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#1 orlyandico

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Posted 27 January 2013 - 07:08 PM

hi all
finally got around to using my C9.25 at prime focus.

here's an Eskimo i imaged a couple nights ago

Posted Image

as can be seen, it's not too great. but there aren't that many amateur images of the Eskimo, and most of them aren't significantly better than this one.

the best amateur image i've seen came from a CDK17.

question is... can i do much better than the above without going for a CDK17? i thought a Mewlon would put in a better show, but the few Mewlon images of the Eskimo i've seen didn't blow me away like the CDK17 image did...

#2 korborh

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Posted 28 January 2013 - 12:00 AM

Wait for excellent seeing and try with a barlow at 2x this FL to resolve more detail. This one calls for very long FL...guiding would need to be perfect though.

#3 mattflastro

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Posted 28 January 2013 - 12:09 AM

It's hard to tell without knowing more details about your setup and image info . What camera did you use ? Apparently you used drizzle , what other details can you tell ?

#4 mattflastro

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Posted 28 January 2013 - 12:11 AM

Wait for excellent seeing and try with a barlow at 2x this FL to resolve more detail. This one calls for very long FL...guiding would need to be perfect though.

Looks like he already used a Barlow , unless the image is cropped and upconverted . Stars look round , tracking/guiding seems good .

#5 korborh

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Posted 28 January 2013 - 12:21 AM

I took "C9.25 at prime focus" to mean at native focal length not barlowed....

#6 orlyandico

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Posted 28 January 2013 - 03:22 AM

it's native, prime focus. not barlowed. that is a heavy crop. drizzle because am using an OSC (QHY8). It's "better upsampling than plain upsampling" because of the image shift between subs.

the image is about 1 hour, composed of 4-minute subs.

i discovered that i actually have a bahtinov mask for the 9.25, will try again if i can get better focus.. the idea of imaging at f/20 and 5-meters odd is quite daunting though. i don't think my setup is up to it. the CDK17 image was at 3m focal length.. i'm not too far from that.

#7 Sunspot

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Posted 28 January 2013 - 09:33 AM

First of all, that's not terribly bad, it's pretty nice in fact. I think the limitation is more focus or seeing than the scope. Back when I was doing DSI I imaged this beautiful object with my Mewlon 250. I think you can get great DSO images with the 9.25 especially if it's equatorially mounted.

For the record, here is my image of the Eskimo:

http://www.sunspot51...2392-reproc.jpg

Looking forward to seeing more great images.
Paul

#8 mattflastro

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Posted 28 January 2013 - 09:58 AM

Wait for excellent seeing and try with a barlow at 2x this FL to resolve more detail. This one calls for very long FL...guiding would need to be perfect though.

Looks like he already used a Barlow , unless the image is cropped and upconverted . Stars look round , tracking/guiding seems good .

Based on the image scale that seems to be around 0.3arcsec/pixel, definitely need very good seeing as well.

#9 orlyandico

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Posted 28 January 2013 - 11:04 AM

actually the scale is 0.6"/pixel. I did the drizzle (which is basically a 2X upsample, but with some "hardware assist") which is why the scale looks like 0.3" ...

#10 orion61

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Posted 28 January 2013 - 11:44 AM

Well, I think it looks great!

#11 Spyke

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Posted 28 January 2013 - 01:28 PM

Yeah I like that image! I'd be happy with that if I'd made it. Those 9.25's... :drool:

Ant:cool:

#12 payner

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Posted 28 January 2013 - 06:12 PM

Beautiful image of the Eskimo PN.
Best,
Randy

#13 orlyandico

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Posted 28 January 2013 - 07:37 PM

thanks for the encouragement guys but this has got to be the gold standard for amateur Eskimos:
http://billsnyderast...m/?page_id=3489

yes it's from dark skies and yes its a planewave 17".

but one has to have something to aim for right? :D

#14 korborh

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Posted 28 January 2013 - 08:00 PM

Another I found which is using a 20"
http://www.noao.edu/...vers/n2392.html

#15 fred1871

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Posted 28 January 2013 - 08:19 PM

I've also got a C9.25, and I wouldn't expect it to match 17" and 20" astrograph-style super-costly telescopes on Paramounts.

Imaging is a combination of a lot of factors - good seeing helps considerably; good optics, accurately collimated; spot-on focus; the right filters; and VERY accurate tracking plus vibration-free. A guy I know who does deep-sky imaging improved his work overnight (as it were) by getting a very high quality mount. With vibration and tracking errors pretty well eliminated, it made a very big improvement before he went to a better optical system specifically designed for imaging.

What you've got of the Eskimo is a pretty fair start. Without spending megabucks you can likely improve on it. But a C9.25 won't match the much bigger designed-for-imaging combinations.






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