Harvard-Smithsonian Center for Astrophysics FLWO Ridge Telescopes Quarterly Report Issue No. 1, May 2003

With this first issue, we inaugurate quarterly reports from the F. L. Whipple Observatory. We report on the status and progress of telescopes, instruments, related equipment and activities. The telescopes involved are the Tillinghast 1.5m, the 1.2m and the ex-2MASS telescope. In this issue, we also present a brief description of the HAT (Hungarian Automated Telescope) project. This initial report covers the period Jan 2002-Apr 2003. All issues of these reports are posted at tdc-www.harvard.edu/flworeport/.

Currently, the staff is led by Emilio Falco. The day-time staff are Ted Groner (computing), Bob Hutchins (mechanical) and Wayne Peters (electronics). Night-time staff (also known as remote observers) are Perry Berlind and Mike Calkins. Although each member of the staff has an assigned area of expertise, all pitch in as required in ongoing projects, in resolution of problems as they occur, and in instrument changeovers.

We concentrate here on the broader view, leaving out the day-to-day activities required to maintain the telescopes and instruments in good working condition. At the risk of taxing the reader's patience, this report is comprehensive, but not necessarily perfectly inclusive. If you have any comments or for further information on any of the projects below, please contact us.

Telescope projects:

1. We now have an FTS chiller system for the primary, with glycol lines and two fans and heat exchangers mounted on the cell. We have installed sensors that monitor the temperatures of the primary mirror at several locations, as well as external and dome ambient temperatures. The sensors are connected to an Omega control system (fiber-isolated from the computer network and on a UPS) that will eventually allow us to actively control the mirror temperature via software. We display the temperatures on an interface Linux PC, based on the system we use for stelircam. TG developed and installed a system to view these temperatures on the web, at a link on the 1.2m site. We are currently testing the chiller system and developing the software to control it.
2. We now have a "dog house" enclosure for the corner of the chamber where the major heat sources (mirror chiller control and helium compressor, hexapod control PC) reside. FLWO support staff built the enclosure shortly after the 2002 shutdown.
3. We have safety brakes installed on the telescope. After a few mishaps such as leaky air hoses, the system is ready except for limit switches and enable/disable controls.
4. We re-aluminized the 1.2m primary and secondary in August 2002 at Steward (we alternate yearly; the 1.5m primary was re-aluminized in August 2001). Unfortunately, the quality of the aluminization of the primary seems to be worsening with the mirror's age. Immediately after the aluminization, there was a gray hazy appearance to the surface in a few spots. The area near the center was worse than after the previous aluminization, and the pattern is appearing in other areas of the mirror. Steward is aware of this degradation. They minimize the amount of time the stripping and cleaning chemicals are on the surface of the mirror, but these still seem to be having a negative impact on the glass. Gary Rosenbaum (Steward), who runs the aluminization process, proposes to lightly scrub the old coating off with hydrochloric acid instead of letting the acid soak the coating. Monitoring the reflectivity has been hampered because the old reflectometer is impossible to use with the mirror in the cell, and the new Minolta reflectometer has failed.
5. In April 2003 we started a program to monitor the seeing systematically. A script is in place that allows users to automatically measure and set the telescope focus, as well as estimate the seeing.
6. Since its installation during the 2001 shutdown, the hexapod support for the secondary mirror has performed very well. It maintains the collimation much more robustly than the pod it replaced, and it is a simple matter to adjust it. We monitor its performance regularly.
7. Over the past two years, remote observing has become popular using both instruments. The system has been tuned to allow that; the internet bandwidth available has proved sufficient. The majority of the observers have been at their Cambridge office, but we have had cases of observers who have broadband running the telescope from the comfort of their home.

Instrument projects:

1. The infrared camera has been functioning, albeit with electronics and temperature-related problems. The blue channel remains far from perfect. At times it has required repeated power cycling on cold nights. In spite of that, observers report that stelircam has produced useful data.
2. We now have a system to display stelircam temperatures in graphical form based on gnuplot. Continually-updated plots show the temperatures of the detectors, electronics, cold head and cold structure at a glance, which helps greatly, e.g., during warm periods that require more frequent LN2 refills or when the He compressor has troubles.
3. Because there were periodic problems, in March 2003 WP and EF replaced the cold head with a refurbished one provided by Andy Szentgyorgyi. We now appear to have a problem with He leaks in the compressor system, which are still being tracked down as of this writing.
4. 4shooter recovered from a warmup that occurred in May 2002, because its ion pump had failed. With a new pump, 4shooter returned to normal. The new pump is not perfect; we are purchasing new ion pumps to have enough spares for all the instruments.
5. After the 2002 shutdown, we noticed a significant degradation in 4shooter flats. WP baked out the CCDs in November 2002, using a recipe provided by John Geary. The result was much improved flats with reduced structure, but there is secular degradation.
6. Under the leadership of AS, we have proposed to upgrade the 4shooter to a monolithic 4k x 4k Fairchild CCD that will not require UV flooding. The format is approximately equal to that of the 4shooter, which will allow recycling the mechanical and optical designs of the 4shooter. SAO will build a new CCD controller, based on those for the Hecto instruments and Megacam, and at least twice as fast in readout as current controllers. An up-to-date CCD, with high QE, without gaps and with appropriate CTE will be a great help to many programs, in particular allowing observers to use the 1.2m to produce astrometric data for the Hecto instruments at the MMT.

Telescope projects:

1. The LKH1000 image integrator, which was used to guide with FAST and the Echelle, started failing in early 2002. It is a model that is no longer made or supported. The LKH1000 now resides at ORO, where it is in use to support observations, e.g., of a pulsar.

2. We replaced the LKH1000 system with a new guider system for FAST and the Echelle, based on a frame grabber and a Linux PC. TG wrote software for the system before and during the 2002 shutdown, including the integration with the Telescope Control System (e.g., rotator) on the Sun.

3. In April 2003 we began a program to monitor the seeing systematically with FAST. A script is in place that allows users to automatically measure and set the telescope focus, as well as estimate the seeing.

Instrument projects:

1. In June 2002, we had a FAST event: novice observers left fingerprints on the 600 gpm grating. We contacted the manufacturer, RGL, who suggested two cleaning procedures, CO2 snow or gentle daubing with dishwasher detergent. We attempted the CO2 first and found little visible improvement. We decided not to attempt anything else that would require contact with the grating and which could damage its coating.

2. In September 2002, Susan Tokarz and Mike Kurtz analyzed FAST spectra of BG Gem for the preceding 4 years. They concluded that there had been a significant drop in FAST sensitivity since Spring 2000 (50% at blue wavelengths). Additional analysis of flats and standards by PB and EF concluded that the sensitivity had indeed diminished, but by a somewhat smaller factor. EF and RH removed and cleaned very carefully the FAST corrector. WP baked out FAST in November 2002, following the success we had with 4shooter. There was some gain, but the sensitivity was still about 20% below the expected value. The one significant improvement was that a large "divot" (a low-sensitivity area clearly visiible in all the flats) was gone. We had Mike Lesser clean the chip and check for vacuum leaks. There was no further improvement in the sensitivity. The current plan is to replace the FAST CCD. An SAO RE proposal was submitted for a replacement chip. However, John Geary still had the old FAST2 chip. As of this writing, he is working on FAST2 in Cambridge. We expect to have FAST2 at FLWO during the Spring 2003 trimester, and new electronics by the end of the 2003 shutdown. Further improvements in 2003 are expected from the work of AS on a new corrector, and of Warren Brown on all new optics for the spectrograph.

3. AFOE lives in a new enclosure, which was installed by Pete Nisenson and Sylvain Korzennik.

4. AFOE had its share of problems. Data since the repair of the optical fibers (torn during a telescope runaway event) in January 2002 were of good quality. However, the instrument had intermittent CCD problems. At the start of the Fall 2002 trimester, the CCD failed. PN and SK were able to acquire a new chip in December 2002. As of this writing, JG is working on the new CCD in the old AFOE Dewar.

5. The venerable Echelle is still producing useful data, despite a slew of small but pesky problems that plagued it over the past year. For example, a grating-tilt motor failed, methanol leaked during observations and the chiller lost significant chilling capacity. The Echelle was repaired on site and in Cambridge. It is operating normally as of this writing. The chiller may now be showing its age and may require replacement. The addition of thicker insulation to its glycol lines has helped to a limited degree.

1. Because there was sufficient interest in trying to use the idle telescope (which now belongs in full to SAO), in February 2002, EF obtained CCD images (with an amateur-grade camera borrowed from the Gamma Ray Project) of defocused stars. Brian McLeod analyzed the images with his wavefront analysis program from Roddier and found that the telescope optics are capable of producing 0.3-0.4 arcsec images.
2. Following the tests, Nelson Caldwell and AS produced a design for a new secondary and support system to allow us to use stelircam on the telescope without modifying the camera. A proposal for IR&D funds was successful. However, Harvard Fellow Josh Bloom became interested in automating the telescope, mainly for GRB work, especially to use in conjunction with SWIFT observations. An automatic system is necessary to allow operations without increasing staffing. JB obtained funding from Harvard to proceed with that part of the project. After a modicum of uncertainty over funding for the telescope refurbishment, JB obtained agreement from Mike Skrutskie to return the 2MASS camera to FLWO, with no strings attached, thus eliminating the need to modify the telescope. We hope to have the telescope and camera back on the sky by the end of 2003.
3. In March 2003, as part of his plan to automate the telescope system, JB acquired a new weather station. Roger Harris and WP mounted it, and JB installed monitoring software that displays wind direction and speed, relative humidity, rainfall amounts, temperature and dew point, and barometric pressure ina web page. It will benefit all the ridge telescopes. Its results are available continuously on the web, with links from each telescope web page and from the overall FLWO site.
4. In 2002, we coordinated with Dan McKenna and Dave Harvey (Steward) the installation of the SCIDAR instrument to measure seeing as a function of altitude above Mt. Hopkins. They acquired data in June 2002 ("The LBT Scidar Facility: Recent Results", McKenna et al. 2002).
5. With Steve Criswell, we submitted a request for an expansion of the control room that would double its size and enlarge its access door, thus making it fit for humans. M3 Engineering produced a design. Construction awaits funding from SI.

1. Gaspar Bakos, a Smithsonian predoctoral student, recently installed the first HAT (Hungarian Automated Telescope), a small autonomous observatory designed for robotic observations with minimal human intervention. FLWO support and Ridge staff have assisted with items ranging from pouring of concrete piers to running optical fibers for communications.

2. The site is next to and reuses the old 11m gamma-ray telescope control room, near the 1.5m. The telescope uses a telephoto lens and a 2048x2048 pixel CCD, yielding a 9x9 degree field of view. Typically with 2x4 minute exposure times, it records the brightnesses of 20000 stars with a few percent accuracy in the I-band magnitude range 6-13mag. The throughput is about one million individual photometric measurement per night, or 2GB of raw data (including calibration frames). The first HAT results are very promising.

3. GB expects to install a total of 3 HATs. The two additional telescopes were delivered to FLWO in April 2003; they await installation at the end of the month. For more information, please visit Gaspar's web site.

1. Ridge staff assisted with SAO instrument installation and maintenance, as required. RH spent the largest fraction of time assisting with these activities, as his Ridge activities allowed.

2. Ridge remote observers have assisted with observations for several observers who had conflicts. That has allowed them to obtain useful experience with the upgraded MMT and its new instruments. We plan to continue such assistance, as their Ridge duties permit.

1. We update online documentation continually as changes occur and, often, thanks to comments from observers. Two examples are the "Change Log", where significant updates to the telescopes and instruments are reported, and the weather station reports of wind speed and direction, relative humidity, temperature and dew point, rainfall amounts, and barometric pressure.

2. The consensus among Ridge and Cambridge staff is that all of Mt. Hopkins network traffic should pass through a firewall, otherwise its security is compromised. Although such consensus in 2002 expanded to include all the projects on Mt. Hopkins, MMT staff decided instead to use router ACLs (Access Control Lists) at CCIT (Center for Computing and Information Technology, at U of A). FLWO purchased 2 Linux PCs (the second one as a backup) to use as firewalls. We will proceed with the installation of a firewall for the mountain, although the MMT network may be excluded.

3. Dan Brocious and EF worked on containing light pollution. They produced a simplified version of the Pima County Outdoor Lighting Code, which would be more appropriate to Santa Cruz County (SCC). They made presentations on light pollution and its control to local civic and business organizations. A study session with the SCC Board of Supervisors will take place during Spring 2003, and adoption is expected shortly thereafter.

4. EF and DB worked with SCC planning & zoning officials and with the developer for the expansion of the Tubac Golf Resort. The developer expressed keen interest in maintaining dark skies, in utilizing appropriate lighting for new housing (about 240 new units) and proper lighting, e.g., for tennis courts. We provided the proposed outdoor lighting code and examples of proper luminaires and lights for sports.

5. EF and DB began considering the Sopori Ranch development, which will have an impact similar to that of the Canoa Ranch. Sopori Ranch contains 13000 private acres and 46000 leased (State and Federal) acres, 9000 of which are in Santa Cruz County and currently planned for development.

6. The active fire season in Spring-Summer 2002 prompted a review of fire safety procedures on Mt. Hopkins at that time, with Karen Myres and the Forest Service. We have established a checklist of steps to protect Ridge equipment in case of a fire threat. Conditions for Spring 2003 are still very dry and prone to fires, although not as extreme as for the past year.

7. We are currently planning an upgrade of the basecamp microwave link to the Summit. The current choice is a 23GHz 100 Mb/s system (the current system has 1.5Mb/s bandwidth) that will equalize the bandwidth for the basecamp to summit link with the summit to Tucson link.