FocusMax questions

[TRAPPIST]

I have a couple of questions about FocusMax :

- when someone forgot to start FocusMax before ACP , or kill FocusMax etc. we got the Active X and/or (?) Error 13 , . The only way I found to get back the system working ok is to reboot the computer. Is there an better way to restore the system ?

- I had not switched off the TCFS focuser since weeks and I dont remember from where is coming the focus position in FocusMAx after a restart of the focuser. Sorry I dont remember. The value in memory of the TCFS ? I cannot find an "absolute" reference position defined in FocusMax (or maybe I did it during the first startup procedure ?)

- We operate with the focuser always on (no daily restart). At the end of the night the CCD is disconnected. The Focuser stays on focus postion of last filter used. When CCD is powered up, the wheels rotate and go to one given filter (always the same). But the focuser is still in FocusMax on the focus position of previous filter. Next focus offset will then be wrong ?

The FilterInfo.txt has been done since a long time and out system is working but I have to check FocusMax is starting with the right focus value.
Maybe I need to reinitialise the TCFS focuser ? (the change the offset values in the filteroffset file). THey were close to 0 for one set of filters.

- last : I noticed acquire star is looking for star sometimes very far (2 deg), then finds a lot of candidate for focus (mag 11-12) about 1000 stars and then it looks to me this is slowing down FocusMax. Is there a way to say to FocusMax to only look to a smaller field ?

Sorry if this is a bit out of topic..., I should register to FocusMax.
Maybe that will be useful to others.
Emmanuel

[Dick Berg]

- I had not switched off the TCFS focuser since weeks and I dont remember from where is coming the focus position in FocusMAx after a restart of the focuser. Sorry I dont remember. The value in memory of the TCFS ? I cannot find an "absolute" reference position defined in FocusMax (or maybe I did it during the first startup procedure ?)

The value is stored in the .ini file you're using that is in the FocusMax/Data Files folder (Windows XP) or User/My Documents/FocusMax folder (Windows 7) - the value is called "PreviousFocus"

- We operate with the focuser always on (no daily restart). At the end of the night the CCD is disconnected. The Focuser stays on focus postion of last filter used. When CCD is powered up, the wheels rotate and go to one given filter (always the same). But the focuser is still in FocusMax on the focus position of previous filter. Next focus offset will then be wrong ?

Yes, it will be wrong. This still happens to me, too. I thought Bob had fixed this in one of the version 5 hotfixes, but it doesn't work right for me now in version 6 either. I typically take a "default filter" exposure at the end of the night so that the focuser is repositioned to the default focus position and the filter itself is moved to the default filter position. It could be, I think, scripted as part of the Terminate() process when ACP shuts down.

The FilterInfo.txt has been done since a long time and out system is working but I have to check FocusMax is starting with the right focus value.
Maybe I need to reinitialise the TCFS focuser ? (the change the offset values in the filteroffset file). THey were close to 0 for one set of filters.

The offsets should still be okay. But the zero point might migrate depending on the ambient temperature and its effect on the expansion or contraction of the OTA. Even if the focus is wrong at the beginning of the night, the first autofocus should find the correct focus right away.

- last : I noticed acquire star is looking for star sometimes very far (2 deg), then finds a lot of candidate for focus (mag 11-12) about 1000 stars and then it looks to me this is slowing down FocusMax. Is there a way to say to FocusMax to only look to a smaller field ?
l

You can adjust this value by changing some program constants in AcquireSupport, if you are NOT using FocusMax's AcquireStar. In AcquireSupport.wsc, search for the statement that says:

"The PinPoint "image" is 30 by 30 pix"

The next little bit of code establishes the FOV window for selecting a focus star. It's set for 5x5 degrees by having PL.ArcsecPerPixelHoriz = 600 and PL.ArcsecPerPixelVert = 600. If you change 600 in both places to 120, you'd search a 1x1 degree field. If you change 600 to 60 it would search a half-by-half degree field. Set your own threshold.

[Bob Denny]

Yes, it will be wrong. This still happens to me, too. I thought Bob had fixed this in one of the version 5 hotfixes, but it doesn't work right for me now in version 6 either. I typically take a "default filter" exposure at the end of the night so that the focuser is repositioned to the default focus position and the filter itself is moved to the default filter position. It could be, I think, scripted as part of the Terminate() process when ACP shuts down.

Hmm... OK, I'll have to fix this one for 6.0. I can't see an old/closed issue in the tracker for this, so here's a new one for 6.0.

http://gemini.dc3.com:8472/Gemini/De...spx?p=17&i=532

[TRAPPIST]

Hola Dick,

Thank you for your detailed answer ! I'm clear now
I thought I was missing something because of this focus reference not ok at start sometimes (we have 2 series of parafocal filters).
I had also this idea to take an image at the end, but I'm not sure how to do a dummy image to move the filter. Looks like a dark would not do it. Can we take an image without giving a target to ACP (telescope disabled) ?

Anyway Bob will fix that for us thank you Bob !

Cheers and thank you again,
PS : one more night on asteroid Scheila in ourtbust which for your info is not a comet (no gas detected with TRAPPIST). Again a collision in the main belt ... ?

[Bob Denny]

While reviewing this for the filter initialization problem, I saw this and some discussion leading up to it:

TRAPPIST - last : I noticed acquire star is looking for star sometimes very far (2 deg), then finds a lot of candidate for focus (mag 11-12) about 1000 stars and then it looks to me this is slowing down FocusMax. Is there a way to say to FocusMax to only look to a smaller field ?
...
Berg - The next little bit of code establishes the FOV window for selecting a focus star. It's set for 5x5 degrees by having PL.ArcsecPerPixelHoriz = 600 and PL.ArcsecPerPixelVert = 600. If you change 600 in both places to 120, you'd search a 1x1 degree field. If you change 600 to 60 it would search a half-by-half degree field. Set your own threshold.

Just so everyone knows, I ran simulations to determine that 5x5 degrees is what's needed to reliably get a lone/usable mag 6-8 focus star all sky. Mag 11-12 aren't considered for focus stars. I don't know what the 1000 stars would do to noticeably slow the AF process, the PinPoint scan is fast, under a second. Small compared to the AF process itself. Maybe this is AcquireStar? But then IT uses its own selection logic, so that's why I thought it was ACP's selection logic you are talking about. ???

[Bob Denny]

We operate with the focuser always on (no daily restart). At the end of the night the CCD is disconnected. The Focuser stays on focus postion of last filter used. When CCD is powered up, the wheels rotate and go to one given filter (always the same). But the focuser is still in FocusMax on the focus position of previous filter. Next focus offset will then be wrong ?

How do I know what this "startup filter" is? Is it "the" reference filter? Or do you have multiple filter groups, thus more than one reference filter? How can I solve this problem in a general way for users other than TRAPPIST? At present, I assume that if the focuser is left powered up, then so is the camera and filter wheel, thus things remain as they were left. If powered down, I assume the filter and focuser could be anywhere, and it's your responsibility to focus once at the beginning of the night to get the optics set for the temperature and synced to the filters. If you want to avoid the focus at the beginning of the night, I need to know (a) which filter gets selected by the hardware on power up, and (b) where I should set the focuser for this filter.

[TRAPPIST]

Hello Dick,
I'm back on an old email. Everything is working very smoothly woth TRAPPIST telescope and data accumulating so I had no much time the last 2 months to upgrade our system.

The value is stored in the .ini file you're using that is in the FocusMax/Data Files folder (Windows XP) or User/My Documents/FocusMax folder (Windows 7) - the value is called "PreviousFocus".

ok thank you. This value is the one stored by focusMax at the end of the night.
I was in fact thinking to the one at start after a *power cycle* of the TCF-S focuser. Sorry my email was not clear. It always start at the same value and that's the value I would like to change it. Is it stored in the TCFS memory itself when i did the setup or can I find it in ACP ? is it possible to change it remotely ? Maybe you know as I think you have also a TCFS ?

Thank you !
Emmanuel

[Tom Krajci]

- We operate with the focuser always on (no daily restart).

If you cycle the power to the TCF-S, it will perform a homing operation to move the focuser drawtube fully in (position 0), and then move back out to the focuser position as 'remembered' in the TCF-S controller electronics.

Doing this homing procedure can help maintain repeatable positioning of the focuser because it is a Crayford/friction drive...and there can be a small amount of slippage...which is not unusual for a friction drive.

[TRAPPIST]

ok Tom, thank you for the tip !

An other question :
Before starting ACP, I start FocusMax which opens MaximDL.
I never noticed before it was connecting the CCD camera. is it normal ? I thought ACP would do it the first ?

And I had a problem in fact. The filter wheels started to rotate when I started FocusMax (I did not start ACP at all) without stopping.
Did Someone already experience that ?

I had to shutdown the CCD to stop this (our FWs takes power from the camera).
The I started again the CCD then focusMax and it was fine.
This is in fact the 2d time I experience the problem, but first time I was not sure from where it was coming. Here it semms it was linked to start of FocusMax.

Any comment ?
thanks,
emmanuel

[Tom Krajci]

Before starting ACP, I start FocusMax which opens MaximDL.
I never noticed before it was connecting the CCD camera. is it normal ? I thought ACP would do it the first ?

That sounds normal for FocusMax.

Because of that behavior, on my rigs I have ACP running first, then connect to the CCD in Maxim...then connect to the CCD in ACP...and FocusMax is the very last software that I start.

If you experiment a bit with sequence of software starting, and device connecting...you may find a workable solution.