chemist

On 08/07/2020 at 09:31, TerryMcK said:

I have the Logitech C270 and a couple of Philips SPC900NC webcams (which are CCDs). The latter are great for planetary, very sensitive and I've converted them easily enough using these instructions http://www.orion-xt10.com/philips-spc900nc-webcam.html

The C270, which is a CMOS sensor, was also easy to convert to have a 1.1/4" webcam adaptor fitted. The hole for the existing lens that comes with the camera just needs opening up to 11mm (13/32") and then simply screw the adaptor in carefully by hand. Throw the lens away as you will no longer need it.

The adaptor will make its own M12 thread as it is screwing into plastic (if you have the metal adaptor like this one - Elerose Telescope Adapter for Telescope 1.25in Thread for Taking Video Capture https://www.amazon.co.uk/gp/product/B07H4CLB88 ) and it works really well.

The best webcams are the Philips SPC900NC's and it is staggering just what they can do albeit with a small sensor size. The C270 is fine for the moon and some of the larger planets although don't expect Hubble type images from either of these.

 

 

TerryMcK, How did you determine pixel size of the C270? I am trying to use one of these in an optics lab.

On 24/05/2015 at 20:51, bitnick said:

The whole contraption looks like this:

... and from the camera end:

Now, I didn't have too high hopes for this: the tripod is quite horrible (very unstable, lots of flexure, there's way too much friction to overcome to move the head, etc), the camera is cheap, the focus is simply a tube one pushes in or out of the main scope tube, and the scope itself is made of plastic and creaks when I touch it...

Also, I think the seeing was quite horrible today. Even bright Venus twinkled to the naked eye, and there was thin sheets of cloud high in the sky. Anyway, here are some star snapshots:

I think I must have succeeded with the focus, right? That's the airy disk and its first ring that's visible, if I'm not mistaken?

The C270 has a pixel size of 2.8 µm square, and a resolution of 1280x720, so the sensor size is 3.58 mm x 2.02 mm. 12 Dimensional String tells me that this combination of telescope and camera gives a resolution of 1.16'' per pixel. The field of view is 25' x 14' or there abouts. This page tells me that the resolvable resolution for a scope of this size is 2.7'', or 2.35 pixels - so even with perfect focus, everything will look blurry, I guess.

Here's an overexposed venus and a blurry jupiter:

And finally a snapshot of the moon:

All these images are unprocessed single snapshots. The camera seems to be capable of about 20 frames/s at full resolution. It will be interesting to try it out on the Mak later, in better seeing!

How was this pixel size obtained? I am trying to use a C270 in my optics lab.