Magellan Telescopes Instrumentation: A Critical Assessment of Current Status

1. Magellan Telescopes Instrumentation: A Critical Assessment of Current Status

2. General Comments • Generally speaking, the instruments currently in use on the Magellan telescopes are working reliably • This is confirmed by the relatively small amount of observing time lost to instrument failure • Nevertheless, none of the instruments have been accepted as commissioned facility instruments • Consequently, there are no support agreements in effect between the instrument teams and the operations staff • In the spirit of insuring that the instruments facilitate the best science possible, I present an assessment of instrument problems or deficiencies as seen from the operations side • This list was compiled at a meeting with Frank Perez, Dave Osip, Marc Leroy, and the Instrument Specialists Mauricio Navarrete and Gabriel Martin

3. MagIC • Instrument is still characterized by low-level noise pattern in bias exposures • Binning and single-amp readout modes not available (currently being worked on at MIT) • Dynamic range differs for different amps in quad readout mode • Contamination in dewar has been an occasional problem • Observing scripts cannot be aborted • Instrument lacks a definitive cable wrap • Spare parts situation generally good, but we are currently low on electronics boards spares due to work being done at MIT • There is no spare for data acquisition computer

4. MagIC (cont.) • Instrument needs a baffle to allow dome flats to be used for calibration • Too much light in dome for daytime calibrations • Need to make regular tests of linearity, gain, noise, etc. • Need a local copy of observing manuals (currently only available on MIT website)

5. MagIC: Update from Jim Elliot • MIT have wired the engineering SITe CCD in a test dewar setup and are (will be?) operating the system with an updated version of LOIS. • This system operates in both quad-amp and single-amp mode. (Status of binning is not clear.) • The new version of LOIS (4.2.0) should (i) make crashes less frequent,(ii) facilitate for aborting observing scripts, and (iii) allow the current MagIC computer to become a spare. • A new computer with the updated control software will be sent to Chile, and installed and tested in June • It is hoped that the new software will allow a single-amp mode, but this failure may be caused by wiring error in the MagIC dewar. If that is the case, the least invasive way to "repair" it may be to change the software to be consistent with the wiring error. • An "occultation mode" for MagIC will also be tested in June that Jim hopes to use for his proposed Charon occultation observations in July.

6. MIKE/MIKE fibers • Brass slit plate does not reflect blue light well; it also would be useful if the slit plate had a single small aperture in the center for focusing • Position of slit plate should be encoded • Linearity and well depth of blue CCD needs improvement • Contamination in blue CCD dewar has been a problem (dewar does not hold vacuum as well as it should); has resulted in high dark current • Occasionally exposures are lost due to the GUI freezing (this is a big problem for MIKE because of the long exposure times which are often employed) • Software control needed for iodine cell

7. MIKE/MIKE fibers (cont.) • Change back and forth to MIKE fibers is risky to optics/dewars; requires TV camera to be taken off; need to schedule at least a day off between such changes to minimize impact on observers • For efficiency and safety reasons, observers using MIKE fibers are going to require significantly more assistance than the operations staff can provide (e.g. in creating pattern for plugging the fibers, and for doing the actual plugging) • An exposure time calculator would be very useful • Documentation of linearity, gain, dark current problems with blue CCD has been poor • Need a local copy of instrument manual (currently only available on Michigan website, which is sometimes down)

8. PANIC • Filter positioning occasionally unreliable • Use of VNCviewer to remote the DEBONAIR display to the observer Linux workstations sometimes gives color mapping problems • Firewall between Observer Workstations and Duke hinders access to data • Quick-look IRAF tasks often do not work • PANIC dithering sometimes doesn’t stop • Bad connector(s) has led to noisy quadrant or complete dropout of quadrant • PANIC electronics are spared by WIRC electronics, but WIRC boards don’t always function in PANIC

9. PANIC (cont.) • Needs a definitive cable wrap • Exposure time calculator not correct • System for heat removal from electronics rack on platform has never been finished

10. LDSS-3 • Shutter unreliable (with no warning) • Positioning of wheels sometimes fails • Opening access door for filters/grisms is painfully slow • Zero point of focus mechanism changes when mechanism is cleaned • Bad charge transfer in lower-right quadrant; this has been shown to be a problem intrinsic to the CCD • An exposure time calculator for spectroscopy would be useful • Too much light in dome for daytime calibrations

11. IMACS • Observers need better documentation and operations staff more training in IFU and Nod & Shuffle modes • Need to design and fabricate masks with standard slits for Nod & Shuffle observations of single objects • Still need a safe way to change gratings • It is currently difficult and unsafe to mount a filter in front of one of the grating positions • Connectors on grating mounts are degrading • All connectors (including coolant lines and piezo electric cable) for dewar changes are degrading • Need accurate labels for all Gratings and Mounts • Require regular documenting of all hardware and software changes.

12. IMACS (cont.) • Noise in limit switches often requires these to be manually reset • Need better documentation of recovery procedures for hardware/software failures • An exposure time calculator for spectroscopy would be useful • Need 6 more mask holders so that masks can be changed during the night • A better way (that doesn’t involve back breaking) needs to be found to transport masks from laser room to telescope and back • IMACS optics need to be realigned to remove focus tilt and coma • Telescope optics need to be better collimated to remove tilt in field focal plane

13. IMACS (cont.) • Need to understand and correct flat-fielding problem which currently precludes precision photometry over the full IMACS f/2 field • Need to make COSMOS software always available to observers • Spare parts need to be better organized