H-NGC4088
Galaxy in Ursa Major
About
Sharply defined arms mark this barred spiral in Ursa Major, about 51 million light-years away. Halton Arp listed it as Arp 18 because one arm looks as if a piece has come loose. It forms a pair with the fainter NGC 4085, and William Herschel found it in 1788; it is in the Herschel 400.
Imaging tips
- About 6′ by 2′, so it is too small to frame: use a long focal length and a fine pixel scale.
- NGC 4085 lies roughly 11′ away, nearby rather than in a tight field. One imager used a 38′-wide frame that held both, plus many small, distant background galaxies.
- That imager stacked 16 luminance frames of 9 minutes and 8 colour frames of 4.5 minutes, from a 235 mm aperture at f/7.
- Best in March and April, when it passes almost overhead from 50°N at 89.5°.
Facts
- Size
- 6′ × 2′
- Magnitude
- 10.6
- Coordinates
- RA 12h 5.6m, Dec +50° 32′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Mar, Apr
- Peak altitude
- 90° from 50°N, 75° from 35°N