PDA

View Full Version : 1/3" CCD


Lurking Luser
October 11th 03, 10:33 PM
I'm new to astro photography and have been using a little Vivitar 1/4 inch
color ccd camera with 'alright' results, but I want sharper images. I don't
have a lot of cash. But I found a 1/3 inch black and white ccd for about $50
on the web. It is the cvc 50 bc. It is a very small board camera sold as a
spy cam, but I'm thinking it might work well for astro photography.

Does anyone have any expierence with this camera?

How clear will details of planets be with a black and white camera?

Chris L Peterson
October 11th 03, 11:02 PM
On Sat, 11 Oct 2003 21:33:17 GMT, "Lurking Luser" >
wrote:

>I'm new to astro photography and have been using a little Vivitar 1/4 inch
>color ccd camera with 'alright' results, but I want sharper images. I don't
>have a lot of cash. But I found a 1/3 inch black and white ccd for about $50
>on the web. It is the cvc 50 bc. It is a very small board camera sold as a
>spy cam, but I'm thinking it might work well for astro photography.
>
>Does anyone have any expierence with this camera?
>
>How clear will details of planets be with a black and white camera?

I'm not familiar with the specific camera you found. However, a B&W camera will
generally give substantially better performance and resolution, and will likely
show more detail with planets. Note, however, that the larger format sensor
probably also means the pixels are larger, so you may need to operate at a
longer focal length if you are currently operating near the optimal sampling
size for your system.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Lurking Luser
October 11th 03, 11:39 PM
"Chris L Peterson" > wrote in message
...
> On Sat, 11 Oct 2003 21:33:17 GMT, "Lurking Luser"
>
> wrote:
[snipe]
>Note, however, that the larger format sensor
> probably also means the pixels are larger, so you may need to operate at a
> longer focal length if you are currently operating near the optimal
sampling
> size for your system.
>
> _________________________________________________
>
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com

Hmm, I have been using a 80mm f/5 scope which gathers a fair amount of
light, but of course has a short focal lemgth of 400mm. Do you think a
barllow would help extend the focal length?

Chris L Peterson
October 12th 03, 01:26 AM
On Sat, 11 Oct 2003 22:39:48 GMT, "Lurking Luser" >
wrote:

>Hmm, I have been using a 80mm f/5 scope which gathers a fair amount of
>light, but of course has a short focal lemgth of 400mm. Do you think a
>barllow would help extend the focal length?

For planetary imaging, you aren't even in the ballpark. Figuring that these
small sensors typically have pixel sizes around 5-9u, you are operating at a
pixel scale of 2.5-4.5"! That is at least 10 times too big for imaging planets,
where short exposure times can beat atmospheric seeing.

Put another way, you are getting only about 5 pixels across Mars, where you
should be getting 50 or more. With such a short scope, it is going to take more
than a barlow to improve things much. If you don't have a longer focal length
scope available, you should be looking at eyepiece projection. Otherwise
switching to another camera will give no improvement at all, and if the pixels
are larger (as they probably will be) you will lose even more of the scarce
detail you already have.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Lurking Luser
October 12th 03, 07:09 PM
"Chris L Peterson" > wrote in message
...
> On Sat, 11 Oct 2003 22:39:48 GMT, "Lurking Luser"
>
> wrote:
>
> >Hmm, I have been using a 80mm f/5 scope which gathers a fair amount of
> >light, but of course has a short focal lemgth of 400mm. Do you think a
> >barllow would help extend the focal length?
>
> For planetary imaging, you aren't even in the ballpark. Figuring that
these
> small sensors typically have pixel sizes around 5-9u, you are operating at
a
> pixel scale of 2.5-4.5"! That is at least 10 times too big for imaging
planets,
> where short exposure times can beat atmospheric seeing.
>
> Put another way, you are getting only about 5 pixels across Mars, where
you
> should be getting 50 or more. With such a short scope, it is going to take
more
> than a barlow to improve things much. If you don't have a longer focal
length
> scope available, you should be looking at eyepiece projection. Otherwise
> switching to another camera will give no improvement at all, and if the
pixels
> are larger (as they probably will be) you will lose even more of the
scarce
> detail you already have.
>
> _________________________________________________
>
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com

Thanks! Like I say I'm new at this. It sounds like projection is my only
hope with the equiptment that I have (or can afford right now).

I do have a 60mm f12 that I used with a 3x barlow to get a blurry picture of
mars.

I know I'm pushing all kinds of optical limts, but using the 80mm f5, a 2x
barlow and a 20mm eyepiece with a project length of 60mm I should be able to
get 160x which -should- be within an 80mm objective's optical range.

Or would I have better luck using the 60mm f12 with a 20mm lens, a 3x barlow
and a projection length of 60mm? If I am doing the math correctly that gives
210x which is beyound a 60mm len's limit. The problem with the 60mm scope is
I can't get it to focus with the barrlow at 2x. I have to put it directly
into the tube, which gives me the 3x barlow.

I guess I am going to have to save up for a better scope.