Imaging during a bright Moon

[Rodd]

This was one of the most productive Moon cycles I have had.  I decided to make the most out of the bright conditions as they were otherwise clear and the temperature was cold (20 degrees F).  Naturally I stuck with Ha, and not being one to pass up a clear night, found myself with an unusally large number of cloudless evenings.  These 3 imges represent a cumulative integration tie of about 45 hours of a wide variety of targets...a galaxy, an emission nebula, and a planetary nebula (a very odd one at tat).  You know the target is dim when 16.5 hours of Ha barely registers an image--That would be the planetary nebula HFG1--a shock wave in the interstellar medium caused by a rapidly moing binary star.  Anyway--here are the fruits of my 60-100% Moon efforts.  The image of the HFG1 is stretched too aggresively in order to bring out the faint shock front in front of the nebula.  I find it discuoraging that there is so much noise and roughness in a 16.5 hour Ha image.  Hopefully the OIII will help.

TOA 130 with ASI 1600 and 3nm Astrodon Ha filter, 300 sec subs

IC 342: 149 300 sec subs

 

Fish Head Nebula: 191 300 sec subs

HFG1: 198 300 sec subs

Edited November 17, 2019 by Rodd

[don4l]

That Fishead raises the bar a bit.  Superb.

[JamesF]

I'd never heard of HFG1.  Had to go and look it up.  Such a shame that Abell 6 didn't quite make it fully onto the top left corner.

James

[Rodd]

26 minutes ago, don4l said:

That Fishead raises the bar a bit.  Superb.

Thanks Don

[Rodd]

11 minutes ago, JamesF said:

I'd never heard of HFG1.  Had to go and look it up.  Such a shame that Abell 6 didn't quite make it fully onto the top left corner.

James

I know.  I was surprised at how bright the little bubble is, and it is bigger than I thought.  After careful consideration I realized that if I tried to get both targets into the image, both would suffer.  Both would be squished into their respective corners more than I would like.  I think Abell 6 will make a nice stand Alone target.  Or, I might image this area again with a wider FOV. Its a hard decision to make though.......a time hungry target 

[Craney]

I'm surprised HFG1  does not have a more 'popular' name.   Just looking at it,   it strikes me as being the  "Cats Paw"  Nebula.

Somebody on astrobin used  1800 second  subs  !!!! to tease it out.   That's more clear sky in one image than I get in a month.

[ollypenrice]

I never go out and battle the moonlight but perhaps I should!

Olly

[Rodd]

5 hours ago, Craney said:

I'm surprised HFG1  does not have a more 'popular' name.   Just looking at it,   it strikes me as being the  "Cats Paw"  Nebula.

Somebody on astrobin used  1800 second  subs  !!!! to tease it out.   That's more clear sky in one image than I get in a month.

Maybe it has no name because it is so faint and new (1982 I Think...sort of new I guess). I think it looks like a horseshoe crab (the HaOIII images). It is not in my planetarium software or the 2000 star atlas.

Edited November 18, 2019 by Rodd

[Rodd]

3 hours ago, ollypenrice said:

I never go out and battle the moonlight but perhaps I should!

Olly

Sometime it’s the only clear sky I get in a month.  If you stick with targets that are not too close to the Moon, you can collect data that would otherwise steal time away from the other filters...I find this especially true for galaxies-targets where the Ha is not the main attraction. I suppose if you get a lot of clear nights missing a few every month wouldn’t be so bad. But if I didn’t image during a moon I wouldn’t image much

Rodd

[MartinB]

Great work Rodd.  Using a Baader 7nm filter I find my background sky glow isn't raised by that much even with a large moon, provided the target isn't too close.  Sure it will impact on contrast to some extent but for those of use who have cloudy, light polluted skies it is important not to be too prissy about such things!

[Rodd]

23 minutes ago, MartinB said:

Great work Rodd.  Using a Baader 7nm filter I find my background sky glow isn't raised by that much even with a large moon, provided the target isn't too close.  Sure it will impact on contrast to some extent but for those of use who have cloudy, light polluted skies it is important not to be too prissy about such things!

I agree--I measure my median value of the subs as they come off the camera and they remain at about 53 (as reported by PI's SFS) for Ha regardless of the size of the Moon.  I do find that background is not as good.  For example, I am sure the above HFG1 would be better if the data was collected with no Moon--I would need much less data.  But that target is very faint.  For targets like the Heart, Soul, NGC 7000, the bright ones, I see almost no impairment.

Rodd

[retret66]

This one @ 82% moon.. The ghost of Casseiopeia, IC 59. Taken 11/16 2019 bortle 6/7. 7hrs of imaging time..

 

Edited November 19, 2019 by retret66

[Rodd]

39 minutes ago, retret66 said:

This one @ 82% moon.. The ghost of Casseiopeia, IC 59. Taken 11/16 2019 bortle 6/7. 7hrs of imaging time..

I think this is a good example of how the targets are not effected much--but background can be a bit more challenging--but dooable.

Rodd