Overexposed now????

[grl570810 (Graham)]

Guys,

Based on feedback to my first post: http://www.iceinspace.com.au/forum/s...ad.php?t=20843
I tried again last night and the results are unexpectedly ghastly!

The 'best' result I got is attached. This was at native f/10 on the C11 with the ToUcam 740 at 10 fps, shutter 1/50, brightness 40%, gamma 35%, saturation 40% and gain around 20%. The k3ccd brightness meter was pretty much bang on 200. The f/20 results are so grotty I'm not even going to post - probably out-of-focus as I was hurrying to beat a band of cloud coming across.

The seeing was not as good last night as the 2nd, but still: what the **** happened? FWIW I think it's gone too far in the over-exposed direction as even in the raw frames the central portion was just an amorphous white blob. But if that's the case how come getting a 200+ setting in the meter is 'right' for you guys but is 'wrong' for me?

Any ideas at all - unless someone has a suggestion to the contrary I'll try aiming for about 180 next time...

Onward and upward...
G

[Rigel003 (Graeme)]

It doesn't look like overexposure to me. Are you sure you are using the default single rather than multi point alignment in Registax? Multipoint alignment can sometimes cause that weird post modernist effect.

I would use the barlow, 10fps, 1/25 shutter, leave brightness on 50% and gamma about 20%, saturation near 100%, and then get the correct exposure by adjusting gain only. Reduce gain from full until there are no saturated patches on screen. Examples from a C11 with similar settings here:
http://www.pbase.com/rigel003/jupiter_images

Good luck.

[ving (David)]

hi. its not a single vs multi point alignment thing for sure. try these settings: brightness 50% gamma 0% (none at all), saturation 100%, gain 50% then adjust the shutter to get the right brightness if the avi onteh screen as close as you can

multi point alignment will cause straight lines thru the image showing the alignment areas, but only if the wavelettes are pushed too hard. see my attached pic.

[grl570810 (Graham)]

It was single point aligned with a 128 pixel box around the planet disk and I'm pretty sure it's not a processing artefect - like I said the centre of the image on each of the avi frames is pretty much a white 'blob' which I assume is what is meant by saturated. The 'right brightness' on the screen is exactly my issue - my first set I could just see the main bands against the disk and figured that stacking would bring out detail (which it did to some extent) but the verdict was 'underexposed'. With this one it just looked like a white blob on the screen and I thought 'that can't be right', but the meter was at 200 as recommended so I went ahead.

Now I'm just really confused.... What should I be seeing on the screen when the exposure is 'right'?

BTW, does the fact that I'm got the older 740K ToUcam (the egg-shaped one) make any difference? Can't see how but it's just a thought.

[ving (David)]

so its not the toucam pro? as long as its the pro you are fine. otherwise kyou have the cmos chip one which is fine for the moon but no good eally for planets.

anyhow i guess ideally you want inbetween the 2. adjust your image so that you can see most of the detail onthe planet with out burning out the image at all... any burn out and you have too much exposure.

[grl570810 (Graham)]

It's the Pro OK, just the earliest model. It has the right sensitive Sony(?) chip for astroimaging. I'm just clutching at straws a tad. I guess I'll just experiment 'til I get something that works for me - given the Sydney forecast it will probably be a week before I can try again.