If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Photographing Space
Came across this photo of space on Pbase and think that it's pretty cool:
http://www.pbase.com/image/38855314 So the question a 1) What is the colourful bit in the middle of the photo called? 2) How do you go about taking a shot like this? Obviously he was using a 400 2.8 is, but what is the other stuff (IDAS LPS filter. A stack of 16x2 min, 6x30s, 30x10s,) |
#2
|
|||
|
|||
Photographing Space
"Ali" wrote:
Came across this photo of space on Pbase and think that it's pretty cool: http://www.pbase.com/image/38855314 So the question a 1) What is the colourful bit in the middle of the photo called? A nebula. 2) How do you go about taking a shot like this? Obviously he was using a 400 2.8 is, but what is the other stuff (IDAS LPS filter. A stack of 16x2 min, 6x30s, 30x10s,) He's taken multiple exposures: two 16 minute ones, six 30 second ones, etc and then combined them. Presumably a single exposure was too dim and noisy. To get a sharp image of the stars would also require some kind of astronomical device such as used by telescopes which moves the camera to follow the stars, otherwise all but the 10 second ones would end up as star trails. In fact I would have thought that image must have been taken through a telescope, but I'm no astronomer so I couldn't say for sure, but with a 400mm lens I'd be surprised if you could get that close to a nebula unless it was pretty enormous. Mind you it does seem to be a selective enlargement of maybe a 1/4 of the frame going by the smallish size of the "original" shot, so maybe it is possible to get that close when you combine the crop factor of the DSLR and the actual cropping, as the result may be the equivalent of a 1200-1600mm 35mm lens. I still surprised though. |
#3
|
|||
|
|||
Photographing Space
Gordon Freeman wrote:
"Ali" wrote: Came across this photo of space on Pbase and think that it's pretty cool: http://www.pbase.com/image/38855314 So the question a 1) What is the colourful bit in the middle of the photo called? A nebula. The Great Nebula in Orion, Messier 42 and 43. 2) How do you go about taking a shot like this? Obviously he was using a 400 2.8 is, but what is the other stuff (IDAS LPS filter. A stack of 16x2 min, 6x30s, 30x10s,) He's taken multiple exposures: two 16 minute ones, six 30 second ones, etc and then combined them. Presumably a single exposure was too dim and noisy. 16 two minute exposures. The short exposures are for the brighter parts of the nebula which are probably overexposed in the 2-minute exposures. To get a sharp image of the stars would also require some kind of astronomical device such as used by telescopes which moves the camera to follow the stars, otherwise all but the 10 second ones would end up as star trails. In fact I would have thought that image must have been taken through a telescope, but I'm no astronomer so I couldn't say for sure, but with a 400mm lens I'd be surprised if you could get that close to a nebula unless it was pretty enormous. Mind you it does seem to be a selective enlargement of maybe a 1/4 of the frame going by the smallish size of the "original" shot, so maybe it is possible to get that close when you combine the crop factor of the DSLR and the actual cropping, as the result may be the equivalent of a 1200-1600mm 35mm lens. I still surprised though. No, that is the full frame. Many objects in the sky are quite large. The Orion Nebula is about 1 degree in diameter, or double the diameter of the full moon. Yes, a tracking mount was used. Click the next button for some other photos if his, which are wonderful! This image is full frame at 700 mm on a 10D of the same nebula: http://www.clarkvision.com/galleries...3.v12-800.html and processed to give the more pastel colors seen visually through a very large telescope. More processing details are given. You can also click the next and previous to see other astro images. The short exposure technique solves several common problems: 1) tracking errors (throw out any frames with bad tracking), 2) limiting the exposure length reduces dark current contributions, 3) imaging from light polluted cities is possible: simple add many frames where a single longer one would saturate. Then add the images and subtract off the sky light pollution. This galaxy, M31: http://www.clarkvision.com/galleries...-v1.6-700.html is over 4 times the diameter of the full moon (over 2 degrees across). That is also a full frame image. Roger |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
God' s summons space/¸t¤lªº¥l³ê/ | goddess | Photographing Nature | 0 | June 30th 06 06:15 PM |
Space Dog! | Jer | Digital Photography | 16 | December 8th 04 07:12 PM |
Space Dog! | Mark² | 35mm Photo Equipment | 11 | December 8th 04 07:12 PM |
Space Dog! | Jer | 35mm Photo Equipment | 0 | December 2nd 04 05:55 AM |
Waste of space | Christopher Woodhouse | In The Darkroom | 5 | April 8th 04 02:34 AM |