Andromeda Galaxy with the A900

[Ian C]

I was just looking at that on DPreview

Amazing that!

[KevinBarrett]

How in the world does one take a five minute exposure with an a900?

[Greg Beetham]

Always a wonderful object, and a very fine photo, for as he says, a fairly rushed job.
There are three galaxies there, originally spotted by Charlie Messier way back when, and thus have the M designation, (as well as other catalog numbers), they are M31 (Andromeda galaxy) and two small satallite galaxies, M32 and M110.
It looks sort of foggy, but it's so far away (2.5 million light years) that it's billions of stars/suns merge into a kind of fog appearance, all those foreground stars/suns belong too our own galaxy (the Milky Way), itself a giant spiral galaxy similar to the Andromeda galaxy.
We also have a few small satellite galaxies, the most notable of which are the SMC and the LMC, a couple of naked eye foggy blodges, they were never seen by Charles, (too far south to be seen from Paris) so they don't have an M number.
Greg

ps Hi Kevin,
The time exposure is probably the same as on the A100 - A700, plug in the remote controller and shoot on "Bulb", the shutter stays open as long as you hold the button on the controller, you can also slide the button while it's pressed down and it locks in the down position until you slide it back allowing it to pop up...closing the shutter, of course he is probably using a timer or stopwatch, to get a reasonably accurate shutter time.

[alfake]

Greg: Interesting information. Let me add (or rather, emphasize) that the Andromeda galaxy is visible to the naked eye, so it could be observed (and most probably was observed) even by our prehistoric ancestors. It was well known many centuries before the great Messier. From Wikipedia: “The earliest recorded observation of the Andromeda Galaxy was in 964 CE by the Persian astronomer, Abd al-Rahman al-Sufi (Azophi), who described it as a "small cloud" in his Book of Fixed Stars. Other star charts of that period have it labeled as the Little Cloud. The first description of the object based on telescopic observation was given by Simon Marius in 1612. Charles Messier catalogued it as object M31 in 1764 and incorrectly credited Marius as the discoverer, unaware of Al Sufi's earlier work.”
Alfonso

[Greg Beetham]

Ah, yes of course Alfonso, I was remarking upon it as a casual observer and it's appearance in a "catalogue" of objects, yep it's most certainly a naked eye object alright but none of those early guys knew what it was, even Charles M. though they did "discover" it before modern astronomers did, I wonder what they thought it was...a cloud that never moved relative to the stars and could only be seen at night and had been in the same spot for centuries...hmmm
Wasn't it Hubble himself in charge of the mighty 200 inch Palomar telescope way back in the 1950's that finally was able too resolve stars in the galaxy, and solve the distance problem as well by being able too measure variable stars accurately....I think.
Greg

[alfake]

Greg: Yes, it was Hubble who finally demonstrated that Andromeda was an external galaxy (different from ours). That was back in the 1920s.

[Dr. Harout]

astroclubalpha

[KevinBarrett]

ps Hi Kevin,
The time exposure is probably the same as on the A100 - A700, plug in the remote controller and shoot on "Bulb", the shutter stays open as long as you hold the button on the controller, you can also slide the button while it's pressed down and it locks in the down position until you slide it back allowing it to pop up...closing the shutter, of course he is probably using a timer or stopwatch, to get a reasonably accurate shutter time.

Ah-ha! I remember that way now! My brother and I used to shoot meteors with his Maxxum 7000 and I couldn't remember if we used the remote or a long exposure...I need to find one of those remotes now!