A (really) noob question

[Vox45]

I am almost ashamed to ask it

When using a webcam with a nosepiece, can I do prime focus or do I have to use something in between the focuser and the webcam. Something about 'projection' but I could not manage to get a good explanation.

The thing that confuses me is: how can I connect a webcam to an eyepiece ? I can understand how a connexion to a barlow would work... but an EP ?

I hope I do not have to buy yet another piece of hardware

[happy-kat]

Hi

The idea is to remove the lens on the webcam exposing the sensor directly then fit your bought or home made nose cone to the webcam and drop that into the focuser unit on your telescope where you would otherwise put an eyepiece.

[Vox45]

Hi,

Yes that part is done it even looks good with my cam

But now I wonder about putting it directly in the focuser ? Is this the only way ? I would expect that an EP be put in the imaging train to add some magnification correct ?

[ronin]

You have sort of both options:

Prime focus you remove the lens and reassemble the webcam without the lens but with the filter (protection for the chip)

You then put the webcam where the eyepiece goes and adjust the focuser to get a good image.

The image on the sensor depends then on the focal length of the scope.

There is an image size not as such a magnification.

The other is afocal, for this you have the webcam as it is in normal use, with lens, you then get an adaptor to fit the webcam on to the eyepiece. Aim scope at object and adjust the focuser to get a good image.

There will be a "magnification" with this as the objective and eyepiece interact.

The prime focus method appears to be the preferred method.

The get a bigger image people will drop a barlow in the path before the webcam in prime focus.

[Vox45]

Aaaah I see ! The adaptor is for a webcam with its original lens, now it makes sens.

I almost threw the lens away yesterday but a little voice said :

- "Remember the 24hrs rule: If you throw it away, you'll need it in less than 24hrs"

to which I replied:

- "Why the hell are you whispering over my shoulder in the dark... go back to sleep honey"

So, it is either prime focus or barlow for me. Don't want to spend money on yet another webcam adaptor !

Thank you for clarifying this for me Ronin

[happy-kat]

Sort of.

You put the webcam with no lens but a nose cone into the barlow into your telescope focuser. This is still considered prime focus.

The barlow will aid/increase magnification.

[Vox45]

ok got it thanks !