The Propeller Nebula (DWB 111) in HST variation

Posted by CraigAndTammy
on Tuesday, July 30, 2013

The Propeller Nebula is an HII emission nebula in the constellation Cygnus, the swan. Not much is known about this nebula. Information such as the source of excitation and distance remain undetermined. It is believed that the mass of this nebula is quite low, probably less than 50 solar masses. There is obscuring dust associated with this peculiar structure, but seems to occur mostly in front of it. Designations for this nebula are DWB-111, Semeis 57 and MRSL 479.

This image is presented here in a variation of the standard Hubble palette (HST) where Ha = green, SII = red, OIII = blue. Some adjustments were made using levels, curves, and hue & saturation to subdue the green, which tends to overpower the image in standard HST, and bring out the reds and blues from the other two channels.

Telescope: Sky Watcher Quantum 120 Apo @ f/7
Accessories: SW Quantum matched flattener; Dew control by Dew Buster; Alnitak Flat-Man; Gerd Neumann Aurora flat panel
Mount: Takahashi EM-200 Temma2
Camera: QSI583wsg CCD @ -10.0C
Guiding: Starlight Xpress Lodestar via PHD
Filters: Astrodon 5nm Ha, OIII, SII filters
Exposure: 18 x 20min. binned 1x1 each in Ha, OIII, SII
Acquisition: ImagesPlus 5.0 Camera Control
Processing: PixInsight 1.8; Adobe PhotoShop CS5; Noel Carboni’s Actions
Date(s): June 19 – 21, July 7, 11 & 12, 2013
SQM reading (begin - end): N1:18.20 – 18.61; N2:18.08 – 18.36; N3:17.87 – 18.11; N4:19.19 – 19.42; N5: 19.15 – 19.21; N6: 19.21 – 19.27
Temperature (begin - end): N1:76.1ºF – 70.5ºF; N2:74.7ºF – 70.2ºF; N3:77.0ºF – 71.1ºF; N4:76.5ºF – 71.2ºF; N5:73.4ºF – 69.4ºF; N6:69.3ºF – 67.6ºF
Capture conditions: N1 - transparency: Avg 3/5; seeing: Good 4/5; N2 - transparency: Avg 3/5; seeing: Good 4/5; N3 - transparency: Avg 3/5; seeing: Good 4/5; N4 - transparency: Below avg 2/5; seeing: Avg 3/5; N5 - transparency: Transparent 5/5; seeing: Below avg 2/5; N6 - transparency: Transparent 5/5; seeing: Avg 3/5
Location: Hendersonville, TN, USA

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