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Gary,
Adding in just the DAF term and removing the Fork Flexure term brings the pointing error down by half and modifies the correction advice!
Southern Hemisphere
************* AZIMUTH ************
MA: +155 seconds (+2.6 minutes).
Rotate axis East (counterclockwise).
For latitude -33.79°, the azimuth adjustment is 3.1 minutes.
Sigma=18.554
************* ALTITUDE ************
ME: +31 seconds (+0.5 minutes).
The polar axis should be lowered +31 seconds (+0.5 minutes).
Sigma=23.135
* fit
coeff change value sigma
1 IH -175.012 -175.01 42.430
2 ID +172.928 +172.93 27.058
3 NP +203.402 +203.40 26.316
4 CH -206.566 -206.57 46.235
5 ME +30.698 +30.70 23.135
6 MA +155.245 +155.24 18.554
7 TF -79.727 -79.73 8.419
8 DAF -550.472 -550.47 33.764
Sky RMS = 24.06
Popn SD = 25.57
* Correlations between terms:
ID +0.3269
NP -0.8292 -0.3387
CH -0.8553 -0.1352 +0.6089
ME -0.3242 -0.9464 +0.4607 +0.1261
MA +0.3078 +0.8857 -0.1415 -0.1185 -0.7154
TF +0.1358 -0.2360 -0.2045 +0.0825 +0.1687 -0.1558
DAF +0.1257 +0.3517 -0.3402 +0.3920 -0.3554 +0.3399 +0.2689
IH ID NP CH ME MA TF
* fit
coeff change value sigma
1 IH +1.430 -173.58 42.355
2 ID -0.912 +172.02 27.085
3 NP -0.965 +202.44 26.225
4 CH +0.232 -206.33 46.234
5 ME +0.718 +31.42 23.114
6 MA -0.446 +154.80 18.596
7 TF +0.724 -79.00 8.412
8 DAF +1.488 -548.98 33.656
Sky RMS = 24.06
Popn SD = 25.57
* Correlations between terms:
ID +0.3274
NP -0.8283 -0.3378
CH -0.8564 -0.1361 +0.6094
ME -0.3234 -0.9462 +0.4595 +0.1259
MA +0.3077 +0.8867 -0.1405 -0.1188 -0.7163
TF +0.1277 -0.2390 -0.1979 +0.0886 +0.1717 -0.1589
DAF +0.1211 +0.3515 -0.3364 +0.3942 -0.3548 +0.3396 +0.2659
IH ID NP CH ME MA TF
IH : = -173.58
ID : = +172.02
NP : = +202.44
CH : = -206.33
ME : = +31.42
MA : = +154.80
TF : = -79.00
DAF : = -548.98
* GSCAT
PS
Ray Gralack's suggestions:
Well, as I like to say, "best-fit" is not always the "right-fit"! TPoint and MaxPoint are just doing a best fit of the data given to them. Try unchecking a term and you'll see that polar alignment changes without having changed anything physically, so who's to say that the model is accurate enough to be trusted precisely?
In particular, look at the sigma value for the Alt/Az terms. If you believe the model and sigma value, which I am not sure I do, then there is about a 68% likelihood that the value is within 1-sigma of the reported values. That means there is almost a 1 in three chance it's outside the range, again *if* the sigma value is accurate.
So, I would trust drift alignment over the best-fit models. It could be that one or other of the point modeling software apps is not adjusting J2000 coordinates to JNow.
-Ray
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