Arp 185 / NGC 6217

Designation(s)Arp 185, NGC 6217
Object Type(s)Galaxy
Relevant Catalog(s)All (Chron), Arp, NGC
Arp CategoryGalaxies with narrow filaments
Obs. Lat/Long42° 17', 073° 57'
ConstellationUrsa Minor
Date and Time Observed2024-05-23 23:56:00
InstrumentEdgeHD 8" f10-2,032mm FL
CameraASI294MC-Pro
Image DetailsUp is 271.9 degrees E of N. Total integration time was 59m. Exposures 30s@305g, UV/IR Cut Filter. Darks subtracted, no flats. Dithered and recentered in SharpCap. No guiding.
DescriptionNGC 6217 is a relatively large and bright barred spiral Arp galaxy, located high in the sky in Ursa Minor. Arp categorizes it as a galaxy with "narrow filaments" and notes in his remarks, "Condensed nucleus. Faint outer arms less curved than inner arms." You know that when the guy with the 200" telescope describes something as "faint", you're in trouble, especially when you're observing on a nearly full-moon night. At the time, I didn't know how to find Arp's remarks so this might have scared me away. However, I was aware of the category, and thought I could see the filaments at capture time. However, in the cold light of day, they're much less evident in the color image than I thought (a common phenomenon in EAA). You can play confirmation-bias with the featured color image and the Arp v color image (2nd in gallery). Fortunately, I've learned that converting a color image to grayscale and inverting it, often helps in this circumstance (first image in gallery). The base of the filament is obvious at the NNW corner of 621 as it exits just above the three bright objects, then takes a wide arc up and to the left (ESE) toward the double-star near the top of the image. The further you go, there's not enough data to resolve it as a "filament", but there's more frequent noise, well above average. Please ignore the faint satellite trail in virtually the same direction. The symmetrical filament out of the SE end of 6217 is much less distinct but still presents a higher noise level.
Catalog Links
 Arp Listings 
Featured Image