NASA IRTF Data Search Documentation

The NASA Infrared Telescope Facility (IRTF)

The NASA Infrared Telescope Facility (IRTF) is a 3.2 meter telescope, optimized for infrared observations, and located at the summit of Mauna Kea, Hawai`i. Observing time is open to the entire astronomical community, and 50% of the NASA IRTF observing time is reserved for studies of Solar System objects.

For more information about the mission, please see the NASA IRTF webpages.

The NASA IRTF Instruments and Archive

The instruments that are included in the NASA IRTF Archive at this time are:

SpeX Spectrograph and Guider: SpeX is a medium-resolution 0.7-5.3 micron spectrograph.
iSHELL Spectrograph and Guider/Imager: iSHELL is a high-resolution 1.1-5.3 micron spectrograph.

Please consult the NASA IRTF website for more information about these instruments.

The NASA IRTF Archive includes public data. Investigators have a 18 month proprietary period; data are publicly available in the archive after that. (PIs obtain their own proprietary data via other means.)

The NASA IRTF Archive can be searched by object or by date range or by program ID. See "Searching", below.

Search results from the NASA IRTF Archive are displayed in a table that can be sorted and filtered further. See "Results", below.

Data downloads from the NASA IRTF Archive are displayed in a table that can be sorted and filtered further. See "Downloads", below.

Searching the NASA IRTF Archive

There are several primary ways to search the NASA IRTF Archive, which we now describe.

Cone searches with a specified radius: Specify a target by name or position in a variety of units (RA/Dec, Galactic, ecliptic) or a table of coordinates (in csv format or in IPAC table file format; use the IPAC table validator to check and reformat your input table before uploading.) By default, the cone search radius is a degree; this value must be between 1 and 5 deg. Optionally, you can also constrain the date range, the program ID, the instrument, and the observing conditions. Note that searches by date range are inclusive of the minimum date and exclusive of the maximum date.
All-sky searches by date or program ID.: Specify a date range or a program ID, and search over the whole sky. This is the easiest way to download all the data associated with a given program. Optionally, you can also constrain the date range, the program ID, the instrument, and the observing conditions.
Solar System objects (moving targets) by name or NAIF ID.: Specify the object name or its NAIF ID. Optionally, you can also constrain the date range, the program ID, the instrument, and the observing conditions.
Precovery searches by name or NAIF ID or orbital parameters.: This search looks for serendipitous observations of a Solar System target. Specify the object name or its NAIF ID, OR the MPC 1-line input, OR manually specify the orbital parameters. It does the calculation to figure where the object is as a function of time, and looks for data covering the object. Optionally, you can also constrain the date range, the program ID, the instrument, and the observing conditions. This calculation can take a long time; use long time baselines with caution.

You can additionally constrain:

Instruments: At this time, the instruments that are available are the SpeX spectrograph and guider, and the iSHELL spectrograph and guider/imager.

Results from the NASA IRTF Archive

A NASA IRTF Archive search results page has three main sections:

Query criteria.: Summary of the requested search.
Matching observations.: This data table is searchable and filterable. See the page on table interactions for general table help; see below for column definitions.
Download Selected Observations.: Specify what data to package and download with your data;see "Downloads", below. Caution: packaged data can be very large files, and may take a long time to package and download.

To select observations, click on the checkbox to the left of the rows you wish to download; click on the checkbox at the top of the column of checkboxes to select all observations.

The results table columns are shown in table 1.

Table 1: Results table columns

Column name	Description	Units
group_id	observing group identification code
previews	links to previews (see below)
name	name of target or "calibration"
ra	right ascension of target	degrees
dec	declination of target	degrees
date_time_of_obs	date and time of observation	JD
program_id	program ID
proposal_pi	program principal investigator (PI)
proposal_title	program title (not shown by default)
datatype	data type in one-letter string: T=target, S=standard, C=calibration
instrument_name	name of instrument
order_sorting_filter	string describing order sorting filter
guider_filter	string describing guider filter
grating	string describing grating
slit	string describing slit
cross_disperser_tilt	cross_disperser_tilt
slit_length	slit length	arcseconds
exposure_time	exposure time	seconds
wavelength_lower	lower wavelength bound	microns
wavelength_upper	upper wavelength bound	microns
lunar_azimuth	lunar azimuth	degrees
lunar_elevation	lunar elevation	degrees
airmass	airmass
seeing	seeing	arcsec
lunar_illumination	lunar fractional light illumination	percent
lunar_light	string describing lunar light level
sky_transparency	string describing sky transparency

Click on the gears in the upper right of the table to change which columns are shown.

Previews: In the previews column, there is a link to an HTML page ("summary") which consolidates information to help you evaluate whether you want to download the data. The included information is:

program information
target information
data quality assessment information, if available
weather information (png)

Observing conditions appear in the results and include airmass, seeing, lunar light level (dark, grey, bright), and the sky transparency (photometric, cirrus, cloudy). These values may be incompletely or incorrectly populated in the database. If in doubt, downloading the data is recommended. See the page on table interactions for general table help, including information on how to filter your results. In brief, click on the "funnel" to enable boxes at the top of each column if they are not already there. To, e.g., filter to only show observations where the lunar light string is "bright", type "bright" in the box at the top of the "lunar_light" column. To only select where the lunar fractional light illumination is less than 0.8, type "< 8" in the box at the top of the lunar_illumination column.

Downloads from the NASA IRTF Archive

To select data for download, click on the checkbox on the far left of the data table, or click on the box at the top of that column to select every row.

By default, related data are automatically packaged together with data downloads from the NASA IRTF archive. Caution: packaged data can be very large files, and may take a long time to package and download. You can choose what to include:

Selected Data: The data you have selected is, of course, included. To select observations, click on the checkbox to the left of the rows you wish to download; click on the checkbox at the top of the column of checkboxes to select all observations.
Related Standard Groups: Include standards obtained near the observation of interest and related to it.
Related Calibration Groups: Include calibration frames related to the observation of interest.
IE Logs: Include instrumenation logs. This file includes key events logged by the TCS and instruments to document sequences of events during observing to help understand the archived data.
Weather data: Include weather data.
Program information: Include information about the program that obtained the observation of interest.

You can also choose to have the observations sorted into directories. (See the "Organize downloads into directories" checkbox.) If this box is not checked, the data will unzip into a flight directory structure (e.g., no subdirectories). If this box is checked, the data will unzip into a multiply-nested set of subdirectories, e.g., 2016B/20160803/data/2016B048/sbd_20160803_151141. If you download only one or two observations, this structure may seem funny; it makes more sense if you are downloading many observations. In any case, you can rearrange the data organization once you download the data.

Click on the 'download' button to download your data.

Note that you control where the data are saved on your disk through your browser; your browser may be configured to store all downloads in a particular location on your disk. Look for a "Downloads" folder or search for recently modified files.

UnzipTroubleshooting

If you have an old computer and/or an old OS, and if you download more than one observation at a time, then you may very well get a zip file you cannot unpack. It complains that it is corrupted :

warning [IRTF.zip]: 4098391235 extra bytes at beginning or within zipfile
(attempting to process anyway)
error [IRTF.zip]: start of central directory not found;
zipfile corrupt.
(please check that you have transferred or created the zipfile in the
appropriate BINARY mode and that you have compiled UnZip properly)

This is because the zip files are bigger than a threshold (likely 4 GB for your machine). If you have a recent version of the unzip software, it should just work and you will never notice. If you have an only sort of old version, you can try to "repair" the file (use "zip -F IRTF.zip --out IRTF2.zip" and then "unzip IRTF2.zip"). If that still doesn't work for you, you can update the unzip software. On a Mac, if you use Homebrew, type "brew install unzip". Homebrew will get the software but then express reluctance to install it for you, making it seem like you are doing something terribly risky in updating the software. So, you should invoke it using the full path /usr/local/opt/unzip/bin/unzip rather than via an unqualified unzip. If you are not comfortable doing that, the workaround is to download one observation at a time (one row from the GUI), and unzip them from the command line (as opposed to double-clicking on the zip file) -- then it will nest all of the files properly, as if you had downloaded just one big zip file.

Last Updated: 2018 Oct 16