Planned HET downtime starting Monday October 23

[Steven Janowiecki]

Dear HET PIs,

I'm writing to let you know that we have some planned engineering work on the HET's Focal Plane Assembly coming up next week, starting on October 23rd. This work is primarily focused on repairing some of the probes that we use for guiding and wavefront sensing, and will result in the telescope being offline for several nights while the FPA is down on the ground for this work.

We expect this Sunday October 22nd to be the last night of regular observing before work begins on Monday morning, October 23rd. We hope to return to on-sky operations by Friday night next week, but the exact timing will depend on how the work proceeds.

Let me know if you have any questions about this downtime and its impact on your science.

Steven

[Steven Janowiecki]

Dear HET PIs,

I'm writing with a short update on HET's downtime. The engineering work is still continuing and appears likely to extend through the weekend. The primary efforts now are to restore the ability to focus the Acquisition Camera (a functionality we have been living without for several years). The work is more complicated than anticipated but our team of dedicated engineers and technicians are planning to keep working throughout the weekend to get it working as soon as possible. Once they have finished their work they will reinstall the focal plane assembly and we will spend several hours re-measuring all of our setup positions on sky - after that we'll resume normal science operations.

Because of the inclement weather forecast for early next week, it's possible that the engineering work will finish but the bad weather will further delay our ability to realign and resume science. We'll do our best and get it back on sky as soon as possible.

Everyone is working hard to finish all the ambitious list of engineering tasks from this week's work, and I hope to email you again next week with good news about our progress towards resuming normal operations.

In the mean time, please reach out if you have any questions about this continuing down time and impacts to your science.

Steven

[Steven Janowiecki]

Dear HET PIs,

After a great deal of extra effort from our tireless and amazing daytime engineering staff, the telescope was reassembled on Thursday afternoon and as of about an hour ago we have resumed science operations after finishing recommissioning and aligning it on sky. This downtime was longer than expected but accomplished all of the goals, including repairing the Acquisition camera focus stage and encoders so we are able to focus the ACQ camera now, and restoring all four probes to full functionality for guiding and wavefront sensing.

We have several more cleanup tasks to verify and validate in the coming days, but we should be in more or less normal operations at this point. Please take an extra close look at your data coming in over the next week or two and raise questions if anything looks in any way different or problematic.

Steven