Motorised Focussers

[narrowbandpaul]

Hi Guys.

I have just returned from an imaging vacation with RichardC, and had the distinct pleasure of seeing robofocus in action.

So my question is:

what motorised focussers work well. What software do we need.

I just want to know the ones that work well, and ideally are transferable from scope to scope. We change instruments quite often.

it needs to be precise and stable. Slop wont be accepted.

The robofocus richard had worked great. Gave sharp stars each time

So what do you experts recommend!

I am thinking MaximDL4 with focus max will work well. But does it support SXV cameras?

any other options?

thanks in advance

Bests

Paul

[Ben Ritchie]

Robofocus with CCDSoft always worked very well for me, FocusMax is another option there.

[MartinB]

I'm certainly not an "expert" but have some experience (very different!). I have a Moonlight motorised SCT on my LX200R. This has a James Lacey PC controller which is wired to be useable with the Robofocuser. I have subsequently got a robofocuser for my FSQ and it works well with the JL controller.

Early versions of focusmax used x3 binning and not all cameras e.g. QHY8 could do this but new versions will use other binned modes.

The big hassle with focus max was that it wouldn't work in Vista. There is now a work around to this which can be found on the focusmax Yahoo group. It worked on my vista laptop initially but doesn't now. It is fine in XP

Focus Max has a good routine for temperature compensated focusing as well. My controller and the Robofocus ones have a built in temperature sensor which inputs the data into focusmax - brill.

Ian King is selling a new line of stepper motor focusers called Lakeside. These are very keenly priced and have the PC controller bundled with them. The last time I asked they didn't come with temperature compensation but I think the chap behind Lakeside was working on it.

In theory, if you have the appropriate adaptors you can move a single robofocus unit between different scopes but this would be a real pain. It is better to have a robofocus for each scope and then just use the one PC controller.

SXV cameras should all work fine in Maxim DL v4, I know the H9 supports x3 binning so there shouldn't be a problem. FocusMax integrates beautifully with Maxim of course.

Once you have gone through the calibration routine in FocusMax running a few Vcurves focusing is effortless, precise focusing in under a minute. FocusMax took me a little while to fully get to grips with but it is actually pretty straight forward.

Backlash is a thing to watch out for. The Robofocus controller allows backlash compensation or you can do the compensation from within FocusMax. Fortunately my Moonlight and Tak focusers don't seem to have any backlash which makes life a lot easier!

[narrowbandpaul]

focussing in binned mode is completely pointless. I will only focus in 1x1 binning.

basically the robofocus was controlled with focus max running through maxim.

yep, Vcurves is the stuff I am after

so robofocus with maximDL4 with focusmax will work well, once I learn how to work it?

sounds good to me.

any other options visa vie focussers?

paul

[MartinB]

Paul, you will find that FocusMax makes use of binning, and does a great job with it as well. You don't tell it what binning mode to use you just let it get on with it!

[SteveP]

NBP

The two I could recommend from personal use are the Robofocus (as others have already said) and the Optec TCS which is a driven Crayford type, even better than the RF in many situations but a little more expensive. It is incredibly accurate and consistently repeatable. Like the latest RF's it is also temperature controlled. It works a treat on SCT's (it was originally designed for them) where there is plenty of backfocus available but is less suitable where BF is at a premium. The RF is great but the supplied 'universal mounting plate is a little flimsy and needs something better and more specific to the scope. It is however only as good as the scopes own R&P focuser. I've used both but only in conjunction with CCDSoft and @Focus. I'd recommend either but maybe in different situations

Steve