be guided for relatively long exposures by a ccd autoguider or manually with a second scope.

    don't let this scare you off, but know what you're getting into. i've seen many people get discouraged because they had too high of expectations. remember, its a life long hobby that takes an investment of time and money.

    good luck.
     
  12. Maldini macrumors regular

    Maldini

    Joined:
    Nov 21, 2007
    Location:
    Riyadh
    #12
    For a beginner i would suggest these telescopes:

    Orion SkyQuest XT4.5
    Orion SkyQuest XT6
    Orion SkyQuest XT8

    but they may not be portable enough for you.

    and my favorite brand, though a little expensive is Vixen, they have the best refractor scopes, they are portable and will give you the best results.

    Edit: Plus the most important thing is the mount, even more important that the scope because if it shakes just a little you cant see clearly.
     
  13. cube macrumors G5

    Joined:
    May 10, 2004
    #13
    I have an ETX-90 that I bought in a rush.

    It is not for astrophotography, as it has plastic gears and cannot be autoguided.
     

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