First timer, focusing (?) problem

Discussions of Electronically Assisted Astronomy using the Live Stacking feature.
psy1280
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Re: First timer, focusing (?) problem

#41

Post by psy1280 »

Thank you Dave, I appreciate your feedback. I can't wait to apply your suggestions.

Yours,
Joe
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oopfan
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Re: First timer, focusing (?) problem

#42

Post by oopfan »

Hi Joe,

I'm not familiar with your camera but I think that 64 FLD is equivalent to a 1.2 second exposure. In my book that is way too short. No wonder you just picked up the galactic core and surrounding stars. If you can increase that to 5 or 10 seconds it would be an improvement.

I think that you and I had the same clear night. I also imaged M81 but I'm in my 3rd year at this, and learned at the school of hard knocks. My scope is a refractor with a 71mm objective at f/5.9. I was taking 90-second exposures. The galactic core came in at 4000 ADU which is way below saturation. I captured a total of 100 frames using a Luminance filter, and processed the stack in Astro Pixel Processor (APP). That's 2.5 hours of integration time! I've attached the final image. It's rough because I have more to go. My goal is 7.5 hours in luminance, and then I'll start capturing RGB.

Keep up the good work, Joe.

Brian
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M81_L_100x90s.jpg
M81_L_100x90s.jpg (978.09 KiB) Viewed 2162 times
psy1280
Posts: 208
Joined: Wed Oct 24, 2018 4:52 pm

Re: First timer, focusing (?) problem

#43

Post by psy1280 »

Brian,
That's an amazing image. I can only hope to reach that level of proficiency one day. I didn't know about a luminance filter, do you recommend purchasing one?

Perhaps you can answer this. I was recently told that there's no need for post-processing stacking since Live Stack does that for you. Is this not correct?
My understanding is that Live Stack does the stacking and produces a PNG file of the stack. If this is true, what are you stacking (since the PNG is one image...I guess you're stacking the raw images?)

Thanks for the suggestion to try for longer exposures, it makes sense.

Yours,
Joe
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oopfan
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Re: First timer, focusing (?) problem

#44

Post by oopfan »

Joe,

I would imagine that your camera already has a built-in "IR Cut" filter so you are good. No need to buy another filter.

Regarding stacking, Robin is the one best to answer that question. I don't know if LiveStack is capable of spanning multiple sessions.

You can make very nice images in just one night. I did that for two years. I don't think my stacks ever went over two hours but I've learned that to get the really outstanding images, the ones you see on Astrobin that win awards, you really need to stack, and stack, and stack over multiple nights. These days people are putting in 20+ hours into an image. One step at a time.

Brian
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turfpit
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Re: First timer, focusing (?) problem

#45

Post by turfpit »

Joe

If you look in the Gallery forum viewforum.php?f=16 there are posts by forum user @BlackWikkett. These are all good examples of Live Stacks captured with a conventional CMOS camera and some post processing.

Dave
psy1280
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Re: First timer, focusing (?) problem

#46

Post by psy1280 »

Thank you Dave,

The photos are encouraging....I shall become a more dedicated student of this craft.

Joe
psy1280
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Re: First timer, focusing (?) problem

#47

Post by psy1280 »

Brian,
I'm a bit confused with your suggestion, "... I think that 64 FLD is equivalent to a 1.2 second exposure. In my book that is way too short. No wonder you just picked up the galactic core and surrounding stars. If you can increase that to 5 or 10 seconds it would be an improvement."

From my regular photography days, I know that opening up the shutter or increasing time will blow out an image more. It seems to my untrained mind that in order to decrease a blown out image (such as my Bodes Nebula) I need shorter, not longer exposures (i.e., less than 1.2 seconds), but many more. Would you mind clarifying this seeming paradox for me?

Thank you for taking the time to clear this up...it does seem like this is where I'm stuck

Yours,
Joe
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oopfan
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Re: First timer, focusing (?) problem

#48

Post by oopfan »

Joe,

From all the photos I've seen just now at the Revolution website it appears to have a limited dynamic range. So your choice is (a) decrease the exposure to get a nice image of the galactic core (minus the arms), or (b) increase the exposure to record more of the arms (while blowing out the core). There is another option and that is to keep the exposure the same but stack A LOT more. According to my math your stack is only 12 minutes long (1.2 seconds * 598 frames). 12 minutes is hardly enough time. If you were imaging the Dumbbell Nebula or Orion then I would say OK. M81 is much fainter.

Brian
psy1280
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Re: First timer, focusing (?) problem

#49

Post by psy1280 »

GREAT SUGGESTIONS BRIAN!!!! I can't wait to give this a "longer" exposure.

Thank you,
Joe
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turfpit
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Re: First timer, focusing (?) problem

#50

Post by turfpit »

Joe

This might have something to do with the camera doing some internal stacking see https://www.revolutionimager.com/pages/deep-sky-objects. I think Stacking/3D-DNR is the setting to look at.

I had a similar experience with a DSO-1 CCTV camera. INTMUL in this case could control the internal stacking. There are 2 tabs in the spreadsheet. The MENU tab lists all the menu items and all available settings. The NOTES tab are suggestions for reasonable settings for different objects.

camera_menu_DSO-1_2015.ods
(428.11 KiB) Downloaded 86 times

Suggestion: get out on the internet and search for images produced with this camera.


Dave
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