The Dolphin Head Nebula (Sh2-308) in NB with RGB Stars

Mike Lewis

Mike Lewis

Staff Member
I was able to image another object that has been on my target list for a while, Sh2-308, also known as the Dolphin Head Nebula. I think one of the few nebulae with a truly representative name.

This was shot in Hα and Oiii narrowband, with RGB data added for the stars. I used the newly updated WBPP script in PixInsight to build the masters, and the frame selection tool was used to cull the data. 20 minute subs were used for the narrowband data collection to get as much detail as possible. The total integration time is 15 hours and 40 minutes.

From Wikipedia:
Sh2-308 is an H II region located near the center of the constellation Canis Major, composed of ionised hydrogen.[2] It is about 8 degrees south of Sirius, the brightest star in the night sky. The nebula is bubble-like and surrounds a Wolf–Rayet star named EZ Canis Majoris. This star is in the brief, pre-supernova phase of its stellar evolution. The nebula is about 4,530 light-years (1,389 parsecs) away from Earth.

I think Sh2-308 is the faint orange and white areas inside of the larger blue bubble of Ionized Oxygen (Oiii) that makes up the Dolphin head itself.

As always, thanks for taking a look and for any sort of feedback you might wish to provide. Once again, this is posted here first prior to posting on Astrobin...


LRCC_sRGB_FW_UTIFF_V2_VC2_Sh2-308_NB_Foraxx_PSCC_HPF_LHE_NXT-85_DSE_Clean_WithStars.jpg



Best Regards,

ML
 
Mike Lewis

Mike Lewis

Staff Member
Thanks Alan! I cannot say enough about what a difference imaging under darker skies makes. I also think the new refractor telescope I started using back in July of last year when I got set up in Texas at SFRO does provide tighter stars and more detail, even though it is running at a slightly lower focal length.

ML
 
JimFox

JimFox

Moderator
Staff member
You got it!!!!

And boy you got it great Mike! I really like the detail in this. When I have captured it, I have always gone in tighter, and I think the majority of images I have seen are tighter shots. So at least I never noticed just how cool the background is in this area. Good one Mike.
 
Mike Lewis

Mike Lewis

Staff Member
JimFox said:
You got it!!!!

And boy you got it great Mike! I really like the detail in this. When I have captured it, I have always gone in tighter, and I think the majority of images I have seen are tighter shots. So at least I never noticed just how cool the background is in this area. Good one Mike.
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Thanks JIm - yes I agree, I wasn't prepared for the extra clouds of Oiii and Hα that are surrounding this target. Really was cool to see and pull out.

ML
 
A

Andy Elliott

Well-Known Member
That's one beautiful image Mike. Love the wider FOV with that Oiii data....and 20 minute subs, awesome! I have tried this several times but it is soooo low down for me and what with trees and buildings I get about 90 mins per session if I'm lucky. What did you think of the Frame Selection tool in WBPP?
 
Mike Lewis

Mike Lewis

Staff Member
Andy Elliott said:
That's one beautiful image Mike. Love the wider FOV with that Oiii data....and 20 minute subs, awesome! I have tried this several times but it is soooo low down for me and what with trees and buildings I get about 90 mins per session if I'm lucky. What did you think of the Frame Selection tool in WBPP?
Click to expand...
Andy, (@Andy Elliott)

Thanks so much for the wonderful feedback! I was also surprised by the 'extra stuff' popping up in the vicinity of the nebula itself. Definitely nice with dimmer targets when one can manage 20 minute subs I think.

As for the Frame Selection tool now in WBPP, I like it quite a bit. In the past I have bounced around with how I cull frames; everything from passing all the data (when I was lazy) or just using the blink tool, to using the blink tool followed by the separate subframe selector tool. Now with the Frame Selection tool built in to WBPP I find it is very quick and easy to do a quick examination of all the data manually and cull out what is required that way. The only thing that maybe isn't well captured there would be like bright satellite or airplane tracks. The ability to examine individual frames is there too, but if you want to flip though a bunch quickly looking for those kind of artifacts then I think something like blink is still the best choice. So going forward I am going to use Blink very quickly looking for gross issues like tracks, or clouds, and then the Frame Selection tool in WBPP to really cull based on things like eccentricity, etc. At some point I might allow the Frame Selector to run in the non-interactive mode if I feel like I really have my selection criteria dialed in, but for now I am enjoying seeing the graphs for all the data sets and juggling some of the parameters to see how the data gets culled. That is the process I used for this image.

ML
 
A

Andy Elliott

Well-Known Member
Mike Lewis said:
Andy, (@Andy Elliott)

Thanks so much for the wonderful feedback! I was also surprised by the 'extra stuff' popping up in the vicinity of the nebula itself. Definitely nice with dimmer targets when one can manage 20 minute subs I think.

As for the Frame Selection tool now in WBPP, I like it quite a bit. In the past I have bounced around with how I cull frames; everything from passing all the data (when I was lazy) or just using the blink tool, to using the blink tool followed by the separate subframe selector tool. Now with the Frame Selection tool built in to WBPP I find it is very quick and easy to do a quick examination of all the data manually and cull out what is required that way. The only thing that maybe isn't well captured there would be like bright satellite or airplane tracks. The ability to examine individual frames is there too, but if you want to flip though a bunch quickly looking for those kind of artifacts then I think something like blink is still the best choice. So going forward I am going to use Blink very quickly looking for gross issues like tracks, or clouds, and then the Frame Selection tool in WBPP to really cull based on things like eccentricity, etc. At some point I might allow the Frame Selector to run in the non-interactive mode if I feel like I really have my selection criteria dialed in, but for now I am enjoying seeing the graphs for all the data sets and juggling some of the parameters to see how the data gets culled. That is the process I used for this image.

ML
Click to expand...
I agree Mike. I will continue to use Blink for the initial visual check, and use the Frame Selection tool for a more 'scientific' culling.
 
Comet Hunter

Comet Hunter

Well-Known Member
20 min subs.... wait WHAT? I have never tried to take anything more than 8 or 10 min's. This target has always been elusive to me but then I only have tried to capture it using 5 min subs.
I guess I need to give it another try. At 20 min long subs, did you lose many? What bortle scale sky was this taken? That make a huge difference too!
Wonderful capture
 
Mike Lewis

Mike Lewis

Staff Member
Comet Hunter said:
20 min subs.... wait WHAT? I have never tried to take anything more than 8 or 10 min's. This target has always been elusive to me but then I only have tried to capture it using 5 min subs.
I guess I need to give it another try. At 20 min long subs, did you lose many? What bortle scale sky was this taken? That make a huge difference too!
Wonderful capture
Click to expand...
Ed,

Thanks for the feedback. I have always wanted to be able to do 20 minute subs, and with this mount I am able to do it. On this target, I took 43 20 minute subs between the Hα and Oiii data and lost 2 of them. pretty good. This was taken from Starfront Remote Observatories in Texas which they claim is Bortle 1, but I think it is likely closser to 2. But quite dark certainly.


ML
 
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