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Buying my first refractor and need advice.

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#1 richard hoyt

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Posted 09 December 2012 - 11:41 PM

I am looking for some advice on getting a refractor. I already have a c8 xlt sct on a cg5 at mount and was thinking of having two scopes side by side. One for planetary and one for wide field or dso imaging. I was going to get the hyperstar system for my sct which is 800.00. So if I got a refractor my budget would be 800-1200. Should I just get the hyperstar or is there a good refractor in my price range. I was looking on opt's site and found a couple but not sure what size vs quality to get for imaging. What size would be good for me, I was thinking about an 80 or 90?

#2 SKYGZR

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Posted 10 December 2012 - 01:48 AM

The AT72 is a sweet size, and a good performer for wide fields, not too hard on the budget also.

#3 astroricardo

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Posted 10 December 2012 - 03:38 PM

Do you have a camera already? If you have a DSLR, I'd go with a short refractor with a field flattener. If you don't have a camera I might go with the Hyperstar and something like an Orion G3 color.

With a short refractor/DSLR setup you'll probably want to guide where with the Hyperstar guiding isn't much of an issue.

By the way, you're going to be pushing the weight limit of your CG5 with both scopes mounted, especially if you're imaging.

You may even be better off spending that money on a better mount if you're serious about astrophotography. I'm finding that my CG-5 is just good enough for me to notice I should have bought a better mount.

#4 Bowmoreman

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Posted 10 December 2012 - 04:12 PM

I've got a CG5/ASGT; and frankly, I think you'd be hard pressed to mount any refractor side by side with your SCT on that mount, and then do AP with it...

I also have Hyperstar (in my case on my C11) and I have to highly recommend it... frankly, with Hyperstar on a C8 you're going to be at roughly the same image scale/focal lengths and field of views you would be with a refractor.

One observation about Hyperstar, you are *probably* going to prefer OSC (either via DSLR, or a color chip) camera uses...

Given your mount is a CG5 and your budget doesn't seem to include much - if any - for a mount upgrade... that even more says "hyperstar" to me... because of the speed (~f2) you get nice short exposures, which - all else being equal - means less sensitivity to mount quality, etc...

HTH

#5 RTLR 12

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Posted 10 December 2012 - 08:21 PM

I don't know about side by side. I stack mine. Makes balancing a lot easier.

Stan

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#6 richard hoyt

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Posted 10 December 2012 - 10:47 PM

I thought about stacking, but thought side by side would be easier on the mount, am I wrong?

Next question, lets say I don't stack or have side by side and just use either the c8 or athe refractor. Would you hyperstar or refractor at that point? One recommendation was the at72 which is pretty inexpensive, any other recommendations or does the quality scopes really start at the 2k and up mark.

I was looking at the

http://www.optcorp.c...x?pid=995-12194

Or

http://www.optcorp.c...x?pid=995-18545

Or

http://www.optcorp.c...x?pid=996-13672

My concern is I don't want to get something that is not good quality and waste my money. Thanks for the suggestions thus far and answering newbie questions.

Now as far as a mount goes, what is recommended for what I am trying to do. I looked at the celestron cgem, while it looked beefier it only holds 40 lbs, mine is 35 so for almost a grand more it didn't seem worth it, am I missing something?

#7 Patrick

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Posted 11 December 2012 - 12:29 AM

I was going to get the hyperstar system for my sct which is 800.00. So if I got a refractor my budget would be 800-1200. Should I just get the hyperstar or is there a good refractor in my price range.



I think you'll find a small refractor to be more versatile and easier to use than the hyperstar. The refractor can make a nice wide field imaging instrument as well as do a great job as a visual instrument. Imaging wise, a refractor is pretty much point and shoot while the Hyperstar takes some effort to setup and use.

Patrick

#8 christinam

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Posted 11 December 2012 - 12:34 AM

I started out with a Williams 80 and my Nikon D50 camera. Terrific for wide field imaging (my favs were NA nebula and Eastern edge of the veil) but I agree with others...if you are going to spend limited money now, I'd upgrade my mount. It can be used for astrophotography regardless of your set up and you won't be disappointed by a poor mount set up. Buy a refractor later when you can afford another purchase.

Chris

#9 Bowmoreman

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Posted 11 December 2012 - 11:53 AM

I thought about stacking, but thought side by side would be easier on the mount, am I wrong?

Next question, lets say I don't stack or have side by side and just use either the c8 or athe refractor. Would you hyperstar or refractor at that point? One recommendation was the at72 which is pretty inexpensive, any other recommendations or does the quality scopes really start at the 2k and up mark.

I was looking at the

http://www.optcorp.c...x?pid=995-12194

Or

http://www.optcorp.c...x?pid=995-18545

Or

http://www.optcorp.c...x?pid=996-13672

My concern is I don't want to get something that is not good quality and waste my money. Thanks for the suggestions thus far and answering newbie questions.

Now as far as a mount goes, what is recommended for what I am trying to do. I looked at the celestron cgem, while it looked beefier it only holds 40 lbs, mine is 35 so for almost a grand more it didn't seem worth it, am I missing something?


wow... lots more questions! ;)

1) One factor in Hyperstar versus slower refractors - given that their focal lengths are similar - is going to be how much light pollution you have in your area...

The beauty of Hyperstar (at f2.0!) is that you can get a LOT of imaging data very, VERY quickly... i.e. your subs can be on the order of 30-120 seconds (or less depending on targets)... this makes data capture effortlessly easy, and is especially valuable if you have a fair amount to a lot of light pollution

2) That said, Hyperstar is pretty much a "one trick" pony, in that it's going to limit you to pretty widefield targets. There are a LOT of such targets though...

I've done the 80mm Apo route (f6ish) and found I preferred Hyperstar... Now, I (mostly) am doing imaging with my Takahashi FSQ106ED (f5), but that's because it's a permanent setup and I have a LOT more experience (and a much better mount these days).

Given you have a CG5, I'd still lean towards just hyperstarring your C8 to start, and learn the basics of imaging (data capture, reduction, post-processing, etc.) that way; like I said, f2.0 is very forgiving... you won't need a better mount

For the slower refractors you're going to find that you will need substantially longer subs, which makes you more prone to mount issues/errors

The CGEM is in a completely different "class" for imaging than the CG5/ASGT... don't pay too much attention to their "ratings"...

In my experience, and likely broadly shared, the CG5 is good to a (typical) maximum of around 10-15# for imaging (some may push beyond it with compact/fast scopes)... the CGEM is good to 25 or 30... (all else being equal)...

With mounts, you don't get what you don't pay for... ;)

When you start out imaging, the shorter your focal length and the faster your exposures; the easier everything gets...

If you can, I'd recommend finding a (used) copy of Ron Wodaski's "The New CCD Astronomy"... a hugely useful reference for all things imaging...

HTH

#10 richard hoyt

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Posted 11 December 2012 - 06:03 PM

@ Dave

Thank you for answering my questions. I think you have pointed me in he direction. I don't know if I am going to upgrade my mount right now since I have to pick it up and move it from my garage to my either front yard or back yard and want something that is light enough to move around easily.

So I think at his point I am going to invest Inge hyperstar and an atik 460ex camera or maybe the 428ex haven't decided yet. This way I will have all of the equipment to grow into.

I do have the celestron auto guider with he celestron 80mm achromatic scope. While it does have color fringing I think it will be ok for just occasional visual use. It is so interesting looking through both scopes and seeing the focal length difference.

Such a fun but expensive hobby and I thought general photography was expensive.

#11 Bowmoreman

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Posted 12 December 2012 - 04:24 PM

Make sure before you get your Hyperstar, that you give Dean K. a call at Starizona... let him guide you on the right camera, etc...

You'll find that with Hyperstar, your polar alignments won't be quite so critical (heck I know some folks that image with it in Alt Az!!!)... and you can really get fun imaging started very quickly.

Also, make certain that your specific C8 is "fastar ready" (Dean can also help you with that)...

I remember those "set up each time" days (not so) fondly... they, more than anything else, drove my decision to build an observatory! (I didn't have Hyperstar then!)...

I think you're making a good decision, given the mount.

Good luck and keep us informed!






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