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09-21-2009, 07:59 AM   #1
graphicgr8s
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Telescopes

Anyone here have any advice for a telescope purchase? Maybe one that can be used for photography that won't break the bank.

09-21-2009, 09:16 AM   #2
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Check out the ETX 125 scope.

You can also check info on www.cloudynights.com

Last edited by wildlifephotog; 09-21-2009 at 09:32 AM.
09-21-2009, 09:47 AM   #3
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i use a celestron C90

It is a catodioptic (I think I spelled this right) lens with corrective front element, and a hole in the primary mirror so that the secondary mirror reflects back through the primary. it is very compact for 1000mm at about 200mm Long, and close focuses to 3 feet.
09-21-2009, 11:20 AM   #4
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QuoteOriginally posted by Lowell Goudge Quote
i use a celestron C90

It is a catodioptic (I think I spelled this right)
No. It's spelled "catadioptric", if I remember correctly. But I might also be wrong.

09-21-2009, 11:54 AM   #5
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Hi there,

What you need to consider:
- Optical formula (refractor, reflector)
- Mount (german equatorial mount on tripod, Altitude/Azimutal arm, dobsonian)
- Motorized or not

For astrophotography, you basically need an equatorial mount (i.e. that's aligned with Polaris), motorized to compensate earth's rotation.

I would suggest to move gradually into the hobby. First of all, grab a good paper sky map (or download one of the many freewares available on internet), and get a good pair of binoculars.
It's lightweight, instantly available (no need to calibrate or install anything) and surprisingly rewarding. You can catch some deep spaces objects and see the biggest planets of the solar system.

Then, if you definitively catch the virus, but are on a budget, I would recommend a reflector on a dobson mount. You get a larger diameter for the dollar, and that's finally what matters.

The larger the diameter of the tube, the more light you can receive on the back mirror, thus giving you the possibility of viewing very faint stellar objects.

Magnification is really a secondary aspect. It could help catching details in planetary observations, but at the cost of the quantity of light you can catch.

Clear skies...

- Vincent
09-21-2009, 12:52 PM   #6
graphicgr8s
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I knew I asked in the right place.

As for budget, look at the avatar and you'll understand how limited it truly is.
09-21-2009, 01:03 PM   #7
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Just what are you wanting to shoot in the night sky?
09-21-2009, 01:44 PM   #8
graphicgr8s
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QuoteOriginally posted by wildlifephotog Quote
Just what are you wanting to shoot in the night sky?
I have no earthly idea. I just like observing. And I want to be able to teach this avatar when he is old enough. I want him to have a well rounded education and I missed out on astronomy when I was a kid. I've always been interested but never took the time to explore it too far. Now I have a reason.

Maybe look at the moon and some of the planets. Stars, things.

My thoughts were if I were to buy a scope I may as well get a decent one. If I can afford it. And it might as well be able to have a camera attached.

09-21-2009, 01:59 PM   #9
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I use an 8" dobson scope. I use my DS and 200D on it. I've done the moon, sun, comets, Jupiter and Saturn. I also use a modded webcam for video of those objects. Dobs are easy to both observe with and take photos. You just have to learn the quirks.
09-21-2009, 04:00 PM   #10
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QuoteOriginally posted by graphicgr8s Quote
And I want to be able to teach this avatar when he is old enough.
Will you also teach him about politics and arguing? That thought is really scary.
09-22-2009, 06:49 AM   #11
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QuoteOriginally posted by flyer Quote
Will you also teach him about politics and arguing? That thought is really scary.
Yep I sure will. And if he turns out to be a bleeding heart liberal I am sending him back. And if his IQ isn't above 140 he goes back too.
09-22-2009, 08:39 AM   #12
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Same advice than wildlifephotog.

My 10 years old son is having a lot of fun with his 200mm dobson (Skyquest Intelliquest).
This model's price was about 600 €, and includes a sky pointing electronic assistance device.

Basically, the 2 axis (altitude and azimut) have coders with a 0.1° angular resolution. you need to align the telescope with two chosen stars and the computer will then know its exact position and orientation.
You can then select an object you want to see (planetary or deep space, like a nebula or galaxy) and the coders will display angular offset. Set the two values to zero by moving manually the two axis, and look in an eyepiece with a large angle of vision. That's it.

One more advice: the quality of your viewing experience will directly depend on the quality of your eyepieces. In my opinion, that's where the spending effort should be.

- Vincent
09-22-2009, 08:46 AM   #13
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Here is a shot taken with a DS and 8" dob in my front yard.
09-23-2009, 07:54 AM   #14
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QuoteOriginally posted by graphicgr8s Quote
Yep I sure will. And if he turns out to be a bleeding heart liberal I am sending him back. And if his IQ isn't above 140 he goes back too.
I thought there was a "no return, no exchange" policy on that kind of "good", but, since you do things differently in Florida, I might be mistaken.
09-23-2009, 09:49 AM   #15
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QuoteOriginally posted by cgw_vince Quote
Same advice than wildlifephotog.


One more advice: the quality of your viewing experience will directly depend on the quality of your eyepieces. In my opinion, that's where the spending effort should be.

- Vincent
Not always the case. The telescope includes all parts as a visual optic system. The optical system is more important as than eyepieces. Manufacturing a high quality eyepiece, small surfaces, is much easier compare to a large optical surface. A scope main optics should have at least a quality of 1/10 wave error on all surfaces. The combined main and secondary mirrors of a newtonian type scope for 1/10 error will show a final error of 1/5 wave at the eyepiece, added errors. A scope should never be below a total of 1/4 wave to be acceptable.
Lots of books and info available out there. I have a 16" F5, table driven newtonian and weights 175 lbs. My optics are 1/22 wave for the main mirror and 1/25 for the secondary, both made by a local master optician. One can find very good commercial telescopes but knowing their capabilities is often the shortfall of many beginners. Astronomy has been a 20 year plus hobby. I used a Meade 8" F10 for 5 years. It was a good one but many have complained of poor quality of optics.
Your telescope eyepiece is equivalent to the viewfinder on you camera with the lens as your main optical unit. In a camera, the image quality from the optical system is viewed by the imaging system (ccd) while a scope transfers it to your eye via the eyepiece. Your viewfinder does not have to be very good but an eyepiece does. In the market, an average eyepiece from a well know producers, Meade or Nagler and few others, will render very good results using a good optical system.

Last edited by Denis; 09-23-2009 at 09:55 AM.
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