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

Related documents: EMIR Installation report by Santiago Navarro et al.

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. The forward efficiencies were derived from Skydips. The ellipticity of the beams is better than 90% in all cases.

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

The following EMIR setups were requested in the proposals for this summer semester and have been commissioned. The Code corresponds to the table created by S.Navarro describing possible setups of the switch box. The listed Bandwidth is the total bandwidth covered by the resulting spectra, given to about 0.5GHz accuracy.

• Band(s)	Sidebands	Polarisations	Bandwidth	Code
  E0	1SB	H/V	8GHz	(13)
  E0	2SBs	one pol.	16GHz	(14)
  E0/E1	1SB	H/V	8GHz	(121)
  E0/E2	1SB	H/V	8GHz	(131)
  E0(8GHz)/E2	1SB	mixed	12GHz	(135)
  E1	1SB	H/V	4GHz	(2)
  E2	1SB	H/V	4GHz	(3)

The following Figure shows the frequencies of the band edges and centers of the lower and upper sidebands, and the inner and outer bands. Note that the band edges and center are not exactly at multiples of 2GHz relative to the local oscillator. This is due to the IF distribution. The backends are centered near the band centers. VESPA is centered at 6.25 or 9.43GHz. For WILMA, the inner and outer bands have 0.1GHz overlap. The inner band runs from 4.125 to 7.845GHz. The outer band runs from 7.835 to 11.555GHz.

Band Edges