Swedish-ESO Submillimetre Telescope – SEST

Calibration Sources Monitoring

By Felipe Mac-Auliffe P.
fauliffe@eso.org

 

Twice a month multiple line transitions from the 3mm, 2mm and 1mm band are observed in at least one of several calibration sources. The center line velocities, antenna temperatures and velocity integrated antenna temperatures (Gaussian fits) are then compared to previous results to check for consistency. Since monitoring of the calibration sources tests the performance of the complete telescope system its results are probably most relevant for the observer. However, this also means that any deviations apparent can have several causes (pointing, wind and weather, receivers) and thus only large, consistent deviations will be investigated in detail.

In the next table the Intcal Monitoring program is presented in terms of the main observing parameters for each object and line:

 

 

 

 

IRC+10216

M17SW

Orion KL

WB947

R.A. (1950.0)

 

09:45:15.0

18:17:30

05:32:47.0

07:02:57.2

Dec. (1950.0)

 

+13:30:45.0

-16:13:00

-05:24:23.0

-12:15:24.0

Pointing Source

 

R Leo

vx Sgr

Orion SiO

Orion SiO

Enter Sun limit

 

June 26th

November 7th

April 30th

June 1st

Exit Sun limit

 

October 7th

February 13th

July 28th

August 20th

Transition

 

CO (1-0)

CS (2-1)

CO (1-0)

CO (1-0)

 

 

CS (3-2)

CS (3-2)

CS (3-2)

CO (2-1)

 

 

CO (2-1)

CO (2-1)

CO (2-1)

 

AOS

 

HRS + LRS

HRS

HRS + LRS

HRS

VLSR

 

-26.2 km/s

+20.0 km/s

+5.0 km/s

+10.0 km/s

Obsmode

 

BSW

PSW

PSW

PSW

 

 

 

-22' 22' Rel

-0.5d 0 Rel

-1d 0 Rel

Inttime Spe/Ref/Cal

 

120 / 120 / 5

60 / 60 / 5

60 / 60 / 5

60 / 60 / 5

 

 


IRC+10216 Observing Procedure

CO (1-0) – RX100 observation

 

                Point & focus on IRC+10216

                                Aim antenna to IRC+10216 (Use pointing catalog)

                                Connect RX100:HRS

                                Line CO (1-0)

Tune & Rectemp
                Obsmode Wide Single Beam Switch

                                3 loop pointing / focus sequence (HPBW Spacing 40” 40”)

 

            Connect RX100:HRS+LRS

            Rectemp

            Set the observing mode to Wide Dual Beam Switch

            Inttime Spe/Ref/Cal 120/120/5

            Take a 1 / 1 integrate cycle, calibrate at the beginning, save and zero average

 

CS (3-2) observation

            Connect RX150:HRS + LRS

            Line CS (3-2)

            Tune

            Rectemp

            Set the observing mode to Wide dual beam Switch

            Inttime Spe/Ref/Cal 120/120/5

            Take a 1 / 1 integrate cycle, calibrate at the beginning, save and zero average

 

CO (1-0) – RX115 observation

 

                Point & focus on IRC+10216

                                Aim antenna to IRC+10216 (Use pointing catalog)

                                Connect RX115:HRS

                                Line CO (1-0)

Tune & Rectemp
                Obsmode Wide Single Beam Switch

                                3 loop pointing / focus sequence (HPBW Spacing 40” 40”)

 

            Connect RX100:HRS+LRS

            Rectemp

            Set the observing mode to Wide Dual Beam Switch

            Inttime Spe/Ref/Cal 120/120/5

            Take a 1 / 1 integrate cycle, calibrate at the beginning, save and zero average

 

CO (2-1) observation

            Aim the antenna to IRC+10216

            Connect RX230 to HRS + LRS

            Line CO (2-1)

            Tune

            Rectemp

            Set the observing mode to Wide dual beam Switch

            Inttime Spe/Ref/Cal 120/120/5

            Take a 1 / 1 integrate cycle, calibrate at the beginning, save and zero average

 

 


M17SW Observing Procedure

 SiO pointing and focus

            Aim the antenna to vx Sgr

            Connect RX100 to HRS

            Line SiO (2-1, v=1)

            Tune

            3 loops pointing sequence

            3 loops focus sequence

 

CS (2-1) observation

            Aim the antenna to M17SW

            Connect RX100 or RX115 to HRS

            Line CS (2-1)

            Tune

            Rectemp

            Set the observing mode to Position switching mode (Refpos –22’ 22’ rel)

            Inttime Spe/Ref/Cal 60/60/5

            Take a 1 / 1 integrate cycle, calibrate at the beginning, save and zero average

 

CS (3-2) observation

            Aim the antenna to M17SW

            Connect RX150 to HRS

            Line CS (3-2)

            Tune

            Rectemp

            Set the observing mode to Position switching mode (Refpos –22’ 22’ rel)

            Inttime Spe/Ref/Cal 60/60/5

            Take a 1 / 1 integrate cycle, calibrate at the beginning, save and zero average

 

CO (2-1) observation

            Aim the antenna to M17SW

            Connect RX230 to HRS

            Line CO (2-1)

            Tune

            Rectemp

            Set the observing mode to Position switching mode (Refpos –22’ 22’ rel)

            Inttime Spe/Ref/Cal 60/60/5

            Take a 1 / 1 integrate cycle, calibrate at the beginning, save and zero average

 


Orion KL Observing Procedure

 SiO pointing and focus

            Aim the antenna to Orion SiO

            Connect RX100 to HRS

            Line SiO (2-1, v=1)

            Tune

            3 loops pointing sequence

            3 loops focus sequence

 

CO (1-0) observation

            Aim the antenna to Orion KL

            Connect RX100 or RX115 to HRS + LRS

            Line CO (1-0)

            Tune

            Rectemp

            Set the observing mode to Position switching mode (Refpos –0.5° 0 rel)

            Inttime Spe/Ref/Cal 60/60/5

            Take a 1 / 1 integrate cycle, calibrate at the beginning, save and zero average

 

CS (3-2) observation

            Aim the antenna to Orion KL

            Connect RX150 to HRS + LRS

            Line CS (3-2)

            Tune

            Rectemp

            Set the observing mode to Wide dual beamswitching

            Inttime Spe/Ref/Cal 120/120/5

            Take a 1 / 1 integrate cycle, calibrate at the beginning, save and zero average

 

CO (2-1) observation

            Aim the antenna to Orion KL

            Connect RX230 to HRS + LRS

            Line CO (2-1)

            Tune

            Rectemp

            Set the observing mode to Position switching mode (Refpos –0.5° 0 rel)

            Inttime Spe/Ref/Cal 60/60/5

            Take a 1 / 1 integrate cycle, calibrate at the beginning, save and zero average

 

 


WB947 Observing Procedure

SiO pointing and focus

            Aim the antenna to Orion SiO

            Connect RX100 to HRS

            Line SiO (2-1, v=1)

            Tune

            3 loops pointing sequence

            3 loops focus sequence

 

CO (1-0) observation

            Aim the antenna to WB947

            Connect RX100 or RX115 to HRS

            Line CO (1-0)

            Tune

            Rectemp

            Set the observing mode to position switching (Refpos –1° 0 rel)

            Inttime Spe/Ref/Cal 60/60/5

            Take a 1 / 1 integrate cycle, calibrate at the beginning, save and zero average

 

CO (2-1) observation

            Aim the antenna to WB947

            Connect RX230 or HRS

            Line CO (2-1)

            Tune

            Rectemp

            Set the observing mode to position switching (Refpos –1° 0 rel)

            Inttime Spe/Ref/Cal 60/60/5

            Take a 1 / 1 integrate cycle, calibrate at the beginning, save and zero average