Guest peepshow Posted February 21, 2014 Share Posted February 21, 2014 I know little about encoders. Have just seen a a pair on ABS rated at 4000 tics per rev. Now dividing this number by 360 degrees doesn't give a nice round number that I expected. It's 4000/360 = 11.11111 recurring !! So why not a nice round number, say like 10 giving 3600 tics per rev? Why 4000? Link to comment Share on other sites More sharing options...
Brantuk Posted February 21, 2014 Share Posted February 21, 2014 It's usually down to accuracy and tracking stars and arc seconds 'n' stuff (forgive the technical explanation lol). But 11 and a bit ticks is gonna be more accurate than 10. Link to comment Share on other sites More sharing options...
Guest peepshow Posted February 21, 2014 Share Posted February 21, 2014 Yes, but 11.111 recurring doesn't seem to have any relationship with degrees/minutes/seconds of a circle nor with RA time values. ( 24 hours/60 mins/60 secs) Link to comment Share on other sites More sharing options...
xanthic Posted February 21, 2014 Share Posted February 21, 2014 4000 does nicely go into the gradian scale though. Link to comment Share on other sites More sharing options...
Guest peepshow Posted February 21, 2014 Share Posted February 21, 2014 Leigh, that's new to me. Thanks, I see now why 4000. I live and learn. Link to comment Share on other sites More sharing options...
Brantuk Posted February 21, 2014 Share Posted February 21, 2014 Ahhhh - thanks Leigh - I learned something new there - didn't know they did this stuff in gradians. Link to comment Share on other sites More sharing options...
xanthic Posted February 21, 2014 Share Posted February 21, 2014 I'm not saying that's correct but it does seem to fit in. I found this - "The process of resolving each encoder cycle into four parts (as described above) is called quadrature, and one quarter-cycle is called a tic. The number of tics-per-revolution is equal to four times the number of cycles-per-revolution. Encoder manufacturers commonly express their encoder resolutions in cycles-per-revolution, but the astronomical community most commonly uses tics-per-revolution." Link to comment Share on other sites More sharing options...
+Graham Posted February 21, 2014 Share Posted February 21, 2014 I'm not saying that's correct but it does seem to fit in. I found this - "The process of resolving each encoder cycle into four parts (as described above) is called quadrature, and one quarter-cycle is called a tic. The number of tics-per-revolution is equal to four times the number of cycles-per-revolution. Encoder manufacturers commonly express their encoder resolutions in cycles-per-revolution, but the astronomical community most commonly uses tics-per-revolution." It also fits very nicely into the Steps of a stepper motor they work in 4's as well. Link to comment Share on other sites More sharing options...
Brantuk Posted February 21, 2014 Share Posted February 21, 2014 That'll make the tech specs in my AZEQ6GT manual more meaningful Leigh - I can plan that into image scale, pixel tracking, and binning, whatever the heck I'm on about. Link to comment Share on other sites More sharing options...
Guest peepshow Posted February 21, 2014 Share Posted February 21, 2014 Read about gradians here........ http://en.wikipedia.org/wiki/Gradian Link to comment Share on other sites More sharing options...
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