feathertouch/autofocus/maximdl RC8 question

[graham.hobart (Graham stevens)]

Greetings. I am having an issue getting the autofocus routine to work with my feather touch focuser on the RC 8 via MaximDl 5 autofocus routine (latest version).
I get a nice V curve with a decreasing FWHM then at the top part of the ascending V it swings to and fro mutliple times then says Error cannot find focus.
I have tried the automatic settings (taken from the focuser and camera)
also as the manual says I have tried adjusting step size and also focal length.
If anyone has got this sorted could they please share the settings they were using?
My set up is feather touch 2" focuser and RC8 adaptor, RC 8 plus QSI 683 running on a windows 7 laptop. I just updated Maxim last week so it is the latest copy.
Many thanks
graham

[jase (Jason)]

Are you starting the V curve run on a star already in focus?
Is the curve consistent on both sides of the V i.e. number of steps?

[graham.hobart (Graham stevens)]

Yes I am starting the run after a focus with a Bahnitov mask. The v curve looks equal both sides until the end when it sometimes just keeps on going

[graham.hobart (Graham stevens)]

Should I be starting with a defocused airey disk?
The focuser last time just went from about FWHM of about 8 to up to 40 and I eventually just aborted it. Seeing wasn't great but I am sure I could have manually get a star <FWHM8. It ended up with a massive donut!

[Paul Haese]

You should start with a focused star.

Have you tried using focusmax? That might be more successful and it give you a log for trouble shooting.

[graham.hobart (Graham stevens)]

No haven't tried that yet. May well read the documents tonight to set it up for fmax- have been a member of the group so I know the settings are crucial. What was your experience Paul with fmax and the RC 8 focuser combo?
Graham

[Peter.M]

Originally Posted by graham.hobart

Greetings. I am having an issue getting the autofocus routine to work with my feather touch focuser on the RC 8 via MaximDl 5 autofocus routine (latest version).
I get a nice V curve with a decreasing FWHM then at the top part of the ascending V it swings to and fro mutliple times then says Error cannot find focus.
I have tried the automatic settings (taken from the focuser and camera)
also as the manual says I have tried adjusting step size and also focal length.
If anyone has got this sorted could they please share the settings they were using?
My set up is feather touch 2" focuser and RC8 adaptor, RC 8 plus QSI 683 running on a windows 7 laptop. I just updated Maxim last week so it is the latest copy.
Many thanks
graham

There is a setting in maximdl that is called "Target 1/2 Flux Dia" This needs to be set to something higher than the value will be at focus (about 2 pixels) otherwise the focuser will continue searching for a better value, even if its getting progressively worse. I would also recommend using focus max though.

[graham.hobart (Graham stevens)]

Yes I have sent that anywhere between 5-10 to make sure , did not help.

[graham.hobart (Graham stevens)]

Now I have a similar problem with Focusmax- even the focus wizard fails to reach focus. I must be doing something basic wrong but I don't know what it is.
Help!
Graham

I will try and attach the logs later.

[graham.hobart (Graham stevens)]

Do you think it might be collimation that is not allowing it reach focus?

[Marke (Mark)]

I had a lot of issues getting Fmax going at first , turns out its just picky with the star you use. Find a 4th mag star focus first then let it do its wizard routine after this I was ok.

[Paul Haese]

Hi Graham I have only been using focusmax this last year. Not used it for narrow field yet but what I have seen so far indicates that there would not be any problem anyway.