Since I am only missing 5 of the 313 I have started redoing some of the older ones, which are classics.
Have done this before with my Tak 180 ED when I first got it. Color here but detail there. Regretting the retirement of the Tak... well my new ASI6200 is getting ready. I will have to make this one of my first targets... assuming the camera gets off my kitchen table.
Sh2 138 139 and PN Pk105 Hydrogen AlphaFrom
GalaxyMap:Sh 2-138: Embedded in this compact HII region is a large star cluster resembling the Orion Trapezium cluster: it is centrally peaked around several massive stars, and is dense - more than 550 stars at its centre.
According to Avedisova, Sh 2-139 is ionised by two giant stars:
LS III +57 38 (O9 III) and
LS III +58 37 (B2 III). SIMBAD disagrees with the spectral classification of LS III +57 38, however, and gives it a much cooler spectral class of B5.
GENERAL NOTE ON SHARPLESS2 OBJECTS>>>>>>>>>>>>>
There are 313 Sh2 objects. As of the date of this image I had imaged 308 (98%).
Here is the scorecard:
There are 12 too diffuse/large to image well with my set up (Sh2 111, 117, 122, 131, 132, 145, 178, 218, 221, 230, 268 and 310). I have imaged the first 6 of these mostly in the Nikon Wide angle shot referenced below and 178 and 230 as part of other images. I will do the rest at least once as they come into view this year. I missed 218, 221, 303, 304 and 310 last year running out of time. So there are 5 more to do here.
There are 5 that are never above 14 DEG (Sh2 2-6) but as of 7/12/21 I can get these now with pier upgrades and the images are completed as best as I can.
Sh2 43 was the last of the lower ones that I was able to complete on August 3 2021.
The 5 remaining all are in Expert Scheduler waiting for them to pass by. They are all higher elevations.
The first one was taken on December 23, 2013.
Many were taken with my old Tak 180 ED, which had a wide field of view, but was replaced with my Stellarvue 130, which is more narrow field. I have also taken two very wide field HA images with my Nikon D800 and a 50mm lens.
This is my collection:
Sharpless2
Wide-Angle Hydrogen Alpha Nikon Image Sh2 79-171
Please note there is also a Sharpless2 Group with now more than 1500 examples.
Sharpless2 Group
Other useful links include:
Gary Imm's Collection
GalaxyMap's Collection
The Sharpless Catalog
The MDW H-alpha Sky Survey
Reiner Vogel's detailed observing catalog
Hope you enjoy these obscure but interesting objects...
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