Moonlite Nitecrawler Focuser Position

Sequence Generator Auto Focus
1

I have a Moonlite Nitecrawler focuser working with SGP. For some reason, SGP thinks that my focuser only has a maximum of 1000 steps, when in fact it has 89,009 steps. I know that I have seen the 1000 number somewhere, but I have reviewed every dialog box associated with “Focuser” and I can’t find where I can enter the total number for steps that my focuser has. Can someone help me? Thanks!

2

Please take look at Control panel, ‘Focuser’ tab, ‘Other’, ‘Override maximum steps’.

Bernd

3

Bernd:

Thanks so much for your response to my question!

Maybe you could help me understand another issue:

My Moonlite Nitecrawler focuser has a maximum movement distance of 1 inch.

There are 25,400 microns in an inch.

If I divide 25,400 by my Nitevrawler’s 89,009 steps, I get .285 microns per step.

I see other people talking about using 22 or 26 steps when setting the parameters for their focuser.

Should I use the .285 number when defining the step size for my Nitecrawler?

Thanks!

Darryl Hedges
Morrison, CO

4

Please read in the SGP manual the chapter “Focusing”, especially sections Auto Focus, Setup, Manually Running, How Auto Focus Works, Auto Focus Variables, and So… How do you set it up for your rig?

The focuser resolution that you calculated (0.285 microns per step) is not needed to set up an appropriate “step size” in SGP. Please do the procedure that is described in section So… How do you set it up for your rig?

In short: focus once with a Bahtinov mask (jot the focus position down), take some images with increased focus position in order to find out how HFR values depend on the deviation from best focus, until the HFR value has approximately tripled. Reset the focus position found with the Bahtinov mask. Calculate the “step size” according to the procedure in the manual and input it in the Auto Focus dialog. Now you can try a first Auto Focus run.

You will have to also configure the focuser backlash compensation in order to get a good AF curve. The procedure is described in the manual as well.

Bernd

5

Bernd:

Thanks for your help. I’ll give it a try tonight!

Darryl Hedges