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Old 05-10-2008, 01:08 PM
Babalyon 5
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Need new scope

Interested in opinions on a new imaging scope, good light gathering, sharpness, reflector or refractor(please no reflector/refractor wars), suggest 6in and over. Have come to the conclusion that there is more than just a focuser wrong with my 10in. Did some testing last night with the same camera in an el-cheapo Celestron 102mm achromatic and stars are pretty round, guiding and alignment seem good, don't wanna waste anymore money on the old 10in, its time to upgrade.
Sample pics with Celestron, NGC253(underdone) and NGC2070, and Helix.
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  #2  
Old 05-10-2008, 01:27 PM
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g__day (Matthew)
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Okay to frame the advice you are after please answer the following:

1. What sorts of targets do you wish to image (what fov and focal length are your considering)?
2. How capable is your mount (tracking and load carrying capabilities)?
3. What budget do you want to invest on the OTA?
4. What sort of camera (with what pixel size and Q/E do you wish to mate it with)?

That would help giving you meaningful suggestions.
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Old 05-10-2008, 03:12 PM
Babalyon 5
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At this stage, I'm after random suggestions form both planetary and deep space imagers. When I see what people are using for what, then I'll move onto making a decision on what to buy that suits my needs.By the way, I have an EQ6 mount(way capable), LX90 & wedge(hate the mirror flop and its my grab'n'go), 3.3 focal reducer, DSI Pro 2 with an Atik EFW(want to move onto narrow band at some stage), DSI Colour 1, Canon 40d, LPI, web cam, yadda, yadda, yadda.
Random suggestions is what I'm after.
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Old 05-10-2008, 04:35 PM
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Starkler (Geoff)
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I guess what would be helpful is to know what you dont like about your 10"er.
Do you know for a fact that its the scope thats limiting you?

Theres some excellent dso images taken with 10" newts on this site.
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Old 05-10-2008, 05:26 PM
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Davros (Lauren)
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I thought those photos were quite good. Especially if its a dob. I would love to achieve this on my dob.
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Old 05-10-2008, 05:33 PM
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g__day (Matthew)
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Ok,

So lets say you keep the mount (which can carry about 22kgs and its tracking is about +/- 15-20 arc seconds per worm revolution untuned) - so maybe up to a 10" OTA plus imaging gear and dovetails.

The cameras you mentioned are okay for that size scope but not brilliant (that's I guess a different price category as you get into purpose built astro cameras API, FLI, S-Big).

Lets also assume you have or soon will have good to great electronic, computerised focusers (TCF, Moonlight etc) to take that issue out of the equation.

So that leaves us strictly with OTAs under say 14kgs. Planets you can image are pretty bright - so a good APO will grab these, and the APO's from 4" -> 6" will give excellent shots of wide field targets.

Now you haven't let us known how dark your skies are - so if its like mine (11 km from Sydney) then the Helix Nebulae - even with Hutech LPS filters - is out of my reach due to light pollution. If your skies are dark then a large APO should be appealing. The ones folk are getting from China North group seem very interesting and a fraction of the Televue or Tak ortho-apo's costs.

If your targets are very small and dim - I don't imagine you'll succeed unless you have very dark skies and an excellent, 5" or larger apo?

Like Geoff asked - interested in what limits you on the 10" you have at present.

Even more detail on the fov and focal length you aspire too will narrow advice. If you say < 1 arc minute targets that are 14th magnitude or fainter - well that's a large RC on a Paramount's terrority. DSO's is too broad a field to offer more specific advice. Why not browse thru the DSO images on this forum and list the sorts of targets you'd like to shoot?

Basically the fainter the targets you are after - the more higher end OTA we have to recommend. But regardless if your targets aren't discernibly brighter than your background sky glow, you're in for frustration.

Also do you want grab and go - or can it be permanently mounted? Is your imaging location sheltered from wind - a EQ6 is going to struggle with a 6" refractor in moderate wind!
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Old 05-10-2008, 05:55 PM
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Astrod00d
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Quote:
Originally Posted by g__day View Post

The cameras you mentioned are okay for that size scope but not brilliant (that's I guess a different price category as you get into purpose built astro cameras API, FLI, S-Big).

The ones folk are getting from China North group seem very interesting and a fraction of the Televue or Tak ortho-apo's costs.

Like Geoff asked - interested in what limits you on the 10" you have at present.

Also do you want grab and go - or can it be permanently mounted? Is your imaging location sheltered from wind - a EQ6 is going to struggle with a 6" refractor in moderate wind!
Hi,

Any OTA over 5" and you're basically looking at a reflector unless you have a big budget.
Your 10" OTA is probably OK but the standard EQ6 might struggle somewhat with the mass and sail area. My EQ6 did not like the weight of a Meade 10" f/6.3 SCT until I ripped it apart and rebuilt it with new bearings.
My interest at the moment is deep-sky and I'm quite happy with the 950mm focal length my 127mm North Group APO.
Another good option may be a 200mm f/4 or f/5 newt but you'd need a coma corrector and you'd have to make sure the secondary mirror is large enough to prevent vignetting.
As far as cameras go, don't forget the QHY8. It has very low noise and an APS-C size sensor so it'll work OK with the moderate field size of most mid-priced OTAs.
For images from a 127mm APO check my latest posts (Astrod00d)
For images from a 5" f/4 Newt check posts from Marc (Multiweb)

Cheers,

Rob
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  #8  
Old 05-10-2008, 06:32 PM
Babalyon 5
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Quote:
Originally Posted by Starkler View Post
I guess what would be helpful is to know what you dont like about your 10"er.
Do you know for a fact that its the scope thats limiting you?

Theres some excellent dso images taken with 10" newts on this site.
I love the 10in, its ability to reduce my exposure time etc, its great! It has a problem in that one side of every image(the left as viewed by us) has stars that are streaks and perfectly round ones on the other side. Visually, you cant notice this, take an image and it shows up every time. Since day one when we got it, we had no end of problems with the mount and collimation, loose corrector plates, secondary mirrors, etc. We were among the first in Australia to own an LXD55. Its time to sigh, take a look around and find a new scope. At the and of the day, I'll probably go for a 10in newt again, just at this point need some random input!!
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  #9  
Old 05-10-2008, 06:34 PM
Babalyon 5
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Quote:
Originally Posted by Davros View Post
I thought those photos were quite good. Especially if its a dob. I would love to achieve this on my dob.
Photos are taken with a cheap Celestron 102mm refractor.
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  #10  
Old 05-10-2008, 06:45 PM
Babalyon 5
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Keep it coming, that's more like it!!
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  #11  
Old 12-11-2008, 07:06 PM
rayman888 (Ray)
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Quote:
Originally Posted by Babalyon 5 View Post
Photos are taken with a cheap Celestron 102mm refractor.
Isn't that like 4"? And to think I cannot see images like that on a Celestron 5" reflector! Anyway, thanks for mentioning that the 3 images were from the 102mm refractor rather than the 10" reflector.
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