S. Karki, M. Chen

While trying to take the ETM images at EndX today  to find the position of the Pcal beams we notice the following things:

1. Blocking the beam at receiver modules with beam dump before it enters the integrating sphere helps to reduce the scattered light (slightly).

2. The optical lever needs to be turned off to get any decent picture showing the Pcal beams on it. The optical lever light completely obscures the Pcal beams. (See attached Pic 1).

3. Take pictures with illuminator off to get the the Pcal beam spot on it. Use small f-number to get Pcal beam on focus. (see attached Pic 2).

4. Keeping all the settings from 3, turn illuminator on and increase the f-number to max to get all the features on test mass (see attached Pic 3).