Beam Splitter for focusing, observing and webcam?

[Screwdriverone (Chris)]

Hi all,

I am contemplating whether this would work and/or is a good idea.

I am having trouble achieving good focus with the webcam and the PC screen so I thought if I put a beam splitter inbetween the scope and the camera, could I pop in a suitable eyepiece that would focus near to the camera's distance and adjust the camera and the eyepiece position to enable me to do two things.

1) Focus the camera accurately on stars/planets etc.
2) Allow me to visually "see" the object through the scope while the camera is connected so I can watch/guide from the scope if necessary. PC views arent as nice as optical ones either.

Or is this just a stupid idea that wouldnt work?

Your thoughts please?

Chris

[bojan]

Idea is OK, but..
Beam splitters are "lossy".. that means they attenuate light by at least 1/2, but normally much more that that. So you will have darker images in both camera and viewer.
I think the better idea is flip mirror.
Get a cheap, film, mechanical SLR from ebay and mount the webcam sensor in focal plane. this way you will have maximum light transmission in both optical paths, but not at the same time, of course.

[asterisk (Geoff)]

Definitely not a stupid idea Chris - with a guide camera in one OTA and a camera in the other, I use a radial guider to make sure everything is pointing where it should be, especially when imaging near the zenith.

You will need to be careful of your balancing with the extra weight of the splitter and eyepiece.

Cheers

[Merlin66 (Ken)]

I modified a Meade OAG body to take a Surplus Shed 50/50 beamsplitter to allow guiding and alignment of the spectroscope slit... works well for me!!
I see that Vixen are selling ( about $100) a beamsplitter prism cube which would also do the job very well ( only available in 1 1/4" though).
A loss of 50% of the light is significant, but only represents less than a magnitude ( each magnitude step is x2.5 the brightness of the previous)

[renormalised (Carl)]

Flip mirrors aren't all that dear (depending on what model you get) and are a very good idea for using with your imaging system.

[Screwdriverone (Chris)]

Thanks everyone,

So the $64 question is : Where do you get them?

Andrews dont seem to sell them, The Meade one's are too expensive and the Vixen one?

Thanks

Chris

[renormalised (Carl)]

Here's something else which may work...

http://www.yorkoptical.com.au/Produc...%2cProductName

[asterisk (Geoff)]

Originally Posted by Screwdriverone

Thanks everyone,

So the $64 question is : Where do you get them?

Andrews dont seem to sell them, The Meade one's are too expensive and the Vixen one?

Thanks

Chris

http://www.myastroshop.com.au/produc...asp?id=MAS-264

http://www.myastroshop.com.au/produc...asp?id=MAS-339

http://www.yorkoptical.com.au/Produc...%2cProductName

Cheers

[Screwdriverone (Chris)]

Thanks Guys...