Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: MarkS on Apr 25, 2018, 00:40:57

Title: M101 Friday 20 April
Post by: MarkS on Apr 25, 2018, 00:40:57
Here is M101 taken last Friday.

Sony A7S on Celestron C11 with Starizona large format corrector (F7.2)

420x30sec at ISO 10000 i.e. 3.5 hours of total exposure time.

Again I used Bayer Drizzle stacking in PixInsight to preserve maximum sharpness followed up by slight deconvolution on the brighter areas of the image.

(http://www.markshelley.co.uk/Astronomy/2018/M101_C11_20180420.jpg)

This is a quick processing job because unfortunately the stars are egg shaped - especially on the left hand side.  My suspicion is that the collimation was slightly out.  So I'm not as pleased with this image as the M51 Whirlpool Galaxy.  M101 is a tougher target in any case - especially those very faint outer arms.

Here's the larger version (crop at 100% scale):
http://www.markshelley.co.uk/Astronomy/2018/M101_C11_20180420.jpg

Mark
Title: Re: M101 Friday 20 April
Post by: Carole on Apr 25, 2018, 10:26:51
Lusciously lovely Mark, Most people would be quite happy with those stars in any case Mark, but you are a perfectionist.

I find this target very difficult and have yet to get a capture of it I am happy with.  Do you think the central detail might sharpen up a bit or have you already done that?

Carole
Title: Re: M101 Friday 20 April
Post by: NoelC on Apr 25, 2018, 12:28:28
Pretty fantastic Mark
Well done.
Noel
Title: Re: M101 Friday 20 April
Post by: JohnP on Apr 25, 2018, 14:04:30
Have to say you are highly critical Mark - this is a really difficult object due to its low overall surface brightness - Have to say this is one of the best presentations of this I have seen.. John
Title: Re: M101 Friday 20 April
Post by: Mac on Apr 29, 2018, 14:58:42
Again a very nice image,

Im sure between all of our imagers, there must be
a messier book to be published somwhere.

Mac