[vlbatests] VLBA receiver pointing offsets update

Wed Sep 30 13:19:50 EDT 2026

Please find attached an updated file with the proposed collimation offset changes. It now also includes offsets for the 3mm receiver at HN and NL, where the 7mm receiver position is changing. The 3mm receiver gets the same change in offset as the 7mm.

Best wishes,
Kirill

________________________________________
From: Kirill Sokolovskii <ksokolov at nrao.edu>
Sent: Wednesday, September 30, 2026 9:08 AM
To: vlbatests at listmgr.nrao.edu
Subject: Fw: VLBA receiver pointing offsets update

I'm forwarding the message sent earlier to vlba-test-maint
I'm also copying the attached ptanal.parm in the body of the message to guard against any potential problems with attachments in a mailing list.

________________________________________
From: Kirill Sokolovskii <ksokolov at nrao.edu>
Sent: Tuesday, September 29, 2026 6:19 PM
To: vlba-test-maint at listmgr.nrao.edu
Cc: Jay Blanchard; Kirill Sokolovskii
Subject: VLBA receiver pointing offsets update

Dear everyone,

I propose the updated values for the receiver-specific pointing offsets (Az/El collimation) that you may find in the attached ptanal.parm file.
The new values (expressed in arcminutes) are based on the analysis of all pointing experiments from the beginning of 2026 up to now.
In cases where there is a jump in offset values, a shorter time interval that follows the jump was used.
For MK 13cm, PT 20cm and PT 6cm the interferometric poinings where used jointly with single-dish pointings to derive the proposed offsets while in other cases the values are based on single-dish pointings with interferometric poinings (where available) used as a consistency check for the single-dish values.

For SC there seems to be a room for improvement of the antenna poinitng model as there are correlated offsets between multiple receivers. I'm not suggesting new receiver offsets for SC for now and will work on the pointing model update.

Best wishes,
Kirill

======== updated ptanal.parm ========
BR,6cm   ,AZCOLIMATION,-02.61 # from Current:           AZ:-01.12 EL:+01.48
BR,6cm   ,ELCOLIMATION,+02.06 # from Current:           AZ:-01.12 EL:+01.48
BR,2cm   ,AZCOLIMATION,-01.04 # from Current:           AZ:-00.84 EL:+03.22
BR,2cm   ,ELCOLIMATION,+03.47 # from Current:           AZ:-00.84 EL:+03.22
FD,SX    ,AZCOLIMATION,+00.91 # from Current:           AZ:+00.52 EL:+06.75
HN,20cm  ,AZCOLIMATION,-04.01 # from Current:           AZ:-03.50 EL:+02.20
HN,20cm  ,ELCOLIMATION,+03.28 # from Current:           AZ:-03.50 EL:+02.20
HN,4cm   ,AZCOLIMATION,-03.62 # from Current:           AZ:-03.83 EL:+08.38
HN,4cm   ,ELCOLIMATION,+08.67 # from Current:           AZ:-03.83 EL:+08.38
HN,2cm   ,ELCOLIMATION,+08.09 # from Current:           AZ:+03.54 EL:+08.22
HN,7mm   ,AZCOLIMATION,+03.78 # from Current:           AZ:+04.05 EL:+05.44
HN,7mm   ,ELCOLIMATION,+05.73 # form Current:           AZ:+04.05 EL:+05.44
HN,3mm   ,AZCOLIMATION,-00.19 # from current HN: AZCOLIMATION: +0.08, ELCOLIMATION: +3.45 new_AZ=+0.08-00.27=-0.19
HN,3mm   ,ELCOLIMATION,+03.74 # from current HN: AZCOLIMATION: +0.08, ELCOLIMATION: +3.45 new_EL=+3.45+00.29=+3.74
KP,6cm   ,AZCOLIMATION,+00.56 # form Current:           AZ:+01.00 EL:+01.05
KP,SX    ,ELCOLIMATION,+01.57 # from Current:           AZ:+00.00 EL:+01.21
KP,2cm   ,AZCOLIMATION,-00.40 # from Current:           AZ:-00.19 EL:+02.31
KP,2cm   ,ELCOLIMATION,+02.03 # from Current:           AZ:-00.19 EL:+02.31
LA,20cm  ,ELCOLIMATION,-07.90 # from Current:           AZ:-01.62 EL:-06.55
LA,SX    ,AZCOLIMATION,+01.63 # from Current:           AZ:+02.04 EL:-06.41
LA,2cm   ,ELCOLIMATION,-05.31 # from Current:           AZ:-01.40 EL:-05.85
MK,13cm  ,AZCOLIMATION,+01.06 # from Current:           AZ:-00.69 EL:+01.31
MK,6cm   ,AZCOLIMATION,+03.30 # from Current:           AZ:+02.70 EL:+00.95
MK,6cm   ,ELCOLIMATION,+00.69 # from Current:           AZ:+02.70 EL:+00.95
MK,1cm   ,AZCOLIMATION,+00.55 # from Current:           AZ:+00.80 EL:+01.11
NL,SX    ,ELCOLIMATION,-01.16 # from Current:           AZ:+02.54 EL:-00.54
NL,1cm   ,ELCOLIMATION,-00.72 # from Current:           AZ:+03.25 EL:-00.45
NL,7mm   ,ELCOLIMATION,-00.88 # from Current:           AZ:+00.92 EL:-00.73
NL,3mm   ,ELCOLIMATION,-02.75 # from current NL: AZCOLIMATION: +1.65, ELCOLIMATION: -2.60 new_EL=-2.60-00.15=-02.75
OV,20cm  ,AZCOLIMATION,+01.67 # from Current:           AZ:+04.00 EL:-06.70
OV,20cm  ,ELCOLIMATION,-07.93 # from Current:           AZ:+04.00 EL:-06.70
OV,13cm  ,ELCOLIMATION,-09.47 # from Current:           AZ:+01.47 EL:-09.00
OV,SX    ,AZCOLIMATION,+01.85 # from Current:           AZ:+01.97 EL:-10.50
OV,SX    ,ELCOLIMATION,-10.40 # from Current:           AZ:+01.97 EL:-10.50
OV,2cm   ,ELCOLIMATION,-08.99 # from Current:           AZ:+00.92 EL:-09.21
PT,20cm  ,AZCOLIMATION,+00.92 # from Current:           AZ:+00.24 EL:+00.00
PT,20cm  ,ELCOLIMATION,+01.19 # from Current:           AZ:+00.24 EL:+00.00
PT,6cm   ,AZCOLIMATION,-08.10 # from Current:           AZ:-07.35 EL:+03.82
PT,4cm   ,ELCOLIMATION,-04.31 # from Current:           AZ:-00.43 EL:-03.82

=========================
-------------- next part --------------
A non-text attachment was scrubbed...
Name: ptanal.parm
Type: application/octet-stream
Size: 3082 bytes
Desc: ptanal.parm
URL: <http://listmgr.nrao.edu/pipermail/vlbatests/attachments/20260930/4f47a615/attachment.obj>