Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

(Telescopes) Certifiably confused.

  1. Jun 27, 2005 #1
    Well I'm surely interested in astrophotography. Or maybe not. I really don't know -- to be completely honest. I am sure however, that i want to buy a telescope, and observe the far sides of this perpetually expanding, glorious universe of ours. So i won't be modest, and arrogantly demand help.

    My real predicament is the fact that i live in Toronto. Toronto, if you don't know, is a place where the coorprorate world frankly does not give a "poo" about the environment. So i am covered by a greyish sort-of cloud that seems destined to suffocate me in my sleep. Could someone provide a list of telescopes (reflectors, refractors, i don't really know; although refractors are smaller, so i 'guess' that's most acceptable) and their respective ranges; that is, which aperatures and magnifications provide, let's say, a view of Neptune.

    Also, from what i have read, digital cameras are the outcasts of the astrophotography world. What camera is best for me? What are the "adapaters" which provide access to my telescope with a camera called?

    Any information is truly very helpful.
  2. jcsd
  3. Jun 28, 2005 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    No amateur telescope is going to provide a 'view' of Neptune. The best you're going to get is a small blue object that is noticeably larger in size than other nearby stars.

    I will warn you beforehand that trying to begin with astrophotography is practically futile. The kind of astrophotography you are considering, using the telescope as a super-telephoto lens, is called prime focus astrophotography. It is the most challenging sort of astrophotography. It generally takes years of experience and tens of thousands of dollars of equipment to get the sort of photographs you see in magazines like Astronomy and Sky and Telescope. I strongly recommend that you begin as a visual observer, learn the sky and the operation of telescopes, and then venture into imaging.

    I should also mention that the equipment needed for good astrophotography is quite different than the equipment that would provide the best visual observing experience. If you have only enough money to get one rig, you will (pretty much) have to decide between photography and visual observation.

    That said, I'll explain the two features you need for good astrophotos: high-quality optics, and an excellent mount. For imaging purposes, the size of the aperture is far less important than is the quality. The best telescopes for the purpose are generally the apochromatic refractors, which are small (2" to 5"), expensive, and equisitely good telescopes. These telescopes are fantastic for planetary and wide-field deep sky work. They do not collect much light, so they are not at all ideal for deep-sky visual work. The cheapest apochromatic in existence is the Orion ED80, and by all accounts it's a tremendous value for the money.

    A mount good enough for astrophotography will often cost as much or more than the telescope itself. Astrophotography demands equatorial mounting, and equatorials are much more difficult to set up and use than other simpler mounts. Astrophotography also demands a very precise drive, and often manual or automatic guiding equipment to fully eliminate residual drive errors. You might want to look into some of the Vixen mounts, as they're relatively cheap and relatively good.

    In my opinion, you'd do better to start your foray into astrophotography without a telescope -- just use a stable mounting and a wide-angle camera lens, and take some star trail photos, some moon photos, and so on. When you're ready, move up to piggybacking, which simply means mounting your camera and lens on top of a modest telescope mount. A wide-angle piggyback photograph will be much more forgiving of drive error than a prime focus photograph. Finally, when you've cut your teeth on simple photos, move up to prime focus.

    As far as cameras are concerned, there are two extremes: very expensive specialized digital cameras from companies like SBIG, and dirt-simple fully-manual SLR cameras. Consumer-grade hand-held digital cameras are only modestly useful for astrophotography, and only for bright objects like comets, planets and a few emission nebulae.

    Here's an article I've written on choosing telescopes: http://users.vnet.net/warrenc/astro/telescopes.pdf

    - Warren
  4. Jun 28, 2005 #3


    User Avatar
    Gold Member

    Go to a star party before you spend a dime!

    dekoi, before you make any purchase decisions, you must attend a star party, preferably at least a couple of them - one in a light-polluted venue, and one out in the country. This will tell you more about the relative strengths and weaknesses of telescopes and their mounts than you can ever hope to absorb from a couple of posts. I've been stargazing for over forty years, and I could write pages about what I like and why, but ultimately, the choice of equipment boils down to storage space, transportability, access to dark skies (or not), availability of spare time for observation (including travel, set-up, take-down, travel again), choice of objects to observe (which can strongly constrain focal lengths and apertures you can choose from), and myriad other factors. Go to some star parties and look through as many different scopes as you can. You will gravitate toward the things that appeal to you, and then you can start figuring out what you can afford on your budget (budget can come into play very quickly if you want great optics), what you have room and time and energy enough to deal with comfortably, etc. Don't make your choices based on the claims and the pretty pictures in the telescope ads - when some outfit shows a beautiful color illustration of the Horsehead Nebula in an ad for a 2-3" refractor, they are committing a gross fraud. Go to some star parties!

    Here's a link to the website of the Royal Astronomical Society of Canada. Click on the star parties or activities links and attend a few. It will save you a lot of money and frustration if you start out with some practical experience.

    Last edited: Jun 28, 2005
  5. Jun 28, 2005 #4


    User Avatar
    Gold Member

    Don't ignore the low-cost solutions

    One more thought, although I touched on it earlier. When Charles Messier was searching for comets (and hoping to prove their periodicity) he charted a whole lot of fuzzy objects that might look, under Parisian skies of those days, like comets. Nowadays, we refer to them by the order in which he charted them - M1 is the Crab Nebula, etc. He sometimes used small crude refractors (top-notch equipment at the time), and he often used long, narrow-field reflectors with speculum (polished metal) mirrors. He would have given his right arm to obtain today's nicely figured optics with anti-reflection coatings. A small but decent commercial-grade refractor or a good pair of binoculars will allow you to view and identify all the objects that he discovered, and more besides.

    I never go observing without my 7x50 Nikon binoculars. They are base-level quality binoculars for Nikon, but the the optics are good, and the high contrast and wide field of view are fantastic for large faint objects that are tough to see (or even photograph) in a typical telescope. You or a relative may have a pair of decent, rugged 7x50s kicking around. If they are dirty and neglected, go to a camera store and get some lens tissue, mix up a 50:50 solution of distilled water and isopropyl alcohol, and gently clean the lenses, then go discover the night sky. Binoculars and a Peterson's Field Guide are a great way to start.

    To use these effectively at night, you have to preserve your night vision, so you should also buy a flashlight with a deep red lens (Maglight used to sell these lens sets with their flashlights-maybe you can still get them) or perhaps coat the bulb in a conventional flashlight with a deep red nail polish. If you use a regular flashlight at a star party, people will yell at you to shut it off, because it can take a long time (valuable lost observing minutes) for their eyes to become adequately dark-adapted again.

    I thought I should mention these things because:

    1) binoculars are a great way to explore the sky while you are standing in line waiting your turn to look through the 20" Dobsonian light-bucket or the exquisitely figured 6" refractor.


    2) You will not be very popular if you fire up your white flashlight to consult your star atlas while standing in line.
  6. Jun 29, 2005 #5


    User Avatar

    Staff: Mentor

    I'm going to have to respectfully disagree. I'll post a full opinion later, but the setup I'm using to take the photos I posted in the astrophotography thread (check it out, dekoi) cost me about $1500, not including the laptop. I have several years of experience using a K-Mart special (your typical 60mm refractor - though it does have an equatorial mount), but I'm only 6 months into my current rig. Some of my pictures of Saturn were accomplished with a modified $50 webcam and literally only a few days of experience using the new setup. If planets are all you're interested in, $500 (including a webcam and a Barlow lens) and a willingness to learn is all it takes to get photos like mine.

    I have yet to attempt a photo of Neptune though..... :wink:
  7. Jun 29, 2005 #6


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member


    Webcam photography can be exceptionally good when using a register-and-stack program to eliminate bad frames and increase SNR. On the other hand, a webcam astrophoto is really just a neat little thing to show your friends; they're only noteworthy because they came from such cheap equipment. Webcams are useless for scientific inquiry (you cannot do, for example, accurate photometry with them), and their small size and low sensitivity make them useless for everything but planetary work. If you want to take an image of the Horsehead good enough for publication, you'll need real equipment. Don't get me wrong -- webcam photography is fun and is a good way to get started, but it cannot even begin to compete with more advanced equipment.

    Perhaps we need dekoi to tell us exactly what objects he hopes to image?

    - Warren
  8. Jun 29, 2005 #7


    User Avatar
    Gold Member

    I've got a really nice 6" apo made by Roland Christen almost 20 years ago, with a rock-solid mount. Getting nice prime-focus astophotographs with that set-up was a piece of cake compared to the trials I went through with my previous equipment.

    I sweated blood (actually, mostly I froze my butt off) to get great astrophotographs, and have gotten some images that I am very proud of, but never managed with a tripod-mounted scope to get images that I thought were sufficiently nice to submit to Sky&Telescope, although several adorn the walls of our home. You've got to mount a superior instrument to a rock-solid mount and tweak it regularly to get the sort of results that Tony and Daphne post. To achieve the results that Roland posts, you might have to go back to school again:


    Please, please follow that link and check a few images. You will be impressed at what properly-designed modest-aperture instruments can do.
  9. Jul 6, 2005 #8


    User Avatar

    Staff: Mentor

    Sorry this took so long....
    That's exactly it: right out of the gate, about the only thing a complete beginner should hope for is a "neat little thing to show you friends". Its also precistly because its fun and a good way to get started that I would recommend it. Since about all we know is that dekoi is a complete beginner (thats an assumption, but it seemed reasonable from the OP), even if he said he wanted to produce professional photos as a complete beginner, you wouldn't recommend he actually try to do it, would you?

    For me, the recommendations start with the budget, but for a complete beginner probably top out at about $1500 (ehh - maybe $2500, for an 8" scope).

    For someone willing to spend $150 or less, a good book and a pair of binoculars is certainly the way to go. For telescopes, K-Mart special is all you can afford at that price and will likely do more harm than good because they are so difficult to use.

    At $300, a good little Newtonian reflector on an equatorial mount is probably the typical recommendation, but I'd probably go with a scope like Meade's $230 70mm refractor. The reason is precisly the "gee-wiz"/instant gratification factor that traditionalists tend to discourage. IMO, the "gee-wiz" factor is what will keep a novice interested and motivate him to learn. Too many people buy telescopes that they never figure out how to use correctly and as a result never really get into astronomy.

    And while I'm not a complete novice, for a complete novice who really thinks he's going to be picking up this hobby long-term, my rig is about the max that I'd recommend for someone who wants to jump right in with both feet. Its possible that two months with it will generate a passion and a desire to throw down another $5-$10 grand, and if that happens, so be it - you don't lose that much in the grand scheme of things if you end up selling a 2 month old, $800 telescope on E-bay for $500.

    One little wrinkle in my plan there is Dobsonians. I've never used one, but you get a lot of aperature for the money. In a scope like mine, there is very little to see with the naked eye as far as galaxies and nebulae are concerned and such a scope may allow a better appreciation of what is out there without having to get into astrophotography.

    HERE is what the planets look like with a scope like mine and an unmodified webcam. HERE is what you can do with an 8" scope and a modified webcam (or low-end astro-cam like the Meade DSI). Some truly impressive pics of galaxies and nebulae.
    Last edited: Jul 6, 2005
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: (Telescopes) Certifiably confused.
  1. Radio Telescopes (Replies: 0)

  2. Building Telescopes (Replies: 3)

  3. Telescopes & astronomy (Replies: 6)

  4. Muons and telescopes (Replies: 4)

  5. Telescopes (Basics) (Replies: 15)