Imaging Mars with Webcam

[StevenA]

I am using a QC Express webcam with lens removed, (thus I believe so is the IR filter), I use an 8" (200mm) Newtonian Reflector and run the imager through the standard Logitech software. I also try using WXAstro and a luna imaging software package(Name illudes me right now). So far the best comes from the Logitech program.
My problem lies in the programs. I have to reduce the Exposure to close to Zero and increase the gain to about 30% to get an image that appears like Mars. My best images however were taken when I used my home made Hatman Mask to focus. These images were of a better quality even though 'taken with the mask on'. What is happening here? Is the Mask reducing what the IR filter would have compensated for? Is it simply reducing the amount of light enetering the Scope and thus the WebCam imager? May I have you ideas and comments on this.

Please note my Bintel Barlow (the only poor purchase I have made from Bintel) is out of action and my images are visually small and thus lake detail for close examination. Yours Sincerly StevenA

[mswhin63]

For a lot of webcam images I previously used a double polarizing filter to manipulate the intensity of the image. On a tracking scope (which I do not have) this would be fine, but on a non tracking scope I had a lot of difficulty in adjusting it and re-inserting back while remaining close to the point on the screen, otherwise spent ages trying to get the image back in the FOV before finding that I have to re-adjust again :D

Double polarising is the best bet, but to allow quick adjustment I simple placed the cover on my scope and opened up the 2" hole and bingo was able to get a good variation in camera exposure levels.

If and when I get my scope tracking I will go back to polarizing filter. BTW I found that moon filter reduced level but not enough for some cameras especially mine which is a low light webcams.

Another alternative I am considering is using multiple % filters and stack to give a level I need. Unfortunately combining lense put just a little more stuff in front of the image and unsure what the final quality would be.

Quick test solution - Put the cap on the end and open up the 2" cover.
Double polarising Filter.
multiple % intensity filter (correct name eludes me ATM :help:)

[iceman]

It sounds like the webcams you're using don't have the proper exposure control to be effective.

I started with a very basic microsoft webcam and had the same problem - I had to use an aperture mask to reduce the exposure so that the planet wasn't an overexposed blob.

However it's not the best approach long-term. You're reducing your resolution and resolving ability by HEAPS, and all you're doing is making your 8" f/5 scope into a 2" f/15 (or whatever) scope.

You really need to invest in a proper astro webcam. The best budget one is still the ToUcam ProII or ToUcam 900nc.

Using these, you can change the frame-rate and the exposure so you can properly expose the planet while still using your whole 8" of aperture.

Hope that helps.