Casitas de Gila, Gila, NM, October 14 - 15, 2023

There are many interesting dark and reflection nebulae in the Taurus molecular cloud.  Barnard 7 is the large dark nebula in the center with blotchy dark patches.  LBN 782 is the blue reflection nebula in the lower center of B7.  To the left side is vdB 27, illuminated by RY Tauri, a young variable star.  To the right is another reflection nebula illuminated by variable star CW Tauri (J. Trezzo, Cosmic Colors).  There are also three small, distant galaxies in the upper right corner of the image (the brightest is PGC 14705).  A few other distant galaxies are scattering amongst the stars.

This project was an experiment to determine if using only red, green, and blue filter data could produce an image with the same sharpness/contrast as one incorporating Luminance data.  As the second target of the night, limited R,G, and B subframes were taken, totaling 7.2 hours of integration time.  The final image is not as sharp as others and has some mottling effect as the noise was significant, even with repeated applications of NoiseXTerminator.  Normally, I would take 3+ hours of luminance and 1 hour each of R, G, and B.  This would require 6 hours of total integration time.  Luminance captures all photons across the filter’s passband, whereas there are gaps between the passbands of the color filters.  I could add 1 more hour of luminance to get 7 hours of total integration.  Thus, using luminance with RGB can capture more photons for the same imaging time.

Once again, there were issues with the beta version of GraXpert using the AI gradient removal method, so I used DBE to reduce color gradients.  SPCC in PixInsight failed, so I had to use the ColorCalibration tool.  I am using the Gaia DR3/SP small set downloaded from the PixInsight software distribution system.  Perhaps with such a dense star field, SPCC needs to use fainter stars found in the full catalog (to be determined).

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, Luminance, 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

Red             4 min x 37 subframes (148 min), Gain 100, Offset 32, 1x1 binning
Green          4 min x 37 subframes (148 min), Gain 100, Offset 32, 1x1 binning
Blue            4 min x 34 subframes (136 min), Gain 100, Offset 32, 1x1 binning

Total integration time: 7.2 hours