NGC 6888 - Crescent Nebula,Cygnus

[Mike JW]

Oh no not another image of the Crescent Nebula!!! However having checked the EEVA section we last had a post in 2018 and previous to that it was 2014. What prompted me to have a look was an image with a small scope that had 3 hours or so of run time. and wondered what the EEVA technique would achieve.

What you see is 4m 30 sec of 10 second shots using my 15" Dob and the ultrastar. A pity I don't do colour. I had to combine two shots to get the full width of the nebula in view.

A few facts: this emission nebular is about 25 lyrs across and around 5000lyrs away. It is caused by the Wolf Rayet star (WR136,HD 192163) - it is the bright star more or less at the centre of the fov. This star is shedding the mass equivalent of our sun every 10,000 years. Its super fast solar wind has caught up the slow moving wind from when it became a red giant and the interaction is heating up the gas - shockwave effect; which is what we see.

 

Mike

 

 

Edited September 5, 2021 by Mike JW

[AKB]

32 minutes ago, Mike JW said:

we last had a post in 2018

…so this one isn’t yours … ? 😉

 

[Mike JW]

Well spotted - I thought I had posted something but could not find it!! Oh dear age is catching me up - must up the medication!!!!!!!

Thanks for highlighting it. This second attempt is somewhat better?

Cheers,

Mike

[AKB]

On 05/09/2021 at 11:44, Mike JW said:

This second attempt is somewhat better?

You’re not wrong there!

There’s clearly a difference between:

• C11 at f6.3, ultrastar mono. 10 x 15 sec subs.
• 4m 30 sec of 10 second shots using 15" Dob and the ultrastar.

plus, of course, the presence of the moon in the first one.

Wish I had a telescope with me last night.  It was warm and clear and looking great to the naked eye, but I was away from home.  Typical!

Tony

[roelb]

I can't resist either to image NGC 6888 once a year...😀

ASI533MC-Pro

11 x 30 s

 

[Mike JW]

The crescent is not the only DSO worthy of an annual visit.

Mike