I don't get it, using webcams

[Vargojones]

I've been reading the primer for using webcams as an imaging device.

Now i know a dob mounted scope isn't ideal, but it would be nice to take some vids of stuff i see.

But i just don't get how you use a webcam, i get that you have to pop on an eyepiece adapter but after that, not a clue. Do you have to also use other eyepieces, or do you just drop the webcam in? Are the any good links or summaries of how to do it elsewhere on the web?

Apologies for the newb like questions.

Cheers

Vargo.

[malc-c]

I'm no expert, and yet to try this for real, but what you do is take a short clip and then process each frame of the avi using software which effectively registers and stacks the individual frames on top of each other to produce a detailed end result.

I found a "tutorial" on youtube - might explain how it works and what the end results can be

[JamesM]

I'm not an imager but after connecting the eyepiece adapter, my belief is that you just pop it into the focuser (as you would an eyepiece) and use the focuser on the scope to bring the image to focus. If a more qualified opinion does arrive soon, might be better to repost your question in the equipment advice section under the imaging heading.

James

[John]

I'm no expert either but I've done a little web cam imaging of the moon and planets. Firstly you remove the web cam lens. You then fit an adaptor to the web cam so it will fit in the eyepiece socket. The telescope has then effectively become the lens of the web cam and can focus images onto the chip in the web cam.

After carefully focusing (not easy I found !) you then take an AVI movie clip and save it on to a PC. Separate software is then used to process each frame of the AVI clip, discard the poorer ones and eventually stack all the good ones into a single image, which is a composite of all the good frames. Further processing can then be done before the image is complete.

Thats really simplified and there is a lot more to it but those are the basics as I understand them.

[The Bat]

The webcam, fitted with a 1.25" adapter, does indeed slot into where the eyepiece would normally fit.

Without motorised tracking, however, you will find it tricky to get your chosen object on screen (the chip is quite small), and then to keep it there for one to several minutes.

The use of a webcam is primarily for imaging (ie. getting ultimately a still shot), not for taking movie clips of what you see down the scope (apologies if I have misinterpreted you here). Planetary imaging involves taking a short video clip of a planet or the moon, then using software to sort out the good frames from the bad and stack them up, enhancing the signal to noise to bring out fine detail. What you see on screen will be a largely out of focus image (due to atmospheric disturbance) with very little detail. It is only when you stack lots of frames that you get the detail. So the movie itself will not be particularly impressive. You won't be able to use the webcam to capture anything like deep sky objects, they are just too faint and need long exposures.

Hope that helps.

Rachel

[Vargojones]

Thanks for the info, i just needed it explaining a little more clearly. I'm not expecing amazing results like we see in the imaging section of SGL, and given that a webcam from Morgans (the spc880 i think) coupled with the adapter is ~£30, it's no great loss if the images are poor.

Thanks again

[kentronix]

if you click the link in my sig and then from my site click on 'photos of example setups' it shows you a photo of exactly how its connected to the scope. Down near the bottom.

Basically, no lenses at all. just scope and webcam sensor. It means there is no option to alter the magnification (other than a barlow) so it acts like about a 6mm eyepiece.

to mods, I hope I am allowed to point people at my site ? Its kind of why I did it

[umadog]

Here's the view through a Mallincam, which is designed for the job:

You're watching it do on-line averaging in those movies. It's not a simple webcam, therefore, and is much more expensive.