How much more data for M82? - Forums

Topic starter

Mar 2, 2023

It took me four years, but I finally got around to guiding. I took this image of M81+M82:

https://www.astrobin.com/a3tu2v/0/

I used a total of 94 x 2-min subs for 188 minutes (3.13 hr) total under a Bortle 6 sky and some moonlight.

I tried to process it to preserve the core details but get the fainter spiral arm extensions on M81 to show up.

My question is M82. I've seen plenty of photos that show red tendrils sprouting from the core extending perpendicular to the galaxy's plane. I just baaaarely got them in my shot.

But, again, 3.1 hours under a Bortle 6 sky.

Question -- if I tacked on data from, say, a Bortle 4 or 5, roughly how many hours would I need to get those red wisps from M82's core to show up nicely?

Clear Skies,
Phil

Well Written Engaging

Tim McCollum

Mar 2, 2023

You need some Ha data to add to your color data.
Mine is an HaLRGB image.
Tim

Jonny Bravo

Mar 2, 2023

Got some kind of Ha filter available? Those tendrils are Ha. Also, 3 hours is barely scratching the surface. Add another 10 hours of integration time to your image and see how it looks

Concise

Tim McCollum

Mar 2, 2023

His camera is color, maybe extract the red channel and add it back using the PI NBRGBXCombination script would give it more red.

Jonny Bravo

Mar 2, 2023

Tim McCollum:
His camera is color, maybe extract the red channel and add it back using the PI NBRGBXCombination script would give it more red.

Might... color masking might work, too. I figured since he had the 533MC and the Optolong UV/IR cut, he might also have one of the dual bandpass filters like the L-eXtreme. In any case, he's going to need more than the 3 hours of data he's got now to bring out the wispy tendrils of Ha.

Nick Grundy

Mar 3, 2023

Phil Creed:
I tried to process it to preserve the core details but get the fainter spiral arm extensions on M81 to show up.

are they present at all in your stacked frames? (if you play with the stretch to they show up if you forget the main portion of the galaxy)

I think the question you are asking is "How much more aquisition should I do and what to expect"?

I really dont have this figured out either, but I can say that collecting a ton more frames allows me to be more selective in the integration and that's led to much sharper stacked frames. (rather than taking 90% of them I can take 50 or 60)

Dale Penkala

Mar 3, 2023 · Edited: Mar 3, 2023

I’m currently imaging this one myself. I’m using my 071mc pro. I got 4.5hrs of data with my L-pro and 3min subs and it looks very nice but, like you I wanted to pull in more of the core tendrils of the Ha. I shot another 4hrs with my Antlia ALP-T using 10min subs and was easily pulling the data in 1 sub. Mind you I’m using a 12” f5 DBA Certified Newt. My plan is to get at least another 4-8 hours of NB data. Your only shooting with a 4” scope and a UV/IR Cut filter so like others here suggested defiantly more time is needed and especially if you have a dual narrow band filter like the ALP-T or even the NBZ will pull in the Ha. Once you do that you can extract it and add it back to your image in PI or whatever software you use.

Good luck and let us know what you endup doing.

Dale

Helpful Supportive

Phil Creed

Topic starter

Mar 3, 2023

Dale Penkala:
I’m currently imaging this one myself. I’m using my 071mc pro. I got 4.5hrs of data with my L-pro and 3min subs and it looks very nice but, like you I wanted to pull in more of the core tendrils of the Ha. I shot another 4hrs with my Antlia ALP-T using 10min subs and was easily pulling the data in 1 sub. Mind you I’m using a 12” f5 DBA Certified Newt. My plan is to get at least another 4-8 hours of NB data. Your only shooting with a 4” scope and a UV/IR Cut filter so like others here suggested defiantly more time is needed and especially if you have a dual narrow band filter like the ALP-T or even the NBZ will pull in the Ha. Once you do that you can extract it and add it back to your image in PI or whatever software you use.

Good luck and let us know what you endup doing.

Dale

Dale,

If I use, say, an L-Enhance (which I have) or an NBZ and image for several hours, will the color balance be all out of whack on M81? I'm a bit leery about blending NB and true colors; is it a case where the colors are merely muted or go cray-cray?

Clear Skies,
Phil

Dale Penkala

Mar 3, 2023 · Edited: Mar 3, 2023

Phil Creed:
Dale Penkala:
I’m currently imaging this one myself. I’m using my 071mc pro. I got 4.5hrs of data with my L-pro and 3min subs and it looks very nice but, like you I wanted to pull in more of the core tendrils of the Ha. I shot another 4hrs with my Antlia ALP-T using 10min subs and was easily pulling the data in 1 sub. Mind you I’m using a 12” f5 DBA Certified Newt. My plan is to get at least another 4-8 hours of NB data. Your only shooting with a 4” scope and a UV/IR Cut filter so like others here suggested defiantly more time is needed and especially if you have a dual narrow band filter like the ALP-T or even the NBZ will pull in the Ha. Once you do that you can extract it and add it back to your image in PI or whatever software you use.

Good luck and let us know what you endup doing.

Dale

Dale,

If I use, say, an L-Enhance (which I have) or an NBZ and image for several hours, will the color balance be all out of whack on M81? I'm a bit leery about blending NB and true colors; is it a case where the colors are merely muted or go cray-cray?

Clear Skies,
Phil

Hi Phil,
Your L-Enhance will defiantly give you more Ha and yes your colors will probably change a bit but from what I have seen in my images it’s not anything that is horrible. Something that you can fairly easily adjust with software, however you’re going to want to be careful when doing so. Small slow adjustments.
In my case I’m going to play with processing the galaxy 2 ways. I’ll use my RGB data (L-Pro filter) as my start image and then process my NB data, extract the Ha and add it back to the RGB and see how things look. Then I’ll probably do the reverse but extract luminance from the RGB data (as well as the stars for color) and add it back to the Ha data and work from there. In either case I’ll always use the stars from the RGB data because it gives the most accurate star color once its SPCC.

BTW, there are several excellent M82 images here on AB and they have inspired me to attempt to do the same as you are so I’m learning as well but based on what I know (not much 😆) this is my plan of attack 😊

Hope this helps!

Dale

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dkamen

Mar 3, 2023

Hi,

Try integrating all guided and unguided subs. This will give you six hours and probably some more of the red stuff.

Only make sure you choose a sub from whichever imaging train has the lowest resolution as reference (since upscaling will decrease SNR).

Cheers,
D.

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