The Coronal Multi-channel Polarimeter (CoMP) Sees First Light at MLSO
On February 23 Steve Tomczyk, Pete Nelson, and Andy Watt arrived at MLSO to decommission PICS, re-deploy the Coronal Multi-channel Polarimeter (CoMP) on the main spar, and install a new H-alpha telescope. The trip started off on a good foot and stayed that way. By the end of the first day most of PICS has been removed and the rails for the new counterweight system were mounted to the spar. This was no small task! Including all of the counterweights, over 500lb of material was removed from the spar. At least 350lb of that was the PICS instrument. In addition to all of the mechanical work, all of the wiring for PICS was pulled and much of the electronics-rack was started.
The next day saw the start of moving and re-mounting instruments to the spar. New holes had to be drilled and tapped in the spar. CHIP was moved from the top of the north face to its new home on the west face. Moving CHIP required very little new hardware or wiring. Although it was reconnected by day three, the spar was not rebalance and pointing towards the Sun until the following week.
It was a pleasure meeting the newest member of the MLSO staff, Ben Berkey. Ben supported the deployment roughly half of the days and provided a wide variety of help throughout the deployment and showed particular expertise with the various computer systems. He also provided a late-night rescue of Pete and Andy from a dead rental car. Thanks Ben!
Only part of the work took place in the main telescope dome. A huge amount of work was involved in the logistics of packing, unpacking, and preparing the observatory's control room for the changes. Andy Watt led this effort which included removing PICS cables from the telescope through to the electronics racks and moving furniture, monitors and computers around so the CoMP and H-alpha electronics could be installed. After all the electronics for the new instruments were setup they had to be tested and configured to work with the observatory's data handling systems. Also important was salvaging useful components from the decommissioned PICS instrument and packing those for the return to Boulder. Chief among these was the PICS birefringent (Lyot) filter which will be used in the CroMag instrument currently under development.
Not everything went perfectly to plan. In the process of removing old cables and routing new ones, some connections to the Mk-IV coronagraph were broken. These were found near the end of the deployment and repaired but caused no small amount of teeth gnashing in the meantime. The optical alignment of CHIP also needed much attention at its new location. There were numerous other mechanical and electronics problems (The shutter box doesn't fit! CHIP won't power up!) but none of these were left unresolved by the end of the deployment.
Of course the deployment team was counting on a nice, uneventful, relaxing weekend. Chile had other plans. By 6am on Saturday morning the tsunami alarms were sounding throughout Hilo and by 6:10 the hotel manager was pounding on doors telling everyone to evacuate. Seeking higher ground we piled into a car and left for Volcano National Park to try to see the tsunami from a safe vantage point, only to be evacuated a second time due to toxic sulfur dioxide gas from one of the volcanoes. We were told that being evacuated twice in one day was unusual, but the team remains unconvinced.
By day seven the first images of the Sun were captured with the CoMP instrument. Although these were not of science quality it did demonstrate that all the systems were up and functioning. The initial alignment also showed that the CoMP instrument could be pointed at the Sun simultaneously with both CHIP and the Mk-IV.
By the sixth day of the deployment the CoMP instrument was nearly complete. The mechanical installation was finished and the work of installing the various filter wheels, optical components, and the camera began. Steve started work in earnest on bringing CoMP to life by day seven while the rest of us worked to breathe life back into the rest of the instruments.
Unfortunately business on the mainland drew Steve away from the mountain before the instrument could be fully commissioned. He is planning a return trip this Spring. At that time there will be a small amount of tweaking to the alignment expected to take less than a day. The observers will then be trained on how to run and maintain the instrument. It is expected that CoMP will be used to collect daily observations, whether permitting.
By day 8 and 9 the rest of the instruments were back on line thanks to experience and patience of the MLSO observing crew. The Mk-IV had to have its objective cleaned since the construction had caused some contamination. The CHIP instrument was finally re-aligned and resumed normal data collection by the end of the week. The new Coronado H-alpha telescope also underwent fine focusing and recentering.
The mainland team would like to thank Darryl, Allen, and Ben for their excellent support in all phases of the deployment. It was a difficult two weeks but they made it really an enjoyable experience. We would also like to thank the National Science Foundation and the NCAR Strategic Initiatives Program for support of the CoMP project and of the Mauna Loa Solar Observatory.