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Old Apr 13, 2010, 3:19 PM   #1
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....but anytime I see someone making these type images, I am totally blown away...

http://photo.net/photodb/photo?photo_id=8561303

Check out his other images in the astrophotography folder.
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Old Apr 15, 2010, 6:08 AM   #2
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That's great stuff. I would love to do astro stuff but I just can't afford all the equipment. That can be an expensive hobby, I love the home observatory setups, I should have been born rich : )

www.pulsarobservatories.com
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Old Apr 15, 2010, 8:27 AM   #3
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Greg – thanks for posting that. It’s very impressive. And Eric, you’re right – you can spend way more money on astrophotography than terrestrial photography. The reason is that the Earth rotates on its axis, and because long FL lenses magnify distance, they magnify motion. If you put a long lens on your camera, mount it on a tripod and aim it at the moon, you’ll see the moon gradually drift out of view. And the longer the lens, the faster the drift.

Paschalis Bartzoudis has a couple of different scopes but he probably took that photo with his 8” diameter Celestron, which is a 2000mm f/10 “lens”. Because the Andromeda Galaxy is very dim like most celestial objects, he had to do a long exposure to accumulate enough light. The problem that you run into is that unless you have the scope mounted on an extremely good (i.e. expensive) equatorial mount, stars become elongated blobs. Astrophotographers define good photo sharpness as having stars be pinpoints, not blobs. If he’s using the Takahashi mount I think he is, it sells for $15K (not including the scope itself). For that photo he only needed to take 103 exposures and stack them, because the Takahashi allowed him to take longer exposures. If he had the kind of mount that we normal folks can afford, he would have had to take a lot more because each one would have needed to be shorter to keep the stars as points. It is, indeed, a very time-consuming hobby…

In case you’re interested, the Andromeda galaxy (M31) is the nearest large galaxy to us, at only 3 million light years away and is one of the most remote objects visible with the naked eye. (A light year - the distance light travels in one year - is about 6 trillion miles). When the light from M31 started on its journey to us, woolly mammoths in the Pleistocene Era roamed the earth. It is one of the largest galaxies known, with an estimated 300 billion stars. Sadly, you can’t see the colors that are in that photo, by observing it directly in a scope – the cone photoreceptors in your eye are what perceive color but they need a lot more light to function than you get from such a distant object. That’s one reason amateur astronomers like to do imaging.

The stars you see in that photo are relatively close, in that they’re within our Milky Way galaxy, between us and M31. They are useful for astrophotography because you use them to determine if you have a sharp photo. However, the blob you see below M31 in that photo, is one of 14 small satellite galaxies surrounding M31. Finally, M31 is approaching our Milky Way galaxy and may collide with us but that's some 2.5 billion years in the future.

Ted

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Old Apr 15, 2010, 9:03 AM   #4
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....thanks Ted, that is a really comprehensive & concise amount of interesting information (to me), I enjoyed reading it and usually I become bored within the same amount of time when reading about such things...... not this time.

Could it be that at my new age (birthday in March) I am relating to woolly mammoth time... lol
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Old Apr 15, 2010, 9:27 AM   #5
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Quote:
Originally Posted by boBBrennan View Post

Could it be that at my new age (birthday in March) I am relating to woolly mammoth time... lol
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Thanks for your kind words. But don't feel bad about your age - I could have mentioned Quasar 3C273. It is one of the most distant objects you can see in an amateur scope - it's 2 billion light years away, close to the other side of the universe. In a scope it just looks like a faint blue star, not impressive unless you realize what it is. It is a galaxy with a luminosity 2 trillion times that of the Sun, or 100X that of the entire Milky Way galaxy. When the light from 3C273 left that galaxy, the first abundant fossils of living organisms, mostly bacteria, had just appeared on Earth.

It is one of the most fascinating objects I've ever observed in my scopes, not because it is beautiful like M31 but because you can see it at all.

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Old Apr 15, 2010, 9:56 AM   #6
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........oh this puts it in a perspective I can feel 'young' about.

While I've never developed an interest in astrology I have related in a way to some of my contacts via amateur (HAM) radio and always did chuckle at the most often asked question which is, "how far away can you talk to someone" with the answer as ... "wherever there is someone to talk to, no limit.. it just takes some time for the signal to get there".

10,000 miles over the horizon with less than 2 watts RF was, to me, always just an amazing feat using equipment I built myself on the kitchen table and antennas scraped together in the back yard........then the card exchange to support it, much like a photo of some far off galaxy.
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Old Apr 15, 2010, 12:44 PM   #7
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[QUOTE=boBBrennan;1080218
10,000 miles over the horizon with less than 2 watts RF was, to me, always just an amazing feat using equipment I built myself on the kitchen table and antennas scraped together in the back yard........then the card exchange to support it, much like a photo of some far off galaxy.[/QUOTE]

That's where the SW signal bounces off the ionosphere, right? I always thought that was pretty amazing also.

Now, to move this closer to being on-topic for our (very understanding) Moderators, note that to do the type of astrophotography like the image Greg posted, with an Oly DSLR (and, um, for any other brand) requires a camera modification. DSLR manufacturers install a UV/IR filter in front of the imager on DSLRs on the silly assumption that folks will use them for terrestrial photography . To use them for astrophotography requires that that filter be removed.

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Old Apr 15, 2010, 1:24 PM   #8
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[QUOTE=boBBrennan;1080218]........oh this puts it in a perspective I can feel 'young' about.

While I've never developed an interest in astrology....QUOTE]

Now....there's a way to really get under an astronomer's skin....use "astronomy" and "astrology" as interchangeable terms!

I've always had a fascination with astronomy and a few years ago owned a Meade 10 inch SCT with one of the first generation (didn't work so well) motor drives meant to keep everything in line....once you went through the process of alligning the thing correctly. Well before the days of digital photography so I was reading all kinds of articles on stuff like hyper-sensitizing films to shoot those ultra-long exposures.

There is one guy who shows up from time to time in the Olympus DSLR forum at DPReview with the handle Olynaz or something like that, and he does this type shooting and will often display some of his work. Just to listen to him and others talk about available equipment today always gets me interested, that is, until I start doing the research into what all it costs..

http://forums.dpreview.com/forums/re...ssage=26824443

http://forums.dpreview.com/forums/re...ssage=25200688
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Old Apr 15, 2010, 2:26 PM   #9
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[QUOTE=Greg Chappell;1080325]
Quote:
Originally Posted by boBBrennan View Post
........oh this puts it in a perspective I can feel 'young' about.
While I've never developed an interest in astrology....QUOTE]

Now....there's a way to really get under an astronomer's skin....use "astronomy" and "astrology" as interchangeable terms!
Hah! But, Greg, I wasn't going to give Bob grief about that. Especially since astronomy and astrology have been unified fields of endeavor for almost 4000 years of human civilization, and were only separated maybe 150 years ago. As a physicist and not an astrologer, I still have mixed emotions about the dogmatic scientific distinctions made between the two. I'm not OK with 4000 years of human knowledge being dismissed by modern astronomers since as far as I can tell, they've never bothered to study astrology enough to be competent in having an opinion. They're just being arrogant...

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Old Apr 15, 2010, 3:11 PM   #10
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[QUOTE=tkurkowski;1080357]
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Originally Posted by Greg Chappell View Post

Hah! But, Greg, I wasn't going to give Bob grief about that. Especially since astronomy and astrology have been unified fields of endeavor for almost 4000 years of human civilization, and were only separated maybe 150 years ago. As a physicist and not an astrologer, I still have mixed emotions about the dogmatic scientific distinctions made between the two. I'm not OK with 4000 years of human knowledge being dismissed by modern astronomers since as far as I can tell, they've never bothered to study astrology enough to be competent in having an opinion. They're just being arrogant...

Ted
It's all in fun!

I gave my girlfriend a lot of grief about just this very thing a few nights ago. She called and told me she was watching "Dancing with the Stars", and I said I was watching something with a little more depth on the Science Channel, which started her in on me about "all these shows on astrology I watch...", to which I then said what I was watching had nothing to do with telling the future.

I would bet an astrologist today would say an astronomer knew nothing about their "profession", too!
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