Andromeda Galaxy - M31 .... C&C

Started Oct 1, 2017 | Photos
RudyPohl
RudyPohl Veteran Member • Posts: 5,889
Andromeda Galaxy - M31 .... C&C
10

Andromeda Galaxy - M31

This is my most recent attempt at reprocessing this image which I shot in September 2017. I am working with rnc-color-stretch and Photoshop to try to render this image in its actual natural colours... still learning... hoping to get a lot more integration time this month. C&C welcome.

Nikon D5500
Nikon 300/f4 with aperture mask using step-down rings
Aperture: 5.2
ISO: 1600
White Balance 5300
Exposure: 59 x 1-minute = 59 minutes
No calibration frames used
Hoya Intensifier anti-light pollution filter
Sky Conditions: Yellow zone, 3/4 Moon
Tracked and stacked
Tracker: Sky Watcher Star Adventurer
Raw conversion to 16-bit TIFFs in Adobe Camera Raw
Stacking in Deep Sky Stacker
Colour Processing of image stack in rnc-color-stretch
Final Processing in Photoshop CS5

RudyPohl
OP RudyPohl Veteran Member • Posts: 5,889
Re: Andromeda Galaxy - M31 .... C&C
3

RudyPohl wrote:

Andromeda Galaxy - M31

This is my most recent attempt at reprocessing this image which I shot in September 2017. I am working with rnc-color-stretch and Photoshop to try to render this image in its actual natural colours... still learning... hoping to get a lot more integration time this month. C&C welcome.

Nikon D5500
Nikon 300/f4 with aperture mask using step-down rings
Aperture: 5.2
ISO: 1600
White Balance 5300
Exposure: 59 x 1-minute = 59 minutes
No calibration frames used
Hoya Intensifier anti-light pollution filter
Sky Conditions: Yellow zone, 3/4 Moon
Tracked and stacked
Tracker: Sky Watcher Star Adventurer
Raw conversion to 16-bit TIFFs in Adobe Camera Raw
Stacking in Deep Sky Stacker
Colour Processing of image stack in rnc-color-stretch
Final Processing in Photoshop CS5

A slightly darker black point on this one... not sure which is better.

DLHill Forum Member • Posts: 70
Re: Andromeda Galaxy - M31 .... C&C
1

Rudy,

Love it! I think I prefer the second one. I'm impressed with how much detail you've gotten in the dust lanes with just one hour's worth of exposures. Well done.

-- hide signature --

Darren.

JeffGM Regular Member • Posts: 247
Re: Andromeda Galaxy - M31 .... C&C

Beatiful image! I believe dslr and mirrorless cameras have improved so much it my not be worth the expense and extra hassle to use a camera built just for astronomy. The exception might be if you are doing research or have the money for a high end astronomical imaging camera. Even then the differences can be subtle.

 JeffGM's gear list:JeffGM's gear list
Panasonic G85 Sony a7R III Sony a7 III Tamron SP 70-200mm F/2.8 Di VC USD Sony FE 28-70mm F3.5-5.6 OSS +6 more
RudyPohl
OP RudyPohl Veteran Member • Posts: 5,889
Re: Andromeda Galaxy - M31 .... C&C

DLHill wrote:

Rudy,

Love it! I think I prefer the second one. I'm impressed with how much detail you've gotten in the dust lanes with just one hour's worth of exposures. Well done.

Thanks Darren, and yes I like the second one better too!

Rudy

RudyPohl
OP RudyPohl Veteran Member • Posts: 5,889
Re: Andromeda Galaxy - M31 .... C&C

JeffGM wrote:

Beatiful image! I believe dslr and mirrorless cameras have improved so much it my not be worth the expense and extra hassle to use a camera built just for astronomy. The exception might be if you are doing research or have the money for a high end astronomical imaging camera. Even then the differences can be subtle.

Thanks Jeff!

Modern DSLRs really are quite amazing.... it's hard to believe that this little camera, the D5500, is one level above Nikon's DSLR entry level D3300 and that it's the same camera that we use to take snaps of our kids and dogs at the park and not some specialized high-end unit costing thousands.

Rudy

Marco1227 Forum Member • Posts: 57
Re: Andromeda Galaxy - M31 .... C&C

Great stuff Rudyard.

How is the tracker you are using handling the weight of a 300mm f4?

It is on my buy list and I am using a very similar setup.

Congratulation again for a great shot.

rnclark Veteran Member • Posts: 3,957
Re: Andromeda Galaxy - M31 .... C&C

RudyPohl wrote:

RudyPohl wrote:

Andromeda Galaxy - M31

This is my most recent attempt at reprocessing this image which I shot in September 2017. I am working with rnc-color-stretch and Photoshop to try to render this image in its actual natural colours... still learning... hoping to get a lot more integration time this month. C&C welcome.

Nikon D5500
Nikon 300/f4 with aperture mask using step-down rings
Aperture: 5.2
ISO: 1600
White Balance 5300
Exposure: 59 x 1-minute = 59 minutes
No calibration frames used
Hoya Intensifier anti-light pollution filter
Sky Conditions: Yellow zone, 3/4 Moon
Tracked and stacked
Tracker: Sky Watcher Star Adventurer
Raw conversion to 16-bit TIFFs in Adobe Camera Raw
Stacking in Deep Sky Stacker
Colour Processing of image stack in rnc-color-stretch
Final Processing in Photoshop CS5

A slightly darker black point on this one... not sure which is better.

Very nice Rudy. Both are excellent images. Which one looks better to me depends on the monitor. On 2 out of 3 monitors I looked at the images on, the first image looked better, and on the 3rd the second image looked better.

Did you test the white balance settings with sunlight on a white target with your filter?

Roger

sharkmelley
sharkmelley Senior Member • Posts: 2,457
Re: Andromeda Galaxy - M31 .... C&C

Well done!  The colour in that image has come out really well.  I prefer the first version but to be honest there's not much between them.

Mark

 sharkmelley's gear list:sharkmelley's gear list
Sony a7S Nikon Z6 +1 more
rnclark Veteran Member • Posts: 3,957
Re: Andromeda Galaxy - M31 .... C&C

rnclark wrote:

RudyPohl wrote:

RudyPohl wrote:

Andromeda Galaxy - M31

This is my most recent attempt at reprocessing this image which I shot in September 2017. I am working with rnc-color-stretch and Photoshop to try to render this image in its actual natural colours... still learning... hoping to get a lot more integration time this month. C&C welcome.

Nikon D5500
Nikon 300/f4 with aperture mask using step-down rings
Aperture: 5.2
ISO: 1600
White Balance 5300
Exposure: 59 x 1-minute = 59 minutes
No calibration frames used
Hoya Intensifier anti-light pollution filter
Sky Conditions: Yellow zone, 3/4 Moon
Tracked and stacked
Tracker: Sky Watcher Star Adventurer
Raw conversion to 16-bit TIFFs in Adobe Camera Raw
Stacking in Deep Sky Stacker
Colour Processing of image stack in rnc-color-stretch
Final Processing in Photoshop CS5

A slightly darker black point on this one... not sure which is better.

Very nice Rudy. Both are excellent images. Which one looks better to me depends on the monitor. On 2 out of 3 monitors I looked at the images on, the first image looked better, and on the 3rd the second image looked better.

Did you test the white balance settings with sunlight on a white target with your filter?

Roger

I forgot to mention, the brighter blue stars are looking a little funky, perhaps due to some chromatic aberration.  I suggest using the blur brush on the brightest few stars to reduce the harshness of that problem.

Roger

BlackgumNate Contributing Member • Posts: 634
Re: Andromeda Galaxy - M31 .... C&C

Looks excellent, Rudy. I'm glad to see that this has worked out for you. Very nice!

Roger's tip on those blown out blue stars is really the only thing I see. I have used content aware fill on areas like that with success too.

You might try some star reduction (carboni actions)? The thing with star reduction I find is that it can leave blotchyness in nebula/gas/dust areas. But I'd give it a shot here.

Nate

RudyPohl
OP RudyPohl Veteran Member • Posts: 5,889
Re: Andromeda Galaxy - M31 .... C&C

Marco1227 wrote:

Great stuff Rudyard.

How is the tracker you are using handling the weight of a 300mm f4?

It is on my buy list and I am using a very similar setup.

Congratulation again for a great shot.

Hi Marco,

Thanks for your kind and encouraging words!

I find that the Star Adventurer handles the weight of my heavy Nikon 300/f4 ED lens just fine. In fact, I suspect that the limiting factor is not so much the weight or focal length of the lens, but the periodic error of the tracker.

Its ability to handle this lens is the reason why I opted for the Star Adventurer because I wanted a tracker that would allow me to dabble in some DSO astrophotography on brighter objects like M42 and M31 along with doing the standard Milky Way landscapes and widefield astrophotography that all entry-level trackers can do very well. It is very rugged and robust while still being quite light-weight and portable.

It seems that the optimum tracking time for this tracker/lens combo is between 60-90 seconds which puts the histogram in the 1/4-1/3 from the left sweet-spot and still gives fairly round stars with a good keeper rate.

Best regards,
Rudy

RudyPohl
OP RudyPohl Veteran Member • Posts: 5,889
Re: Andromeda Galaxy - M31 .... C&C

rnclark wrote:

RudyPohl wrote:

RudyPohl wrote:

Andromeda Galaxy - M31

This is my most recent attempt at reprocessing this image which I shot in September 2017. I am working with rnc-color-stretch and Photoshop to try to render this image in its actual natural colours... still learning... hoping to get a lot more integration time this month. C&C welcome.

Nikon D5500
Nikon 300/f4 with aperture mask using step-down rings
Aperture: 5.2
ISO: 1600
White Balance 5300
Exposure: 59 x 1-minute = 59 minutes
No calibration frames used
Hoya Intensifier anti-light pollution filter
Sky Conditions: Yellow zone, 3/4 Moon
Tracked and stacked
Tracker: Sky Watcher Star Adventurer
Raw conversion to 16-bit TIFFs in Adobe Camera Raw
Stacking in Deep Sky Stacker
Colour Processing of image stack in rnc-color-stretch
Final Processing in Photoshop CS5

A slightly darker black point on this one... not sure which is better.

Very nice Rudy. Both are excellent images. Which one looks better to me depends on the monitor. On 2 out of 3 monitors I looked at the images on, the first image looked better, and on the 3rd the second image looked better.

Did you test the white balance settings with sunlight on a white target with your filter?

Roger

Thanks Roger!

Yes, I did get a chance to shoot a white sheet of paper in indirect daylight and the color temperature was 5365. I shot in Program mode with Auto white balance to get arrive at this figure. I have not yet done a raw conversion at this setting because I already did one at 5500 which is close. As well, I reproduced yours from the other day at 4250.

I also tried one yesterday at 3500 and it resulted in a blurred, horrendously coloured mess coming out of the rnc-color-stretch algorithm. I shot these subs at a white balance of 5300 and did a raw conversion at 3500 and they turned out really weird, a pinkish mess with major loss of detail.

The reason I tried this experiment is because I see so many high-quality M31 images done in Pixinsight by apparently excellent, experienced astrophotographers whose core is a more soft yellowish-beige-chartreuse colour, rather than reddish-purple like mine, and whose outer perimeter is a pronounced range of blues from a light baby-blue to a darker blues. I figured that by doing the raw conversion in ACR at a much lower color temp (3500) than the 5500 I shot the subs at I could force out the reds and bring in the blues in the final image... apparently not.

Anyways, I have been studying official NASA images of M31 to see what the general censuses is regarding colours and there doesn't really seem to be one. Since colours of astro objects is your professional specialty perhaps you can comment on what a naturally coloured M31 should look like. (Oh oh, I hope I have not opened up another Pandora's box in the colour wars).

Thanks,

Rudy

RudyPohl
OP RudyPohl Veteran Member • Posts: 5,889
Re: Andromeda Galaxy - M31 .... C&C

sharkmelley wrote:

Well done! The colour in that image has come out really well. I prefer the first version but to be honest there's not much between them.

Mark

Thanks Mark, very much appreciated!

Cheers,
Rudy

RudyPohl
OP RudyPohl Veteran Member • Posts: 5,889
Re: Andromeda Galaxy - M31 .... C&C

rnclark wrote:

I forgot to mention, the brighter blue stars are looking a little funky, perhaps due to some chromatic aberration. I suggest using the blur brush on the brightest few stars to reduce the harshness of that problem.

Roger

Thanks Roger, will do!

Cheers,
Rudy

RudyPohl
OP RudyPohl Veteran Member • Posts: 5,889
Re: Andromeda Galaxy - M31 .... C&C
1

BlackgumNate wrote:

Looks excellent, Rudy. I'm glad to see that this has worked out for you. Very nice!

Roger's tip on those blown out blue stars is really the only thing I see. I have used content aware fill on areas like that with success too.

You might try some star reduction (carboni actions)? The thing with star reduction I find is that it can leave blotchyness in nebula/gas/dust areas. But I'd give it a shot here.

Nate

Thanks Nate!

Thanks also for the heads up regarding Carboni's astro tools, I do have these plugins and sometimes I use the star reduction process to put more os a spolight on the main subject in the image, but like you, I find that the results are not always all that great. I will give it a go on this image though.

Right now I'm concentrating on developing a consistent workflow for my DSO images that will produce the best and most natural colours and overall best appearance for fine details without artificially adding colours or over manipulating the image. I am experimenting with Astro Pixel Processor (I bought a 1-year license), Pixinisght (I have a 45-day trial version good for the next 5 weeks), Deep Sky Stacker (the old favourite of almost everyone), Photoshop and rnc-color stretch. I am trying integrations with raw files straight out of the camera, with and without calibration frames, and with raw conversions to 16-bit TIFF files in Adobe Camera Raw stacked in all three astro programs.

Anyways, it's all a lot of fun and very interesting and it's great to be getting expert advice input from folks like Roger and Mark. I know this is probably massive overkill for my humble little Star Adventurer and my 10-year old Nikon wildlife lens which has disastrous coma without the aperture mask,  but I'm really quite enjoying the whole discovery process.

Cheers,
Rudy

RudyPohl
OP RudyPohl Veteran Member • Posts: 5,889
M31 - Flickr version posted in my gallery

Hi Roger,

Here is the way Flickr processes and displays this same image. I have always preferred the look of the Flickr versions, they seem to have a bit more punch and pop than how they appear in DP Review.

https://www.flickr.com/photos/rudypohl/23575625488/in/dateposted/

Rudy

sharkmelley
sharkmelley Senior Member • Posts: 2,457
PixInsight ArcSinh

Hi Rudy,

I didn't realise you were trying out PixInsight.  Try the ArcSinh module I've written - it performs a colour preserving stretch:

https://www.cloudynights.com/topic/569440-pixinsight-arcsinh-stretch/?p=8034861

It has an interactive preview window so you immediately see the effects of using the slider to change the amount of stretch.  Read the Cloudy Nights thread for how to use it - you first need to perform a white balance and background extraction on your linear data.

This will soon be part of the official distribution of PixInsight.

Mark

 sharkmelley's gear list:sharkmelley's gear list
Sony a7S Nikon Z6 +1 more
Marco1227 Forum Member • Posts: 57
Re: Andromeda Galaxy - M31 .... C&C

thanks a lot for your explanation.

I will try your settings and will keep following your results, posting mine when I will manage to get something decent.

thanks again.

RudyPohl
OP RudyPohl Veteran Member • Posts: 5,889
Re: PixInsight ArcSinh
1

sharkmelley wrote:

Hi Rudy,

I didn't realise you were trying out PixInsight. Try the ArcSinh module I've written - it performs a colour preserving stretch:

https://www.cloudynights.com/topic/569440-pixinsight-arcsinh-stretch/?p=8034861

It has an interactive preview window so you immediately see the effects of using the slider to change the amount of stretch. Read the Cloudy Nights thread for how to use it - you first need to perform a white balance and background extraction on your linear data.

This will soon be part of the official distribution of PixInsight.

Mark

Hi Mark:

I've been crazy busy all day today, but I finally got a chance to install your ArcSinh module in my trial version of Pixinsight. The installation was very easy and went without a problem. Unfortunately, I have once again run out of time for today, but hopefully I will be able to play with it tomorrow. Looking forward to it.... thanks for this.

Rudy

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