Webcam as a kind of Telrad?

[toc (Tim)]

This afternoon I had a thought. One of my least pleasurable aspects of Astronomy is bending myself in all sorts of positions to centre stars in my telescope for alignment. I was thinking that I could mount a webcam with a widefield view to act as a sort of telrad replacement. That way I could sit my butt on a chair looking at a laptop screen, rather than get sore knees and a bad back

Has anyone done this? Thoughts?

Edit: I was even thinking of mounting the webcam at the rear of my Telrad...

[Astroman (Andrew Wall)]

Why not use the 90 degree Dew Shield + for the Telrad, only a few bucks and handy so you don't have to bend down. Bintel sell them... http://www.bintel.com.au/Accessories...oductview.aspx

Or...

Going by your original idea, you would probably be better off using a low light camera such as a watec902h or 902h2. these are low light cameras they use for meteor observations. I doubt the webcam would have the sensitivity for you. You could feed the video into a program like Sharpcap or even PHD and superimpose the reticule onto it.

Pointing the camera at the Telrad to use it's circles wouldn't work either unless the lens you were using is all-in-focus. If focused on the stars the Telrad would be out of focus, if focused on the telrad, you wouldn't see any stars.

I am no expert, but I do think using a low light sensitive camera such as the watecs would be the better solution. And there maybe other solutions also..

[iceman (Mike)]

It's a good idea.

Anthony (bird) put a Toucam in the end of a 6x30 finder and used it as a substitute telrad/guide scope.

I always had a plan to do it, but never got around to it.

[Screwdriverone (Chris)]

Hi Tim,

I actually use my DBK21AU618.AS planetary webcam on my 50mm Orion finder/guider scope for just this purpose.

As soon as I plonk down the HEQ5 and set the tube to SCP (using the marks on the concrete), I connect the DBK and the Atik CCD to the PC and fire up the capture programs as well as Stellarium Scope and connect it to the mount using EQMod through the hand controller (set to PC direct).

When Stellarium starts, I get the "Telescope" cross hair sitting on the SCP and then I click on say, Sirius or Canopus and the scope slews off to where it thinks it is, which I monitor on the Webcam capture program.

As the Orion finder guider is an F3 (ish) 50mm widefield, I can normally capture the star I have slewed to on the screen in the field (or can see where it went when it slewed past) and then I jog it back to the centre of the screen and take some test shots with the CCD to make sure its in the centre of the FOV.

Some slight adjustments of the guidescope to make sure its centred with the main scope and then I SYNC the mount and Stellarium by using the CTRL-3 sync command and the "Scope" icon moves to the star I am on.

From then on, all I have to do is point and click the object I want and then hit CTRL-1 and off the scope goes, to the next object. By monitoring on the Webcam display, I can see, even with a 2-3 second exposure, the DSO I am looking for when the scope stops.

Fine tuning with the EQMOD arrows then allows me to frame the object, do some test shots with the CCD to make sure I am happy with how it sits and then I simply fire up the guiding and start the image capture sequence.

This way I DONT have to do any initial alignment on the hand controller, I simply fire up the mount, set the date, time etc, then just put it in Sidereal tracking mode and then PC - Direct mode, sit back and control the whole lot from the chair without even LOOKING through a piece of glass.

Have I said too much?

Cheers

Chris

[entity62]

I use a GStar colour camera, with a 50mm F1.6 lens as my view finder.
Being a lazy sod, i only have to open my Ob's, remove cover over scope, and plonk my butt down on comfy chair and view ( Mallincam video camera) the night sky on the PC's.

Darrell

[Poita (Peter)]

I use one of those cheap security cameras and a portable DVD screen and do exactly that. Works a treat.