Map
| Log Entry
| Scan
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Scale +/- 50 Microns
| Day 2 September 10, 1998
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First full map of 1998.
RMS of ring 1 = 8.0 microns
RMS of ring 2 = 12.5 microns
RMS of ring 3 = 24.8 microns
The average map at the end of the last holography session in 1997 gave
8.5, 9.6, 21.6, and 16.3 microns, respectively. So over a year, the
inner ring of panels held their positions. Ring 2 shifted slightly,
but still exceeds the accuracy goal. Ring 3 has gotten worse.
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Scan 4050 Sept 10, 1998 (65 by 65 map)
Overall RMS of map = 18.8 microns
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Scale +/-50 Microns
| Day 3 September 11, 1998
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After a few adjustments of the worst panels (5 and 9 o'clock), we realized that
these were the panels that were jammed against each other in 1997. Most of the
deterioration was probably due to those panels releasing over the year. We
overshot the adjustment at 5 o'clock when they came unstuck from each other,
again.
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Average Map
4153+4172 Sept 11, 1998 (65 by 65 map)
RMS's by rings: 9.4, 17.3, 20.3; overall
RMS = 18.0 microns
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Scale +/-50 Microns
| Day 6 September 14, 1998
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Changes to panels in rings:
Panels near 9 o'clock are still giving trouble. The pattern of dots around the
circumference are probably not real, as they come and go.
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Average of Scans 4357 and 4390
Sept 14, 1998 (65 by 65 map)
RMS's by rings: 9.4, 11.1, 19.2 microns; overall RMS = 15.2 microns
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Scale +/-50 Microns
| Day 10 September 18, 1998
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The adjustment goals have almost been reached. We are now being limited to the
extent that successive maps, made without making any adjustments, fail to
repeat themselves exactly. We are trying to understand the source of this
limitation. If we understand it and can avoid it, we may be able to refine
this antenna adjustment procedure even further.
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Average of scans 4661 & 4684 Sept 18, 1998 (65 by 65 map)
RMS's by rings: 11.5, 10.0, 16.2; overall RMS = 13.3 microns
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Scale +/-50 Microns
| Day 14 September 22, 1998
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It's hard to beat this map, although we may have just been lucky that the
variations we see between what should be identical maps happened to cancel
each other in this average. We'll make only a few adjustments more and then
take a few more maps to try to average out the map-to-map variations and
estimate to what extent we can trust the maps.
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Average of scans 4935 & 4963 Sept 22, 1998 (65 by 65 map)
RMS's by rings: 6.6, 6.7, and 16.0 microns; overall RMS = 11.8 microns
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Scale +/-50 Microns
| September 24-30, 1998
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Average of last 8 maps. The inner two rings are essentially perfect, as
the individual panels are only supposed to have an RMS of about 7 microns.
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RMS's by rings: 7.9, 7.5, 15.4 microns; overall RMS 11.8 microns
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Scale +/-30 Microns
| September 24-30, 1998
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Same as above, but displayed on a +/- 30 micron scale.
Many of the remaining errors would be impossible to remove as they lie in
between the adjustment screws.
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RMS's by rings: 7.9, 7.5, 15.4 microns; overall RMS 11.8 microns
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Scale +/-25 Microns
| September 24-30, 1998
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From this animation, one may get a better idea of which features come and
go, and which were consistent between maps. They are the result of
subtracting the average map from each of the maps that went into the average.
The RMS's of these difference maps give an estimate of the measurement
accuracy (as opposed to how well the panels were aligned).
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Difference maps. Sept 24-30, 1998 (65 by 65 map)
Mean RMS's by rings: 3.2, 4.0, 8.1 microns; overall RMS 6.2 microns.
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