Walton OR and Likely CA, June 11 and 15, 2022

I started this project in Oregon and finished it in Likely California.  LDN 1235 has become a very popular target for astrophotographers.  Conditions in Oregon and California had average transparency and seeing.  The object started low in the sky, and with short nights, it finished approaching the meridian just before dawn.  Processing was straight forward using PixInsight, Russ Croman’s Xterminator tools, and some tools in Photoshop.  I was satisfied with the resulting nebula.  However, the bright stars had large halos, diffraction spikes, and some color distortion.  The halos could be due to my laziness when blinking through the subframes.  There were a few Luminance frames with bright background and less detail, caused by either high, thin clouds or the approaching morning light.  I need to reprocess without those frames.  I have noticed, with the widefield telescope in particular, that there seems to be more and more satellite trails from Starlink; a plague on us all.

Dark dust like that in the Dark Shark is somewhat like cigarette smoke and created in the cool atmospheres of giant stars.  This molecular cloud also contains organic compounds, the building block of life.  After being expelled with gas and gravitationally recondensing, massive stars may carve intricate structures into their birth cloud using their high energy light and fast stellar winds as sculpting tools. The heat they generate evaporates the murky molecular cloud as well as causing ambient hydrogen gas to disperse and glow red.  The remaining clouds form into a myriad of shapes waiting to be imaged.  LDN 1235 spans about 15 light years and lies about 650 light years away toward the constellation of the King of Aethiopia (Cepheus).  (NASA)

LDN 1235 does indeed look like a shark (no stretched or averted imagination required).  There are several nice reflection nebulae near the head, including the blue vdB 149 and vdB 150. Another small gem can be seen shining through the dust, spiral galaxy PGC 67671, with its light scattered and reddened by the nebula’s dust.  It is about 81 million light years away.  Near the upper left edge of the frame is a very small, edge on galaxy, PGC 68620.

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 (-10oC)
Chroma 36mm Luminance, Red, Green, and Blue filters
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 a Polemaster camera,
    PixInsight 1.8.9-1,
    Photoshop 24.5 2023

Luminance  2 min x 120 subframes (240 min), Gain 100, Offset 32, 1x1 binning
Red             4 min x 19 subframes (76 min), Gain 100, Offset 32, 1x1 binning
Green          4 min x 22 subframes (88 min), Gain 100, Offset 32, 1x1 binning
Blue            4 min x 22 subframes (88 min), Gain 100, Offset 32, 1x1 binning