FocusMax woes

[daz]

rather than hijack some else's thread, I'll start this...

So:

ED80 with an Orion Accufocuser, interfaced to a USB controller (FCUSB iirc), latest version of FocusMax, MaximDL5, SXVF-H9

I used the First Light Wizard as instructed, and at the end of it, FM managed to get an oversized blob on screen.

I deleted the MySystem record and started again - got the star in good focus using Maxim and FocusPal - ran the routine again and got a nice big blob on the screen again!

So, where do I start looking for problems?

Ta

[Ford Prefect]

Hi

Im not sure if your focuser works the same as mine but did you do a rough focus first and then run FM?

cheers Jon

[daz]

Yep - more than a rough focus...

[RobH]

Did you let it do the first light wizard, and then focus?

At the end of the FLW, it will be out of focus, but will then focus after a couple of seconds.

I don't know the Orion focuser.

I use robofocus, and the first thing you need to do is find the maximum travel so that the software knows where it is.

Cheers

Rob

[Dave]

You're not having a good time with technology at the moment, are you mate?

Do you know someone in IT who could help you out?

[daz]

Hi Rob

Yes, I ran the FLW and yes, it paused when it completed and then it focused - to the big fuzzy blob.

Is there a setting somewhere that I tell FM what the focus travel looks like, or should it work this out?

Dave -

[RobH]

Hi Daz.

I'm going down the obs in a few minutes and will fir up Focusmax and have a look to see if I can figure out what is happening.

Cheers

Rob

[daz]

Most kind!

Did you get my message on sending you my Spyder to test if you need it?

[daz]

It's OK, just seen your reply

[RobH]

Hi Daz....I didn't realise it was you

I've just had a look at focusmax, but can't see anything obvious that would cause your problem.

A few things to check....what is yout target FWHM?

How many V-Curve training runs have you done?

What is the step size you have set? This should be 50 to start with. After you have a few V-Curve runs done, drop it to 20 for greater resolution.

When you do the V-Curve run, at the bottom of the slope, is the star in focus...in other words, is there enough travel in the focuser to actually achieve focus?

Cheers

Rob

[vincentnm]

This comment may be a bit off thread.

I used FocusMax for around 6 months before I got myself a Bahtinov mask. Never touched FocusMax after that! I've found the Bahtinov mask routine much faster and more accurate.

Thanks,

Vincent.

[RobH]

I love Bahtinov masks, but they don't do temperature compensation (FM/Robofocus does), and in several A/B comparisons I've run, I found focusmax, if correctly set up, to be just a hair more accurate.

Plus, I can sit in the warm and refocus the scope, even on very faint stars, which you can't do effectively with a mask as you need a certain brightness to see the spikes properly. This means that you don't need to slew off target to find a bright star...you can just select one that is already in your FOV and focus on that.

Cheers

Rob

[daz]

Thanks Rob

I'll go check the settings and try again next time the stars are out! I have no doubt it's something I have done!!