Space Photos Taken From Shed Stun Astronomers 149
krou writes "Amateur astronomer Peter Shah has stunned astronomers around the world with amazing photos of the universe taken from his garden shed. Shah spent £20,000 on the equipment, hooking up a telescope in his shed to his home computer, and the results are being compared to images taken by the Hubble Space Telescope. 'Most men like to putter about in their garden shed,' said Shah, 'but mine is a bit more high tech than most. I have fitted it with a sliding roof so I can sit in comfort and look at the heavens. I have a very modest set up, but it just goes to show that a window to the universe is there for all of us – even with the smallest budgets. I had to be patient and take the images over a period of several months because the skies in Britain are often clouded over and you need clear conditions.' His images include the Monkey's head nebula, M33 Pinwheel Galaxy, Andromeda Galaxy and the Flaming Star Nebula, and are being put together for a book."
Re:Beautiful pictures (Score:5, Informative)
Information found:
He used an ORION OPTICS UK AG8 Astrograph and a STARLIGHT XPRESS SXV-H16 CCD.
http://www.astropix.co.uk/equipment.html [astropix.co.uk]
Google says... (Score:4, Informative)
Re:Beautiful pictures (Score:5, Informative)
There's info on the telescope and CCD here [astropix.co.uk]
Re:Beautiful pictures (Score:5, Informative)
It takes quite a while to collect enough light from 100s of light years away in order to create a usable image.
For example, looking through my 6" telescope you can't see any nebula's like in pictures. Another thing they do is take multiple images and stack them together to amplify the signal and minimize the noise.
Re:Hubble? I don't think so (Score:4, Informative)
They may resemble some of the aesthetics of Hubble, but not the resolution. Thus, the comparison is potentially misleading.
I know. They look decent, but a ~200KB image does not compare to a ~200MB (~204800KB) Hubble photo.
Re:Beautiful pictures (Score:4, Informative)
Dobs are useless for photography. You would have to use an equatorial mount.
It would me even more interesting to know his digital process. That's where the magic happens. Of course you have to start with a good set of the right kind of exposures, but it's the processing that brings out the sort of details you see in the photos. The images that come out of the hardware don't look anything like the photos.
In fact, with a fairly modest mount/tracking setup, a DSLR, and the right processing (also a healthy dose of patience), you can get surprisingly good astrophotos.
Not THAT stunning. (Score:2, Informative)
Re:Hubble? I don't think so (Score:5, Informative)
And NASA isn't the only group putting out viewable Hubble images. The ESA publishes quite a few (which get published through the Hubble Heritage site). Check out www.spacetelescope.org. The lovely full view of Orion was done by them.
Re:Stunning? (Score:3, Informative)
From the article: "....The superb photos, each made up of about 30 frames..."
Re:Beautiful pictures (Score:3, Informative)
Why worry about smooth equatorial tracking? Rig your camera using the cheapest tracking solution you have or move it by hand if you have to. Who cares if it jitters. It just can't jitter during the exposure. Merge the photos into 1 frame by removing the jitter and combining exposures.
A 100 second exposure pic is equal to 100 one second exposure pics. The problem is in finding software to stitch the photos into 1 frame. The easiest to try is to just get PhotoShop. Stitch the photos into 1 with Photo Merge [adobe.com]. You can also experiment with PhotoShop HDR merge [slashdot.org]. You may have to tweak the contrast/brightness and light levels before or after.
2nd option is using video stabilization software to remove the jitter. There are tons of software options for that but you want one will accept very large resolution pics with large dimensions. You want apps that will work on frames as individual photos instead of enforcing video formats on import and export. Off the shell software might be tuned for pics with normal daylight exposure, so look for options to fine tune the algorithm to work on dimly exposed pics.
If the software won't work on dimly exposed pics, perhaps you can experiment with batch processing the files to increase contrast and brightness or tweak the lighting levels. (Lots of software options.) Feed the result into the stabilization software. Batch process again to reverse the contrast/brightness increase.
The post-process step is to stitch and merge the photos into one as before. Plain stitching used to create panorama shots won't work. It needs to sum the exposure data. Photo apps solve these types of problems so there's a good chance it would work with PhotoShop or Paint Shop Pro (with "HDR Photo Merge [amazon.com]). You could shoot a series of fast exposures for the raw data and 1 long blurry exposure to use as a reference point for the HDR merge. Example. [photoshopcafe.com]
Re:Beautiful pictures (Score:3, Informative)
Re:Hubble? I don't think so (Score:4, Informative)
Nice web site. Very first image I pulled up was of Perseus A, and the text said "Detail and structure from optical, radio and X-ray wavelengths have been combined for an aesthetically pleasing image which shows the violent events in the galaxy's heart." And you seem to be saying that all images produced for mass consumption are like that. So these images are even more different from the ones that scientists care about than I thought they were.
The fact that the European counterpart to NASA also uses these photos for PR is kind of beside the point. And I'm not condemning either agency for doing this. Eye candy may not be as important as science, but it does help justify the budget that gets the science done. I'm just debunking the idea that eye candy is what Hubble is for.
Nor do I want to trivialize what Shah does. His work not only gives us cool-looking pictures, it raises interest in backyard astronomy — a "hobby" which does a lot of serious science [hobbyspace.com].
Re:Stunning (Score:5, Informative)
Indeed, as an astrophotographer I can say his images are high quality and I'm sure the comparison with Hubble is not his own. We know better than that... I use an even simpler setup (Losmandy GM-8, Canon 300mm f/2.8 Lens or 20cm Newtonian f/4.5 and modified Canon 20D camera) and even those images get compared to Hubble by people. That setup cost me less than 5k euros.
Hubble is about science, astrophotography as you get to see it is about "pretty pictures". We get as much sciene return as a casual wildlife photographer... By accident we may discover something (and we all dream of it...). Hubble press releases are "pretty pictures" as well; but usually distilled from valuable scientific data.
There are a lot of amateurs contributing to science, but you don't get too see much of them. Tom Boles for example has discovered over 120 supernova's (from Britain) and has been featured in the media (BBC). And he's picked a hot subject. Many others monitor asteroids, variable stars, faint comets and will never get noticed by a news channel...
His and astrophotographers' work is important though to popularize science. I myself got started by seeing images of the sky in books. Now I'm making them myself...
Comparison (Score:3, Informative)
Sorry for duplicated post
Compare the referred author picture of NGC 6888 here [astropix.co.uk] to a professional job there [nasa.gov]. The former is still very impressive for an amateur, indeed this is the verbatim comment from the IAC site [www.iac.es] (where the professional picture was taken):
Re:Beautiful pictures (Score:4, Informative)
"A 100 second exposure pic is equal to 100 one second exposure pics."
Not quite. Averaging multiple exposures lets you remove noise yes. Digital sensors are so sensitive that for reasonably bright objects what you say is true. But, if you want to image dimmer objects, you have to have a longer exposure simply to make sure you actually catch enough photons.
Not Impressive (Score:5, Informative)
I'm sorry, but his pics just aren't that great compared to other amateur imagers.
Compare Peter Shah's image [astropix.co.uk] of M42 with Rob Gendler's [robgendlerastropics.com]. Or how about this even more stunning one [astrophoto.com] captured by Tony and Daphne Hallas with a 6" refractor at the Winter Star Party.
IMHO, Peter Shah's self promotion is more impressive than his images.
stunning starbursts? (Score:2, Informative)
The starbursts are aesthetically pleasing (stunning) but I suspect they would be detrimental to any scientific use of the images. Their presence is most likely the result of post processing that favors artistic appearance over scientific accuracy. IANAA but I doubt that the images have any scientific relevance.
Re:Stunning; but compare (Score:5, Informative)
so really, from a strictly photographic perspective, yes, this guy's pictures are better, because they show what the thing *really* looks like.
Re:Hubble? I don't think so (Score:5, Informative)
Most amateur level astronomical CCDs (amateur is a relative term in this case) are pretty low resolution. The SBIG ST-7 I use for the observatory I run is only around 800x600. For this kind of equipment you're not looking for number of pixels nearly as much as low noise, good cooling, and pixels that are sized right for the optics you're running.
When the parent refers to resolution, he means the angular size of each pixel, not the sheer number of pixels. This is a function of aperture size and atmospheric clarity -- all the CCD can do is take maximum advantage of whats available by making each pixel about half of what can be resolved by the optics.
Re:Beautiful pictures (Score:4, Informative)
Suppose my sensor registers 1 instead of zero, on average, when it is hit by ten photons. If my exposure is so short and the object I am imaging is so dim that I only collect five photons from it during each exposure, it will generally not register. I can average all the frames I want and I'm not going to get a good image of it.
Yes, it is simple math. Just not quite as simple as you're doing. You don't suppose you've discovered some novel concept that both amateur and professional astronomers have missed, do you? You better tell them - all the money they pour into larger apertures and better tracking is completely wasted!
Re:Beautiful pictures (Score:3, Informative)
Try Astroart 4.0 [msb-astroart.com] seems like it'll do it all.
Re:Computer ? (Score:4, Informative)
That part isn't hard. As a former astronomer:
:-)
1) Take a dark frame. Lens on, potentially the same duration of your planned exposure. This captures all the non-responsive/stuck pixels on your camera, and captures any heat noise caused by the rest of the instrument.
2) Take the image.
3) Subtract #1 from #2.
There might be additional post-processing, but that depends on the quality of your setup, and how into it you are. Most astronomers that I know of use custom written scripts in IDL or MATLAB to do such processing, although there is a bit of a trickle to move to things like R and Python, due to their being more full-fledged programming environments.
When I was doing astronomy, we'd set our exposure up, then go play video games for a half hour. Ten minutes of dark-frame, ten minutes of exposure, couple seconds of automated transfer over the nextwork, a button push, and a minute or so of processing. Then we'd have to pause our game, and move to the next target.
Re:Beautiful pictures (Score:4, Informative)
The number of photons over a fixed amount of time isn't going to change whether exposure time is sliced into a single exposure or multiple exposures. It's basic math.
Your assuming that the CCD is going to be equally sensitive to every photon many of the initial photons are going to be buried in the detector thermonic noise, this is why amateurs use peltier devices to cool their detectors and pros use cryogenic liquids. Additionally the electronics reading the charge on the CCD pixels will have a threshold level you have to get above. There are probably other factors that I am not aware of.
Modern hardware makes it relatively easy (Score:4, Informative)
Modern DSLR cameras have come a long way in the last three generations. Extremely high "pushed" ISOs, relatively low noise, combined with some really great lenses and just a little bit of software sophistication, and astro becomes very accessible.
If you add a tracking mount, which allows the camera to pivot on the tripod at the same rate the earth turns, keeping the camera pointed at the same subject for several minutes, you can use even lower-noise ISO ranges of the cameras and sharper f-stop ranges of the lenses. You can build yourself a "barn-door" mount for the cost of lumber, and a few bucks for screws and a clock drive (or a gear and a handle to turn it.) Or you can buy a premade tracking device like the Astrotrac I selected (because I'm too lazy to build a mount -- about a grand); or you can go nuts and buy a telescope mount that tracks (can cost ((up to many)) thousands.) Tracking really helps.
But, you don't have to go there. Just go outside, pop the camera on a tripod, use a lens you can set for f/2.8 or faster, crank the ISO up to 1600 or faster, and expose for 1...8 seconds (depending on how much magnification the lens provides... at 85mm, 4 seconds is good. At 400mm, about one second is all you can go before the starts begin to trail.) Personally, I like 85mm; it's enough mag where with a modern sensor (15mp for the 50D) you get a goodly amount of detail, but it's short enough that you get some exposure time.
So with this setup, shoot multiple shots, then align and "stack" them using pretty much any image processsing software that lets you rotate and translate, preferably to sub-pixel precision. The more images you stack, the better the result will be. The rule is, random noise reduces to the square root of the number of frames, so you can get a 4:1 noise reduction with only 16 shots. To get 10:1, you need a hundred. For impulse noise, like a satellite track, averaging gets you reduction of N:1 where N is the number of frames... BUT... if you use median instead of average, odds are excellent that impulse noise will disappear completely. I always try both, just to see which looks better.
There are dedicated programs out there than can stack and align for you, too. A little googling goes a long way.
The biggest challenge has little to do with the camera, and more to do with where you live. Light pollution, that is, the amount of light sourced from streetlights and so forth, competes with the dim deep space objects; so someone who lives east coast, say, NJ or in the metro area... not going to do very well. Where I live - rural Montana - it's not a problem at all. If you live in an urban area, it's the kind of thing you keep in mind for when you go cross country and have an opportunity to cross some desert (or most anywhere in Montana. :) Refer to a light pollution reference, watch the weather (which can really screw up your plans.... clouds.... I flipping despise clouds at night), and then it's all down to your timing.
Anyone who has a modern DSLR, I can't recommend this highly enough. It's fun.