Version 1 (modified by trac, 16 months ago) ( diff )


ASTR 535 APO Observing Run: 2019

What is the purpose/goals of the trip?

  • a main goal is to become more familiar with the telescopes/instruements that astronomers use, and to gain some familiarity with the different types of data and data collection: imaging and spectrscopy, working in the optical and near-infrared.

  • another main goal is to learn and get experience with planning observations: understanding when objects are visible and optimal scheduling for observing them, understanding what calibration data need to be taken, why, and how much
  • at a lower level, a goal is to learn the specifics of the APO observing system, which mainly involves learning how to use the Telescope User Interface (TUI), and to become a certified user (so that you are allowed to observe remotely). It is easy to get caught up in this, but it is important to remember the broader goals above! The observing specialists like to focus on this goal. It is clearly more important if you think you may be a user of the 3.5m in upcoming years, but even if so, try to think about things more broadly: you will probably move on after NMSU to observe at other locations, where the details will be different, but the principles the same!


  • Travel
    • Directions : Google Maps , about 2 hours from Las Cruces
    • Passports for foreign nationals!
    • speed and tickets!

  • Climate / clothing
  • Food
    • No food on the mountain, need to bring everything. Space is allocated in cabinets and refrigerators for specific rooms. No alcohol.
    • There are two well equipped kitchens
    • It is our responsibility to clean up after ourselves! You can use dishwashers; they should be started when full and unloaded when clean (there's a magnetic placard used to indicate clean or not).

  • Altitude awareness
    • drink water,
    • eat carbs in advance,
    • beware of even short-burst strenuous activity (stairs); if you are feeling marginally, take it easy!
    • eat regularly
    • planning for emergencies

  • APO Staff
    • Observing specialists
    • daytime staff
    • dormitory awareness
  • Schedule:
    • Friday: when to arrive, planning for daytime activities
    • Saturday, daytime activities
    • Sunday, daytime activities; 10/20 Sunspot?

Basic observing principles

  • Efficiency is important: telescope time is expensive. Want to be collecting photons as much of the time as possible. If you are sure that you are collecting "bad" photons, e.g., wrong target, stop. If you are unsure, collect photons while you are figuring out if you are doing the right thing
  • If you have ANY questions or notice ANYTHING that you don't understand, ASK IMMEDIATELY. The observing specialists know a lot and are there to help. Don't waste time trying to figure it out on your own. If you are observing remotely, use the Message window (and always be alert for message beeps)
  • Plan your observations, taking into account beginning and ending times (these should be strictly observed).

Important Resources

Instruments: configuration and calibrations

ARC 3.5m is an alt-az telescope. Most of the instruments are located at the Nasmyth ports. ARCES is permanently mounted on NA1. DIS, TRIPLESPEC, ARCTIC, and the eyepiece are mounted at NA2. It takes ~15 minutes to change an instrument at NA2, so instrument changes there want to be avoided or minimized. It takes just a couple of minutes to rotate the tertiary back and forth between NA1 and NA2, so switching to ARCES and back is not so bad.

    • Configuration: cal channel and cal lamps only
    • Calibrations: internal: flat fields and ThAr wavelength calibration, biases
  • DIS
    • Configuration: grating pairs (B400/R300, B1200/R1200, imaging), wavelength centers, (CCD parameters)
    • Calibrations: truss lamps: flat fields, HeNeAr wavelength calibration, biases
    • Configuration: detector parameters
    • Calibrations: truss lamps: flat fields (lamps on/off), wavelength calibration, darks
    • Configuration: filter, CCD parameters (binning)
    • Calibrations: flat fields (dome + twilight), biases, darks(!)
    • Configuration:
    • Calibrations:


  • TUI
    • Note password and program ID
    • permissions
    • message window
    • slew window and user catalogs
    • instrument windows: configuration and exposure windows
    • TUI scripts
  • there is a MacOSX machine, obs3, that is located on site on which some standard software should be installed. Note password and arcgateway
  • data are saved in /export/images
  • looking at images
    • ds9
    • python options: pyvista/tv
    • simple image analysis: count levels, cross-sections, image size, etc.
  • data reduction
    • important to understand basic principles; some tension between this and more sophisticated analysis with existing packages
    • IRAF and its issues
    • Imaging: ARCTIC and NICFPS
      • ARCTIC custom readout mode
      • IRAF tools
      • astropy-affiliated ccdproc
    • Spectroscopy:
      • DIS: IRAF scripts, PyDIS
      • ARCES: Various related IRAF/PyRAF scripts
      • TRIPLESPEC : IDL SpexTool
  • data analysis
    • imaging: photometry
    • spectroscopy: line positions/RVs, line strengths, spectral modeling

Observing/calibration scripts

List of science projects

  • Spectrophotometric standards for ETC, e.g. see links here
    • photometric conditions only!

  • KH15D

Observation planning and schedule

  • almanac (from skycalendar)
(2019 at start) JD-2450000 LMST midnight Sun set twi.end twi.beg Sun rise LMST eve LMST morn moon rise moon set moon %illum Moon RA Dec
Fri Oct 18/Sat Oct 19 8775.8 0 46 26 18 27 19 49 5 48 7 10 20 35 6 35 21 58 ..... 73 5 52.3 21 47
Sat Oct 19/Sun Oct 20 8776.8 0 50 23 18 26 19 48 5 49 7 11 20 38 6 40 22 51 ..... 63 6 49.6 22 28
Sun Oct 20/Mon Oct 21 8777.8 0 54 20 18 25 19 47 5 49 7 12 20 41 6 45 23 49 ..... 52 7 48.0 21 50
Fri Oct 25/Sat Oct 26 8782.8 1 14 02 18 19 19 42 5 53 7 16 20 55 7 08 5 26 17 11 5 12 30.7 1 39
Sat Oct 26/Sun Oct 27 8783.8 1 17 59 18 18 19 41 5 54 7 17 20 58 7 13 6 35 17 48 1 13 25.0 - 4 05
Sun Oct 27/Mon Oct 28 8784.8 1 21 55 18 17 19 40 5 55 7 18 21 01 7 17 7 44 18 25 0 14 19.5 - 9 34

Things to keep in mind

  • Calibrations should be taken during daytime/twilight as much as possible!
  • Remember that the telescope needs to be focussed at the beginning of the night, and after instrument changes. Images should be monitored to see whether there might be a need for additional focussing during the night. After focussing, record the FWHM of the best image as a record of the seeing; ask the obs spec if they did the focussing.
  • for faint objects, you may need to have finding charts ready in advance! Remember that N may not be up in the slitviewer! Use the TCC/Focal Plane window.
  • basic idea is to have two people in the control room observing. One has the primary responsibility of operating the telescope and instrument, and a main goal is for efficiency, ie. to be ready to slew as soon as exposures are done, to be ready with the next exposure when the previous one has finished, i.e., to have the shutter open as much as possible! The other person should inspect each image after it is taken, and make sure that it looks as expected, and to raise question if it doesnt about whether something needs to stop and be changed. The second person is also responsible for filling out the log sheet, with as much detail as possible.
  • your observing plans should contain as much detail as possible. Note the instrument that will be used and the science program, and give a tentative list of objects in an appopriate order based on their position in the sky. Identify which pair of people will be making the observations. Ideally each pair of people would do two objects per instrument, but this may not be possible if the science requires longer exposures, so that the total number of objects may be limited.


  • logs should include as much information as possible. In particular, the most useful information is the qualitative comments about things like conditions, instrument/observing problems/issues, things that happened at the site/telescope/during observing. Log sheet often include lots of columns with information about object names, exposure times, position, etc. etc: this is fine to fill out, but note that almost all of this information is stored in the image headers, so this is not the most important stuff to record: the important stuff is the stuff that happens out of the routine that isn't stored in headers, e.g. files that are named incorrectly, and, as noted, other stuff that happens that you hear about in words/discussions.

Primary responsibilities for delivering data to PIs (but all will share in observing all programs!)

  • ARCES:
    • NM04 Jackiewicz:
    • NM05 Chojnowski:
    • NM09 Pan
    • NM11 Bizyaev :
  • DIS:
    • NM06/NM10 Prescott:
  • TSPEC:
    • NM03 Decolibus
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