Whale and Stick from Petts Wood

[Roberto]

I took this one over the last week or so and because of the above average conditions, I did not have to push the luminance or colour much for it to look decent enough to post.
Both galaxies have plenty of Ha knots which show well when the RGB and Ha data are combined. Check the annotated version at the link below. 
I last imaged these two in 2015 with a smaller chip:  https://www.astrobin.com/158735/C/

Roberto

Image details: https://www.astrobin.com/iuuqnp/C/

[ApophisAstros]

The Galaxy images are piling up , very good. I particularly like your stars that seem to have natural spikes.
Roger

[Roberto]

Hi Roger

Thank you.  I see you noticed the spikes in the stars; they shouldn't really be there as I use a refractor with no spider or central obstruction.  I believe they are caused by scattering effects on my CCD chip.  They don't look too bad though.

Roberto

[Carole]

These small galaxies have come out well Roberto.

Carole

[NoelC]

Lots of little galaxies in there too! You have really got a lot of detail out of the main targets.
Whats the reason for the slight stretching in the top right - is that optics?
A lot of work there Roberto, well done.
Noel

[Roberto]

Hi Carole, Noel

Thank you!

Yes Noel, the stretching is my field flattener not being properly spaced in that corner.  At 4k pixels a side, the sensor is quite large (36mm square) and spacing is critical.  I will work on improving this over the next full Moon.  Also, when the scope flips on a regular imaging session, the elongation is compensated as images are averaged in the final one.  In this case, most of the frames were taken with the scope on the East side of the pier and the optical error re-inforced.  This is visible in my recent image of the Virgo Cluster also.
Spacing varies a bit with temperature also and is more pronounced in spring; I machined my spacer out of Delrin which seems to do better than aluminium with changing temperatures; I may try to machine one out of aluminium and see if that is actually the case.

Thanks

Roberto

[RobertM]

Lovely detail and colour on those galaxies Roberto, lots of faint fuzzies too

[MarkS]

That's a great result with plenty of detail.  The seeing conditions on a couple of nights last week were superb which also allows a lot of fine detail to be extracted.

Mark

[Roberto]

Thank you Robert and Mark.  Indeed; the seeing was way above average for a few nights in a row.  I managed to split some doubles with my 10" f/20 Maksutov that I had struggled even to elongate in previous years.

Roberto

[MarkS]

Thank you Robert and Mark.  Indeed; the seeing was way above average for a few nights in a row.  I managed to split some doubles with my 10" f/20 Maksutov that I had struggled even to elongate in previous years.

I managed to obtain some unprecedented galaxy resolution from my C11 using the Sony A7S - unprecedented for me, that is.  I'm still processing the data but it's quite clear that a camera with smaller pixels would have been worthwhile on those nights

Mark