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M51 (again!) 6 hours 23 mins

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#1 kevinbreen

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Posted 17 April 2021 - 07:27 AM

Well I got autoguiding to work - it has to be the easiest thing ever and I use my 224MC as the guide camera which is heartwarming as that poor little camera has been perched atop my C11, unemployed and neglected for what seems like an age. I've actually had the guidescope for a year but it took an inordinate amount of time to find the right adaptor to mount it to the ES ED80. But onwards and upwards. I got very well polar aligned several nights ago and the mount is left out now permanently in that position. The first night this week I pushed exposure times to 5 minutes, then 7 and finally 10 minutes, with no star trailing at all. I suspect I may be able to go higher, but even if not, the benefits of the longer exposures here are very evident. StarTools has been an enormous boost to my processing abilities and I highly recommend it. 

Darks, flats and bias frames used. Can you identify the two distant galaxies at the 2 o'clock position, or a means of doing so?

EDIT: NGC 5169 and NGC 5173 respectively waytogo.gif

Thanks for looking.

 

M51 383mins StarTools.jpg


Edited by kevinbreen, 17 April 2021 - 07:36 AM.

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#2 Dynan

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Posted 17 April 2021 - 07:36 AM

Run it through www.astrometry.net

 

Could have been done for you, but it's a good thing to learn. Very helpful for plate solving, image scale, rotation angle, and many more things. Invaluable...

 

+1 for Star Tools!


Edited by Dynan, 17 April 2021 - 07:37 AM.

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#3 kevinbreen

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Posted 18 April 2021 - 03:48 PM

This must be the best pic ever taken of M51, ever, because nobody criticized it.

Wow! If I'd known that I wouldn't have bothered posting it here at all. 

Thank you all!

 

waytogo.gif waytogo.gif



#4 Dynan

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Posted 18 April 2021 - 04:35 PM

OK. You have:

 

~ Chromatic aberration

~ A crosshatch pattern in the middle of your image, most likely from the Bayer matrix

~ Background so dark as to almost be clipped

~ Focus looks a little soft on the galaxy itself, but maybe large image scale

~ Slight eccentricity in your stars

 

But all in all, a nice image. But don't get full of yourself lol.gif


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#5 kevinbreen

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Posted 18 April 2021 - 04:55 PM

OK. You have:

~ Chromatic aberration
~ A crosshatch pattern in the middle of your image, most likely from the Bayer matrix
~ Background so dark as to almost be clipped
~ Focus looks a little soft on the galaxy itself, but maybe large image scale
~ Slight eccentricity in your stars

But all in all, a nice image. But don't get full of yourself lol.gif


Thanks. Best response ever!

#6 kevinbreen

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Posted 18 April 2021 - 06:26 PM

OK. You have:

~ Chromatic aberration
~ A crosshatch pattern in the middle of your image, most likely from the Bayer matrix
~ Background so dark as to almost be clipped
~ Focus looks a little soft on the galaxy itself, but maybe large image scale
~ Slight eccentricity in your stars

But all in all, a nice image. But don't get full of yourself lol.gif


Thanks for the feedback.

Do you think my longer exposures were too long (10 mins)?

I used darks, flats and bias from a month ago with subs from this latest session. Bad idea?

Chromatic aberration. I thought the field flattener I have would have prevented that. Bummer.

The matrix. It was there when I did the first autodev in StarTools. That was a shock. I ran through the DSS checklist for ST by the letter prior btw and followed it to the letter. I guess I got overwhelmed with ST and what it can do with mediocre data.

I still have a lot to learn, clearly.

Thanks

#7 Dynan

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Posted 18 April 2021 - 07:02 PM

If you can guide that well for ten minutes, that's great! The best way to tell is to (no plug, just fact) get SharpCap Pro for about ≈$15/yr. It will analyze your sensor and sky, and recommend best gain and exposure settings for a given image session (hours integrated). You can adjust from there. You also get a great PA tool with Pro. 

 

Darks and biases can be used for a year, or more, depending on the sensor and its treatment.

 

Flats need to be taken every session, unless you can verify the dust motes haven't moved, changed size, or replicated. Best to take them, since they only take minutes.

 

I don't know what program you calibrate and integrate with, but the matrix should calibrate out with the proper cal frames.

 

(+1 for Star Tools) Keep practicing with ST and you'll get better. Ivo Jager (creator) is very responsive to users' questions, if you have doubts about your method.


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#8 vidrazor

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Posted 19 April 2021 - 09:53 PM

You cores are blown, can you recover them with ST? How 'bout CA? Did ST deduct the Bayer pattern? Can you choose a different Bayer process? Colors seem mostly yellow overall, can you adjust color balance in ST? Personally I like the black skies, I hate seeing dull, flat, gray skies, they look like crap to me. This file has good contrast. Personal tastes, of course.

 

Out of curiosity, I ran the image here first through Topaz DeNoise, then Topaz JPEG-to-RAW, between the 2 seems to have neutralized the Bayer pattern (which is actually all over the image}, and "refocused" the image, then brought it into Camera Raw and ran the CA fix, and finally made a star alpha and saturated them a bit. This is what I wound up with. smile.gif

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  • star tools-DeNoiseAI-low-light-edit.jpg

Edited by vidrazor, 19 April 2021 - 09:56 PM.

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