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Simeis 57 Propeller Nebula

Technical card

Resolution: 3240x2397

Dates: June 24, 2017June 28, 2017July 1, 2017July 2, 2017

Astronomik Ha 12nm 1.25": 20x600" -10C bin 1x1
Astronomik OIII 12nm 1.25": 20x600" -10C bin 1x1
Astronomik SII 12nm 1.25": 20x600" -10C bin 1x1

Integration: 10.0 hours

Darks: ~30

Flats: ~30

Bias: ~100

Avg. Moon age: 5.48 days

Avg. Moon phase: 35.99%

Temperature: 29.50 job: 1638883

RA center: 304.041 degrees

DEC center: 43.694 degrees

Pixel scale: 0.519 arcsec/pixel

Orientation: 91.696 degrees

Field radius: 0.290 degrees

Locations: Lighthouse Observatory, Burleson, Texas, United States


From: The Peculiar Nebula Simeis 57: I. Ionized Gas and Dust Extinction
F.P. Israel, M. Kloppenburg (Sterrewacht Leiden, The Netherlands), P.E. Dewdney (DRAO, Penticton, Canada), J. Bally (Univ. of Colorado, Boulder, USA)
(Submitted on 19 Nov 2002)
" ........... At optical and at radio wavelengths, the nebula has a peculiar ``S'' shape, crossed by long, thin and straight filaments. The radio maps, combined with other maps from existing databases, show essentially all radio emission from the peculiar and complex nebula to be thermal and optically thin. Although neither the distance nor the source of excitation of Simeis 57 are known, the nebula can only have a moderate electron density of typically n(e) = 100 cm-3. Its mass is also low, not exceeding some tens of solar masses. Peak emission measures are 5000 pc cm-6.Obscuring dust is closely associated with the nebula, but seems to occur mostly in front of it. ......"

The image was captured with the new Celestron CGE Pro mount and the venerable Meade 12"LX200 SCT, using my Atik 383L+ mono at F7.16 (i.e. 2182mm FL). Astronomik's Ha, OIII and SII narrow band filters were used. All subs were taken at 1x1 bin, and -10C and 10 minutes each.

Image information -- 2017
Ha : 20 subs (3.33 hr) Jun 24th and 28th.
OIII : 20 subs (3.33 hr) Jul 1st.
SII : 20 subs (3.33 hr) Jul 2nd.

Color Mix is the Hubble Palette (SHO):
Ha = Green
S2 = Red
O3 = Blue

Processing was done with PixInsight. Each filter set was integrated, processed and stretched. These were then combined with PixelMath per the Hubble palette. This final image was further processed in PI, bringing it to the level presented.
I continue working with RickS' ColorMask script to defeat the green and enhance the blue. I was not able to get much green out of the image.
North is to the right (I think), and this is a small crop due to inevitable sub movement from night to night.




Sky plot

Sky plot


Simeis 57  Propeller Nebula, niteman1946