M13 LgRGB

[Rodd]

I had forgotten my infatuation with globular clusters--then I realiz3d M13 was in prime imaging territory.  Condirons were good for the green channel--infact I decide to use the green channel as a luminance due to its lower FWHM  values.  I deconvolved the red and blue.  This is only version 1, so plenty of time for improvement. 

TOA 130 with ASI 1600 and Astrodon series E True Balance filters

Red: 25 300 sec

Green: 43 300 sec

Blue" 32 300 sec.

 

 

 

Edited June 25, 2019 by Rodd

[Rodd]

And here is the original-not downsampled.  I thought maybe it was too much--but now I am not so sure.  Anyway--opinions welcome.   Big or less big

Rodd

[alan potts]

As normal that makes my effort look very second rate, an excellent shot though I am not over keen on the way the bright stars have come out, but maybe this is scope related. Can I ask you to take a decent shot of M4, I tried it a few days ago and posted it but it is far from as good as I would like. Not sure of your location I could well be in a better place for this cluster. Great cluster shot though.

Alan

[Zakalwe]

3 hours ago, alan potts said:

 on the way the bright stars have come out, but maybe this is scope related

 

Its the micro-lenses causing refraction. Its a known "feature" of this sensor.

 

Lovely shot overall though

[Rodd]

6 hours ago, alan potts said:

As normal that makes my effort look very second rate, an excellent shot though I am not over keen on the way the bright stars have come out, but maybe this is scope related. Can I ask you to take a decent shot of M4, I tried it a few days ago and posted it but it is far from as good as I would like. Not sure of your location I could well be in a better place for this cluster. Great cluster shot though.

Alan

Thanks Alan.  Alas--the problem with the stars, as someone pointed out, are camera related.  And yes, I do not like them either.  Hopefully M13 draws the eye away from them (that's the goal anyway!).  Regarding M4--it is in a bad part of my sky, low to the south usually awash in New Haven's light dome.  On most nights I can't even see the scorpions tail.  It is a goal though, so maybe if I get a few decent nights over the course of the next month or so I will give it a shot--it is the right time of year!  On a good night...what a difference!

Rodd

[Rodd]

2 hours ago, Zakalwe said:

Its the micro-lenses causing refraction. Its a known "feature" of this sensor.

 

Lovely shot overall though

Thanks Zakalwe.

Rodd

[Rodd]

I just noticed that the slightly reduced first image is actually sharper than the second--so I agree with those who feel its better (based on likes).  Not sure I understand it.  When an image is reduced resolution is diminished--seems that the opposite is true in this case.  Hmmm. "Oh where oh where is Vlad-a-mir, oh where oh where did you go?"  An old nursery school tune---forget everything but the tune.

Rodd

 

[alan potts]

1 hour ago, Rodd said:

Thanks Alan.  Alas--the problem with the stars, as someone pointed out, are camera related.  And yes, I do not like them either.  Hopefully M13 draws the eye away from them (that's the goal anyway!).  Regarding M4--it is in a bad part of my sky, low to the south usually awash in New Haven's light dome.  On most nights I can't even see the scorpions tail.  It is a goal though, so maybe if I get a few decent nights over the course of the next month or so I will give it a shot--it is the right time of year!  On a good night...what a difference!

Rodd

It gets about 21 degree high here and I am sure I can do somewhat better as the night I tried it was poor seeing. We have had so much rain and high heat the horizons were very hazy. I am stuck with about 90 mins where I can get a camera onto it at all due to trees in my garden, time to get the chainsaw out.

As for M13. really don't think I have ever seen it better and a target for me to achieve when I get a ASI071.

Alan

[Rodd]

5 minutes ago, alan potts said:

As for M13. really don't think I have ever seen it better and a target for me to achieve when I get a ASI071.

Thanks Alan--I was pleasantly surprised that the cor was not blown.  I bet Lum would blow the core.  I figured its basically stars and no one adds LRGB stars to NB images--but they do at RGB stars.  that was my thinking anyway.

As far as M4--I am in the same predicament as you--which is also true for M8, M16, M17, and M20 for me.  NB is easier and more forgiving.  You really need as good conditions as possible for BB.    But if you collect a lot of data, you will have a larger data set to pick the best subs from.   It will be challenging, but worth it!

Rodd

[alan potts]

18 minutes ago, Rodd said:

Thanks Alan--I was pleasantly surprised that the cor was not blown.  I bet Lum would blow the core.  I figured its basically stars and no one adds LRGB stars to NB images--but they do at RGB stars.  that was my thinking anyway.

As far as M4--I am in the same predicament as you--which is also true for M8, M16, M17, and M20 for me.  NB is easier and more forgiving.  You really need as good conditions as possible for BB.    But if you collect a lot of data, you will have a larger data set to pick the best subs from.   It will be challenging, but worth it!

Rodd

As we are getting our 4 storm of the day I am not going to hold my breath on adding to it any time soon, June has been worse than May, that was bad enough. I have had 20 plus clear nights in both these months on more than one occasion. The core of the M13 is superb, yes you have excellent gear but you also know how to use it, I'm still learning, slowly.

Alan

[Rodd]

15 minutes ago, alan potts said:

I'm still learning, slowly.

As are we all!  That's the fun part of the journey (something I have to remind myself of quite frequently).    I appreciate your comments.  The weather patterns will improve (they Must!!). 

Rodd

[gorann]

Great image Rood as allways! Just a minor pity with the ASI1600 handling of bright stars. Had a go at your microlensed stars in PS. Quick and dirty mainly using curves and layers:

Edited June 25, 2019 by gorann

[Rodd]

1 hour ago, gorann said:

Quick and dirty mainly using curves and layers:

It does look better--but you can see that its manipulated.  I know the bright stars are unfortunate--but I have learned to ignore them for the most part.  Once I get the image where I want it--I probably will attack them as you did--it will be a complicated experimental approach though, and down and dirty will definitely not fly, so I am putting it off until the end. But I appreciate the input.  

Rodd

[Rodd]

Here are a couple of re tries.  2 distinct approaches.  Which is better--the first, with obviously larger stars--or the second, which like the original has tiny stars.  I guess I am questioning the naturalness of the tiny stars.  Also both of these versions are more colorful than the original.  I actually added a small amount of noise in the second image to help the background look more natural--it was getting pretty dark.  Which version is better?  The original, or one of these?  Something tells me the first of these is more natural, even though the second, like the original seems to have more depth.

 

 

 

Edited June 26, 2019 by Rodd

[gorann]

The big stars looks slightly better in the first image.

All processing is in some sence manipulating the image but I think it is ok if the goal is to remove artifacts introduced by the scope, camera or guiding, since the manipulations then are aimed at getting closer to what it should look like with perfect equipment that just magnifies and record the sky. The same goes for shrinking stars since they are point objects that have become oversized by the scope, camera or guiding. Then it is of course best if the manipulations look natural and not quick and dirty as mine - just wanted to see if it could be done particularly since I also have an ASI1600 and will run into the same problem.

Edited June 26, 2019 by gorann

[Rodd]

7 hours ago, gorann said:

he big stars looks slightly better in the first image.

Not what I was wondering.  ALL stars in the first of the subsequently posted images look bigger than ALL stars in the other versions.  I was wondering if they looked more natural.

Rodd

[ollypenrice]

In the later ones I think the blues are a bit highly saturated but that's partly because the colour is coming from the edges of the stars and, in such a stellar-crowded environment, this gives the impression of a kind of blue background in the core rather than blue stars.

The criss-cross pattern around the bright stars (microlensing or some kind of read artifact?)* is a little distracting but might yield to some kind of processing fix. Wim's was a valiant effort using techniques I'd have tried myself but these always risk a manipulated look when there are the horizontal-vertical spikes you have. In the two attempts below (from crude screen grabs) I tried to avoid visible intervention. In the first I just made a copy layer, pinned the background on the bottom layer and pulled down the Curve just above that before erasing the top layer around the two bright stars. I also lowered the saturation in the bright red star.

In the second I went a little further and, on a bottom layer, ran Noels Actions horizontal and vertical banding reduction. This did reduce the criss-cross pattern but the top layer needed erasing carefully. By now I was in full-on Photoshop Thuggery mode I went a bit further and pasted your image onto an even and objectless background sky which I keep in stock for emergencies! I adjusted it to just your background level and then very carefully erased the fainter evidence of criss-cross just around the two bright stars. I'm not sure this was worth the bother but it's fun to try.

So the big bright stars are not rounded out as Wim did (and as I sometimes do) but just toned down a tad.

Anyway I do like your M13 very much. Good thinking regarding green as L.

Olly

 

* Given well known and similar artifacts affecting QSI 8300 cameras I wouldn't discount the possibility of a firmware solution to this one day.

[Rodd]

19 minutes ago, ollypenrice said:

Anyway I do like your M13 very much. Good thinking regarding green as L.

Thanks Olly--I have a bit of work to do yet....I appreciate your efforts

Rodd

[Rodd]

14 hours ago, gorann said:

The big stars looks slightly better in the first image. 

All processing is in some sence manipulating the image but I think it is ok if the goal is to remove artifacts introduced by the scope, camera or guiding, since the manipulations then are aimed at getting closer to what it should look like with perfect equipment that just magnifies and record the sky. The same goes for shrinking stars since they are point objects that have become oversized by the scope, camera or guiding. Then it is of course best if the manipulations look natural and not quick and dirty as mine - just wanted to see if it could be done particularly since I also have an ASI1600 and will run into the same problem.

 

On 25/06/2019 at 02:12, alan potts said:

Great cluster shot though.

 

6 hours ago, ollypenrice said:

n the later ones I think the blues are a bit highly saturated

Well--not as easy as I thought.  Here is my best effort to lesson the blue but keep the palette as natural as possible.  modifying yellow is not an easy thing--there are controls for r, g and b--but not y!  I am trying to avoid a reprocess--but its starting to look like that will be necessary.  Are ny of my versions to date "final" worthy--or is there a better image in there--what do you think?

 

 

[MarsG76]

Looks great.. nice and crisp... I think the original is best.... overly saturated images lose their edge, and start looking cartoony...

[Rodd]

Just now, MarsG76 said:

Looks great.. nice and crisp... I think the original is best.... overly saturated images lose their edge, and start looking cartoony...

AHHHH all that for nothing?  arrrrg!

[Rodd]

Actually I posted the wrong image.   This one is a bit less saturated.

 

 

[MarsG76]

Yeah, that's great... thats the keeper.

 

[Rodd]

8 minutes ago, MarsG76 said:

Yeah, that's great... thats the keeper.

 

Nope--one more--this is it.  thanks Mars....Still looks green to me--but it isn't.  But it looks it!

Rodd

[ollypenrice]

The glob is just right for me.

Olly