help stting webcam for astrophotography

Roobi · #1 19-10-2010, 10:25 AM

Hi there everyone.

A little while ago i tried to setup a webcam to my astromaster 130eq. I followed some of the turorials out there and dismantled the webcam attatched it to the doorstop as shown and popped it in the focuser.
No matter what i did though, i could not get it in focus. The only thing i could do was put an ep in first, then re attatch the camera (using lacka bands lol) to get any sort of clear picture. Anyway, im thinking of trying again, but im wondering if any of you could shed some light on this so i know what im doing next time.
I have a barlow lense now, so would that help?

Cheers

erick (Eric) · #2 19-10-2010, 12:18 PM

Can you describe a bit more on how you are trying to do this? Have you removed the lens from the webcam? When you say you couldn't get it in focus, was it approaching focus but you ran out of inwards travel on your focusser?

[1ponders] (Paul) · #3 19-10-2010, 01:33 PM

I'm with Eric on this one Roobi, sounds like an intravel issue. Try putting a barlow in the line and see how you go.

Roobi · #4 19-10-2010, 04:02 PM

cheers guys, i'l try it with the barlow.
Last time i took the lens out so that the ccd chip was showing, added the makeshift adapter on and popped it in the focuser. The only way i could get an image, was to actually put an ep in first, then attatch the camera. I should be able to get focus without an ep tho right, if i dont use a barlow?
Also i was wondering about the drift, as i would have to keep shifting manually. What would you suggest, or can it not really be done without one of those motorised mounts?

Cheers again

erick (Eric) · #5 19-10-2010, 04:21 PM

Yep, you need to have "prime focus" which means camera lens out so you can see the chip, then some form of adapter (there are commercial ones available) that mount it rigidly into the focusser. The problem is that the CCD chip is then usually well back from the focal plane and you run out of in-travel on your focusser trying to get there. Frequent solutions are 1) a low-profile focusser and 2) moving the primary mirror up the tube towards the secondary mirror. A barlow lens may well solve the problem - it's worth a try. But your image size gets larger (field of view smaller) and it is often already quite difficult to get your object in the view of the small CCD chip before you add the magnification of a barlow. You'll want your finderscope very well aligned!

Re: how to use it on a non-tracking telescope, read:-

http://www.iceinspace.com.au/63-201-0-0-1-0.html
http://www.orion-xt10.com/philips-spc900nc-webcam.html

Lots of good information and ideas in both of these! But your targets are really limited to the Moon and the bright planets.

Try Craterlet as your webcam control and acquisition software:-

http://www.stark-labs.com/craterlet.html

I have just started to play with this software - looks promising as a tool for webcam dummies like me!

Happy experimenting!

ballaratdragons (Ken) · #6 19-10-2010, 04:34 PM

Quote:

Originally Posted by Roobi

dismantled the webcam attatched it to the doorstop as shown

Cheers

I have 2 queries.

1. What's a doorstop got to do with the webcam

Did you make an adaptor out of one?

2. "as shown"

Where?

Please show us

Roobi · #7 19-10-2010, 04:52 PM

Yup. I've seen a couple of tutorials that use a door stop thingo as the adapter. heres the link mate.

http://www.iceinspace.com.au/63-431-0-0-1-0.html

one last quick question. So am i able to use the webcam, with my own lenses (if i can connect em up properly)?

ballaratdragons (Ken) · #8 19-10-2010, 05:07 PM

Quote:

Originally Posted by Roobi

Yup. I've seen a couple of tutorials that use a door stop thingo as the adapter. heres the link mate.

http://www.iceinspace.com.au/63-431-0-0-1-0.html

Well how about that

Never seen it done that way before.

Quote:

Originally Posted by Roobi

one last quick question. So am i able to use the webcam, with my own lenses (if i can connect em up properly)?

Yes, absolutely.

Roobi · #9 19-10-2010, 05:17 PM

awesome awesome. I'm getting excited now. Skies look clear for tonight. Fingers crossed. So i'm guessing what would be the best way for me to proceed would be to take off the lense and try to get the focus right with it in the focuser first. Then try the barlow lense, If that doesnt work then i'll put the webcam lense back in, and attatch it (somehow) to my eps.

-Edit-

I've just found out this version of the logitech quickcam doesn't have a ccd chip, only cmos. How much does this change things for me?

Roobi · #10 19-10-2010, 10:06 PM

Just nticed also, when i have the webcam hooked up to my ep and looking at the moon, i can see a large black dot which im assuming is my secondary mirror, is this normal, or what can i do so that it wont show up?

Cheers

erick (Eric) · #11 19-10-2010, 10:53 PM

I understand that CMOS chips are less sensitive to low light levels than CCD chips? Won't make any different when photographing the Moon, Jupiter, Saturn.

Black dot in the centre of a large defocused image of a star, Moon or planet - yes, sounds like the secondary mirror.

But what do you mean by "webcam hooked up to eyepiece"? "Afocal" (as compared to "Prime Focus") means that you poke the webcam at the eyepiece - where you would normally place your eye. But you would have to play with the focus of the webcam - I haven't done this (but I'm going to to see if I can aid my Cheshire collimation step on my big dob) so I'm not sure how it would perform. One might have to adjust the webcam focus and the focusser position to get a sharp image??

mswhin63 (Malcolm) · #12 20-10-2010, 01:23 AM

Quote:

Originally Posted by Roobi

Just nticed also, when i have the webcam hooked up to my ep and looking at the moon, i can see a large black dot which im assuming is my secondary mirror, is this normal, or what can i do so that it wont show up?

Cheers

Black dot is usually a small amount of dirt on the CCD element, I have had this numerous times while experimenting. Careful cleaning gets rid of this problem (very careful)

Roobi · #13 21-10-2010, 09:17 AM

ok well i got it all going reasonably well last night.... except, The screen capturing program im using (craterlet) seems a bit finiky. Firstly i have to have webctrl going to be able to change any settings in craterlet, then i actually have to start recording, then open up settings and change them while recording, and leave the settings window up, otherwise as soon as i click ok (apply button is blanked so i can't click it) it switches back to auto exposure and gain.
Not only this, Craterlet wants to keep changing where its saving my files so im having a hell of a time finding them, and a fair few are corrupt. Alas my best shots of jupiter last night are now lost.

does anyone have any ideas on a better capture program, though i think ive tried them all at this point.

Thanks again guys