Casitas de Gila, Gila, New Mexico, October 21-24, 2022

During my trip to New Mexico, I wanted to image LBN 576, the Popped Balloon nebula, a faint supernova remnant in Cassiopeia.  However, there was an issue in Sequence Generator Pro’s Framing and Mosaic Wizard where it set the RA to 24hr instead of 0hr.  When SGP attempted to calculate the Alt/Az coordinates to send a slew command to the mount, it gave me a calculation failed error (the problem was sent to Main Sequence Software).  So, I picked SH2-132, the Lion Nebula as the first target of two since it was high in the sky.  This is a large emission nebula with newly formed, bright stars.  I captured narrowband Hydrogen-alpha, Oxygen-III and Sulfur-II filter data for the nebula and Red, Green and Blue broadband subframes for the stars.

In post processing with PixInsight, I used the calibrated and integrated red, green and blue master images for the stars.  I used StarXTerminator to remove the red nebulosity.  The stars image was denoised, stretched and saturated.  I decided to have some fun constructing the false color image with the narrowband master images.  First, I used StarXTerminator to remove the stars and then NoiseXTerminator to denoise each channel.  I deviated from the classic Hubble pallet (SHO) and the HOO bicolor combination.  Instead, I used the SHO-AIP color combination script with rescaling to add differing amounts of each filter into the R, G and B color channels: Red – 90% SII and 10% Ha, Green – 80% Ha and 20% OIII, Blue – 120% OIII.  The result was pleasing and interesting to me as it enhances structure detail with color.  I did notice a significant improvement in image quality using Chroma filters.  The rest of the image processing workflow was straight forward, made easy with starless images.  The stretched, sharpened and saturated starless nebula was combined with the stars using the PixelMath combine function with the opscreen() parameter.

SH2-132 is a large, visible emission nebula at the southern edge of the constellation Cepheus near Lacerta, placing it in the Perseus arm of the galactic disk.  It is about 10,400 light years from Earth.  The stars responsible for the ionization of its gases are very hot and massive.  In particular, two Wolf-Rayet stars have been identified (HD 211564 and HD 211853 (WR 153)), as well as a star of spectral class O8.5V and a dozen stars of class B.  Around the class O star and one of the Wolf-Rayet stars extends a clearly visible bubble in the band of radio waves, Shell B, which probably originated from the stellar wind of the two massive stars.  A similar but smaller structure, Shell A, houses a star of class K near its center.  It is believed that chain star formation processes have taken place in the nebula in the past. (Wikipedia and SkySafari Pro).

Imaging details:

Stellarvue SVX102T with SFR0.74 focal reducer (FL = 528mm, f/5.2)
ZWO off-axis guider (OAG-L) with a ZWO ASI 174MM mini guide camera
Losmandy G11 mount with Gemini 2
ZWO ASI 2600MM Pro cooled monochrome camera (-10oC)
Chroma 36mm filters:  5nm Hydrogen-alpha, 3nm Oxygen-III, 3nm Sulfur-II, Luminance, Red, Green, and Blue
Equatorial camera rotation: 0o

Software:    Sequence Generator Pro, ASTAP plate solving, PHD2 guiding, 
    Losmandy Gemini ASCOM mount control and web client interface,
    SharpCap Pro for polar alignment with the Polemaster camera,
    PixInsight 1.8.9 with StarXTerminator (AI version 10) and NoiseXTerminator,
    Photoshop CC 2022

Hydrogen-a    10 min x 22 subframes (220 min), Gain 100, Offset 68, 1x1 binning
Oxygen-III       10 min x 22 subframes (220 min), Gain 100, Offset 68, 1x1 binning
Sulfur-II           10 min x 22 subframes (220 min), Gain 100, Offset 68, 1x1 binning
Red        4 min x 22 subframes (88 min), Gain 100, Offset 68, 1x1 binning
Green    4 min x 22 subframes (88 min), Gain 100, Offset 68, 1x1 binning
Blue       4 min x 22 subframes (88 min), Gain 100, Offset 68, 1x1 binning

Total integration time: 15.4 hours