Mars focus for imaging

[jambouk]

Finding it really hard to know when Mars is in focus.

I tried using a Bahtinov on a nearby star, but the focus back on Mars was miles off. Tried by eye, but just so featureless to know when it's right and the range of what appears to be right is enormous. Did one run of avi and it was clearly out of focus.

Any Mars focus tips?

Thanks

James

[Pete Presland]

its really tough trying to focus on Mars at the moment because its low and the seeing is pretty poor. you could trying dimming the image by lowering the gamma/gain when you are focussing to show some of the darker surface reatures, that is what i have been trying.just remember to to raise them again when you are capturing.

tonight i started on Jupiter which i was fairly happy with the focus on, moved to Mars without touching the camera and it still looked pretty poorly focussed.

[oldpink]

nothing new there
mars is at best a wobbly jelly and the hardest target I've tried so far

[Steve Ward]

Nail the focus on Spica with a mask , lock the focuser , recheck after locking and adjust if/as required and then swing back to Mars.

The atmosphere plays merry hell with the view with the planet so low .

Don't be tempted to 'chase the seeing' just shoot long AVIs and then let PIPP find the decent frames for you.

[jambouk]

ok, I'll give that a go when [if] the cloud clears.

Thanks

JD

[lensman57]

Nail the focus on Spica with a mask , lock the focuser , recheck after locking and adjust if/as required and then swing back to Mars.

The atmosphere plays merry hell with the view with the planet so low .

Don't be tempted to 'chase the seeing' just shoot long AVIs and then let PIPP find the decent frames for you.

+1, this routine works.

A.G

[jambouk]

I didn't get chance to try the Spica method as the cloud persisted, but here is the result of the one run I managed to get.

Captured 04/04/2014, 23:31 to 23:39. Celestron C11 with 2.5x powermate, and ASI ZWO 120MC (one shot colour, CMOS) with Firecapture. 74fps, 35858 frames captured, best 20000 used in final stack (AS!2 (first time I’ve used this)); wavelets adjusted in Registax 6. Given the focus was off, I’m quite pleased with this.

[DMouse]

Hi, your processing looks good, but I would have thought with that many frames your are going to get rotation of the planet. That video was about 8 minutes long. For crisp details I feel 2 minutes max would be a bettor solution, and then say 4 x 2 minutes, would be better still. Especially if you de-rotate the images with winjupos. 

Clear Skies

Paul

[jambouk]

Yes, I agree; I just did the 8 minute run by accident. The data looked so poor I couldn't face using it to for my first attempt at using winjupos, so i was hoping to get some better data first and then use that to practice using derotation.

Not an easy planet to work with, with it being hard to focus on and being so low in the sky.

Thanks for the ideas and comments.

Jd

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