Last week we reported on a incident with the HET tracker that put us in a hard skew condition and shut us down. We had recovered from that skew condition but the software issues that led to the skew had continued. This week I am happy to report that we have not only installed additional skew sensors but we have found the source of the software issues. The software teams in Austin and West Texas were able to perform a series of experiments which allowed them to isolate the problem as coming from the ethernet card inside the dSpace box. This is a very specialized ethernet card but thankfully we were able to swap out a different card for it and found that all of our TCS communications problems, hexapod faults, and loading trajectory errors have gone away. We will look into getting a spare card and send the card in to see what kind of fault occurred in the card.

With the improved tracker performance we were able to start our early science operations. We took our first science targets on the night of the 16th. Unfortunately, we are now headed towards full moon which is not the ideal time to do science targets with LRS2. However, it does give us a chance to work out any inefficiencies in our PI interface, night operations interfaces and queue tools so that we can be fully ready once we get some dark time a few days after full moon.

Two weeks ago we had a fairly serious tracker issue. While recovering from a fairly typical tracker failure, the telescope operator requested that the breaks be set but instead the tracker moved in X and generated a hard skew. This hard skew actually caused the bearing to come out of the bearing block. This occurred the day that the blogger and most of the chief engineers were going to their summer conferences. Upon the return the engineers were able to determine that no permanent damage was done to the bearings or the tracker in general. The engineering team was able to move the tracker back into the block using the tracker motors. Unfortunately, the software issues that led to the skew are still present and have not yet been sorted out. This has severely limited our ability to run trajectories for engineering or the start of early science operations.

In the mean time work continues on VIRUS enclosure 2 and with re-coating of the primary mirror segments.

While much work has continued during the day focus has begun to shift to support of night operations and commissioning. The blogger has moved back to working the night shift so updates on day operations may be second hand.

The day staff have installed the acquisition camera, pupil viewer, guide probes and Deployable Wave Front Sensors (DWFS) on the Focal Plane Assembly (FPA). In addition, they have gotten glycol lines hooked up to the VIRUS enclosures and those lines have been pressure tested. The glycol lines to the top of the telescope for cooling the electronics boxes and cameras are still on order.

The software team in Austin has been out to the telescope twice over the past few weeks to commission various aspects of the telescope and mount model. The preliminary mount model has been completed and we can now track on a star and keep constant focus and tracker induced coma through a trajectory. The DWFS will be used in the next weeks to determine the exact tip and tilt zero point to minimize the tracker induced coma and to search for any problems with the mounting of the tracker optics. This will be done on geostationary satellites which allow us to have a constant point source at infinity for long periods of time with minimal tracker motion. We have confirmed that we can acquire these geostationary satellites on the Acquisition camera.

The night staff is also in the process of commissioning the guide probes. We have been able to obtain star fields in both guide probes and the acquisition camera at the same time. With this data and probably a few more similar data sets at different guide probe positions we will be able to set the zero points to pointing with the guide probes.

While we continue to work out small problems and inefficiencies with the tracker electronics and telescope control software overall the telescope is coming along well and some ways is far more impressive than the old HET.