Gold Canyon, AZ, Tucson, AZ, December 25, 26 and 31, 2022

These galaxies were the last target of three to be imaged over three nights.  The weather in Arizona has been awful, with clouds and sustained rain.  This limited imaging time during my holiday trip to Gold Canyon and Tucson.  I captured as many subframes as possible from 3AM until 6AM using Red, Green, Blue and Hydrogen-alpha filters.  Once again,  I used BlurXTerminator, NoiseXTerminator and StarXTerminator in PixInsight at various points in my workflow to bring out the best in limited data.  The most challenging step was to blend the Hydrogen-alpha data into the RGB color image.  It turned the core region of M81 reddish.  GAME script masks and the CurvesTransformation tool were used in PixInsight to tune the color balance.  Photoshop was used to affect specific areas in the galaxies with selective sharpening, saturation, desaturation, dodging and burning.

All three galaxies are a part of the M81 group, gravitationally bound to each other.  The three largest members in the M81 group are prominent in the image:

M81, Bode’s Galaxy, or the Great Spiral in Ursa Major, is a spiral of type SA(s)ab.  It is a popular object for observers and astrophotographers.  M81 is about 11.8 million light years away.  It is about 70,000 light years in diameter, smaller than our Milky Way galaxy and it contains around 250 billion stars.  M81 has a close partner galaxy, M82 which is about 130,000 light years away from it.  M81 caused a large gravitational distortion in M82 in their last close interaction.  M81 and M82 were discovered by Johann Elert Bode in 1774 (Wikipedia, NASA, SkySafari Pro).

M82, the Cigar Galaxy, is a starburst type IO galaxy with massive jets of hydrogen and new stars emanating from its disk.  The distortions caused by the last M81 flyby caused upheaval in the galaxy structure leading to the new star forming regions that are the glowing red hydrogen filaments.  It was thought to be an irregular galaxy, but recent observations have detected two spiral arms.  M82 is about 40,800 light-years in diameter, and it is approximately 12 million light years distant.

NGC 3077, the Garland Galaxy, is of type IOpec.  It is similar to an elliptical galaxy, and at one time was classified as peculiar; it has wispy edges and scattered dust clouds, a result of gravitational interaction with its larger neighbors, and this galaxy has an active nucleus (an emission source).  NGC 3077 is about 12.8 million light years from Earth.  It was discovered by William Herschel on November 8, 1801. (Wikipedia).

Other galaxies in the image include Holmberg IX (PGC 28757) an irregular galaxy just above M81, PGC 28731 a faint spiral to the left of M81, PGC 28802 a spiral galaxy near the left edge of the frame, and PGC 28225 a spiral galaxy at the bottom of the frame.

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 (-10C)
Chroma 36mm filters:  3nm Hydrogen-alpha, Red, Green, and Blue
Equatorial camera rotation: 270 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 the Polemaster camera,
    PixInsight 1.8.9-1 with BlurXTerminator, StarXTerminator, NoiseXTerminator,
    Photoshop CC 2022

Red        4 min x 28 subframes (112 min), Gain 100, Offset 68, 1x1 binning
Green    4 min x 28 subframes (112 min), Gain 100, Offset 68, 1x1 binning
Blue       4 min x 32 subframes (128 min), Gain 100, Offset 68, 1x1 binning
Ha.        10 min x 11 subframes (110 min), Gain 100, Offset 68, 1x1 binning

Total integration time: 7.7 hours.