Core of the lion nebula-RGB OOH

[timh]

Sky conditions poor for some time but managed to do some HA imaging on Monday night

Astro-imaging - especially with a Newtonian - involves so many moving parts and complications that it is almost impossible not to fall foul of at least one error when returning after a break. The main one here was to have aligned the camera sensor differently from the alignment of the rest of the data from last year thus making for a rather small overlap and final field of view. Nevertheless the collimation, focus and quality of the 90 min of HA collected (FWHM ~ 2.05 arc sec) was very good before high humidity (93%) finally clouded up even the main mirror.

Here - using a SW PDS200 F 5.0 and ASI294 MC and MM cameras at 4.63 uM pixel size (0.95 arc sec/ pixel) - an image comprising 50 x 110s RGB frames (astronomik UHC filter gain 124), 20 x 3min O3 frames (Astronomik 6 nm, gain 151) and 31 x 3 min HA frames (Optolong 7 nm, gain 151). Mount was a CEM 70, guiding with PHD2 via a 80, 400mm guidescope plus ASI 120MM camera. Capture was with Sharpcap 4.0 and processing in PixInsight. Starless NB OOH and RGB images were prepared using StarExterminator 2.03, combined using Pixmath, streteched and RGB stars re-added at the end.

SH2-132 contains a number of new tight star clusters and the core region depicted below also comprises a (double) Wolf Rayet star WR153. There is a curious straight line edge - almost like a beam - in the OIII emission. This may be part of a blue ring around the WR star formed by high speed solar winds forming part of an expansion perimeter that, locally, appears straight? SH2-132 is distant at 10,000 light years or more. The Stellarium database puts the distance to WR 153 (AKA HD211853) as~ 15500 light years. One ( I now think unreliable?) source put WR153 at only ~ 1500 light years https://www.universeguide.com/star/110154/hip110154 . A University of Sheffield WR star database puts the distance to WR153ab at 4.06 kpsc http://pacrowther.staff.shef.ac.uk/WRcat/ - so the whole nebula and its ionizing stars are really quite distant at ~ 15000 light years

Tim