Trouble with modified webcam

[Astro-Nova]

I had an old cheap webcam laying around and thought by myself to have a go making it usefull for astro imaging. (see below)

I took the lens out and stuck a 35mm canister at the end and taped it nicely around the edge so no light could come through.

I took it out and aimed for saturn....nothing, just darkness and obviously pixels jumping around which happens with any webcam.

Could anyone tell me what could have been the problem? i.e. the way i modified it, software settings or scope focusing??

[dav1d]

First, your sensor is going to be roughly in the centre of that webcam 'ball' - Focussing will be waaay out & possibly to the point where you wouldn't even get the white disc.

Second, your field of view will be very very small - even if Saturn seems dead centre in say a 10mm EP, it may be completely outside your FOV with the webcam.

I'd suggest practicing on the moon to get your focussing right and try Saturn again once you have the basic operations sussed.

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[Astro-Nova]

ok ill wait for the moon to come out first next time. have to wait again cause it be quite late before it appears again but i deffo take that advise, thank you

[JamesF]

First thing to do is to check it still responds to light though, just in case something you did whilst modifying it caused it to fail. If you start SharpCap up with the camera connected and cover the end with your hand (during the daytime, or in a lit room) then it should go dark and then light again when you take your hand off.

If that works then as David says, the moon is a good first target to confirm that it's functioning correctly, and you'll need to remember that the focus point may be a long way from where it would be with an eyepiece. I think I'm right in saying that to get focus with the camera you need to have the camera sensor in about the same position as the field stop in an eyepiece would be.

If you don't want to be tearing your hair out it's also important that the nosepiece should hold the camera sensor exactly at its centre. That will allow you to align (say) Saturn centrally using an eyepiece and then swap to the camera and stand some chance of the image being on the sensor. The sensor itself is probably only something like a 4mm x 3mm rectangle, so the alignment only needs to be fractionally out for you to stand no reasonable chance of finding the target. This is why screw-in nosepieces make life so much easier.

James

[Geesus]

What capture software are you using? I started webcam imaging recently and found that SharpCap works brilliantly... (It's a free download, check it out if you havent already) but some people prefer k3ccdtools... I have no experience with that I'm afraid.

One thing you could try is imaging during the day... I got this

of some trees about 50m away from my house, just to check that the camera was working nicely!

With night time captures it's possible that if the Gain setting on your software isn't high enough you can spend hours trying to find something without realising it's already slap bang in the centre of your field of view... Try turning the gain all the way up and whatever other settings your software has to make it more sensitive to fainter objects in order to find saturn, and when you've found it work from there at turning it back down to a level nice enough tor imaging... kind of a "location" setting rather than a "capture" setting, if you get my drift?

Hope this helps!

Ginger

[JamesF]

That's a very good point that I completely forgot. You can always test during the day If you centre part of some distant landmark in the field of view with an eyepiece then you can also check how well centred the camera sensor is relative to the nosepiece.

James

[wyx]

It can be very frustrating, with my vx5000 i can focus on the planets but having trouble with my new xbox cam. It definitely works better on the moon than the lifecam so looks promising but because the sensor size, sharpcap settings and focusing is different i couldn't get anything last night. Just takes patience. Took me three sessions to get a blob on the screen with the vx5000. When you do get an image, note down the settings! Also don't shout 'YES!' and wake the neighbours:) getting a postable image is another story!

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[JamesF]

Remember that SharpCap does allow you to save the settings once you have them sorted.

James

[Astro-Nova]

thank you all for the helpful tips, there are a lot of things you mentioned I should have a go at so first stop ill have a go at day time as well as the moon.

I have tested the cam at day time to make sure it worked and when i cover cam up its dark and lights up again if i remove the cover so I assume it should be in good working order.

The capture software I have downloaded is called wxAstroCapture

[JamesF]

Sounds good. In that case your only problem should be getting the image aligned on the camera sensor.

James

[StarryBob]

Some cmos webcams will only work on really bright stuff like the moon. Make sure you have the gain turned right up to start with and also remember that things move fast through a 6mm EP which is about the equivalent to a webcam so by the time you might find focus it's gone. For what the cost the only cheap webcam worth trying with in my opinion is the xbox viewcam, I would bother with a cmos cam unless it's a good quality HD type.

[Astro-Nova]

I just tried webcam at daytime but no succes I think i cant get an object from a distance enough as im surrounded with houses and trees. I try the moon next time when it is high up for my best bet.

In the meantime I took a photo from the webcam lensthing and if there is anything noticable that is rather wrong, please let me know

[JamesF]

Your nosepiece doesn't look very central to me. I'd try to get it better than that, so the same amount of the camera housing shows inside the nosepiece all the way around. Glue may be easier than tape. Using glue might also allow you to shorten the nosepiece and put the camera further into the focuser, bringing the camera sensor closer to the image plane. I suspect that the reason you couldn't see much is because the scope can't reach focus with the camera in. By way of comparison, the camera sensor on my xbox camera is about 23mm from the end of the eyepiece holder. With my Lifecam, the sensor is in line with the end of the eyepiece holder, give or take a millimetre or two.

James

[JamesF]

It may be relevant to also point out that there is another reason for getting the nosepiece central. In the setup you have, with a spherical camera housing, if the nosepiece isn't central then the camera sensor won't be parallel to the image plane and you'll not be able to get all of the camera sensor to focus at the same time.

James

[Astro-Nova]

thank you James. I shall try to get it more centred. I should be able to saw off more of the canister so the nose wont be too long, I dont know why i left it on the long side in the first place, I think ill make it as short as possible as long I can tighten the screws to hold the camera in focuser.

[JamesF]

The ones I have for my SPC cameras are about 40mm from the open end to the camera sensor, if that helps.

James

[Stargazing_Cliff]

Sometimes i noticed on some cams when modding need to get the sensor more closer into eye piece of telescope maybe shorten the canister little or remove bit of front plastic before the sensor. and tape up that way.

Maybe focus and sensor not in middle i usually test cam on local lamp post

get telescope pointing at light from lamp post middle of screen and move spotting scope i do that with any cam i use on telescope lamp post get spotting scope aligned middle with cam sensor

view lamp post in distance then easyer to point telescope at object in skies

I allways align spotting scope with cam's sensor

then just look through spotting scope and image of what ever was viewing appears on me computer or laptop.

[Stargazing_Cliff]

Astro-Nova is that a Trust spacecam make by any chance i'm sure shape of it looks familiar.

did you manage to get any imaging from it ?

i would test on local lamp post move telescope around till image of lamp post is in middle of screen then i would move spotting scope to same lamp post then look for objects in space and maybe lucky image appears on your laptop/computer.

[Astro-Nova]

its logitech but not far off from a cheap trust i think.

I might try and do that to align my finderscope with the cam. another thing to add on my to do list