Andrew's Astronomy Blog

Given a very dark clear night, a good pair of binoculars and a set of sharp eyes, it’s possible that you may just be able to see a faint fuzzy blog under the handle of the plough in Canes Venatici. This is ARP 85, the galaxy pairing of Messier 51 & NGC 5195. M51, also known as The Whirlpool,  is one of the finest examples of a spiral galaxy, discovered by Lord Rosse in 1845 who first recognised the spiral structure using his 72 inch reflecting telescope at Birr Castle, Ireland.

For many years it was believed that NGC 5195  was merely on the same line of sight as M51 and further away, however, simulations suggest that NGC 5195 first passed through the disk of M51 some 500 – 600 million years ago travelling towards us before another encounter 50 to 100 million years ago took it back through the spiral. The resulting gravity waves have triggered areas of star formation in the spiral arms of M51.

About 23 million light years away, M51 has a diameter of 76,000 light years and a total mass of about 160 billion suns.

Imaged on GRAS-001, this is a stack of eleven two minute exposures, processed in IRIS.

Just over a moons width away from M81 lies the galaxy M82, also in Ursa Major. With a really dark sky both are visible in binoculars as faint smudges. In space, the two are about 150,000 light years apart and are part of a galaxy cluster that is about 12 millions light years distant.

A bright moon and high haze limited imaging to bright objects on Tuesday evening  but I did get a picture. I also determined that I had some issues with the imaging process, more on this below.

After the imaging run I noticed that the camera was set to jpeg rather than RAW image quality. After some work I traced this to a ‘fast mode’ setting in the capture software. Now that I’ve isolated this problem, next time out I should get some rather sharper, lower noise images.

After a cloudy start to Tuesday evening the sky cleared so I took some pictures of M81 in Ursa Major. M81 was discovered by Johann Bode in 1774 and is named Bode’s Nebula. At about 12 million light years distance it’s one of the closest galaxies outside the local group.

Telescope was the Celestron 9.25″ with f/6.3 reducer. 13 exposures of 2 minutes each were taken with the Canon 350D plus 5 dark frames.

The slightly mis-shapen star at 2 o’clock from the galaxy is actually a double star, HP38635A & B.

Making the news this week; M31, the Andromeda galaxy is due to collide with our own Milky Way in some 3 billion years. While this isn’t anything to lose sleep over, there are plenty of galaxies out there already experiencing this. Whilst individual stars are unlikely to collide in this process (there’s too much space between them, even in the relatively crowded space of a galaxy), the galaxy structures are massively disrupted due to gravitational forces. In this picture, we can see NGC 3226 (small elliptical) and NGC 3227 (spiral) interacting. Collectively, this pairing has the catalog id ARP 94 and is about 55 million light years away.

This picture is taken with GRAS-005, a Takahashi Epsilon 250 (Hyperbolic Flat-Field Astrograph) with an SBIG-10XME camera, 4x 5 minute exposures.

Also known as the Silver Coin galaxy this is a fine spiral galaxy, presented almost edge on at a distance of 10 million light years. It is visible from the UK but never rises very high above the horizon. This picture is a stack of 6 one minute exposures taken with the GRAS G-15 telescope and processed with Maxim DL.