Eastern Veil with 'Quad-band' filter and ASI294MC

[AKB]

I'm still in the process of commissioning my latest imaging rig:

• Esprit 120ED
• ASI294MC Pro camera
• Avalon M-Uno with new Dual mount head

I've also run across two new things recently (new for me, anyway):

• Altair Triband and Quad-band filters for OSC
• Starnet++ processing to remove stars

I wanted to share the latest results from a combination of all of these.  I didn't think I'd have the chance for a while, what with the weather, but, unexpectedly, I got a window last night and captured 20 x 2 minutes  before the moon came up, on my benchmark target for this sort of thing, the Eastern Veil.  The filter is actually a Dual band filter, but as described on Altair's site:

    "Quad Band - combines Sii AND Ha into a red zone, and H-beta + Oiii into a green/blue zone. (Recommended for moderate light pollution)."

Here are two images:

1. 20 x 2 minute stack with just an arcsinh stretch plus another histogram stretch after colour calibration and background removal,
2. starless version of that image straight out of Starnet++

This is definitely the best image I have to date of the Veil.  Not too shoddy for 40 minutes total.  Can't wait to try adding some more time to this... (a long while, though, until I attain the sort of result here)

https://stargazerslounge.com/topic/342730-eastern-and-western-veils-ngc6960-and-ngc6992

Anyway, here we are.  Comments and suggestions welcomed.

Tony

 

 

 

[AKB]

Thanks for the likes.  In the end, of course, a mixture is probably best, with a more conventional red/blue palette (thank you SCNR!)

 

Edited October 20, 2019 by AKB

[fwm891]

Great image Tony, This with the 294 and the Tri-band or Quad-band as they have different red pass band widths?

Might be worth imaging without the narrow band combination filters for star colour (+UV/IR Cut) then over lay the starless NB image - just a thought.

 

[AKB]

57 minutes ago, fwm891 said:

This with the 294 and the Tri-band or Quad-band as they have different red pass band widths?

This is the Quad-band. 

I know what you mean about the star colour, but, for me, the whole point of these filters with an OSC is just get away with”one shot.”

Although... perhaps I need a dual rig ...?!

[smr]

This is really impressive! I can't believe I am faffing around with a DSLR unmodified and imaging for 16 hours to get an image with way less SNR than this. 

I need to buy myself my ASI294MC Pro !

 

[edarter]

love these images, just had my first serious go at DSO imaging and it was the same subject. Wish mine looked half as good as this!

How do you remove the stars? The image with them added back in faintly is my favourite, on my image they almost overwhelm the nebula itself.

Thanks
Ed

[AKB]

On 24/10/2019 at 22:46, edarter said:

How do you remove the stars?

This is entirely the purpose of Starnet++, which you’ll find discussed in several places here on the forum and you can get from here...

https://sourceforge.net/projects/starnet/

Workflow is essentially

• calibration and background removal
• modest stretch with, say, arcsinh stretch
• Starnet++ to remove stars
• subtract starless from stretched original to give stars
• process/stretch each separately to give the result you want
• combine/merge in some ratio 

I’ve suffered exactly the same issues with the background (or foreground) stars dominatng RGB images, but this processing seems to work very well.  You can find a very good example of this here, on a difficult target with rather poor data, for Ced 201 which I recently reprocessed with the above workflow here (original processing in same gallery.)  

Tony