Amateur Astronomer Grabs Amazing ISS Picture

The Bad Astronomer writes "Ralf Vandebergh is an amateur astronomer, and using a simple telescope with a video camera attached to it, he took an incredibly detailed picture of the International Space Station. You can easily see the recently-installed truss and solar panels, as well as the Space Shuttle Discovery docked to the station."

Comments

Par for the course...

[Wiener]

Ralf, quite simply, takes amazing photos. From what I understand, these are manually tracked snapshots.

He has a number of photos posted at Cloudy Nights in the "Planetary and Solar System Observing" forum.

A simple technique taken to an extreme

[The Hooloovoo]

He basically used a method reminiscent of a technique used by amateur astronomers to take pictures of planets and asteroids: take a lot of frames using a cheap webcam and stack them together, weeding out the bad ones as you go.

The principle behind it is pretty simple. When it comes to seeing nearby planets (Pluto and friends are obviously exceptions), telescopes are limited less by magnification and more by atmospheric distortion. What's not clear from the article is if this is a single frame grab (which is pretty cool but not an incredible technical feat) or if he managed to track it precisely enough to stack a few frames.

Re:A simple technique taken to an extreme

[Skapare]

Stacking frames does not require precision tracking. You only need to track it well enough to keep it in the frame. And in some cases partially out of the frame still has limited usefulness. The software correlates the positions based on what is in the picture. If there's enough of a pattern to make the alignment (at sub-pixel resolution), then it's easy. If it's fuzzy, you might have to do the alignment manually.

Re:A simple technique taken to an extreme

[david.given]

...take a lot of frames using a cheap webcam [wildimaging.co.uk] and stack them together, weeding out the bad ones as you go.

You might be interested to have a look at some software called ALE, which can be used to do this more or less automatically; you give it a sequence of frames and it'll synthesize a superresolution image combing data from every frame.

(You can also use it to generate panoramic images from video pans --- it automatically locates, rotates and transforms every frame correctly, figuring everything out for itself!)

The only problem with it is that it's really slow, so you'll probably want as big a computer as you can humanly manage.

One day I should try taking some simple digital camera footage of the moon and running it through ALE just to see what happens...

Re:If they want to save power

[MeanMF]

It's blurry because it's taken through miles of atmosphere. That's why Hubble is in orbit and most observatories are on top of mountains.

What about Rayleigh Criteria?

[NotSoHeavyD3]

I mean I wouldn't be surprised if he was getting pretty close to that limit. http://en.wikipedia.org/wiki/Rayleigh_criterion#Explanation To make that short I kind of remember this from my physics class that ultimately the limit on being able to differentiate between 2 objects depends on the size of your main mirror/lens and the wavelength of light you use. (IE a bigger main mirror or shorter wave length of light means you can differentiate between closer and closer objects.) If I remember correctly I did the math and found out that you'd need a mirror about 250 meters across to resolve the landing site on the moon from an earth based telescope. (But I can't remember if that resolution was 1 meter or 30.)

No Subject

[Orphaze]

It's certainly a good image, but not the best. This image of Ralf's, for instance, is noticeably more clear. He has many more amazing images though on his site here.

Re:Vandeberghâ(TM)s 25 cm Newtonian Telescope

[The Bad Astronomer]

It's a 10 inch mirror. I owned a 'scope like that for over 20 years, and it's a pretty decent instrument. It looked like a water heater; a foot across and two yards long.