NGC6888 - Crescent Nebula (DLSR)

[Aramcheck]

From last night & early this morning... NGC6888 the Crescent nebula taken with the SW200dps & Canon 600d (astromodified), IDAS D2 light pollution filter & EQ6 mount + Bortle 6 sky. 44 x 3min subs.

According to the inter-web, it's about 5000 light years away & is about 25 light years across. The bright star at it's centre is a Wolf-Rayet star which is shedding it's outer envelope in strong stellar wind (ejecting the equivalent of the Sun's mass every 10,000 years). The Stellar wind is colliding with material previously ejected from the star, when it was in its Red Giant phase, with two shock waves moving inward & outward. The inward bound shock wave is said to be heating the stellar wind to x-ray emitting temperatures (million kelvin to hundreds of millions kelvin?).

Removing the light pollution gradient was a bit tricky due to the extent of the Ha in the region & I consequently lost some of it. Also had to drop 12 subs due to random movement in the RA, which I've yet to account for. I checked no cables were snagging & paused the image run to switched the initial guide star. Towards the end of the night I also had to change battery in the DLSR & tried running PHD2 calibration assistant (without success, though the RA seemed to better behaved afterwards).

Attached guide log, in case anyone can suggest anything I can improve on the dithering time-outs & the odd RA pulses.
Cheers,
Ivor

PHD2_GuideLog_2020-09-09_215940.txt

[MarkAR]

That's come out really well. This area is thick with nebulosity and can be tricky. Star reduction is a big benefit to this and similar targets, it'll bring forward the nebulosity.

[JeremyS]

Majorly impressed @Aramcheck!

[Aramcheck]

18 hours ago, MarkAR said:

Star reduction is a big benefit to this and similar targets, it'll bring forward the nebulosity.

So far, I haven't managed to get Deconvolution to produce decent results & on this image Starnet++ also didn't do a great job. I did tone down the stars to some extent using a star mask & Morphological Transformation in Pixinsight, but I think I need to spend more time playing with Deconvolution!

Cheers
Ivor

[MarkAR]

2 minutes ago, Aramcheck said:

using a star mask & Morphological Transformation in Pixinsight

You can always repeat the process see how it goes.