The “Sculptor Galaxy” NGC 253, also known as the “Silver Coin Galaxy”, is a bright local spiral galaxy, smaller than the Milky Way and only 12,000,000 light years distant.
The apparent width of the galaxy is about one lunar diameter. You could spot it with binoculars – but it looks better with a Skywatcher telescope. With a ZWO camera.
Its circular disc is about 12° from the edge-on position and it has a concentrated central nucleus and mottle-textured dust lanes & dark patches.
It is located only 2° from the South Galactic Pole.
The pair of foreground bright stars adjacent are:
HD 4555: (magnitude 9.3) 247 light years from the Solar System; and;
HD 4572: (magnitude 8.9), 510 light years from the Solar System
Designation: NGC 253, Caldwell 65
Visual magnitude: +7.0
Apparent size: 26.8′ x 4.6′
Diameter: 94,000 light years.
Distance: 12 million light years.
Altitude during exposure: 79° above eastern horizon.
Astrometry overlay image: All the details at: Astrometry.net
Whilst compiling my blog posts, I often refer to my astronomy reference books, including the three volume Burnham’s Celestial Handbook. Written half a century ago by Robert Burnham Jr., this masterpiece is still a very useful tool which is highly recommended and is still available from Dover Publications Inc.
Below is a photograph of NGC 253 reproduced from volume 3 of the book for comparison. It was taken by the 100 inch telescope at Mt Wilson. That instrument had 455 times greater light gathering aperture than my 4.7″ diameter telescope!
Image: Mt Wilson Observatory/Burnham’s Celestial Handbook
So the images which small modern amateur telescopes can take are, at the very least, comparable to those which were taken by the world’s largest telescopes fifty or sixty years ago. That is mostly due to developments in camera technology and I have no doubt that since taking that image, Mt Wilson Observatory took advantage of modern photographic equipment and techniques too.
One thing leads to another and I found myself web-surfing to this page which tells the rather tragic story of the author of Burnham’s Celestial Handbook, Robert Burnham Jr.
Apart from writing this epic reference manual, Burnham took part in the discovery of: six comets; 1,500 asteroids; 9,000 high-motion stars; 2,000 new white-dwarf suspects; and thousands of new proper-motion stars.
Sadly, this high achieving astronomer’s story did not end well. After leaving Lowell Observatory, he became reclusive, went into decline and earned an income from selling paintings of cats.
He died prematurely at the age of 61 and it was another two years before his family even learned the news.
Blog ends here.
All the technical stuff follows:
Exposure: 60 x 90 sec = 90 min.
Image acquisition: SharpCap.
|Telescope:||SkyWatcher Esprit||Type:||120ED triplet refractor|
|Focal:||840 mm F/7||Mount:||SkyWatcher EQ6-R Pro|
|Camera:||ZWO ASI 071 MC Pro
||Type:||CMOS 28.4mm 16 Mpx
|Optical aids:||Flattener: Y; filter: LP||Guiding:||Yes|
|Polar aligning:||QHYCCD PoleMaster||Polar Error:||53”|
[ZWO ASI071MC Pro]
Auto Exp Target Brightness=100
Image © Roger Powell