M31 luminance 2 panel mosaic WIP

[tooth_dr]

I decided to try M31 again, but always feeling like it was squashed in at 500mm, I am trying a 2 panel mosaic.

Luminance data so far - 2 hours per panel in 120s subs.

APP done a decent job of combining the panels.

Any feedback welcome.

 

TIA

Adam.

 

[Allinthehead]

Nice start. I do like a widescreen image.

[geeklee]

Looks stunning, so much detail and contrast showing in both panels. 

Looking like a very good decision to split this target into two. 

I really like the ultra wide view that's come out as a result.

[Hughsie]

I am liking that. Fingers crossed for some clear skies and finishing the project.

 

John

[MarkAR]

Very good so far, I think the hardest thing will be to tame the core a little.

[tooth_dr]

3 hours ago, MarkAR said:

Very good so far, I think the hardest thing will be to tame the core a little.

I did also take a few 20s subs to add to each panel for the core, just haven’t processed them yet. 

[tomato]

Looking really good, I’ve just started a 12 panel mosaic on M31, as my 6 panel “Panavision” experiment looked too hemmed in. Alas, the weather isn’t playing ball on the current moonless period.

[Rodd]

This is looking amazing--what scope did you use?  The signal strength is excellent without being garing

[tooth_dr]

1 hour ago, Rodd said:

This is looking amazing--what scope did you use?  The signal strength is excellent without being garing

Thanks Rodd. It never fails to impress me how much signal the Tak Epsilon 180 gathers in a short time.  It’s F2.8 500mm.

I haven’t really had a chance to work out the ideal sub length for luminance yet, so tried 120s.  
 

Any suggestions on ideal sub length would be appreciated. 

[tooth_dr]

2 hours ago, tomato said:

Looking really good, I’ve just started a 12 panel mosaic on M31, as my 6 panel “Panavision” experiment looked too hemmed in. Alas, the weather isn’t playing ball on the current moonless period.

12 panels wow. That will certainly look good.

[tomato]

3 minutes ago, tooth_dr said:

12 panels wow. That will certainly look good.

Thanks, you have set the bar regarding the quality of the subs, your Lum image looks flawless. Unless the weather changes, the  12 panels are looking like an all of Autumn project, even with the dual rig.

[Rodd]

3 minutes ago, tooth_dr said:

ny suggestions on ideal sub length would be appreciated. 

I would go much shorter for M31.  Using the FSQ 106 at F3 I think I used a combination of 60 sec and 30sec  subs and you have  74mm aperture and .2 FL over me.  And I felt I could have used less exposure.  It does depend on the camera to a large degree, as well as your sky.  With a low noise camera, you don't need long subs at all.  Also, it will allow you to go deep into the core where there are a lot of structures that get washed out with brightness.  Then again, your lum stack looks great.  So I guess its a matter of ease--which way will require less work.   For another then again,--I used 120 sec subs for M31 with the TOA 130 at F7.7 (and 5.38)--both of which are way slower than F2.8 and with less aperure as well.  I struggle with optimum sub length as well

[tooth_dr]

53 minutes ago, Rodd said:

I would go much shorter for M31.  Using the FSQ 106 at F3 I think I used a combination of 60 sec and 30sec  subs and you have  74mm aperture and .2 FL over me.  And I felt I could have used less exposure.  It does depend on the camera to a large degree, as well as your sky.  With a low noise camera, you don't need long subs at all.  Also, it will allow you to go deep into the core where there are a lot of structures that get washed out with brightness.  Then again, your lum stack looks great.  So I guess its a matter of ease--which way will require less work.   For another then again,--I used 120 sec subs for M31 with the TOA 130 at F7.7 (and 5.38)--both of which are way slower than F2.8 and with less aperure as well.  I struggle with optimum sub length as well

Thanks Rodd.  I was noting that my minimum brightness ADUs were around 2500, which was pretty high, but I havent shot much luminance so still trying to find my way.  I'm using a noisy old KAF-8300 sensor, so at the back of my mind, I'm always conscious of going too short due to the high 10 e- read noise.  I have started shooting 20mins ha subs with the epsilon and getting really nice results. 

[Rodd]

1 hour ago, tooth_dr said:

Thanks Rodd.  I was noting that my minimum brightness ADUs were around 2500, which was pretty high, but I havent shot much luminance so still trying to find my way.  I'm using a noisy old KAF-8300 sensor, so at the back of my mind, I'm always conscious of going too short due to the high 10 e- read noise.  I have started shooting 20mins ha subs with the epsilon and getting really nice results. 

For Ha the skys the limit--even 30min.  Luminance will require shorter subs than RGB (unless you are in dark skies).  As long as sky fog doesnt dominate and you don't excedd the FWC, you should be fine

[tooth_dr]

It turned out the RGB camera wasnt rotated properly, even though I checked, and focus wasnt great either in green or blue.  I will take Ha and RGB the next night it is clear.

I have tried to process it anyway even with the extra crop and dodgy RGB.

 

 

 

 

 

Edited August 17, 2020 by tooth_dr
Added image

[Xiga]

On 16/08/2020 at 10:32, tooth_dr said:

I decided to try M31 again, but always feeling like it was squashed in at 500mm, I am trying a 2 panel mosaic.

Luminance data so far - 2 hours per panel in 120s subs.

APP done a decent job of combining the panels.

Any feedback welcome.

 

TIA

Adam.

 

I was away at the weekend so only saw this on my phone. Now i see it on the computer monitor, i can fully appreciate it. I like the framing too. 

The Lum looks awesome Adam. That Tak 180 really does suck down the photons! The plethora of teeny-tiny stars it's picked up throughout just look amazing. 

Looking forward to the final version. 

[tooth_dr]

An image from the same night using a QHY9 and Nikon 180mm lens.  The stars are really huge, and overall it makes for uncomfortable viewing.  Back to the drawing board I think.

 

[tomato]

Your widefield Nikon lens image reminds me of NGC 7331, funny how the FOV can affect your perception of the galaxy.

[x6gas]

Lovely mosaic Adam.  As said having some space around M31 give it a very different feel and I love the panavision look!

[gorann]

On 16/08/2020 at 19:44, tooth_dr said:

Thanks Rodd. It never fails to impress me how much signal the Tak Epsilon 180 gathers in a short time.  It’s F2.8 500mm.

I haven’t really had a chance to work out the ideal sub length for luminance yet, so tried 120s.  
 

Any suggestions on ideal sub length would be appreciated. 

Great Lum data Adam! I have with interest compared it to my recent RASA8 image and these two low-f scopes appear to get about equally deep in a similar amount of time. You appear to have no problem with tilt as I seem to have, but then I am pressing it using an APS-C chip. Good luck with grabbing the colour data!

Edited August 19, 2020 by gorann