Focusing accuracy

[Coastliner]

Hi all, 

I have a question re accurate focusing when imaging planets. My method is to use a Bahtinov mask to focus on a bright star near Jupiter and then slew to the planet, then I will not touch the focus again for that session. I've just watched one of Damien Peache's vids and he says that you should go straight to the planet and focus on that. Which is correct? If I try to focus directly on Jupiter I can never be certain I have it spot on because of atmospherics and the lack of any distinct features.  

Which method do you use?

Many thanks!

Neil.

[PeterCPC]

Same as you. I find it impossible to focus on Jupiter - it's even difficult to focus on the Moon for the reasons stated.

Peter

[Coastliner]

That's why I thought focusing on a star first was the way to go.

[carastro]

If you can see stars then I would focus on them. totally agree about how impossible it is to focus on the planet itself.  If you can't see stars with your camera then get as best focus you can on the Moon craters.

I was told once you could focus on Jupiter's Moons but as they are dimmer than stars I don't find this an easy option. 

Carole 

 

[Coastliner]

I've ended up using the Bahtinov on a nearby star and then slewing to Jupiter, it seems to work fine. Also, I fancied having a go with my 200p Dob tube, but didn't want to fork out on yet another Baht mask so I mounted the one for the 150pds over a hole in a piece of card and hung that over the 200p - works a treat!

[CSM]

If Jupiter's Moons are within the field of view - Use Stellarium to check if that is likely - then turn up the gain until you can see them.  Get the best focus on them then reduce the gain.