Any tips for focussing on Jupiter?

[Helen]

I'm struggling a bit tonight with Jupiter - any tips very welcome!

Ta

Helen

[pete_l]

Try focusing on one of moons, instead. It's smaller and more like focusing on a star.

[Steve Ward]

I find that it's better to nail the focus using a Bahtinov mask on a bright star .    ( Pollux is ideal at the moment )

Lock the focuser when you're happy with the focus then slew back to the planet.

It eliminates all the potential time wasted 'chasing the seeing' , you can be confident that the focus is correct and that when those fleeting moments of still and steady air occur the detail will just pop into view. 

[Jannis]

I agree with Steve. I also use a mask on a star close by. I usually use live view to get a roughly precise focus, then i lock focus and take a 10-30 sec test shot to check the focus. At this long exposure i'll have the focus mask make sharp lines very long, and it averages out the seeing, so it's easy to check using for example batinov grabber.

Then i just slew over to Jupiter, or any other planet, and start recording.

I know a planet theoretically is still far closer to us then any star, but i still belive this gives the most precise focus?

[hobsey]

Also, if jupiter is quite low wait until it is higher up as I had this problem the other night due to air turbulence or whatever you call it.

[Helen]

Thanks everyone - and sorry for not saying so earlier (I thought I'd replied last week   )

This was the result on the night - there are hints at more detail (ie if you squint it looks better!!) but I'm not sure if that is focus, seeing, processing or just the lack of resolution because it was only a 123mm scope

(The dot over the GRS is Europa  )

I need to get a Bhatinov mask for the refractor, and I've also been investigating getting Maxim working with the DBK so that I can use my autofocusing routine.

I'm looking forward to getting the C11 on it next time.  I've got a mask for that!  (that'll probably just move my problem from focusiing to collimating  )

Helen

[stargazerslivingroom]

That's a cracking shot...I'd be very pleased!

Great how you caught the moon over the GRS.

Steve