Webcam, Question and Idea....

[Grant]

Hi everyone,

I wonder if anyone has ever heard of or seen people using multiple webcams at once for astroimaging? It maybe a weird question, but if you think about it, the more cameras you can run in parallel the more frames you get and the more frames you get the better your image (arguably). Is there anyway then, to mount two webcams via some form of prism to split the image and use this through a telescope?

The reason I ask is, I am currently building a multiple webcam application for my Dissertation project and wondered if I could perhaps use some of the skills to develop a program to help astrophotographers. Can you guys think of any features that you'd like to have in a webcam application but can't find something that provides them for you?

Cheers,

Grant

[Ant]

I'm wondering if you could use one of those bino veiwers with two webcams - would be a absolute sh*te to ensure that they were in exactly the same orientation?

It would be a lot easier to do for long exposure imaging, as the stacking software will rotate the image accordingly during the alignment process.

This may seem like a silly question but assuming that you have a newt. You're going to loose 4% of the light on the main mirror, 4% on the secondary mirror. So by the time that the lkight hits the chip you're talking about 92.1% of the light getting through. Then add in a prism and your going to loose (not sure about this) 4%, so your down to 88.5% - would this amount be divided by two so each chip (assuming that there were two webcams) would receive 44.25%?

With the plaets you could get around this maybe, by increasing the exposure slightly. But seeing as your final image quality is restricted by atmospheric seeing more than anyting else - would there be any advantage to having twice the number of frames...

You would end up with twice as many good frames and twice as many bad frames. Two good frames would be effectivly identical - so would that inhibit the stacking process - in the same way that you can't just duplicate a single frame and then stack them for a better result.

I don't know!

Ant

Wibble

[Grant]

A frame taken at exactly the same moment by one webcam won't be the same as the one taken by the other though because of CCD noise, I think the light thing is definitely something to think about though, it's a pity theres not such a thing as a light amplifier....

[Ant]

There is grant - it's called a telescope...

You could always write some capture software - there are plenty out there to see what they do. You may be able incorporate that into a web browers front end. add some extra functionality.

What would be usefull is some #software that enables you to attache to capture devices (maybe 300D and Toucam Pro) and have one coming through as an avi for guiding - like a live view or near enough and then another window to control and download the image taken witht eh 300D.

Ant

[GazOC]

Ant,

Another problem with the prism/binoviewer approach is that binoviewers work by splitting the light into two and sending half to each eye. The reason that the image doesn't seem half as bright is that the brain is 'fooled' and compensates for the darker image with the fact it can 'see' it with both eyes. A camera would not be fooled and would only register half the light in each camera.

Gaz

[Ant]

Yeah thats what I was trying to get accross - you may be able to get around that by increasing the exposure time / gain to compensate. But for DSO work there is no way around it.

Ant

[GazOC]

Yeah thats what I was trying to get accross - you may be able to get around that by increasing the exposure time / gain to compensate. But for DSO work there is no way around it.

Ant

Ah sorry. I read your post properly next time eh? I'd just got up off a night shift and wasn't quite with it.

[OXO]

This maybe going off topic but i wonder if you could image with two differant telescope's with 2 webcams then combine the result's into a Final image? say one scope with filters IR etc nd one without?>...

James

[Grant]

Would the stacking software have trouble matching up the object from a filtered image to an unfiltered image? Also, the telescopes would need to be identical with identical eyepieces etc... so the object was the same size.... or maybe they wouldn't? It depends how good the stacking software is I guess. It would be an awesome thing to do though, is there such thing as a scope with a built in ccd?

[Ant]

If you were doing star glusters and galaxies etc (i.e. not planets) then having two different FOV's wouldn't be a problem. Images Plus and Registar can both handle different orientations and image scales. Images plus does require the images to be the same size in pixels whereas from memory Registar doesn't.

A scope with a built in CCD would have a fairly short shelf life grant. Things are moving on so fast now that within a few months it would be out of date. Also to have a built in CCD would imply that you couldn't use eyepeices. And although I myself don't use eyepeices very much now, I do use them for locating the object to image in the first place...

Ant