robrj
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home town/country: Escondido, CA
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Post by robrj on Apr 17, 2017 16:29:04 GMT
I did a first light with my Orion ED80T-CF on the AVX M51 (12x30s), Ultrastar-C w/Optolong CLS-CCD filter I did a brightness/contrast adjustment in Photoshop.
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Post by Dragon Man on Apr 18, 2017 12:32:59 GMT
Looks good Robert. Nice detail.
Did it really need 12 stacks of 30 seconds? Does it look anywhere near as good using a lot less stacks? (I'm wondering how close to 'Live' it can go).
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robrj
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home town/country: Escondido, CA
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Post by robrj on Apr 18, 2017 14:12:11 GMT
I didn't really have time to try out a bunch of different exposures. The clouds came in right after I took that shot. I spent a lot of time fiddling with the setup. I had an issue with mounting Starsense. I figured it would just slip in but the notch that prevents it from slipping out of the bracket {on it's foot} is on the lens side of the bracket so it blocks me from putting it in through the rear of the bracket. However, the finder bracket is a little to close to the area of the scope that starts getting bigger. So I couldn't get the foot into the clamp. Eventually I loosened the bracket just enough to get the foot in and then tried to tighten it down with the starsense as far forward as it could go. Then I could drop the starsense back and tighten it. For the next time, I stuck it under the scope on the mounting bar so I don't have to swap it out. I also didn't have enough focus and had to put in some extensions. Fortunately, I had some Baader Hyperion Rings that did the trick. I went with 30 seconds to start since Howie mentioned that an f/6 scope is going to require a longer exposure than an f/5 (which is what all my other scopes are). I typically did my f/5 sessions at 30 seconds or longer. I'll try some shorter exposure shots next time out, probably tomorrow. But my camera seems to like longer exposures better (higher read noise). I want to try it with the ASI185MC as well. That camera should be closer to the 224 experience.
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Post by Dragon Man on Apr 18, 2017 14:46:52 GMT
Rob, the detail in your image is great, I was just wondering what it looked like without all that stacking, not shorter exposures. 30 seconds is OK I'd be interested in seeing what only 3 or 4 stacks of 30 seconds would be like. Even a stack of only 2 or 3 at 40 seconds. The nearer to 'near-live' the better. The habit lately seems to be lots and lots of stacking which slows down the observation for those watching (at outreach, public nights, etc). I am regularly seeing people post images now that they call 'near-live' that took 15-20 minutes or more to get. The public aren't going to stand there watching for more than about 2 minutes to see a nice object. Same on broadcasts. Some broadcasters now stack for 20+ minutes while viewers log out from boredom. I log out after about 5 minutes if there is no result. So, my main question is, how fast can this setup get a reasonable observation using 30 exposures? 1 frame? 2 stacked frames? 8 stacked frames?
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Post by davy on Apr 18, 2017 17:30:38 GMT
Looks great rob,, like the scope set up,,
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robrj
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Posts: 248
home town/country: Escondido, CA
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Post by robrj on Apr 18, 2017 18:18:49 GMT
Rob, the detail in your image is great, I was just wondering what it looked like without all that stacking, not shorter exposures. 30 seconds is OK I'd be interested in seeing what only 3 or 4 stacks of 30 seconds would be like. Even a stack of only 2 or 3 at 40 seconds. The nearer to 'near-live' the better. The habit lately seems to be lots and lots of stacking which slows down the observation for those watching (at outreach, public nights, etc). I am regularly seeing people post images now that they call 'near-live' that took 15-20 minutes or more to get. The public aren't going to stand there watching for more than about 2 minutes to see a nice object. Same on broadcasts. Some broadcasters now stack for 20+ minutes while viewers log out from boredom. I log out after about 5 minutes if there is no result. So, my main question is, how fast can this setup get a reasonable observation using 30 exposures? 1 frame? 2 stacked frames? 8 stacked frames? Oh, okay. I get what you're asking. I think about 3-4 where it starts looking good. One is pretty grainy and two is a big improvement. I would say after 5, improvement in the image is there but marginal. But I'll do multiple saves at different times in the stack next time out and post them here. When I'm by myself, I just tend to let it run and watch it build. But I get what you're saying about watching it on a broadcast. The only thing that could save a long exposure broadcast for me would be where the conversation was at least interesting to listen to. Don Rudny's broadcasts tend to be longer exposures but he's pretty good at keeping the conversation going, though some people tend to dominate. He also seems pretty good about moving off it once the object stops improving. When I do video astronomy at star parties, I'm usually not the only scope there so people don't typically hang around for long anyway. There are typically 20 or more scopes present. So I just let it run on an object of interest or will switch if they ask. If I were the only scope or one of very few, I would tend to do shorter stacks and keep it moving. I like to show objects that would be difficult even for the bigger scopes. My biggest challenge is my wife. She wants to see something different at star parties but I tend to keep it on the more spectacular images for people who have never seen it. I got lots of ooh's and ahh's from many with Omega Centauri through my cheap Celestron 130SLT. It's not a difficult object other than it's very low on the horizon (about 8 degrees at it's peak). But many of them have never seen it in a scope because of the San Diego light pollution.
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robrj
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home town/country: Escondido, CA
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Post by robrj on Apr 21, 2017 16:56:14 GMT
I did a run with M51 and saved off the exposures as it went along. Orion ED80T-CF on the AVX, Ultrastar-C, no filters 1x45s 2x45s 5x45s 10x45s
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robrj
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home town/country: Escondido, CA
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Post by robrj on Apr 21, 2017 17:03:33 GMT
M81 1x45s 2x45s 5x45s 5x45s X^0.25 mode (vs Linear). This mode lightens the faint areas and tamps down the bright core 10x45s
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robrj
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home town/country: Escondido, CA
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Post by robrj on Apr 21, 2017 17:16:00 GMT
M90 (not sure what happened to the 5 stack) 1x45s 2x45s 10x45s
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robrj
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home town/country: Escondido, CA
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Post by robrj on Apr 21, 2017 17:22:03 GMT
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Post by Dragon Man on Apr 21, 2017 18:05:59 GMT
Wow Rob, these are great samples, thank you. I am amazed at the minor difference in DSO's and stars between a single stack and a stack of 10 frames. What I notice the most is that the object doesn't really change very much and the stars remain about the same. I would have expected a major difference. What does change is the amount of noise. That is very noticable. It shows that stack of 2 would be almost presentable as a good clean view. That tells me that stacks of 3 would be great for public observing and broadcasting without having to go to a stack of 10. If you wanted to save tham as pretty pictures for Astrophotography, then you would go the full 10, or maybe about 7 or 8. But for general observing, your results show that just 2 or 3 stacks would be plenty. Here are 2 of your images to show that the detail in the Object and stars isn't really improved, only the background noise is cleaned up. They are animations jumping between single stack and a stack of 10 frames.
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Post by ChrisV on Apr 22, 2017 0:05:42 GMT
Thats what I see with stacking. It doesn't make it brighter, just cleans it up so you will start to pick out fainter stuff.
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Deleted
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Post by Deleted on Apr 22, 2017 8:43:11 GMT
The Touptek camera software in its various forms (I use this most often) has two kinds of stacking avaialable - Average (Integrative) and Additive.
"Average" performs as Ken and Chris have described - it cleans up the background nicely but doesn't make any real difference to the exposure.
"Additive" on the other hand, does just that, It adds whatever it "sees" - incuding noise etc. If you can set up a clean image, then use a 3-4 additive stack, you can effectively double your aperture.
I've been using this a lot lately. You will bring up some noise - but that doesn't bother me personally when you see the amount of extra detail.
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elpajare
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Post by elpajare on Apr 22, 2017 16:35:37 GMT
Im agree with you, Robert.
Im a user of this software in Mallincam's version( Mallincamsky) and this form of stacking additively is the only one i know between other softwares.
Infinity software, used by me with this camera, does only a mean type stacking. Like Rob explains here.
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Post by Dragon Man on Apr 22, 2017 17:58:41 GMT
Personally I have never liked using additive stacking. It might be OK for old cameras that could only do 2 second exposures The only way I use any form of additive stacking is 'HDR' stacking in Miloslick. But that's a totally different kettle of fish
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elpajare
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Post by elpajare on Apr 23, 2017 6:33:09 GMT
Yes, one thing is that Additive staking exists and other is if it really works.
In my case don't work. I never use it. ASI224 chip of my Skyraider is sufficiently sensitive not to need it.
Maybe this software is and old one and keep old mores...
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robrj
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home town/country: Escondido, CA
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Post by robrj on May 1, 2017 18:25:37 GMT
Starlight Live has a couple of options as well: Sum stacking (additive), Median Stacking, Mean Stacking (which is what I typically use), and Sum & Mean stacking (does a set number of sum stacks and then a mean stack).
I've toggled between Mean and Sum stacking if an image needs a little boost (usually just a frame or two of Sum stacking, then back to median stacking. It can be changed on the fly.
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Post by Deleted on May 4, 2017 2:42:29 GMT
"It can be changed on the fly."
Rob - that looks like a really useful feature.
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robrj
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home town/country: Escondido, CA
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Post by robrj on May 4, 2017 15:27:00 GMT
It is. I find Sum stacking by itself is too noisy, but switching back to mean stacking tamps down the noise again while keeping some detail. I've not done much with Median stacking. I should probably try it out to see how the results differs from Mean stacking.
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robrj
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home town/country: Escondido, CA
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Post by robrj on Jun 30, 2017 23:10:19 GMT
Here are some shots I did at my local dark site: M17 (10x15s) M20 (6x60s) M16 (5x60s) NGC 6334 (10x30s) Cat's Paw Nebula Barnard 72 (4x30s)
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