Jupiter and Europa with GRS 29 1330 UT

[rumples riot]

Hi all heres another from last night.

324/ 835 frames
3x barlow TV
f30
processed in Registax and astra image

seeing was around 5/10 just after front passed through. Reasonable detail present. Just happy to get GRS in shot.

[iceman (Mike)]

Nice Paul, one of your best in terms of sharpness. Where's Europa?

Also i'd still use 640x480

[rumples riot]

Heres the original you can see europa up on the top right. I was imaged at 640 res

[iceman (Mike)]

Very nice, good detail. Got some in the GRS too!

[rumples riot]

Thanks Mike, pretty reasonable shot but seeing was pretty average and this obviously affected the shot. Not my best, but am working on getting a better shot.

[Comet Hunter]

Another nice shot Paul, what level was the gain + brightness at? I'm having trouble adapting to the sensitivity of the Toucam... ending up with a "burntout" centres - slowing weeding out the problem though.

Cant wait to see a shot when everything falls into place for you...will be a ripper!!

[ving (David)]

getting a laptop in a week or 2... next up is an lpi or toucam or something

nice shot ther btw. the grs has plenty of detail and plenty in the bands too

[rumples riot]

Andrew this is a really hard question to answer, but I will try as best as possible.

I keep brightness down as low as possible (thats the easy part), in fact I keep it about 15%. Now as far as gain is concerned. I usually jack it up a bit to help with final focus. Then I lower it down so that it gives good brightness but not so much that I start burning out the image. I usually check after the first avi and run it through media player. That will show you straight away if you are under exposed or over exposed.

If you try as a general rule to maintain gain below 50%. That being said though, when you use a 4x or higher powermate this rule will need to be stretched. The main thing is that you don't get what you are getting now or are so under exposed that you get rings when the frames are stacked.

With a 3x barlow I use gain of around 20%. This gives a nice exposure.

Anyway try this if you like and see how you go. Everything is trial and lots of error. Hope I helped.

[Comet Hunter]

Thanks for the response Paul, a great reply. I seem to be coming from the other way... set the gain first then play with the brightness...

Just for comparison the settings I tried to have with the QC (and initally with the Toucam) was having gain as low as possible (sometimes a little was required up to 10-15% at times) with brightness set so that the overall image looked good, this usually ended up at around atleast 50-60% depending on the shutter speed/conditions etc... its just a matter of re-learning what to look for with the standard frames and how they will turnout once they are stacked+processed to give the final image.

[rumples riot]

Andrew I might be wrong, but brightness seems to have little effect on the image quality. So having it up high will give you a false reading and thereby an underexposed image. Strange that you should get overexposure with these settings. A lot of guys on CN swear by having brightness really low. Anyway I have found it works, just need to get my focus and collimation right, and jag a night where the seeing is really good. I suspect that collimation is a slight factor. It only needs to be 128th of a turn out and I would get these sort of images. Really frustrating. Any tips on collimation?

[Comet Hunter]

Thanks, its a new method I'll try when I'm out next. The main reason I've been using that method was that by having the gain down as low as possible it helps reduce the background noise that is visible when the gain is set high, then I would set the brightness so the chip would record just enough light so that detail would be captured... it seemed to have worked ok with the QC but the method requires a little fine tuning/complete overhaul due to the extra senstivity of the Toucam chip...

As for collimation, I tend to struggle with getting it spot on as well. I've found Bob's Knobs to be great if you dont have them already, makes adjustments easy and fast. I use K3CCDtools reticle as a guide to help getting the disks central. As with imaging, the steadier the conditions the more accurate you'll get, and also practice and be patient.

I also thought this was important so thought I'd include it...

"The New CCD Astronomy" - Ron Wodaski p85

Always (repeat:always!) re-center the star after every adjustment. Collimation pertains only to the exact center, the exact optical axis. Adjusting for a star that isn't on the optical axis leads to miscollimation

[iceman (Mike)]

Guys check out exfso's thread in the camera's & photography forum.. some interesting thoughts there about brightness and gamma.

[rumples riot]

Thanks Mike, very interesting, will try that next time I image.

Andrew, Yeah got Bobs knobs and they work great, I do what Ron says and return the image to the centre each time after an adjustment. Might use the K3ccd tools reticle in future for collimation. I generally collimate each time I go to image the planets and now have it down to a fifteen minute operation. I get the airy disk and then slowly work on it to get the rings all the way round. Very minute turns of the collimation screws. Its not perfect as is but very close. The sort of detail I am getting is not possible without being close. But it is a struggle for perfection.

Thanks chaps and thanks Peter for that thread.

That is the beauty of this site, we are all here to help each other, and boy, personally I need some more help for sure. It is good that one does not feel "stupid" posting here, other places make you feel like you need to be a professional to put anything up.
Nice place to be guysNgals.