Revisiting my old friends with the new camera. More work fine tuning the star coloration. Tested several NB masks over the bright stars varying Scale at 3, 4, 5 and 7. . This is with Noise threshold =2; Scale 4; Smoothness 14. I put up 5 scaling also to show the difference.
There is also a O-III signal under all this H-alpha but I cannot find a way to bring it out without distortions. Seems to completely overlap the H-alpha in my hands.
From
GalaxyMap:This HII region lies in the same direction as the radio source W71 and is ionised by the O6 Ib supergiant
LS III +46 12 which is part of the star cluster
Berkeley 90. The cloud surrounding Berkeley 90 (part of which is visible as Sh 2-115) contains 4400 solar masses of gas and dust and is about 30 pc long.
GENERAL NOTE ON SHARPLESS2 OBJECTS>>>>>>>>>>>>>
There are 313 Sh2 objects and I have imaged all one way or another.
The first one was taken on December 23, 2013 and the series completed October 17, 2019.Some of the challenges with this series are FOV size and low declination:
FOV: There are 11 too diffuse/large to image well with my set up (Sh2 111, 117, 122, 131, 132, 145, 178, 218, 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.
DEC: 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.
EQUIPMENT: 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. I transitioned from my CCD SBIG 8300M to a CMOS ZWO ASI6200M Pro in September 2021. 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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