Shadowalker
Apocaloptimist
Reged: 11/23/04
Posts: 10857
Loc: Carriere, Mississippi, USA
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I like this one. Best I've done on M27 and I think there's room for improvement too.
28 images, 30 seconds each, ISO800
Calibrated, aligned and adaptive add combined with ImagesPlus
Curves, Levels and Color balance with Photoshop
Noise reduction with Neatimage
Gradient Reduction with GradientXterminator
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"The truth rarely gets in the way of a good story. ~ R. Woods
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Fabio Papa
Carpal Tunnel
Reged: 03/01/05
Posts: 1734
Loc: Piacenza, Italy
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It's incredible how much you can do with an F/5...
With my F/7.7 30secs won't do any good, me thinks... 
Anyway, that's really great!
By the way, is your 300D modded or not?
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Shadowalker
Apocaloptimist
Reged: 11/23/04
Posts: 10857
Loc: Carriere, Mississippi, USA
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Well, F7.7 captures less than half as much light as F5.
But I'd still do longer exposures if I could. Still working on mount issues. Autoguiding isn't working as well as it needs to. I can get about 1 to 2 minutes unguided, but I need to throw out about half. With 30 seconds they're all usable. And I'm still proving to myself that a bunch of short images don't add up to a few long images. I'm almost there. I am a stubborn person!
The 300D is not modified. I may do the surgery on it. I'm still deciding. On DSOs like this, I don't think it's necessary. But on extended diffuse nebula, I know it would make a big difference.
Finally, It's a little difficult to see in this image, but there are vertical noise artifacts. I don't know what they are. Any hints would be welcome.
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"The truth rarely gets in the way of a good story. ~ R. Woods
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Dean
Postmaster
Reged: 12/31/04
Posts: 5431
Loc: Bailey Co Elev 8780 feet
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Very nice Tom. You've made some incredible progress in a very short time.
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"Don't sweat the petty things and don't pet the sweaty things" - George Carlin
deanrowe.net/astro
Whats with that avatar?
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Shadowalker
Apocaloptimist
Reged: 11/23/04
Posts: 10857
Loc: Carriere, Mississippi, USA
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Thanks, Dean! Praise is a motivator for me  8200 ft altitude, huh? My wife used to live in CO Springs and wants to move back to high altitude. Maybe Conifer is the place Although I was thinking more along the lines of Ft Davis, TX...
Anyway, I re-processed that image set. Noise is a good bit lower and color and detail are better, I think. Biggest difference is I used Sigma Clip averaging in my combining process.
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"The truth rarely gets in the way of a good story. ~ R. Woods
Edited by Shadowalker (08/05/05 10:14 AM)
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PeteD
member
Reged: 06/28/05
Posts: 71
Loc: Southwick, Sussex, UK
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Thats a stunning image Tom, well done.
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LX200GPS 8" UHTC
Nexstar 4GT
Canon 400D DSLR (un-modded)
DSI-Pro Mono
NexImage
LPI
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tjensen
Carpal Tunnel
Reged: 02/16/05
Posts: 2488
Loc: Chapel Hill, NC
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Hey Tom. Great shot. I'm jealous, the weather has kept my scope inside for almost 2 months now. I have seen the same artifacts with my 10D. I think it is due to adding short exposures rather than averaging long ones. So, more and longer exposures should remove it. With the longer exposures, less processing needs to be done to bring up the detail. So there is less chance of amplifying noise too. At least, that is my theory. I do think adding images does work... to a point. There has to be a few photons captured in the pixel for it to register on an added image, so longer exposures will help with that.
Keep 'em coming!
Cheers.
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Tim
Celestron C14 on CGE mount
HyperStar
Meade 10" LX200GPS
Canon T2i
Flea3
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Shadowalker
Apocaloptimist
Reged: 11/23/04
Posts: 10857
Loc: Carriere, Mississippi, USA
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Many thanks, Neighbor... Same problem here - you're only about 100 miles away. Butlast night had a little opening. was battling misty clouds and humidity all night, but I did manage to get two pretty good images. well, I was desperate! Hadn't been out in over a week. I was having withdrawl. Processing other peoples' images and my old pics just ain't the same thing!
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"The truth rarely gets in the way of a good story. ~ R. Woods
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Astrodave
Pooh-Bah
Reged: 05/28/04
Posts: 1206
Loc: Manassas Park, Va. USA
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That is a fantastic image Tom! Im going to start going for 2 minute unguided with the 80ED and stack 10 or 20 of them whenever the humidity, dew and haze leave my area.
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Northern Virginia
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JakeJ
Carpal Tunnel
Reged: 08/31/04
Posts: 1556
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Tom -
I believe the vertical artifacts are caused by read noise. Your exposures are too short to give you good enough signal/noise ratio - so stretching to pull out the details also pulls out the noise. You might want to try your 2 min shots, and/or use ISO1600 - it will help alot.
Glad it cleared up for you to shoot finally! My only chance at going is this weekend, and the weather forecasts aren't looking good. 
-Jake
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12.5" Discovery TD
Vixen ED103S
...and way too many eypieces to list!
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Shadowalker
Apocaloptimist
Reged: 11/23/04
Posts: 10857
Loc: Carriere, Mississippi, USA
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Quote:
I believe the vertical artifacts are caused by read noise. Your exposures are too short to give you good enough signal/noise ratio - so stretching to pull out the details also pulls out the noise. You might want to try your 2 min shots, and/or use ISO1600 - it will help a lot.
Figured as much. I solved most of my gremlin problems last night - autostar kept locking up. traced it to a dirty connector on the power line. After I cleaned it no problems. Other stupid problems like breaking my flashlight... A comedy of errors - but after 2 hours I was able to get going. But I didn't want to push my luck and engage the autoguider. maybe tonight. looks somewhat promising - at least no worse than last night. and I do want to go after the Draco Trio again.
Tom
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"The truth rarely gets in the way of a good story. ~ R. Woods
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Shadowalker
Apocaloptimist
Reged: 11/23/04
Posts: 10857
Loc: Carriere, Mississippi, USA
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One more thing, JAke.. I've been avoiding ISO1600. Do you think that I'll capture more light than noise (over ISO800) even with 30 second exposures?
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"The truth rarely gets in the way of a good story. ~ R. Woods
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JakeJ
Carpal Tunnel
Reged: 08/31/04
Posts: 1556
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Quote:
One more thing, JAke.. I've been avoiding ISO1600. Do you think that I'll capture more light than noise (over ISO800) even with 30 second exposures?
It never hurts to try - Here is an image I took last year using 5min exposures at ISO1600:
IIRC - this is only five images stacked. I would still try for a longer exposure than 30secs - but M27 is pretty bright, you should be able to get good SN at 1.30 - 2min exposures.
-Jake
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12.5" Discovery TD
Vixen ED103S
...and way too many eypieces to list!
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Chris Graham
mmmm...Haggis
Reged: 04/01/04
Posts: 4886
Loc: Stirling, Scotland
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owww !
nice !
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-Skywatcher 8" Reflector on HEQ5 with Skyscan
-Orion ED80 Refractor
-70mm Guidescope/grab and go scope
-Canon EOS 350D
-Toucam Pro 2
Astronomy & Veggies
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c131frdave
Post Laureate
Reged: 01/17/05
Posts: 4376
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I'm pretty sure Dan uses ISO 1600 exclusively. And Dan is the man. (Auroraseeker)
Are you sure those vertical streaks aren't from your diagonal mirror? It doesn't look like noise to me- more like a smear in your optics. Mount your camera on your mount and shoot some widefields of M31 or something and see it it still does it.
Great shots, by the way.
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Tak NJP
Various sizes and shapes of formed glass
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Shadowalker
Apocaloptimist
Reged: 11/23/04
Posts: 10857
Loc: Carriere, Mississippi, USA
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well, my optics are dirty. so much dew, and then dust gets kicked up. I don't like to clean it very often, though. Maybe it's time. There are one or two splotches on the primary from dew dropping. Well, you're in Pensacola. You know how it gets around here.
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"The truth rarely gets in the way of a good story. ~ R. Woods
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