> I positioned the NGFs' variable pot to provide maximum voltage to the
> focuser
> and then using the above prg counted the number of "blasts" or steps of fast
> and slow focus to go to both end stops of the focuser.For my config with the
> various equipment attached (ccd & flip mirror) it requires 47 fast focus
> steps to move the focuser from a fully out to fully in position (called
> focus out) and 46 fast focus steps to move the focuser from fully in to
> fully out (called focus in). Similarly to move the focuser from a fully out
> to fully in position using slow focus requires 110 steps and from fully in
> to fully out it requires 93 steps. I then convert each step to a percentage
> of the full range of the focuser - it is now calibrated (for my setup one
> step of out fast is 2.13% of full range, one step of out slow is 0.91% of
> full range, one step of in fast is 2.17% of full range and one step of in
> slow is 1.08% of full range). I did a number of experiments on the number of
> steps required for in and out fast and slow and got surprisingly consistent
> results. The focuser is now calibrated!

Woa ! Great !
Last summer I added this sort of feature to one of my programm
for a Meade Focuser.
My strategy is differents but the results are quite good.
I don't look at the temperature.
What I do is pointing to a star of magnitude between 7 and 9
with my LX200 10' + Maxfield 3.3 + CCD.
After I take small picture of this star and I measure its FWHM
with gaussian modelisation.
I move the focuser fast in a direction if the FWHM decrease
I continue. If the FWHM increase, I go in the opposite direction
and I divide the time of focus by 2.
There a limit behind I stop to divide by 2.
When the FWHM is below 3 I pass to slow speed and I do the same.
I managed to have FWHM of 1.9 with my configuration.
To move the focus with small steps I begin to move with a big step
then I come back of little less big step. The diffrence between
the two steps is equal to the little step. This is because there
is a low limit on the Meade focuser.
All this is still Beta.

Regards

Philippe



PAP : http://www.astrosurf.org/pap/
Obs Narbonne : http://perso.wanadoo.fr/jacques.cazenove/
Ccd Bazar : http://www.astrosurf.com/ccdbazar/

View index by [date] [author] [subject]
Previous message: OT Dew Zapper: was [M]: First light - dew problems, mapug mike
Next message: [M]: Lummicon finder / finder brackets???, Peter Kaletsch Astronomy
Previous message in thread: [M]: Autofocus for LX200, Marc Castel