M82 revisited

[timh]

Finally some new images from this year's imaging. All at Bortle 7 (unfortunately more light pollution now)

Here revisited RGB Ha imaging of M82 to try and capture not only the streams of Ha and star formation erupting from the galaxy core under the tidal influence of M81 but also to use a combination of luminance lucky imaging and deconvolution (RC astro BlurXterminator) to uncover better detail of the dust lanes at the centre. Once thought to be an irregular galaxy it is now thought that we have an end on view of what is actually a small spiral galaxy - so disrupted by the gravitational effect of M81 that it is a starburst galaxy forming stars 10X faster than the entire (and much more massive) milky way.

VX12 300 mm/ F4 Newtonian with SW aplanatic coma corrector mounted on a CEM70 mount and guided using a f = 400mm 80mm achromat and ZWO ASI 120mini camera using PHD2 software. Focusing using a Pegasus Astro controller and Baader Steeltrack focuser. ZWO IR/UV cut filter used for all imaging.

407 x 40s OSC exposures at gain 140 using an ASI 294 MC camera at -5 C. 517 x 10s ASI 294 MM exposures at gain 150. 344 x 3 min and 33 x2 min using the mono camer and a 7 nm HA filter.

All of the above equipment was controlled from within SharpCap 4.0 and frames captured --along with master flats and darks - in Sharpcap using filters to reject high FWHM and dim frames. Pre-pocessing and processing was in PixInsight. The 10s luminance mono frames were combined into a relatively sharp FWHM 2.0 image. The HA was combined into the red channel of the OSC image and the combined luminance further combined with the BlurXterminator deconvolved mono10s image into an overall high dynamic range luminance composition made starless with StarExterminator 2.03. This HDRC luminance was then combined into the starless OSC image and further stretched in PI using EXP, local histogram equalization and Curves before RGB stars were combined back in. The image was further improved in Affinity Photo.

[Menno555]

Insane details Tim!

[turfpit]

Outstanding detail Tim.

Dave

[oopfan]

Amazing! Great work, Tim!

Brian

[timh]

Thanks very much Menno, Dave and Brian

I am pleased with it. This close up detail stuff is the kind of astrophotography that is possible under Bortle 7 skies -- and so it is an area that I have been focusing on cos it fits my home location - I must say that StarExterminator and BlurExterminator do make it easier. The latter is really just deconvolution but being now so much less laborious I find that I now apply the process to more images and more routinely.

Still room for improvement in M82 though - the HA data were poor (2 years old) and could be done in higher resolution ... the blue colour of the disc isn't really there and some of the transitions in the HDRC luminance are visible and giving some stippling. So hoping to add a version 2

Tim

[Vesmaobs261]

Way to go Tim. There sure is some dramatic happenings in
that galaxy that we in our quiet corner of the Milky Way want
no part of . Nice one.
George

[timh]

Thanks George, yes indeed - as I understand anyway in the midst of those streams of HA trailing away it's supernova alley with one going off every 20-30 years. Tim

[timh]

Getting a reasonably clear picture of the HA streaming from M82 takes a lot of imaging! The updated picture here has ~ 7 h total of HA with a 300mm F4 telescope - much under somewhat turbulent skies - I am glad in this instance to have had a mono camera because achieving the same (still fairly low) final SNR at the same resolution using an OSC would have taken about 28h!

Anyway picture now complete - think it is improved over the original - butprobably taken beyond the point of diminishing returns with respect to doing any more on it.




Tim