Re: Programmed focusing question


Ray Gralak <groups@...>
 

Hi Keith,

I doubt you will get reliable results by just sending a set of commands like that every half hour. But if you really
want to move the focuser (sort of ) precisely you will need to have accurate timing between the focus start and stop
commands. In your example below you could move the focuser 10 milliseconds via the following commands (not sure if the
Sleep function is there for your scripting environment. If not, search for an alternative function):

t.CommandBlind("FS")
t.CommandBlind("F-")
Sleep(10)
t.CommandBlind("FQ")

If you want quality focusing you will need closed-loop feedback... that is visually you will have to determine when a
star is best focused or use an application to do so (like FocusMax).

In any case I'll take a look at the driver code to see if I can determine why focus is jumping like you say.

-Ray

-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...] On Behalf Of astromfm
Sent: Wednesday, July 07, 2010 11:30 AM
To: ap-gto@...
Subject: [ap-gto] Programmed focusing question



Between PulseGuide, the V2 driver, and a Cat5e connection through the ICRON Ranger to my backyard observatory, I'm
pretty much
able to do my imaging from the comfort of my office. The only issue is focusing. I can focus manually using the
buttons in PulseGuide
as I have a motorized JMI focuser (this works better for me than the ASCOM V2 driver, as I can't seem to keep the
latter from making
large jumps when I hit the buttons, even on the slow setting). However, after a night of waking myself up every hour
to refocus, I'm
looking for a more automated solution. I know about FocusMax, but I don't have MaximDL or CCDSoft and I like
Nebulosity for camera
control.

The solution? It seems to me that it shouldn't be that hard to program a vbs script to send focus commands to the
control box. Looking
at the command protocol, I should be able to send :F-# (or perhaps more completely, :FS# :F-# :FQ#) to the box at
automated intervals
to adjust the focus as the night cools. For automation, I'm thinking low tech, just setting up a scheduled repeating
task in Windows that
sends an adjustment every half hour or so throughout the imaging session. What I don't know is how to do this. Before
I got my Mach1,
I used to send a timed Park to my LXD75 mount using the following vbs script via a scheduled task:

set t = CreateObject("Meade.Telescope")
t.Connected = True
t.Park
t.Connected = False

Is it as simple as creating a vbs script to send :F-# to the control box, then running a scheduled task to send the
command every half
hour? If so, how would I do this?

Please be patient with my novice programming skills. Any help (or other suggestions) appreciated.
...Keith



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