WFCAM Arrives Safely in Hilo

Paul Hirst

All 14 of the WFCAM crates safely arrived at JAC on 17th August 2004, marking the end of a long period of anticipation, and the start of a long period of engineering. With the arrival of the WFCAM team from the ATC the following week, unpacking and assembly of the instrument in Hilo commenced.

The instrument was shipped with all the optics and the detectors packed separately for safe transport, so our first job was to build up the instrument in Hilo, starting with mounting the large tertiary mirror onto the baseplate and building up the instrument from there. WFCAM was transported to UKIRT on 14th September, and mounted onto the Michelle manipulator in the dome the next day. Warm functional tests were carried out the following week and everything appears to be in order.

WFCAM is unpacked and partially assembled in the lab at JAC in Hilo
WFCAM is then loaded onto a truck for the slow drive up to UKIRT

Due to the delay in fabrication of the WFCAM corrector plate (a large aspheric optical component that seems to have been particularly difficult to fabricate), we had been planning on carrying out the first stages of commissioning with an aperture mask in place of the real corrector plate. This would have given us adequate image quality to complete many stages of the commissioning, though at the cost of very low throughput. However, we have recently received good news - the corrector plate has now been shipped and should be arriving at JAC the last week in September. With some fine tuning of the commissioning schedule, we're now planning on having the corrector plate in the cryostat before first light - very welcome news to all!

WFCAM arrives safely at UKIRT, where it is transported into the dome through the roller doors.
Mechanical engineers Keith Burch and Jim Elliot and, in the UKIRT control room, software engineers Alan Pickup and Andy Vick - just part of the WFCAM team from the UK-ATC.

Currently, our commissioning schedule calls for lifting tests during the first week of October. These will finalise the technique for mounting the instrument on the telescope. The lifting tests will be followed by cool-down the week after and installation on the telescope. We're aiming for first light towards the end of October or in early November.

WFCAM on the "Michelle" handling rig inside the UKIRT dome.

The UIST Grisms Saga...

Chris Davis

Many UKIRT users will know that we've been trying to acquire a usable IJ grism for UIST for some time. Its a long and somewhat painful story, and the upshot is that we're still working on this.

The first IJ grism was manufactured by Hyperfine Inc., along with an HK grism that has been is use with UIST ever since. Both grisms used fairly innovative technology in that they were "replicated"; a layer of epoxy is spread onto the Infrasil prism face and a master grating is then 'stamped' onto it, leaving behind the required grating as an impression in the epoxy. These replicated grisms were expected to give better throughput than the more commonly-used direct-ruled "KRS-5" grisms. The HK grism has indeed been a real winner, being by far the most popular spectroscopy mode with UIST (see e.g. the report from Richard Wilman et al. earlier in this newsletter!). However, the Hyperfine IJ was found to give very poor throughput when cold. So UIST was commissioned in Autumn 2002 without a low-resolution IJ capability.

A replacement IJ was immediately ordered from Zeiss, a popular supplier of optics in Germany who had provided many of the other grisms in UIST. The new IJ grism was delivered in Spring of 2003 and installed and tested (a number of other upgrades and improvements were also carried out at that time). However, the IJ was again found to perform extremely poorly over most of its wavelength range, giving almost no throughput in the I-band. The plot below shows the transmission of the grism plus UIST optics over the 0.8-1.35 mm wavelength range.

FIGURE 1: An IJ spectrum of HIP68209, showing the poor throughput at over most of the wavelength range.

Rather than pay in full for a second unusable grism, JAC and the UKATC negotiated partial payment and the return of the bad grism to Zeiss. But removing the grism obviously involved an instrument warm-up and potentially lost observing time. Add to this the busy schedule of the ETS group in Hilo (Michelle was being recommissioned at UKIRT for a brief period of use in early 2004 before its return to Gemini), and the return of the grism was delayed by almost a year.

We have recently sent out tender documents for a third IJ grism. This time we plan on resorting to the more widely used, and therefore hopefully safer option of a direct-ruled KRS-5 grism (all the short- and long- grisms in UIST are made of KRS-5). We've also had similar throughput problems with the HK-low grism that was to be used for cross-dispersed spectroscopy. However, given the relatively small gains offered by this mode, and the possibility of freeing up two slots in the grism wheels, we've decided to replace the cross-dispersed mode with a JH grism and a second wollaston prism. The latter will mean that spectro-polarimetry is possible with all grisms in UIST.

Its still early days, but we hope to procure these three optical elements in the next few months. If all goes to plan, IJ, JH and additional spectro-polarimtery options should be made available sometime in 2005.

View from the Top

Thor Wold

We are now in the semester that never was...technically, we have no semester 04b because of the WFCAM commissioning which is coming up shortly. This left us with just a couple of months for regular observing, so we decided that rather than stamping that few weeks with 04b, we would just continue with the 04a label. This was also inspired by having to extend 04a somewhat in the first place, in order to fill the months of August and most of September prior to the advent of the commissioning.

So, you won't see a UKIRT semester 04b in the record books anywhere. But do not be alarmed...

We are greatly looking forward to the first round of WFCAM commissioning. The second round, it is hoped, will occur early in 2005 and then we expect to start with WFCAM observing soon thereafter.

The reorganization of the computer room facilities, both to rationalize things and to be ready for the terabytes of data from WFCAM, was completed in mid-August.

The very long-awaited new Puainako Street Extension was finally dedicated on September 21 and is now available. We will probably be changing our instructions to visitors to use this route up to Hale Pohaku, rather than the old way up Kaumana Drive. The only reason to go the old route would be if you had to put gas in the car, as there are no gas stations available along the new road. However, this road will not only be much faster but it'll also be very much safer. It connects with Kaumana Drive at the 6-mile marker, well above all the narrow, curving road, and so directly onto Saddle Road (okay, I know Saddle Road is also narrow and curving!).

Speaking of the Saddle Road, you will note a sign at the 8 mile marker signifying roadwork underway. This is odd, and somewhat misleading, as there is no roadwork for the next 11 miles. The construction of the bypass of the military training area at Pohakuloa (the other side of the Mauna Kea Access turnoff) is well underway. I think the sign refers to the next segment, which will be from the turnoff by the 27 mile mark, east back to the 19 mile mark. Thus far, there is scant evidence of any real construction.

Following this, and of course pending funding, the idea is to then re-align and widen the road from there down to the 8 mile mark - but this will be a few years away. For more information as to Saddle Road plans, see my previous column in the Spring 2004 issue.

Down in Hilo and in the University of Hawaii-Hilo Science Park, the construction of the new Mauna Kea Astronomy Education Center is underway, with the titanium cones and main center taking shape. For some shots of the construction that is underway, visit maunakea.hawaii.edu/menu.html and click on construction. There are other pages giving general information on the facility also available from this main page. This is happening right at the corner where you turn left to get to the JAC offices, so it'll be rather surprising for anyone who has not visited us in the past few months. Contracts have been issued for the equipment for the theater and planetarium. Upon completion in late 2005, this facility will give our visitors and their families a rich experience in culture and science.

Your beloved home-away-from-home, Hale Pohaku, experienced an invasion of honeybees this summer, following the wet winter and spring which contributed to an explosion of flowers. At one point, this resulted in having to vacate building C entirely and having a beekeeper come and remove the hives, which were nicely stuffed into the double-walls between rooms (necessitating the removal of portions of walls). One wonders if it might not be productive to have bee hives located out in the mamane forest away from the buildings. This is not the first time they have found the dorms to be nice hive spots, and the hive removal does not result in having any honey to harvest.

Curiously, the moist first part of the year also caused the pastureland lower down to become green and lush, yet no cattle were brought in. The result is tall grass, and perhaps the strategy is to allow the land to lie fallow and re-seed itself to create a better pasture for next year.

In the meantime, MKSS appears to be still bent on replacing the exterior siding of the dorms. Very slowly. This is kind of a Chinese water torture situation. While they try to do the work in "late afternoons" (which seem to be defined as after 1 or 2 PM), it is still noisy at times. They are now working on building B, the largest dorm, which cannot be entirely vacated. Yet, they do the work every now and then and with a very small crew (often one person), rather than hiring a contractor with a large crew and getting this done in a matter of a few days - even if working only late afternoons. Even though they try to keep the nearby rooms empty during the times they do work, the noise can still permeate at times...and I really want to sleep past 2 PM, thank you!

The rare Mauna Kea Silversword plant which bloomed last year (see previous articles) grew some side shoots from the main plant. These shoots have also bloomed this year, but with flower spikes only about a meter high. It will be interesting to see how the plant continues to grow and change. The tourists are certainly not leaving it alone.

While WFCAM will begin occupying blocks of time on our telescope, I do hope to see you soon, as we will certainly still be conducting our usual observing with our suite of instruments in between the WFCAM runs. We shall still aim to deliver the best observing experience you will run into on the planet.

Aloha!

Aloha to Dean Shutt

Dean Shutt (right) with Tim Chuter and Andy Adamson (left and centre) on his last day at the JAC.

Dean Shutt, the JAC Chief Engineer, retired at the end of July 2004. Dean was with the JAC for four years, in which time his energy and enthusiasm for UKIRT have been demonstrated repeatedly as we have installed new instrumentation (Michelle and UIST), and worked through the development cycle for WFCAM. One of Dean's key responsibilities was safety - of staff, visitors and the telescopes; the most obvious aspect of this from the point of view of visiting observers was the implementation of the safety briefings which observers are now routinely given before leaving for the summit. The JAC's safety record over the past few years has been second to none on the mountain. This is just one aspect of Dean's dedication to the JAC which was repeatedly demonstrated and recognized by all who worked with him.

Dean and Laura will be moving to Oregon later this year. We wish them all the best and a happy time in the workshop they are planning to build!