M82 - Ursa Major

Object data: M82 (NGC 3034), also known as the Cigar Galaxy, is an irregular magnitude 8.4 galaxy in the constellation of Ursa Major. The spectacular 'explosion' of material from it's core is caused by severe gravitational disturbance, almost certainly due to a close encounter with M81, its neighbouring galaxy. M82 and M81 were both discovered in 1774 by Johann Bode, and independently by Pierre Méchain (Messier's colleague) in 1779. M82 is estimated to be 12 million light-years distant.

Date: 09/02/03
Location: Wiltshire England
Conditions: calm, transparency=7, seeing=5
Optics: RCOS Ritchey-Chretien 12.5" working at f/9
Mount: AP 900 GTO on Portable Pier
Camera: SBIG ST-8E / CFW-8
Guiding: ST-8E integral guiding chip controlled by MaximCCD
Exposure: LRGB: Luminance: 4x15 minutes; RGB: 15:15:30 minutes binned 2x2

Processing: Image acquisition and initial processing was done using Maxim DL, subsequent processing was done using Registar and Photoshop.

Notes: Seeing was rather poor with FWHM measuring 2.6 arc seconds on the best frames. As usual in my experience, the seeing followed the Jetstream which was quite strong over the western part of the UK at the time (see image at right). Conditions were mostly clear with reasonable transparency, but a period of high altitude cloud limited the luminance frames to only four, hence the image has more noise than it should. The sky cleared later, leaving enough time for one hour's worth of RGB exposures.





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