Instrumentation Overview

Updated on February 20, 2015

ASTE

The Atacama Submillimeter Telescope Experiment (ASTE) is a project to promote ground-based observations at submillimeter wavelengths with a telescope in Atacama desert in Chile, operated by Chile Observatory and Nobeyama Radio Observatory (NRO) of National Astronomical Observatory of Japan (NAOJ), under the collaboration with University of Chile and Japanese Universities including University of Tokyo, Osaka Prefecture University, Ibaraki University, Hokkaido University, Keio University, and Joetsu University of Education. The ASTE observatory consists of the high-precision 10 m dish for submillimeter wavelengths, SIS mixer receivers for heterodyne observations, IF transmission system, digital spectrocorrelator, continuum backend, computers for monitor and controls of observations, and infrastructure including power generators, satellite communication system, dedicated rooms equipped with air conditioners, and so on.

The location of the ASTE telescope

The Telescope

Visit the URL below to find out the descriptions on the telescope performance (angular resolution, main-beam efficiency, pointing accuracy, etc.) and pointing strategy.

Receivers

Operating and Upcoming Instruments

Here is a summary for the current status of the receivers that ASTE is/will be equipped with. A dual-polarization side-band separating (2SB) mixer receiver for the 350 GHz band, DASH 345 , is open during 2015 season (2015a & 2015b), and a cartridge-type dual-polarization side-band separating (2SB) mixer receiver for the 490 GHz band, ASTE Band 8 (ALMA Band-8 Qualification Model), is open during 2015a only. Click the instrument name to find out the specifications and performance of each receiver.

Table 1. Current status of ASTE receivers. (Jun. 14, 2016)
Instrument Type Frequency
(GHz)
HPBW
(arcsec)
Npix Band width
(GHz)
Back-end
Option
Status Note
DASH345 Heterodyne 321-376 22 1 IF=4.0-8.0 MAC/WHSF Open  
ASTE Band8 Heterodyne 387-498 17 1 IF=4.0-8.0 MAC/WHSF Open  
CATS345 Heterodyne 324-372 22 1 IF=4.5-7.0 MAC/WHSF N/A  
TES Camera Bolometer 270 28 169 ~50 None. N/A The status is for Phase I.
350 22 271 ~30
DASH 345/CATS 345 go
A two-sideband single-polarization heterodyne receiver operating at frequencies of 324-372 GHz.
ASTE Band 8go
A two-sideband dual-polarization heterodyne receiver operating at frequencies of 400-500 GHz.
TES Camera go
A large bolometer array simultaneously imaging the sky in the two bands (1100 and 850 micron for Phase I and II; 850 and 450 micron for Phase III).

Decommissioned Instruments

The decommissioned instruments are listed below. Note that these instruments are currently not available.

SC 345
See Inoue et al. (2008).
AzTEC go (Astronomical Thermal Emission Camera)
A spider-web bolometer array operating at 1100 micron, which has been moved to the LMT. See the AzTEC web site.

Spectrometers

Operating and Upcoming Instruments

Here is a summary for the current status of the ASTE digital spectrometers. The MAC and the WHSF are currently available.

Table 2. Current status of spectrometers. (June. 27, 2014)
Instrument Type Bandwidth
(MHz)
Nchan Spectral
resolution
Velocity
resolution
at 350 GHz
Velocity
coverage
at 350 GHz
Status Note
MAC XF 512 1024 0.5 MHz 0.43 km/s 445 km/s Operating  
128 0.125 MHz 0.11 km/s 111 km/s  
WHSF F-FX 4096 2048*1 2 MHz 1.7 km/s 3500 km/s Operating*2  
2048 1 MHz 0.86 km/s 1750 km/s  
64 31.25 kHz 27 m/s 56 km/s N/A  
32 15.625 kHz 13 m/s 28 km/s  
  • *1: Full resolution (Nchan = 4096 ch) of WHSF is not available due to the limitation of the data generator.
  • *2: Please see available modes in the status report of the WHSF.

Distribution of IFs to Backends for DASH345 and ASTE Band8

Receiver Selection

Note that simultaneous observations of both receivers are not available.

Distrubition to MAC

In default configuration, an input of E/O-O/E #1 selects P0USB or P1LSB and that of E/O-O/E #2 selects P0LSB or P1USB.

Distribution to WHSF


Please see more detailed configuratons in WHSF.

Intensity Calibration (Spectroscopic Observations)

  • A standard chopper wheel method using a room temperature absorber is employed to obtain antenna temperature of the source.
  • It is recommended to observe a standard source every night (at least) for intensity calibration within your observing time.
  • A list of the standard sources is available.

Observing Modes (Spectroscopic Observations)

Two observing modes, position switching and On-The-Fly (OTF) mapping, are available. Frequency switching is not available. Chopping/wobbling of the secondary mirror is also not available.

  • Position switching: The target position (ON position) and nearby sky position (OFF position) are alternatively observed to subtract atmospheric emission. It is suited for deep observations of a single point or a small number of observing points of a small portion of the sky.
  • OTF mapping: Continuous acquisition of the data during a raster scan of the telescope. It is appropriate for wide area mapping of a (relatively) bright line.

Observing scripts will be prepared using a dedicated GUI tool, aobs. You may consult with your collaborator from ASTE team about the preparation of scripts as well as planning of observations in advance if you are not familiar with observations using ASTE.

Observations and monitors

  • PI/co-Is are expected to visit ASTE operation room in Mitaka (headquarter of NAOJ) to conduct their observations by themselves. You may visit ASTE operation room in San Pedro de Atacama in Chile if you want, although a support for observations will be highly limited in Chile.
  • A real time monitor of the currently acquired spectra, a quick look, is available during your observations.
  • A real time monitor of the weather conditions, including ambient temperature, wind direction and velocity, atmospheric pressure, humidity, partial pressure of water vapor, zenith opacity at 220 GHz, envmon, are available.
  • All sky monitors at 183 GHz is available.
  • The acquired spectral data are recorded in the hard disk at the ASTE telescope site. At this moment, network transportation of the data is prohibited due to a limited bandwidth of the satellite communication. Whole data set will be transferred to Japan after the end of the observations, and it typically requires about a few weeks. The full-size ASTE science data will be provided to the PIs via a FTP server in the NAOJ Chile observatory within 1.5 months after their final observations.

Data Reduction (Spectroscopic Observations)

  • The CASA software, an astronomical data analysis software package for ALMA, is available for the tools for analysis of ASTE data.
  • A dedicated data analysis tool, NEWSTAR, is available for the data from position switching observations. See the NEWSTAR manual for details.
  • OTF data will be reduced with a tool, NOSTAR, an IDL based package developed at Nobeyama Radio Observatory. Visit the OTF data reduction page for usage of NOSTAR.