Weasner's Webcam Astrophotography Page

ASTROPHOTOGRAPHY WITH WEBCAMS

Last updated: 8 February 2012

This page documents Quickcam, ToUCam, and similar video/web cameras comments, tips, and photos. Also, see the Quickcam references on the Astrophotography - Basics page. webcam the site for other items about webcams. Contributions welcome.

Subject:	RE: ETX-90 : trouble focusing SPC900NC webcam
Sent:	Sunday, February 5, 2012 04:40:40
From:	Rob Voorend (r.voorend@chello.nl)
I tried several things to get a clear image with my webcam but it didn't
work. I can't use my webcam in the rear port because it doesn't fit. Now
that i'm into astrophotography, I want to try a digital camera.

Somewhere on your site I read that a Sony F828 could work just fine (I want
to start low level because of costs). Do you know if I can mount a Sony F828
on my ETX-90? And if so, do you know what other things I need to mount it?

Regards,

Rob

Mike here: If you search the ETX Site for "Sony F828", you will find a couple of pages that discuss it. You will need the appropriate adapter to mount the camera on the telescope. See the Accessory Reviews: Astrophotography page for more on adapters. As to the webcam, for mounting at the rear port, you would need an ETX Visual Back. The Visual Back allows mounting of 1.25" eyepieces, etc, at the rear port.

End of today's update

Subject:	ETX-90 : trouble focusing SPC900NC webcam
Sent:	Wednesday, February 1, 2012 09:18:57
From:	Rob Voorend (r.voorend@chello.nl)
First of all, thank you for keeping your website in the air for so long.
It helped me out in numerous occasions.

There's only one thing I can't find and can't fix, and that is how to
get good focus with my ETX-90 and a SPC900NC webcam with a IR blocking
filter.
I used this webcam before on my older telescope and it worked fine.

What is the issue? When I try to get good focus on let's say the moon,
the image stays blurry. I use Craterlet as software on a XP machine.
I was wondering, what do I do wrong here?

Hope you can help me out.

With kind regards,
Rob Voorend
The Netherlands

Mike here: By "blurry", do you mean "out of focus" or blurred from motion (either atmospheric distortion or telescope movement)?

And:

Thanks for the quick reply. With blurry I mean out of focus.

Mike here: Infrared light will focus at a different point than visible light. So, if you have focused a "parfocal" eyepiece using your eye, the image would be out of focus using the IR filter. If you are monitoring a "live" webcam image on your computer, you should be able to achieve a good focus.

And:

Thats the problem, I can't get a good focus when watching my live webcam
on
my laptop. Removing the ir filter doesn't work.

Mike here: Oh, so the image on the computer screen is not changing as you rotate the focus knob. Does it change if you slide the webcam in and out of the eyepiece holder?

And:

Yes its changing, i can adjust the focus but i can't seem to get a clear
picture. I havent tried sliding the webcam in and out. Could it be the
focal
lenght?

Mike here: Depending on where the webcam sensor is located in its housing, it is possible that there is not enough focus travel on the ETX to achieve a focus. If you have an ETX Visual Back, you can try using the rear port.

And:

Thanks for "clearing" my skies :)

I will try that tomorrow evening. I will also try to slide the webcam
more
out.
I'll update you with my findings.

Regards Rob

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