Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

M51 HA-LRGB- last Galaxy image of the season

  • Please log in to reply
6 replies to this topic

#1 pyrasanth

pyrasanth

    Surveyor 1

  • *****
  • topic starter
  • Posts: 1542
  • Joined: 08 Jan 2016

Posted 17 May 2019 - 08:04 PM

It was suggested by John Hayes that I should add some HA data to the M51 image that I recently posted. John also noted that the colour was slightly out so I did my best to work on this. As always John's advice has been really valuable and indeed the rest of the forum

 

I have added 6 hours of HA to the image and have reprocessed. I also used the TVGnoise processing which using well constructed low contrast masks has done a really good job at removing high frequency noise. Thanks to Mike for suggesting this works very well.

 

The HA was combined into the red channel using Pixelmath at a density of 0.7 and was taken with the Baader 3.5nm enforced filter under a fairly bright moon but it came out very clean.

 

The image consists of over 200 images and as always was taken with the C14 at F7.7 with Baader LRGD filters and the G3 16200 at 2x2 bin.

 

Let me know what you think of the improved image. This will be my last Galaxy image until July/August of this year.

 

I've not flipped the image- I forgot to do this!

 

Clear skies to you all. Best wishes- Mark.

 

RGB4.jpg


Edited by pyrasanth, 17 May 2019 - 08:05 PM.

  • PeteM, elmiko, lbim and 2 others like this

#2 NuclearRoy

NuclearRoy

    Sputnik

  • -----
  • Posts: 30
  • Joined: 11 Apr 2019
  • Loc: Pittsburgh, PA

Posted 17 May 2019 - 09:37 PM

Excellent!

#3 jhayes_tucson

jhayes_tucson

    Fly Me to the Moon

  • *****
  • Posts: 6782
  • Joined: 26 Aug 2012
  • Loc: Bend, OR

Posted 18 May 2019 - 10:05 AM

Mark,

Ah...that's definitely looking better!  Your color balance is looking much improved, but if you don't mind, I still have another suggestion.  You levels are too low.  At the low end, you are losing the dim wispy glow near NGC 5195, which suggests that your black level might be too low.  At the high end, it's a bit too dark.  The challenge here is to avoid driving the contrast too high and you might already be there.  You've got some really nice looking data there so I think that you have an opportunity to take this image to the next level.  

 

As I suggested in another M51 thread, it often helps to look around at what other folks have done with the same object--but it's important to reference well processed images.  Adam Block is almost always a good reference and he has a nice library of images that cover most of the popular objects.  You can find Adam's M51 here:  https://www.adambloc...m/galaxies.html.  Remember that the goal is NOT to reproduce what someone else did.  The goal is learn how to improve your own processing and looking at what others have done helps to reveal things that you might have missed.  There are so many subtle issues that can affect the results that I often find it useful to cross check my images against what others have produced to make sure that I haven't missed anything--and even then nothing is foolproof.

 

Good luck with it and keep up the good work!

 

John


  • pyrasanth likes this

#4 pyrasanth

pyrasanth

    Surveyor 1

  • *****
  • topic starter
  • Posts: 1542
  • Joined: 08 Jan 2016

Posted 18 May 2019 - 10:23 AM

Hi John,

 

I note your observation the levels. I will revisit & carry on working on the image. The challenge I see is also not leaving a dirty background but I guess under a light polluted sky that might be looking too much for perfection!

 

I had a look at M51 produced by Adam & I can immediately see the difference in levels so that's a great pointer. Thanks for all your help & advice. It is appreciated.



#5 pyrasanth

pyrasanth

    Surveyor 1

  • *****
  • topic starter
  • Posts: 1542
  • Joined: 08 Jan 2016

Posted 18 May 2019 - 02:08 PM

Here is a rework.

 

M51_web.jpg


  • elmiko likes this

#6 pyrasanth

pyrasanth

    Surveyor 1

  • *****
  • topic starter
  • Posts: 1542
  • Joined: 08 Jan 2016

Posted 18 May 2019 - 02:14 PM

Here is another version:

 

M51_web2.jpg


  • elmiko likes this

#7 elmiko

elmiko

    Vanguard

  • -----
  • Posts: 2272
  • Joined: 27 Jul 2009
  • Loc: Arizona

Posted 19 May 2019 - 06:31 PM

Definitely the last one is the best! Funny how we can keep finding improvement in our images. Just when you think it can't be any better.....

Great job Pyrasanth.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics