[h0ughy (David)]

ok might not have been exactly polar aligned but - look at the graph and the data, there is a clear spike created - why? Aparently those using EQmod didn t have these issues. V3.35 of hand controller. here is a sample

Analysis covers 11:48 PM to 12:15 AM
Guiding errors





Guider px
Arcsecs
Image px

RA peak error
10.46
69.25
48.31

RA RMS error
0.65
4.32
3.01

DEC peak error
1.01
6.69
4.66

DEC RMS error
0.14
0.96
0.67

Combined peak error
10.50
69.49
48.47

Combined RMS error
0.67
4.42
3.09




Correction drive analysis





RA
DEC

Frames with correction
13.9%
30.0%

Corrections at max
0.0%
0.0%

Average percent of max corr.
4.9%
8.8%



Periodic errors in RA




Top 5 periodic components in RA error, showing period & amplitude. Amplitude is relative to the DC offset.






Guider px
Arcsecs
Image px

DC offset
-0.00
-0.01
-0.01

6.57 seconds
0.08
0.54
0.38

3.6 minutes
0.08
0.53
0.37

5.00 seconds
0.08
0.51
0.36

5.12 seconds
0.08
0.51
0.36

7.06 seconds
0.08
0.51
0.36


Drift estimate





Guider px
Arcsecs
Image px

DEC drift / minute
0.52
3.43
2.39

Std error of drift mean
0.10
0.67
0.47


Estimated polar-alignment error: 18.54 arcmins, based on specified guide-star declination of 45º. Experimental estimate for non-drift-check events.

Field rotation




Estimated maximum field-rotation per minute at farthest edge of imaging field for various guider-to-imager alignment offsets in multiples of imager FOV. Guidestar-to-edge angles in arcmins.





Alignment
Guidestar-edge ∆
Image px

Concentric:
81.9
0.11

Offset 0.5 FOV:
131.7
0.18

Offset 1 FOV:
181.4
0.25

Offset 1.5 FOV:
231.1
0.32