NGC 772 (Arp 78) – Spiral galaxy


NGC 772 is a spiral galaxy twice as large as ours and it is 130 million light-years from us. It is also part of the Arp catalog because of its deformation caused by a gravitational interaction with its neighboring galaxy NGC 770, the small elliptical galaxy located just below in the photo.

NGC 772 is considered a low surface brightness galaxy because it shines less than 1 magnitude brighter than the sky background. Photographing it therefore requires several hours of exposure.

Technical details:

Telescope: Celestron Edge HD14 and 0.7x focal reducer
Mount: Paramount MX+
Camera: ZWO ASI 1600 in 2×2 bin mode
Filters: ZWO 1.25″ LRGB
Exposure: 77 x 4-minute subs ns in LRGB for a total of 5 hours
Location: Backyard Observatory in Sainte-Sophie, Qc
Date: September 2018