After puzzling over last night's (UT Oct. 18) data we realized the phase signal was not being reliably calculated. Elwood scrubbed the code, and the afternoon of Oct. 18 we were able to show that we could control the pathlength of the interfereometer via the 2 um fringes.
This is a video of Elwood demonstrating the loop. We are looking at the FFT image of the 2um detector. The plot (barely visible) is showing the angle of the spots on the screen. As we are watching it, he changes it from 0 to 90 degrees.
The artificial source we were using showed 100-300 nm RMS pathlength variations. This suggests something is creating vibrating in our instrument. While this will not hold up further engineering, it is certainly something we need to fix before regular interferometric observations.
We also notice a drift of ~100-200 um in pathlength difference as the telescope slews from horizon to zenith.
/groups/lbti/search/index.rss?tag=hotlist/groups/lbti/search/?tag=hotWhat’s HotHotListHot!?tag=hot1/groups/lbti/sidebar/HotListphinzPhil Hinz2014-10-05 06:41:02+00:002014-10-05 06:41:02updated7Added tag - hotphinzPhil Hinz2014-10-05 06:40:59+00:002014-10-05 06:40:59addTag6phinzPhil Hinz2014-10-04 03:51:08+00:002014-10-04 03:51:08updated5phinzPhil Hinz2014-10-04 03:48:32+00:002014-10-04 03:48:32updated4phinzPhil Hinz2014-10-04 03:43:21+00:002014-10-04 03:43:21updated3phinzPhil Hinz2014-10-04 03:28:04+00:002014-10-04 03:28:04updated2First createdphinzPhil Hinz2014-10-04 03:21:14+00:002014-10-04 03:21:14created1weblog2014-10-05T06:41:02+00:00groups/lbti/weblog/74d8cFalseLBTI October Run: Night 2/groups/lbti/weblog/74d8c/LBTI_October_Run__Night_2.htmlPhil Hinz7 updatesLBTI October Run: Night 2
Night 2 of our run was clear and calm. We continued Kepler followup in the first half of the night. Justin Crepp and his team were here to obs...Falsephinz2014-10-05T06:41:02+00:00hot/groups/lbti/search/index.rss?sort=modifiedDate&kind=all&sortDirection=reverse&excludePages=wiki/welcomelist/groups/lbti/search/?sort=modifiedDate&kind=all&sortDirection=reverse&excludePages=wiki/welcomeRecent ChangesRecentChangesListUpdates?sort=modifiedDate&kind=all&sortDirection=reverse&excludePages=wiki/welcome0/groups/lbti/sidebar/RecentChangesListmodifiedDateallRecent ChangesRecentChangesListUpdateswiki/welcomeNo recent changes.reverse5searchlist/groups/lbti/calendar/Upcoming EventsUpcomingEventsListEvents1Getting events…