First attempt - Jupiter

[grl570810]

OK guys, this is a big step for me so be kind! I've been a passive reader on these forums for months, but this is the first time I've dared to post. These two are my first attempt at imaging on Jupiter - the moons are Io and Ganymede. The equipment is a C11 on an EQ6 (no SkyScan), a ToUcam 740 unmodified with Baader UV/IR cut filter. First image is at native f/10, second at f/20 with a generic Japanese 2x Barlow. Captured using k3ccd, put through a basic Registax v4 processing since I have very little idea what I am doing there. Align / optimise / stack are pretty intuitive, but can anyone explain wavelets in words of one syllable or point at a decent online tutorial?

I'm OK with the first result, disappointed that second one is so 'soft' . Any ideas as to why would be appreciated, and indeed any comments whatsoever....

Thoughts (randomly) as to why the f/20 shot is poor. Is my Barlow rubbish? Have I got it focussed right (I have used a Hartmann mask, but only have the standard SCT focuser) - it was definitely much harder to 'pick the spot' at f/20 so I took a few sequences varying focus by about 1/20 turn each time from outside to inside - this is the 'best'? Am I just not processing it very well?

With the equipment I have I know I should do much better than this, so there's a big learning curve in front of me and any advice on the first few steps will be gratefully accepted...

Clear Skies
Graham

[matt]

Well.. first of all... hello, welcome, and thanks for posting your images.:)

The good news is your focus doesn't look too bad, but I'm mystified how you've ended up with such dark images.

I use a 3x barlow with my 9.25 and jupiter is very bright. So a 2x in a C11 should be just about blinding!

First of all, we'll need to know what settings you are using at capture time. Particularly your frames per second, exposure (1/25th sec, 1/33rd sec etc) and what gain settings you are using.

The more info you give us, the more we'll be able to help.

We can look at what you are doing in Registax later.

Well done with your images BTW.

[grl570810]

Sorry, should have put these in. The f/10 was at 1/50 sec and the f/20 at 1/25. In both case I had the k3ccd brightness meter at around the 140-150 mark (based on background reading on this and other forums). The gain was set at the lowest possible, and I adjusted the brightness on the meter using the brightness (mainly) and gamma on the sliders.

[matt]

The first bit of advice is get that meter in K3 a bit higher.

Try for somewhere around the 200-215 mark.

That will make a big difference:thumbsup:

Secondly, adjust the gain and leave the brightness slider at the default setting (around 50%, I think). Around the halfway mark. That will give you improved dynamic range.

Use your gain and exposure controls to adjust brightness..

[leon]

I,m not much of a Planet imager at all, but i reckon these are pretty good, well done.

Leon

[grl570810]

Matt,

Thanks for the advice about the brightness meter level - will aim there on the next opportunity. You are right there's plenty in hand with the C11. :) This may be going over old ground but I thought (again from reading, not hands-on) more gain meant more noise so I deliberately kept it down at minimum and adjusted brightness / gamma. But having seen your work in recent posts I'm not about to argue!

Regards,
Graham

[matt]

Higher gain is not a problem since you are stacking lots of frames and thus increasing your signal to noise ratio.

Try your gain around the 40-50% region when imaging at 1/25th sec exposure and 10fps.

That's just a rough guide. Just watch your K3 meter and adjust the gain to get your meter in that 200+ zone.

Leave the brightness in the middle and everything else at default, and use about 15-20% gamma. Only introduce gamma after you've got your focus right.

Hope this helps:)

[Zander]

hey, i played around with ur image a bit with photoshop, hope u don't mind:whistle:
i adjusted contrast and brightness. i think it brings out the detail a bit more.
wat do ya think:shrug:

[iceman]

Hey Graham, great first attempt! The first one looks excellent, but is very dark.

Matt's advice is good - set the exposure to 1/25 or 1/33, use 10fps and keep gain low, but don't be afraid to run it high if it means getting the level meter up over 210.

Look forward to the next batch!

[ronnierigel]

Well done Graham

more importantly what was your seeing like?

ron

[grl570810]

Zander,

Not at all, if I had any objections I wouldn't be posting in a public forum! Can I ask what you did to the image - I agree that it seems to have enhanced the detail around the centre of the disk:) , but it seems to me at the cost of a loss of definition of the rim of the planet.:( Probably a result of the overall underexposure that has been highlighted.

G.

[grl570810]

Ron,

I'd class it as 'better than average' for my location (Northern Beaches of Sydney) - I was seeing more detail visually than usual which is one of the reasons I dragged the imaging gear out. I don't really have a good feel for what ratings such as '7 out of 10' mean when folks use them - is there a standard scale for estimating such things?

G.