Another Walled Plain: J Herschel Crater
A "walled plain" is a term of lunar art describing an ancient impact crater later filled with lava.
Observer Comments
| Target Description | This crater is named after John Herschel, son of William, and nephew of Caroline. These are among the most important astronomers in history, responsible for creating what ultimately morphed into the NGC ("New General Catalog"). William and Caroline personally discovered something like a third of this catalog (with William credited with most of them); John and Caroline, however, made sure they were properly listed. This is a large "walled plain", an ancient, sunken impact crater later filled with lava located near the far NW limb of the visible side of the moon. Orbiter photos show a nearly circular crater. Due to it's location, forcing us to photograph it at an oblique angle, perspective makes it look oblong. |
| Image Capture Description | Technically, this is the best lunar observation in this submission (at least so far). It takes advantage of the EdgeHD at full 2032mm focal length and 294 camera. This was my first experience with SharpCap's real-time lucky imaging. I had turned to it out of desperation because wildfire smoke had ruined multiple observing nights for much of the summer. Smoke turned the original image bright yellow (I converted it to grayscale). Despite the poor transparency, the combination of much longer focal length, lucky-image stacking, and wavelet sharpening delivers a much more detailed image than any of the Seestar captures. |
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| Date and Time Observed | 2024-09-13 21:56:00 |
| Phase Age | 10.5 days |
| Lunar Phase | Waxing Gibbous |
| Illumination | 78% |
| Conditions | Transparency: Poor. Seeing: Good. |
| Obs. Lat/Long | 42° 17', 073° 57' |
| Capture Software | SharpCap |
| Capture Type | Real-time lucky imaging with wavelet sharpening |
| Instrument | EdgeHD 8" f10-2,032mm FL |
| Camera | ASI294MC-Pro |
| Capture Details | Approximately 20 images stacked 50ms exposures |
| Post Processing | Leveled and sharpened in Affinity Photo |