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M106 in LRGB - C&C Welcome

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#1 BenKolt

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Posted 15 February 2019 - 10:30 PM

Greetings!

 

I had a rare stretch of nights recently to image around the New Moon.  I'm not satisfied with my processing on this data set, but given the rarity of imaging opportunities this season, I wanted to post something of my own and not just lazily comment on the work of others.

 

This is an LRGB image of M106 in Canes Venatici. Referring to Jeff Kanipe and Dennis Webb, Annals of the Deep Sky, vol. 3, M106 is classified as a "barred LINER spiral with a Seyfert 2 nucleus." It has magnitude 8.4, size 18.6' x 7.2'. It has a prominent nucleus with double S-shaped spiral arms extending N and S from the center. Surrounding this is a fainter region showing wispy star-forming knots that can be seen in my image.

 

One of the prominent features of this galaxy that has been deduced is a super massive black hole. The central object has "a mass of 36 million suns packed within a volume less than 0.8 of a light year ... in diameter." This is a region of size 51,000 AU's.

 

Its distance is measured to be 7.2 Mpc or 23.5 Mly.

 

To the upper right is companion galaxy NGC 4248, visual magnitude 12.5. Although a bit small in my image, one can see its irregular elongated shape with bright central ridge.

 

My C11 Edge system on the AP Mach1 mount continues to exhibit a prominent underdamped vibration, which can be seen in the stars as vertical elongation. I hope to have this and some other issues resolved soon. As a consequence of these issues, I needed to darken the background more than I would have wished, and I also felt compelled to take additional processing steps in deconvolution and sharpening that I would prefer to forgo in the future once the issues have been resolved. I also pushed the noise reduction, particularly in the color channels, a bit more than I had intended. If I return to process the data again I will dial these steps back a bit.

 

As always, your Comments and Suggestions are welcome!

 

Thanks for your attention.

 

Best Regards,

Ben

 

High Resolution AstroBin Links:

M106_LRGB_085_0180s_20190205_-30C.v005A_LRGB-1.jpg

 

 

 

 


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#2 dhaval

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Posted 15 February 2019 - 10:41 PM

I think you have good data, but it does not look like you've calibrated it well - is this data calibrated? 

 

CS!



#3 elmiko

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Posted 15 February 2019 - 11:11 PM

Great details in the Galaxy . Keep up the great work Mike


Edited by elmiko, 15 February 2019 - 11:13 PM.


#4 BenKolt

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Posted 16 February 2019 - 12:10 AM

Great details in the Galaxy . Keep up the great work Mike

Thank you, elmiko!

 

 

I think you have good data, but it does not look like you've calibrated it well - is this data calibrated? 

 

CS!

And thank you, Dhaval.  (By the way, what does "CS" mean?  "Calibrate Soon?")

 

Yes, I assure you that I do calibrate.  I did not go into detail about some of the other issues I'm dealing with, but one results in inability to calibrate well.  I will be having this looked into soon and hopefully resolved once and for all!

 

I've looked at this post on a couple of different monitors and notice that one of them shows the residual background artifacts more clearly from the calibration problem.  Hopefully we can all overlook this for now.

 

Best Regards,

Ben



#5 bobzeq25

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Posted 16 February 2019 - 12:14 AM

Fundamentally an excellent image.  But I don't see a lack of calibration as much as I see some gradients.  Did you do gradient reduction?  If so, I think that step could use some refinement.  I often make two passes at it.  Sometimes use DBE for one, ABE for a second.

 

That's not intended as a criticism, just a response to your request for suggestions.


Edited by bobzeq25, 16 February 2019 - 12:17 AM.


#6 BenKolt

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Posted 16 February 2019 - 12:32 AM

Fundamentally an excellent image.  But I don't see a lack of calibration as much as I see some gradients.  Did you do gradient reduction?  If so, I think that step could use some refinement.  I often make two passes at it.  Sometimes use DBE for one, ABE for a second.

 

That's not intended as a criticism, just a response to your request for suggestions.

Thanks, Bob.  No offense taken.  It's a good suggestion.

 

That's actually not gradient you're seeing but the effects of the calibration problem I just mentioned.  I could have used DBE aggressively to smooth out the background, but I wasn't seeing the residual artifacts as clearly as some of you may be on your respective monitors.  Now that I see it on the laptop I'm now using to write this, I may go back and try again.  Hopefully this issue I'm having will be resolved soon.  If it gets fixed and my suspected cause for my problems turns out to be correct, I may post more about it, but at this point it's just educated speculation, so I'd rather just keep it to myself.

 

Ben


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#7 dhaval

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Posted 16 February 2019 - 12:59 AM

Thank you, elmiko!

 

 

And thank you, Dhaval.  (By the way, what does "CS" mean?  "Calibrate Soon?")

 

Yes, I assure you that I do calibrate.  I did not go into detail about some of the other issues I'm dealing with, but one results in inability to calibrate well.  I will be having this looked into soon and hopefully resolved once and for all!

 

I've looked at this post on a couple of different monitors and notice that one of them shows the residual background artifacts more clearly from the calibration problem.  Hopefully we can all overlook this for now.

 

Best Regards,

Ben

Ben - CS means clear skies! I think we all need those more than anything else! 

 

Again, like I said, I think your data is solid. I looked at the integrated luminance image and it looks quite good. If the background is stemming from RGB then I suggest de-layering RGB and just getting color from the RGB image. That will ensure you don't see the nasty RGB background. 

 

CS!



#8 NorthField

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Posted 16 February 2019 - 01:02 AM

Cold Showers!!!!

#9 Jeff2011

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Posted 16 February 2019 - 01:30 AM

Nice work Ben.  Hope you get your calibration issue resolved.  I suspect from your location you are dealing with heavy light pollution. 



#10 Tapio

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Posted 16 February 2019 - 02:21 AM

Just looking with tablet and looking good.
Only with brightness I see some color gradients.

#11 rlsarma

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Posted 16 February 2019 - 04:26 AM

Fabulous work (imaging+processing). The dust lanes, the faint nebulae and the core are so distinctly crisp.waytogo.gif bow.gif



#12 BenKolt

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Posted 16 February 2019 - 09:49 AM

Nice work Ben.  Hope you get your calibration issue resolved.  I suspect from your location you are dealing with heavy light pollution. 

Thanks, Jeff.  LP is certainly not helping matters on top of the other issues.

 

Just looking with tablet and looking good.
Only with brightness I see some color gradients.

Thanks, Tapio.  In the future I'll use my laptop as the final "screening" process to check on whether or not my images are ready to go public.  It shows resulting background nonuniformities much better thank my desktop monitors.

 

Fabulous work (imaging+processing). The dust lanes, the faint nebulae and the core are so distinctly crisp.waytogo.gif bow.gif

Thank you so much!

 

Ben - CS means clear skies! I think we all need those more than anything else! 

 

Again, like I said, I think your data is solid. I looked at the integrated luminance image and it looks quite good. If the background is stemming from RGB then I suggest de-layering RGB and just getting color from the RGB image. That will ensure you don't see the nasty RGB background. 

 

CS!

Clear Skies to you as well!  (Boy do I feel particularly obtuse on that one ...)  I've started reprocessing this morning and have added a DBE step.  I can already see the luminance channel is much better, and I suspect the RGB channels will be as well.  Stand by.

 

Ben

 

(And now that I know it isn't shorthand for something profane, CS to everybody!)


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#13 gunny01

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Posted 16 February 2019 - 11:55 AM

Hi Ben,

 

  Just curious as to whether you tried ABE as compared to DBE, and with star mask Hdrmt?



#14 pyrasanth

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Posted 16 February 2019 - 01:13 PM

That's a great image. I'm sorry to read about the issues you face but at least you can carry on imaging. I'm out of luck at present until the controller board gets shipped on my Paramount to replace the one that blew up.

 

I really like the detail you have captured in the core- it's so good to see a core so well resolved. My seeing usually gives me a "mushy" core.

 

I'm using the no imaging time to build a dark calibration library for the new 16200 camera. I now have 5,10,20 & 30 minute dark sets of both 1x1 & 2x2 bin and I've just started the 1 hour dark subs to complete my set for future narrow band imaging sessions.

 

So well done & keep the fabulous images coming.

 

Clear skies to you all.


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#15 BenKolt

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Posted 16 February 2019 - 05:42 PM

Hi Ben,

 

  Just curious as to whether you tried ABE as compared to DBE, and with star mask Hdrmt?

 

Hi, Gunny:  On my first attempt I only used ABE as I thought it was going to be sufficient, however I just completed a second attempt and added the DBE process, which I think has come out with a better result.  I'll post the second image in a few minutes.

 

That's a great image. I'm sorry to read about the issues you face but at least you can carry on imaging. I'm out of luck at present until the controller board gets shipped on my Paramount to replace the one that blew up.

 

I really like the detail you have captured in the core- it's so good to see a core so well resolved. My seeing usually gives me a "mushy" core.

 

I'm using the no imaging time to build a dark calibration library for the new 16200 camera. I now have 5,10,20 & 30 minute dark sets of both 1x1 & 2x2 bin and I've just started the 1 hour dark subs to complete my set for future narrow band imaging sessions.

 

So well done & keep the fabulous images coming.

 

Clear skies to you all.

Thanks, pyrasanth!  I hope you can get to use your new 16200 soon.

 

Ben



#16 BenKolt

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Posted 16 February 2019 - 05:57 PM

Greetings!

 

Here is the result of a fresh processing of the LRGB channels.  This time I used and abused DynamicBackgroundExtraction (DBE) in PixInsight on the stacked, linear data.  It looks to me that the residual artifacts resulting from my calibration issues have been better flattened out and reduced.  I'm curious what you think about this.

 

This time around, however, I detect more remaining chromatic noise than in the first go around.  Maybe at some future date I'll go at this again and see if I can reduce more of the noise, but, frankly, I've had enough of it for now.

 

Thank you all again for the very helpful critique and suggestions.  This is exactly the level of detailed feedback I wish to get when posting my images for the purposes of improving technique.  And it's the kind of feedback I try to give others when asked.  So, thank you again!

 

Hopefully soon I'll get past the vibration and calibration issues and be able to dial up the quality of imaging and processing some more.

 

Best Regards,

Ben

 

High Resolution Link:

M106_LRGB_085_0180s_20190205_-30C.v006C_LRGB-1.jpg

 

 

 


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#17 elmiko

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Posted 16 February 2019 - 06:04 PM

That looks 100% better to me Ben. Good job



#18 elmiko

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Posted 16 February 2019 - 06:08 PM

Ben, what settings did you use in DBE? Samples per row and size? Did you use the samples that it generated, or did you change them? Just courious, because it did a great job.

Mike



#19 BenKolt

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Posted 16 February 2019 - 07:46 PM

Ben, what settings did you use in DBE? Samples per row and size? Did you use the samples that it generated, or did you change them? Just courious, because it did a great job.

Mike

Thanks, elmiko.

 

I say that I "abused" DBE in the sense that I used it precisely the way that one really shouldn't, which is to auto generate lots of points and then remove or replace them where needed.  Underlying my background is a widespread patchwork pattern of broad lines and columns that results from the calibration failing to work well because of some camera problems I believe that I am having.  Unfortunately, the scale of the residual artifacts is too broad to be tackled through dithering, except maybe under severely amplified dithering beyond what I'm comfortable doing.  I sure hope I can get the camera issue resolved so that I don't have to deal with this calibration failure anymore.

 

I really hesitate to post my DBE settings because one really shouldn't have to use it the way I did under normal circumstances.  In fact, if calibration were working properly for me, I would prefer to have just used ABE to generate a broad, low order gradient fit to subtract off simple sky gradient.  If you find yourself in a situation where you really have to use DBE, I suggest you spend some time exploring the many options and see what they do for you and then place as few samples as required.  But as I said, it's my personal goal to get my calibration working well enough to curtail or maybe even terminate my use of DBE.

 

Best Regards,

Ben


Edited by BenKolt, 16 February 2019 - 09:20 PM.


#20 TimN

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Posted 16 February 2019 - 07:53 PM

You've got some excellent detail there, Ben. I can't see any calibration issues but I'm on a tablet. What I can see looks really good!



#21 BenKolt

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Posted 16 February 2019 - 10:40 PM

You've got some excellent detail there, Ben. I can't see any calibration issues but I'm on a tablet. What I can see looks really good!

Thank you, Tim.  I think I've hidden my problems better now.

 

Ben




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