Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

VDB 140

  • Please log in to reply
11 replies to this topic

#1 schmeah

schmeah

    Fly Me to the Moon

  • *****
  • topic starter
  • Posts: 6,249
  • Joined: 26 Jul 2005
  • Loc: Morristown, NJ

Posted 06 August 2022 - 03:35 PM

VDB 140 is a blue reflection nebula associated with the star HD 203025 (V421 Cephei) a spectral type B2III blue giant binary star in the constellation Cepheus. It is 2741 light years distant. Although primarily known as a reflection nebula, some recent widefield images taken of the popular nearby Flying Bat and Squid Nebula have included VDB 140 in the periphery, and HA filters clearly show some dense emission nebulosity surrounding the same star. A hint of red is apparent in this LRGB image. Since I've not seen this nebula shot in detail at long FL, perhaps I'll try to shoot some Ha. I'm unable to find a designation for the dark nebula to the lower left, but it is part of a complex that I was not able to fit in the FOV.

https://www.astrobin.com/l3ih4w/

https://pbase.com/ds...image/172849445

Thanks for looking.

Derek

 

9D0F5AF0-3B76-4A03-BDD0-22A611D3057A.png


Edited by schmeah, 06 August 2022 - 04:51 PM.

  • Jim Thommes, Mert, rwstanley and 12 others like this

#2 Mert

Mert

    Cosmos

  • *****
  • Posts: 9,546
  • Joined: 31 Aug 2005
  • Loc: Spain, Pamplona

Posted 07 August 2022 - 05:09 AM

Great capture and processing!


  • schmeah likes this

#3 wb6pco

wb6pco

    Explorer 1

  • -----
  • Posts: 69
  • Joined: 18 Jun 2022
  • Loc: Hereford, AZ

Posted 07 August 2022 - 09:31 AM

This is a good start but you need a lot more exposure time. I shot this with an OSC camera in 2010. With 21 hours of data it was still anemic. In 2015 I added 4 hours of Lum data and that helped. Now with new software I've been able to improve it further (less noise, fewer stars & brighter nebula). There's a lot of the brown dust in the field and indeed there is a hint of red within the main blue nebula. I don't think there is a dark nebula in the lower left. It's just fainter brown dust.

 

http://astrophotogra...tos/vdb140.html

 

It's not a perfect image but I don't think I'll be returning to it. 


Edited by wb6pco, 07 August 2022 - 09:32 AM.

  • yzhzhang and SoDaKAstroNut like this

#4 schmeah

schmeah

    Fly Me to the Moon

  • *****
  • topic starter
  • Posts: 6,249
  • Joined: 26 Jul 2005
  • Loc: Morristown, NJ

Posted 07 August 2022 - 11:02 AM

This is a good start but you need a lot more exposure time. I shot this with an OSC camera in 2010. With 21 hours of data it was still anemic. In 2015 I added 4 hours of Lum data and that helped. Now with new software I've been able to improve it further (less noise, fewer stars & brighter nebula). There's a lot of the brown dust in the field and indeed there is a hint of red within the main blue nebula. I don't think there is a dark nebula in the lower left. It's just fainter brown dust.

 

http://astrophotogra...tos/vdb140.html

 

It's not a perfect image but I don't think I'll be returning to it. 

That’s a beautiful image. And you’re right of course about the exposure time. However, from my bright skies (SQM 17.8), I suspect that even with 10x the exposure I could never approximate the detail that you got in your image. But how is that not a dark nebula at 7 O’Clock? It’s pretty clearly a dark nebula in your image.

 

Derek



#5 wb6pco

wb6pco

    Explorer 1

  • -----
  • Posts: 69
  • Joined: 18 Jun 2022
  • Loc: Hereford, AZ

Posted 07 August 2022 - 02:31 PM

But how is that not a dark nebula at 7 O’Clock? It’s pretty clearly a dark nebula in your image.

 

Derek

 

Maybe we're not talking about the same thing. I'm referring to the extreme lower left corner where I see brown dust. If you're talking about the small dark patches closer to the orange star then those certainly are dark nebulas.



#6 schmeah

schmeah

    Fly Me to the Moon

  • *****
  • topic starter
  • Posts: 6,249
  • Joined: 26 Jul 2005
  • Loc: Morristown, NJ

Posted 07 August 2022 - 07:12 PM

Maybe we're not talking about the same thing. I'm referring to the extreme lower left corner where I see brown dust. If you're talking about the small dark patches closer to the orange star then those certainly are dark nebulas.

Sorry.  I thought it was obvious. More visible in formats other than that permitted on CN.

 

16058130-8EE6-4757-BA79-6968DC321848.png



#7 wb6pco

wb6pco

    Explorer 1

  • -----
  • Posts: 69
  • Joined: 18 Jun 2022
  • Loc: Hereford, AZ

Posted 07 August 2022 - 08:03 PM

Sorry.  I thought it was obvious. More visible in formats other than that permitted on CN.

 

attachicon.gif16058130-8EE6-4757-BA79-6968DC321848.png

I see the area you're talking about in my image but I'm not seeing the lack of stars typically associated with dark nebula. I only see thin brown dust in my image with a similar density of stars to other areas in the image. I suspect you can't find it in any catalog because it's not there. wink.gif



#8 schmeah

schmeah

    Fly Me to the Moon

  • *****
  • topic starter
  • Posts: 6,249
  • Joined: 26 Jul 2005
  • Loc: Morristown, NJ

Posted 07 August 2022 - 08:17 PM

I see the area you're talking about in my image but I'm not seeing the lack of stars typically associated with dark nebula. I only see thin brown dust in my image with a similar density of stars to other areas in the image. I suspect you can't find it in any catalog because it's not there. wink.gif

So, no need to wink. I have no idea what you are talking about or implying. The -thing- that I circled is clearly in your image, just far more detailed than in mine. And it is clearly a dark nebula as far as I know them to be defined. If not, then what is it?  PM me if you can’t be frank in a thread post.

 

Derek



#9 wb6pco

wb6pco

    Explorer 1

  • -----
  • Posts: 69
  • Joined: 18 Jun 2022
  • Loc: Hereford, AZ

Posted 07 August 2022 - 08:49 PM

So, no need to wink. I have no idea what you are talking about or implying. The -thing- that I circled is clearly in your image, just far more detailed than in mine. And it is clearly a dark nebula as far as I know them to be defined. If not, then what is it?  PM me if you can’t be frank in a thread post.

 

Derek

 

In my image the density of stars in the area you circled in your image is essentially the same as the upper right corner in my image where there is no nebulosity. A dark nebula needs to block stars to some extent. That's how I understand it. I don't see that in my image. If you removed the splotchy brown dust there would just be clear background sky.

 

In my image there are a half dozen or so dark areas with very few stars between your circled area and the orange star. Those meet my definition for dark nebula.

 

What is your definition of a dark nebula? 



#10 schmeah

schmeah

    Fly Me to the Moon

  • *****
  • topic starter
  • Posts: 6,249
  • Joined: 26 Jul 2005
  • Loc: Morristown, NJ

Posted 07 August 2022 - 09:02 PM

No, the density of stars in your image over that dark dusty segment is not the same as in the surrounding area. In fact it seems as though it is sitting in a starless area, with the exception of a single star which is no doubt a foreground star. When the dust is so dense that it appears black, or at least far darker than the surrounding background, I would say that is a dark nebula. Would you then also say that this is not a dark nebula?

https://www.myastros....com/barnard150

 

Derek


Edited by schmeah, 07 August 2022 - 09:05 PM.


#11 wb6pco

wb6pco

    Explorer 1

  • -----
  • Posts: 69
  • Joined: 18 Jun 2022
  • Loc: Hereford, AZ

Posted 08 August 2022 - 08:35 AM

Of course B150 is a dark nebula and is a great example of one but I don't see anything like that in my vdb140 image except for the half dozen or so small dark spots that I previously mentioned. Anyway, I think we've beat this to death. We just don't seem to be seeing the same thing.



#12 schmeah

schmeah

    Fly Me to the Moon

  • *****
  • topic starter
  • Posts: 6,249
  • Joined: 26 Jul 2005
  • Loc: Morristown, NJ

Posted 08 August 2022 - 11:28 AM

Of course B150 is a dark nebula and is a great example of one but I don't see anything like that in my vdb140 image except for the half dozen or so small dark spots that I previously mentioned. Anyway, I think we've beat this to death. We just don't seem to be seeing the same thing.

I agree completely ... that we've beaten this to death. Thanks.

 

Derek




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics