Galactic cirrus: First light with ASI2400MC Pro


David Elmore
 

Folks,

Hi, I am David Elmore, a new member here at DSNM for installation in Building 11 later this week.  Meanwhile I have been outside testing my new wide-field imaging system that includes three imagers of 50mm, 200mm, and a whopping 380mm focal length.  This is from the 200mm.  
After some alignment and focus tests I wondered what to image. How about pointing due north?  Here is a deep exposure of a region including the bright star Polaris that shows regions of Integrated Flux Nebulae (IFN) also called galactic cirrus.  This gas and dust dispersed throughout the Milky Way is visible by reflecting light of many stars within the galaxy (integrated flux) and therefore shows up above and below the plane of the galaxy.

This was the first imaging I have done using a new ZWO ASI2400MC Pro camera.  This camera has large (for CMOS) 5.94 micron pixels and is back-illuminated therefore very sensitive.  The filter is a dual band IDAS NBZ.  These were mounted behind a Borg 55FL 200mm focal length F/3.6 astro-graph.  This is a stack of 64 five-minute exposures processed in APP.  There are issues with guiding and tip-tilt of the camera that need to be corrected and perhaps a night glow suppression filter may have provided more useful signal but I think this little scope, camera, and filters will spend many nights chasing similar clouds.

Please let me know how this link works for you.  Should I try some other method of sharing images?

David


https://www.icloud.com/iclouddrive/0qAv26wMGn6kLNDwWqY-YwBSw#Sh2-178_Borg_ASI2400_NBZ_64X300_140_10


Dan Crowson
 

David,

 

Really neat and deep. The sharing link worked just fine – a lot like Dropbox which tries to get you to sign up but there’s still a button to just download the file.

 

1.       I would think using the filter would be counter-productive for imaging IFN. It is my understanding that most of this is dust (and not really Ha/HII) illuminated by our galaxy. I would have thought you would have gathered even more without the filter and it would have been more brown / tan?

 

2.       I wouldn’t judge my guiding on pointing toward Polaris. J

 

3.       I’m unfamiliar with APP but in PI and PhotoShop you can use tools to remove the green tint that tends to not be ‘real’. Some OSC cameras add to it with the two G’s in the bayer matrix, too. Just running the HastaLavista Green action in PhotoShop yielded this (just a screen capture of the image).

 

 

I don’t think Steve’s site is still up but I recently found a PDF of a PowerPoint of his ‘Unexplored Nebula Project’ where I learned about IFN years ago. I can post a link to it if you want it. It was a really nice resource.

 

Excellent image. I look forward to seeing what you get. I really makes me want to get a decent CMOS camera to mate with one of the newer real short refractors or lenses to take these kinds of images when the seeing doesn’t support my larger scope.

 

Dan

----          
Dan Crowson                          dcrowson@...
Dardenne Prairie MO               http://www.crowson.com

 

From: DarkSkyNewMexico@groups.io [mailto:DarkSkyNewMexico@groups.io] On Behalf Of David Elmore
Sent: Saturday, March 13, 2021 9:42 PM
To: DarkSkyNewMexico@groups.io
Subject: [DarkSkyNewMexico] Galactic cirrus: First light with ASI2400MC Pro

 

Folks,



Hi, I am David Elmore, a new member here at DSNM for installation in Building 11 later this week.  Meanwhile I have been outside testing my new wide-field imaging system that includes three imagers of 50mm, 200mm, and a whopping 380mm focal length.  This is from the 200mm.  

After some alignment and focus tests I wondered what to image. How about pointing due north?  Here is a deep exposure of a region including the bright star Polaris that shows regions of Integrated Flux Nebulae (IFN) also called galactic cirrus.  This gas and dust dispersed throughout the Milky Way is visible by reflecting light of many stars within the galaxy (integrated flux) and therefore shows up above and below the plane of the galaxy.

 

This was the first imaging I have done using a new ZWO ASI2400MC Pro camera.  This camera has large (for CMOS) 5.94 micron pixels and is back-illuminated therefore very sensitive.  The filter is a dual band IDAS NBZ.  These were mounted behind a Borg 55FL 200mm focal length F/3.6 astro-graph.  This is a stack of 64 five-minute exposures processed in APP.  There are issues with guiding and tip-tilt of the camera that need to be corrected and perhaps a night glow suppression filter may have provided more useful signal but I think this little scope, camera, and filters will spend many nights chasing similar clouds.

 

Please let me know how this link works for you.  Should I try some other method of sharing images?

 

David

 

 

https://www.icloud.com/iclouddrive/0qAv26wMGn6kLNDwWqY-YwBSw#Sh2-178_Borg_ASI2400_NBZ_64X300_140_10

 


David Elmore
 

Dan,
For this image I focused using a night glow suppression filter, IDAS NGS1, but entered the IDAS NBZ in the sequence by mistake.  Thank goodness these IDAS filters are par focal. Since this field is relatively low in the sky, my thinking is that night glow suppression might be a benefit compared to unfiltered RGB -- but I plan to try RGB, NGS1, NBZ, Triad, and L-Extreme on both reflection and emission nebulae to see exactly what they do.

Guiding on the equator to quantify the amount of Image drift almost agreed with the multi-star alignment routine results.  I am practicing for when I actually set up on the pier.

The reduced green effect looks much more 'natural' to me.  I suspect you saw in the histograms that the Red, Green, and Blue histograms had different dark points and widths.  Balancing dark points and widths of blue and green (red is wider) results in something close to what Hastalavista Green did.  APP understands Bayer filters and even has a nice setting for dual band filters treating colors separately and automatically merging them at the end.

Yes, please I am searching for more targets.  On the list so far are regions around M81/M82, Baby Eagle, Dark Shark, Taurus molecular cloud, and NGC 7497 .MM81/M82, Baby Eagle region, DarShark Shucks, you can't reply in-line.
David


Dan Crowson
 

Here’s a link to the file - http://www.crowson.com/Downloads/The_unexplored_nebula_project-smandel.pdf

 

As a testament to how decent the skies are down there, I regularly image down to around 12-13 degrees when I’m on site with my refractor (600mm).

 

Dan

----          
Dan Crowson                          dcrowson@...
Dardenne Prairie MO               http://www.crowson.com

 

From: DarkSkyNewMexico@groups.io [mailto:DarkSkyNewMexico@groups.io] On Behalf Of David Elmore
Sent: Sunday, March 14, 2021 9:07 AM
To: DarkSkyNewMexico@groups.io
Subject: Re: [DarkSkyNewMexico] Galactic cirrus: First light with ASI2400MC Pro

 

Dan,
For this image I focused using a night glow suppression filter, IDAS NGS1, but entered the IDAS NBZ in the sequence by mistake.  Thank goodness these IDAS filters are par focal. Since this field is relatively low in the sky, my thinking is that night glow suppression might be a benefit compared to unfiltered RGB -- but I plan to try RGB, NGS1, NBZ, Triad, and L-Extreme on both reflection and emission nebulae to see exactly what they do.

Guiding on the equator to quantify the amount of Image drift almost agreed with the multi-star alignment routine results.  I am practicing for when I actually set up on the pier.

The reduced green effect looks much more 'natural' to me.  I suspect you saw in the histograms that the Red, Green, and Blue histograms had different dark points and widths.  Balancing dark points and widths of blue and green (red is wider) results in something close to what Hastalavista Green did.  APP understands Bayer filters and even has a nice setting for dual band filters treating colors separately and automatically merging them at the end.

Yes, please I am searching for more targets.  On the list so far are regions around M81/M82, Baby Eagle, Dark Shark, Taurus molecular cloud, and NGC 7497 .MM81/M82, Baby Eagle region, DarShark Shucks, you can't reply in-line.
David


William McLaughlin
 

Nice first shot.  We are also operating a 200 mm system piggybacked on our refractor. I would question whether a color camera alone is good for this nebulosity. The pixels may be sensitive but the Bayer filters plus the added filter cause too much light loss, IMHO. 

I would also suggest some star reduction if you are trying to display the nebula well. These wide shots tend to have, as Sagan would say, "billions of stars". That can distract from the nebula. PixInsight has a nice method (RBA has a page on it) for reducing the impact and size of small and medium stars. I use the method almost all the time so some degree on nebula shots.

It is a great start, however!

Picture attached of my 200 mm /STT8300 system (not the DSNM system but similar)


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My images can be found at:

and


David Elmore
 

Dan,

Many thanks for the link.  These features are huge!  A 10° field of view does not even start to cover the extent.

My concern was not sky brightness but air glow.  The night of the Polaris exposures sky brightness was measured at 21.8 using a couple of hand-held SQMs and 22 from an automated SQM.   The Rancho Hildalgo all sky camera was showing bands of air glow and that is more pronounced at lower elevations.

David

On Mar 14, 2021, at 8:18 AM, Dan Crowson <dcrowson@...> wrote:

Here’s a link to the file - http://www.crowson.com/Downloads/The_unexplored_nebula_project-smandel.pdf

 

As a testament to how decent the skies are down there, I regularly image down to around 12-13 degrees when I’m on site with my refractor (600mm).

 

Dan

----          
Dan Crowson                          dcrowson@...
Dardenne Prairie MO               http://www.crowson.com

 

From: DarkSkyNewMexico@groups.io [mailto:DarkSkyNewMexico@groups.io] On Behalf Of David Elmore
Sent: Sunday, March 14, 2021 9:07 AM
To: DarkSkyNewMexico@groups.io
Subject: Re: [DarkSkyNewMexico] Galactic cirrus: First light with ASI2400MC Pro

 

Dan,
For this image I focused using a night glow suppression filter, IDAS NGS1, but entered the IDAS NBZ in the sequence by mistake.  Thank goodness these IDAS filters are par focal. Since this field is relatively low in the sky, my thinking is that night glow suppression might be a benefit compared to unfiltered RGB -- but I plan to try RGB, NGS1, NBZ, Triad, and L-Extreme on both reflection and emission nebulae to see exactly what they do.

Guiding on the equator to quantify the amount of Image drift almost agreed with the multi-star alignment routine results.  I am practicing for when I actually set up on the pier.

The reduced green effect looks much more 'natural' to me.  I suspect you saw in the histograms that the Red, Green, and Blue histograms had different dark points and widths.  Balancing dark points and widths of blue and green (red is wider) results in something close to what Hastalavista Green did.  APP understands Bayer filters and even has a nice setting for dual band filters treating colors separately and automatically merging them at the end.

Yes, please I am searching for more targets.  On the list so far are regions around M81/M82, Baby Eagle, Dark Shark, Taurus molecular cloud, and NGC 7497 .MM81/M82, Baby Eagle region, DarShark Shucks, you can't reply in-line.
David




David Elmore
 


On Mar 14, 2021, at 9:13 AM, William McLaughlin <IC5070@...> wrote:

Nice first shot.  We are also operating a 200 mm system piggybacked on our refractor. I would question whether a color camera alone is good for this nebulosity. The pixels may be sensitive but the Bayer filters plus the added filter cause too much light loss, IMHO. 

Interesting trade and in general I agree one gets sharper images using a monochrome camera.  Here was my analysis. For RGB, one needs R, G, and B images.  With one-shot color (OSC) one gets all three but must integrate sort of 3 times longer to collect the same number of photons in each color (OK, 4 for red and blue, 2 for green).  So I consider this signal to noise a wash since both RGB and OSC require the same total integration time to achieve the same signal to noise. OSC is easier and works for moving objects when appropriate.  Then there is spatial resolution to consider.  Monochrome and separate R, G, and B filters can achieve higher resolution.  But, the measured resolution (CCD Inspector) of this little Borg astro-graph is not perfect especially in the corners of a full frame imager and in fact its resolution nicely matches two RGGB super pixels of this OSC camera.  Therefore I went with the ASI2400MC as opposed to an ASI6200, which I tried and found to have too many pixels.


I would also suggest some star reduction if you are trying to display the nebula well. These wide shots tend to have, as Sagan would say, "billions of stars". That can distract from the nebula. PixInsight has a nice method (RBA has a page on it) for reducing the impact and size of small and medium stars. I use the method almost all the time so some degree on nebula shots.

Good idea.  When I get a good high signal to noise version of this field (night glow suppression filter instead of narrowband) perhaps I could run it through StarNet to eliminate most stars and then perhaps add some fraction of the stars back in for a little reality but enhanced nebulosity.


It is a great start, however!

Picture attached of my 200 mm /STT8300 system (not the DSNM system but similar)

Fabulous images on your album.


<lens 2.png>
--
******************
My images can be found at:

and