The Hidden Galaxy
Image Details:
This galaxy is the third-largest by apparent size visible to Northern Hemisphere photographers behind the Andromeda (M31) and Triangulum (M33) galaxies. Despite its apparent size it is difficult to capture as it lies somewhat in the band of our own Milky Way, meaning the Milky Way’s own dust somewhat obscures it. While this was captured during a star party in 2024, I previously captured this galaxy in a wider field of view from the same star party in 2019. In this capture the interfering gas and dust of the Milky Way is more apparent, even if my processing skills of the time were more crude.
The dust does not appear as prominent here due to the telescope’s closer in field of view and its slower optical speed. While larger in aperture compared to the refractor of the 2019 capture, it is still less efficient at capturing a good Signal to Noise Ratio (SNR) when under the same time constraints of the star party schedule. This image is also a good example of how much time is required when capturing even fainter narrowband signal versus how much it contributes to the total shot. The pink details lining the faint spiral arms are star-forming regions, but these barely appear in regular broadband color, requiring the use of H-alpha filters for higher-contrast capture. In this shot, despite totaling just above 32 hours in total, the narrowband work was well over half of that while only providing relatively small details.
Equipment:
Celestron C8 + Reducer (1280mm Focal Length, F/6.3)
ZWO ASI1600MM-P, ZWO Filters
ZWO AM5N Mount
Autoguiding: ZWO Off-Axis Guider + QHY178M
Exposures:
Luminance: 157x 180” (Total: 7h 51m)
Red, Green, Blue: 33, 33, 32x 180” (Total: 4h 54m)
Hydrogen-Alpha 7nm: 397 x 180” (19h 51m total)
Misc Details:
Capture Software: N.I.N.A. (capture), PHD2 (guiding), Pegasus Pocket Powerbox (dew heater control, power management)
Processing Software: PixInsight
Taken from: Okie-Tex Star Part 2024, Bortle Class 1 skies (Broadband), Wichita, KS, Bortle Class 5 skies (Narrowband)
Capture Dates: 2-4 October, 28 November, 1-5 December, 2024
