M61 - The Swelling Spiral Galaxy

Posted by CraigAndTammy
on Wednesday, April 21, 2010

by Craig and Tammy Temple


M61 (NGC4303) is a magnitude 10.18 spiral galaxy located about 52 million light-years distant in the constellation Virgo. It was discovered on May 5, 1779 by Barnabus Oriani while searching for a comet. Charles Messier saw M61 this same night, but thougt it was the comet. After a few days of observing the object, he realized that it was not, in fact, the comet, but a nebula (which was later determined to be a galaxy).

Telescope: Celestron C8 Schmidt-Cassegrain
Accessories: Celestron f/6.3 reducer/corrector; Dew control by Dew Buster®
Mount: Orion Atlas EQ-G controlled by EQMOD
Guiding: TS-OAG9 Off-axis, using Orion StarShoot AutoGuider
Camera: Canon Digital Rebel T1i, Hap Griffin Baader modified
Filters: Astronomik CLS-CCD EOS Clip
Exposure: 38 x 480sec @ ISO 800 (5hr. 4min.)
Acquisition: ImagesPlus 3.82 Camera Control
Processing: ImagesPlus 3.80a – Calibrated, registered, averaged, DDP
Post-processing: Adobe Photoshop CS4; Gradient XTerminator; Noise Ninja; Noel Carboni's Tools
Date(s): April 11 & 12, 2010
Temperature(s): N1:65ºF (dropped to 58ºF); N2:67ºF (dropped to 60ºF)
SQM reading (begin - end): N1:19.03 - 19.25; N2:18.77 - 19.15

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