REVISION DATE: 18-Aug-2015 11:48:02

On the day 3 Es data (Page Num 4.01) you could see the infrared artfact in the Es data but also a faint feature to the on track 8 when track 7 was illuminated.

Mike Kehoe Email on 7/6/2015 11:01 AM about the track 8 feature:
I am pondering the cause of the Track 8 artifact. With its flat top, it kind of looks like a ghost image of fiber 8. Once again, it exhibits that peculiar spatial asymmetry we saw in the case of the infrared artifact. That is, given the theoretical planar symmetry of the system, one would at first expect a mirror image type of artifact associated with fiber 7, but I gather no such phenomenon is occurring. Consequently, as before, the filter on the front face of the front prism is a suspect. As we know, this filter both reflects and transmits a lot of stray light in certain infrared wavebands. Would it be possible to check whether the Track 8 artifact is caused primarily by infrared light?

In another email which I can not find he suggests: And suggested a laser at about 715-720 nm and 920 nm and 955 nm should generate big ghost images if the filter coating is the cause of the problem.

So the below data are images of the laser data collected at the wavelengths mentioned above. They are using the MOBY Es head and the Ekspla integrating sphere. The integration times are 30 seconds. I dont see any features. These are on tracks 3 and 12 so either the feature was not caused by the infrared or the problems is not on tracks 3 and 12.

Interestingly there where a few area of HUGE negative and positive numbers, like -4000 or +5000. They looked like the placement was random.

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