Question on imaging Jupiter

Hi All,

Sorry, but I have another newbie question

It was incredibly clear for a change in Galway last night and I tried my hand at imaging Jupiter. Man was it difficult! Much, much harder than Saturn.

Visually it was superb with loads of details so I popped my QuickCam Pro in (the older CCD version) and ran into an odd issue I had not really expected; it was incrediibly bright, looking like an amorphous radioactive blob. So I adjusted the brightness of the camera to it's minimum but still had to use a 3xbarlow to get some contrast on the disk. Still too bright though. Essentially it was at lowest brightness and F30! The final captures showed quite alot of colour bleed around the disk.

Does anyone use filters to image this object? The only filter I used was a Baader IR cutoff. Or would you suggest using an off-axis mask?

Cheers,

Trev

Trevor --

An off-axis mask is no good. Your resolution is proportional to your aperture, so you need to keep all of it.

A neutral-densitiy filter might help, or even more magnification. (Got another barlow? You can stack them.) Sadly, this last part is all conjecture as I've never done any imaging....

-- Jeff.

Trevor --

An off-axis mask is no good. Your resolution is proportional to your aperture, so you need to keep all of it.

A neutral-densitiy filter might help, or even more magnification. (Got another barlow? You can stack them.) Sadly, this last part is all conjecture as I've never done any imaging....

-- Jeff.

Stacking Barlows is something I've read about recently and must give a try some night on Jupiter - would have loved to have one tonight as seeing was pretty decent -I got my best pic yet (well 2nd pic would be more correct, but it's a definite improvement). - Anyone got a spare (good) Barlow I can borrow?

As for colour bleeding, it's odd that visually you say it was perfect yet your images were affected? Focusing Jupiter is quite hard but what I have found to help with the imaging is to manually adjust the blue and red channels as low as you can without turning the image green. You may end up with some reddening of the space around the south pole after stacking but you can clean that up with a paint brush.

Hi Trevor,
I've been dabbling with imaging Jupiter over the last few years with the toucam, I use a 12" scope and the bog standard video capture software that comes with the camera and I've never had a situation where the image was still too bright after adjusting gain and saturation..
so I dont understand why its not working for you with a smaller scope which presumably produces a fainter image due to less light capture.

Like jeyjey says above, off axis is no-good for imaging, but it can help with visual work.

Stacking barlows, I definitely not recommended this, you will almost definitely end up with worse chromatic abberation and get red and blue all over the place.

As for capturing differing levels of the 3 bands, this I would also recommend against, I found that if I capture an avi with an odd colour to it (I tried this a few years ago), thats its almost impossible (for me anyway) to end up with a natural coloured/tinted disk.

Can you give me you settings in the video capture software and what scope/f-ratio you are using, how much of the toucam field fo view (say horisontal amount) is the disk taking?

If it comes down to it, meade supply a polarisation filter, this dims the image without adding a green hue to it, but I suspect this measure can be avoided.

Thanks for the replies everyone.

I have not tried stacking te barlows as I guess that I am up to 300-400 mag already with the 3x. That is already far beyond what I had intended.
The CA is pretty bad with that barlow and mag.

Dave, I was using the meade 8" sct at F10 + the barlow. Saturation and gain at close to their minimum settings.

I also tried my variable ND filter at it's lowest setting but without good results.

One thing I did forget is that I have a set of standard planetary filters. As far as I remember some of them have a lower light transmission so this might be a way to go.

But, I'm beginning to think it's the camera I'm using. I forgot that I had tried this in my 8" Newt when I had it some time ago with similar results. I think it's just getting saturated (even with saturation turned to the minimum) as it worked great for Saturn which is quite a bit dimmer.

Since I have a new GPUSB I'll be looking to get a more suitable webcam or a 2nd hand DSI so I can pick up guide stars. Not a problem really as the Quickcam was just an old device I had already.

I'll try the colour filters out though, but as Dave suggested it will be difficult to fix the colours later on.

Thanks again,

Trev

Dave, I was using the meade 8" sct at F10 + the barlow. Saturation and gain at close to their minimum settings.

Trev

ok, I feel now we're narrowing the problem here somewhat, is there a gamma slide bar, I'd set it to a quarter, otherwise the detail can be washed out. Failing that, is there a shutter speed slide bar, if so I would seriously increase this if possible somthing beyond 1/40th of a second, it's a gaurentee that it'll reduce image brightness as will increasing the frames per second to 30 or so.

I dont know the quickcam so I dont know what level of control you have over this camera.