Webcam - testing the limits

[michaellxv]

:help:
During my allocation of 1 clear night for August I had another go at Jupiter using my webcam with dismal results. :sadeyes: I still can't get anything other than a featureless disc.:shrug:

When I wind exposure and brightness up to max I get the attached image of Jupiter with 3 moons. This gives me some hope that I am just doing it all wrong and need to find the right settings.

Or, maybe I'm just looney :screwy: and should stick to the moon.

When I wind the exposure and brightness back the moons go but I can't get any surface detail. Any suggestions about how to go about this:question:

[ballaratdragons]

Yeah, wind the settings even further back.

You can't get an image of the Moons and a nicely banded Joop at the same time. It's either one or the other.

Bring the gain down to about 5%. Set your frame rate around 30 fps and slowly bring the brightness and Gamma down until you see a nice Joop.

This is a quick basic lesson. The Planetary Gurus will fine tune it for you.

[michaellxv]

Hmmm gain and gamma. The two settings I don't have any control over. Attached is what I do get.

Is a distant street light a valid test while the clouds hang around for at least the next week?

[ballaratdragons]

Yikes, you don't get much control with that webcam software.
What make and model is it?

Is it suitable for Astro work? (is it < 1 lux)

Yes, you can practice on a distant streetlight. I have in the past.

[michaellxv]

Yeah, I guess I should come clean.
It's a M$ Lifecam HD. As per here (http://www.ghonis2.ho8.com/lifecam/lifecam5.html) it can work.
The second part of my extreme testing is I only have an 80mm refractor.
I'm not expecting miracles but I think I should be able to get something.

[mswhin63]

Your only bet is to use filters. I use double polarizing filters to further reduce light. The exposure control is already at minimum but I find these highly in-effective. The auto exposure looks at the overall capture and compensates, this is great for the moon in most cases but planetary is just no good at all. The overall picture is mostly black.

[mswhin63]

BTW noticed on the mod website they set the brightness to minimum and the contrast to maximum, then bring up the controls from there. Not sure if this gives the best results but I may try it myself on mine one day.

[michaellxv]

I was wondering about filters and the fact that having removed the webcam lense the IR cut filter goes with it. What impact does this have on the sensor and the settings I need to use?

[mswhin63]

Not much really, although I have noticed dirt spots on the sensor are more readily seen (can be good and bad) apart from that, the main benefit is no alteration of the contrast with a possible real colour. Altering Brightness and contrast i am not really sure of the affect. In my early days I had no EQ to track the planets but will have mine completed fairly soon. With that i hope to continue testing the webcam with better results.

[asimov]

Without an IR cut in place you'll get colour smear/bleed, especially at low altitude.

[mswhin63]

I use IR cut as well, improves sharpness and contrast, but it wont help the problem your experiencing. Definately something you should invest for planetary

[michaellxv]

This sounds like part of the problem. I have a couple of things to try now.

[michaellxv]

Tried again last night but no great break through. I have some basic colour filters so I put them in. Seemed to make a little bit of difference on the screen but not enough to get a result.

[mswhin63]

I believe the main problem is the drivers, my webcam I think uses the same drivers and the exposure control is next to useless. I used a few filter on my DOB recently. I recently after a long break decided to get into webcam imaging again and with reasonable results.
http://www.iceinspace.com.au/forum/showthread.php?t=65540

I used double polarising filter and IR filter for non barlow, and moon filter with IR filter with Barlow imaging.

[Lurkingpom]

Have one of these modified Microsoft HD cams ourselves, not used it much, but to the point, here is a reference to some software that you may like to look at, still unable to adjust the gain - but that seems to be a feature in the camera.

I have no connection to the software other than its on my netbook and I also 'lurk' on the UK astro forum that prompted it.

Hope this is useful, Mick

https://sites.google.com/site/rwgastro/sharpcap

[mswhin63]

This has a nice application but it restricted to the Drivers. Tied it myself for my HD webcam but the control schema was blank. Only the ability to select resolution, color space and frame rate, all other controls were not there.

I still like the interface so I am gonna play with the drivers, hope this works.