Monthly Archives: September 2017

The week of September 18

We are in another 3 week science period but our big news this week is that we have been able to bring a few more VIRUS Units on-line which brings our total number of active units up to 21 units. Recall that a VIRUS unit is made up of 2 spectrographs so we now have 42 spectrographs on-line. These newest units are located in VIRUS enclosure 2 which means that we are now making use of both of the “saddle bags” which were installed at the HET as part of the Wide Field Upgrade. This makes the VIRUS closer to being ready for the main part of the HETDEX survey. As we add more Spectrograph units the system continues to get more complex with multiplexers and timing systems.

In some recent very clear nights we were able to observe 10 HETDEX shots (what we call a pointing for the survey) in a single night. This is a new record and our setup times are now typically below 5 minutes when moving from one shot to another. Further small milestones….

The week of September 4th

We have now observed one month out of four in the 2017-3 period. The month started off pretty slow with lots of bad weather in August but we have had some good clear nights. We are still conducting 7 days of engineering around full moon, at least until we get our first bright time instrument. So far we have collected 52.9 hours of charged time and completed 21.8% of the TAC allocated time. We have started collecting the first LRS2 Guaranteed Time Observations (GTO) allocated by the HET board for the instrument team as well as the first time allocated by the HET board for the HETDEX experiment. The latter includes time on well studied fields to make sure that our Lyman alpha emitters detected not really other types of emission sources and to better quantify our sensitivity/throughput.