Casitas de Gila, Gila, NM, October 17 - 19, 2023

From my 2020 writeup:

NGC 281 is a large, bright emission nebula in the constellation Cassiopeia.  Astronomers, possessing a vivid imagination, named it after the 1970’s Pacman video game.  This nebula has strong signals in Ha, OIII and SII.  NGC 281 is about 41.5 light years across, and it is about 10,000 light years from Earth (SkySafari Pro).  There are striking dust lanes, with Pacman’s mouth being most prominent.  There are also a few Bok Globules where new stars may be forming.  There is an open star cluster in the center, IC 1590.  The bright star in the center, HD 5005, is actually member of a stable quintuple system.

Historical note:  Pacman was one of the first video games that appeared when I was in college in the 1970’s.  You put a quarter in the machine and then you guided Pacman through a maze to gobble up things to build a score and avoid hazards to stay alive.  It was extremely popular in bars and on college campuses (something I researched extensively).  Later, Ms. Pacman came on the scene in response to the Woman’s Liberation movement and became more popular than Pacman.  By using your imagination, the Pacman Nebula does have some similarity to Pacman and Ms. Pacman gobbling up space.

Waka Waka Waka…

I first imaged NGC 281 in 2020 with a 9.25” SCT.  It filled the frame and was a so-so image.  With the 4” refractor, I collected subframes with Red, Green, and Blue broadband filters for the stars, and Hydrogen-alpha (5nm), Oxygen-III (3nm), and Sulfur-II (3nm) narrowband filters.  I started with the standard Hubble pallet SHO combination, and then processed a starless version to get a blend of colors.

Imaging details:

Stellarvue SVX102T refractor with 0.74x focal reducer (FL = 528mm, f/5.2)
ZWO large off-axis guider with a ZWO ASI 174MM mini guide camera
Losmandy G11 mount with Gemini 2
ZWO ASI 2600MM Pro cooled monochrome camera (-10C)
Chroma 36mm Hydrogen-alpha, Oxygen-III, Sulfur-II, Red, Green, and Blue filters
Equatorial camera rotation: 0 degrees

Software:    Sequence Generator Pro, ASTAP plate solving, PHD2 guiding, 
    Losmandy Gemini ASCOM mount control and web client interface,
    SharpCap Pro for polar alignment with a Polemaster camera,
    PixInsight 1.8.9-2,
    Photoshop 2024

Hydrogen-a 10 min x 20 subframes (200 min), Gain 100, Offset 32, 1x1 binning
Oxygen-III  10 min x 21 subframes (210 min), Gain 100, Offset 32, 1x1 binning
Sulfur-II.     10 min x 22 subframes (220 min), Gain 100, Offset 32, 1x1 binning
Red             2 min x 32 subframes (64 min), Gain 100, Offset 32, 1x1 binning
Green          2 min x 30 subframes (60 min), Gain 100, Offset 32, 1x1 binning
Blue            2 min x 30 subframes (60 min), Gain 100, Offset 32, 1x1 binning

Total integration time: 13.6 hours