Diff for "EmirCommissioningReportOldDraft"

DRAFT Version of EMIR Commissioning Report

Carsten Kramer with contributions from Juan Penalver, Clemens Thum, Hans Ungerechts, Helmut Wiesemeyer, Albrecht Sievers, Gabriel Paubert, Walter Brunswig, Melanie Krips, Sascha Trippe, Dirk Muders, Albert Greve, Karl Schuster

Nasmyth Offsets

The Nasmyth offsets were determined to be -39.0"/+5.5" for the left beam and +51.0"/+5.5" for the right beam. The left beam is used for most EMIR setups, i.e. for single band E0 or E2 observations, and for dual band E0/E2 and E0/E1 observations. The right beam is used for E1, E3, E1/E3. At present, the observer has to set the Nasmyth offsets in PaKo. They are not yet set automatically when switching the EMIR setup.

Alignment

The above figure shows the alignment between the four EMIR bands and between the two polarisations of each band. The overall alignment is better than 1 arcsec.

Foci

The above figure shows the focus between different polarisations of the same band. There are no significant differences between these foci.

This figure shows the focus between different bands. The largest deviation is about 0.3 mm, similar to the situation with the ABCD receivers. For dual band observations, the telescope should be focussed to the high frequency band.

Telescope Efficiencies

• Freq	HPBW	Feff	Beff	Aeff	S/TA*	Comments
  GHz	arcsec	%	%	%	Jy/K
  86	29	95	81	63	5.9
  145	16	93	62	57	6.4
  330	7	89	32	29	12.0

The main beam and aperture efficiencies, and the beam widths, were derived from Mars observations at about 43 deg Elevations, i.e. near the maximum of the gain elevation curve on March, 4th, 2009.

Continuum backends

At present, only the central 1GHz of each 4GHz chunk are being used for continuum detection. Broad band 4GHz wide continuum detectors are in preparation.

Spectrometers

During commissioning, we used the 4MHz filterbank and the two auto correlator backends WILMA and VESPA, partly in parallel. A variety of VESPA setups were checked, covering the range of resolutions between 3kHz and 1.25MHz and a wide range of bandwidths. VESPA parallel mode was also checked. However, it is not possible to check all possible setups. The 1MHz filterbank has not yet been commissioned.

Observing modes

The following switching modes were re-commissioned: position switching (onoff), wobbler switching, and frequency switching. Beam switching was checked using the continuum backends. The on-the-fly mapping mode was re-commissioned, in combination with position switching and with frequency switching.

EMIR setups

Band Edges

Commissioning observations

• The following figure shows a spectrum of Orion IRc2 covering 32 GHz of the 3mm window. It was taken with WILMA in wobbler switched mode in two EMIR setups.

• Cloverleaf

To be done

• The 1MHz filterbank is not yet available
• HERA needs to be tested before being available again
• Polarimetry will be commissioned later
• Band 4 will be fully commissioned later.

• A PaKo manual is in preparation. PaKo online help on new EMIR features is already available.