Markarians Chain - 800 Galaxies

[MarkS]

A revisit to Markarian's Chain. Sony A7S on Tak Epsilon.  340x30sec exposures i.e. nearly 3 hours of data:



Full size version: http://www.markshelley.co.uk/Astronomy/2016/markarian20160115.jpg

Annotated with around 800 galaxies:



Full size annotated: http://www.markshelley.co.uk/Astronomy/2016/markarian20160115_annotated.jpg

This compares remarkably well to the 50 hour image that I took with Canon 350D:
http://www.markshelley.co.uk/Astronomy/2012/markarianschain.html

I can't see anything in the Canon image that is not in the Sony image.  Obviously I'd like to take a few more hours and get those noise levels down further.

Mark

[RobertM]

Great colours in those galaxies.  Quite impressive really the difference in exposure for almost the same result !  I presume this was dithered ?

There should be lots more faint galaxies hiding in the noise so it should be even more impressive with more subs and a nice smooth background.

Robert

[Carole]

Lovely image Mark, that is quite a remarkable camera when you consider the comparison of a 50 hour image with the 350D to the 3 hours + with the A7S.

Have you decided to stick with the A7S Mark, or just processing what you had already captured while you make your mind up?

I'd really love to see what you could achieve with a mono set up, but seems you prefer OSC.
Why not have both?

Carole

[MarkS]

Lovely image Mark, that is quite a remarkable camera when you consider the comparison of a 50 hour image with the 350D to the 3 hours + with the A7S.

Have you decided to stick with the A7S Mark, or just processing what you had already captured while you make your mind up?

I'd really love to see what you could achieve with a mono set up, but seems you prefer OSC.
Why not have both?

I spent the whole of yesterday doing experiments and I think I may have found a way to acquire data on the Sony A7S without banding being too much of an issue.  The sky fog back-of-camera histogram needs to be a long way over to the right - then the coloured fringing in the bands seems to disappear.  It means I need to image at a higher ISO - 16000 instead of 2000.  Next New Moon I'll try it out.

Full colour imaging suits my dark location and OSC suits the variability of the English weather - however long the imaging session I'll always have all the data I need for a complete image.  If I ever run out of targets for full colour imaging I might consider mono!

Mark

[JohnP]

Nice Mark - Impressive stuff - Banding really showing in that image.. John

[MarkS]

Nice Mark - Impressive stuff - Banding really showing in that image.. John

Yes, quite obvious banding