Focus, focus, focus!

[Chris M48]

I'm having great trouble getting my images in good focus both in Planetary & DSO's. Focus when observing seems really quite good and I am using Bahtinov masks for both 250PX Skyliner Synscan AZ and ST102 Synscan and I'm just waiting for a new auto-focuser to see if that helps. Waddya reeckon?

[Kokatha man]

You said it Chris - it's "focus, focus, focus!!!" It's one of the prime ingredients for good planetary images.

But of course (especially for planetary imaging) the seeing has to be good or else focus becomes almost an impossibility - you realise this when huge shifts in the focuser seem to make no difference to the image's appearance.....but in reasonable to good seeing a good focuser becomes a real bonus (and a lot of "learners" really don't appreciate all the talk about "seeing" untill they actually experience good seeing - and then it's "vive la difference!":))

Even a cheap electric drive makes a huge difference in ease/accuracy of focusing.....I have no idea what you mean by "auto focuser" but there's certainly no device that can work for you or is better than your eyes.....unless your own seeing is very poor! (pardon the rotten pun!)

From my perspective Bahtinov masks aren't really much chop for planetary image focusing.....

[26Left]

I agree with Kokatha man completely - to the point where, if I can't easily achieve focus quickly by hand, I don't bother imaging, because I know the seeing is rubbish.

Tom.

[Clayton]

Ditto KM's advice. I have never used a Bahtinov mask or any focusing aid other than an electric focuser, so it's not entirely fair of me to be critical of them, but I don't know of any revered imager that uses one? Lots of practice with the eye hones the skill IMHO

[26Left]

Well, I bought a baht mask for my C11 and I only used it twice. I have better results focusing by hand. And, if I can't, I pack up.

[WayBig]

I'm considering getting a baht mask for my dob, I think good focus is much harder to achieve in a fast scope at high mags, and the posters in this thread who have stopped using their masks have much slower scopes than your dob.

I also turn the brightness up on the display using the exposure setting, so the image on the screen is completely over exposed, and then use one of the moons, which should now be bright white circle, to focus on. This appears to work for me, though I'm told my images are still a bit soft.

I'm considering the auto focuser too, but don't like the idea of being permanently tied into an electronic focuser, or a dual speed focuser but these aren't cheap.