And another M51

[tomato]

I have been continuing my experiments with CMOS cameras for galaxy imaging, this time using an ASI 178. Thanks to two clear nights coinciding with a bank holiday weekend (how often does that happen?), this is 2.92 hrs integration, calibrated and stacked in APP, processed in APP and  Startools. Image capture was done with Sharpcap, following the smart histogram guidance on what exposures to use. 

I was second in line to buy an Atik 460 on ABS, but after this result I am going to stick with CMOS for a while longer, I am very impressed with the sensitivity of this sensor.

L 135 x 20 secs, 62 x 40 secs

RGB 30 x 60 secs each filter

Esprit 150, Mesu 200, Bortle 4 sky

Thanks for looking

[kirkster501]

A nice M51. I like the detail you've got in the satellite galaxy.

 I think there is much more detail in this data set though and you need to tease it out.

Not at all easy is it?!

[tomato]

9 hours ago, kirkster501 said:

A nice M51. I like the detail you've got in the satellite galaxy.

 I think there is much more detail in this data set though and you need to tease it out.

Not at all easy is it?!

Thanks Steve, as for not being easy, you're not wrong there!

My current approach to processing is the same as my image capture - a bit rushed. I will have another go at trying to pull out more detail, it may take a while....

[tomato]

Quote

2 hours ago, tomato said:

Thanks Steve, as for not being easy, you're not wrong there!

My current approach to processing is the same as my image capture - a bit rushed. I will have another go at trying to pull out more detail, it may take a while....

 

Well, a while processing for me is about 2 hours. I think Kirkster501 was right, there was a bit more detail to be had. 

[Starwiz]

4 minutes ago, tomato said:

Well, a while processing for me is about 2 hours. I think Kirkster501 was right, there was a bit more detail to be had. 

Very nice, great detail!

[Jkulin]

Hi Tomato,

I thought you had a nice image, just a little purple which I hope you don't mind I removed and stretched it a bit more for the details and did just a few curves, Its a nice image and it helps me to play a little to see what I can do, I might have added a little bit of noise, but I am still after over a year still trying to get my head around PI

Nice one.

 

[tomato]

Thank you John, yes my second rendition is a bit purple, your version is much closer to the  colour balance  typically assigned to this galaxy. Noise is definitely an issue with this data set, I need more integration time! Interestingly, my previous effort on M100 also with a CMOS camera, ended up with a very similar purple hue, can we get fixated on a personal colour palette when processing, I'm not sure?

I don't yet own a copy of PI, I am waiting until I retire when  hopefully I will have the time to properly learn it's intricacies.

[Jkulin]

3 minutes ago, tomato said:

Thank you John, yes my second rendition is a bit purple, your version is much closer to the  colour balance  typically assigned to this galaxy. Noise is definitely an issue with this data set, I need more integration time! Interestingly, my previous effort on M100 also with a CMOS camera, ended up with a very similar purple hue, can we get fixated on a personal colour palette when processing, I'm not sure?

I don't yet own a copy of PI, I am waiting until I retire when  hopefully I will have the time to properly learn it's intricacies.

Hope you didn't mind my trying to help Tommy!

I discovered some time ago a brilliant magenta removal tool for PI, when you get it let me know and I'll PM you a link or upload on here.

Considering that you achieved this with just under 2 hours of data is really quite remarkable, I did 10 hours and it is true what they say about diminishing returns for longer exposures.

I'm still very junior with PI, after over a year I am only just starting to understand a little, but there are some good tutorials about and I find that reading a combination of them really helps.

ATB

[tomato]

5 hours ago, Jkulin said:

Hope you didn't mind my trying to help Tommy!

I discovered some time ago a brilliant magenta removal tool for PI, when you get it let me know and I'll PM you a link or upload on here.

Considering that you achieved this with just under 2 hours of data is really quite remarkable, I did 10 hours and it is true what they say about diminishing returns for longer exposures.

I'm still very junior with PI, after over a year I am only just starting to understand a little, but there are some good tutorials about and I find that reading a combination of them really helps.

ATB

Thanks very much for the offer. My current set up and take down routine coupled with a current personal commitment to show my family something from each session I spend out in the dark means I rarely get more than 2-3 hrs on a target. I was therefore quite surprised at the level of detail captured, I am really looking forward to having a permanent set up and extending my integration times, but I wonder how much value there is with backyard imaging going beyond 20 hrs or even 10? I suppose it depends on the target, M51 is quite a bright object, in imaging terms.

[ollypenrice]

The colours you found in your first rendition are similar to those being produced by a CMOS camera in a robotic rig I host. The blues are rather cyan and the reds very yellow. If you just combine the colours how do the histograms per colour line up? I wonder if you'd be advised to shoot rather more red? The resolution is fine but the colour seems unsettled.

Olly

[Han Solo]

Firstly, this image is great and so much detail. Congratulations. Stacked short exposures seem to be the way to go with these CMOS cameras.

I quite like you more purple version of your image, I wonder if there is a middle ground between you first version and this. I don’t know about the software you use, but in photoshop there is a selective colour tool which allows you to adjust individual colour ranges. Maybe adjust the purple / blue outer rim to be more blue? 

Obviously I don’t know much about how it realistically looks but may be worth a try. Something like this? I hope you don’t mind.

 

[Guest]

This is NOT just another M51 ?

It's really good!

I like your original process, but of the ones that were submitted to assist I'd say I like @Han Solo example the best because it retains some of the purple/blue that give the image so much more atmosphere than a flat black background which - of course - I suppose - space is - but there is colour out there too

Again, great image, detail and colour

David

[tomato]

Thank you David, and thanks to the other SGL members who have supplied versions of the image to the thread. The  @Han Solo image is also my preferred version of those posted.

I note Olly’s observation with interest regarding the ‘raw’ colour balance delivered by the camera, and I wonder if CMOS sensors could somehow have a colour signature specific to them? It shouldn’t be possible but could it be created by the micro lensing technology applied to the pixels? I’m not even sure if the 178 sensor has this technology? I could be talking twaddle on this one but on the limited number of images I have taken with CMOS cameras, they have all come out with this colour hue. Of course, it’s more likely to be my skewed processing.

If it is clear in North Yorkshire tomorrow, I plan to capture a bit more data to hopefully improve on the noise.