OK, how does it really work?

[Guest peepshow]

When one uses a guide camera to lock the main scope onto an object by using a guide star how does it really work?

 

I suppose, I guess, that an on board PC is looking at where the guide star is falling on which guide camera pixel/s. 

Then if the star begins to move to another pixel a small correction is made to the relevant tracking motor/s.

 

 But  does anyone know about the software program that achieves all this and how 'hunting' is negated?

 

I would like to get to know more about this engineering aspect of AP.  

 

Does anyone have a link where I could find out more about all this, please?

 

Thanks for your 'guidance'.

[+Graham]

Wow thats a project and a half.

Guess you could ask Crhis Hilto on the EQMOD web site.

He must have a fair idea to write the EQMOD program.

[Guest Kheldar]

Wow thats a project and a half.

Guess you could ask Crhis Hilto on the EQMOD web site.

He must have a fair idea to write the EQMOD program.

 

I think you mean Craig Stark (PHD) for guiding Graham?

 

As to Richard's original question, how's your maths? I have a thesis lying around here somewhere about image analysis and sub pixel guiding theory - I will fish it out

Edited February 11, 2014 by Kheldar

[xanthic]

I've been using Metaguide, as that was the software that works for my current setup. It claims to be predictive, rather than reactive. The documentation is not the best, but you can find it here. It might point you in the right direction.

 

http://www.astrogeeks.com/Bliss/MetaGuide/MetaGuide510.htm

 

I'm sure some of the more seasoned imagers can give you some more detail.

[Guest peepshow]

Thanks Stephen and Leigh for that.   It's some learning curve.
 
Don't all laugh, but I was musing around with an idea to put star guidance on the
RA drive of barn door trackers.    
 It would only require a single stepper motor to be controlled, using a DIY system of 
some sorts or other.  

 The idea sure does niggle at me.

[+Graham]

I think you mean Craig Stark (PHD) for guiding Graham?

 

As to Richard's original question, how's your maths? I have a thesis lying around here somewhere about image analysis and sub pixel guiding theory - I will fish it out

 

Yup you try him as well

[xanthic]

I think you'd end up writing your own software for that. All of the programs I've seen (PHD, Metaguide and linguider) all need calibration prior to guiding and this involves the program working the Dec and RA axes back and forth to work out backlash, rate of travel etc. I'm not sure it'd work with a single axis.

[Guest Kheldar]

I think you'd end up writing your own software for that. All of the programs I've seen (PHD, Metaguide and linguider) all need calibration prior to guiding and this involves the program working the Dec and RA axes back and forth to work out backlash, rate of travel etc. I'm not sure it'd work with a single axis.

 

It would work with single axis - for instance if PHD can't calibrate DEC it simply turns it off

 

You would just need to be sure your DEC PA was accurate when setting up

[xanthic]

It would work with single axis - for instance if PHD can't calibrate DEC it simply turns it off

 

You would just need to be sure your DEC PA was accurate when setting up

I stand corrected

[Guest peepshow]

Yes the PA would be critical if only guiding the RA motor, but it would bring barn doors into the 21st cent.

 

I have found a book,' Telescope control,' written by an American engineer, who had an asteroid named after him, "15522 Trueblood."

It looks to be a DIY book on the subject............

  http://www.willbell.com/tm/telecont.htm

Might find a cheap second hand cop somewhere.

 

I have looked at EQmod  and the forum about it too.