*-----------------------*--------------------------*-------------------------* PLAN *-----------------------*--------------------------*-------------------------* use August 29th as the date, this is day 61,429. use 44069.430 as rest freq IF-AC IF-BD I05358 -17.6 km/s at 02 30 LST 44074.872532 MHz 44024.872532 MHz I05358 -17.6 km/s at 07:30 LST 44074.822326 MHz 44024.822326 MHz where the source coords are: 05 39 10.4000 +35 45 19.000 this source is 05391+35453 within AIPS *-----------------------*--------------------------*-------------------------* OBSERVATIONS *-----------------------*--------------------------*-------------------------* Now, this source was observed twice, once on 26-aug-2008 and once on 31-aug-2008. That is, on LST days 61,426 and 61,431. So I re-do the DOPSET calc for these two days, at the same time as above, and get: 61,426 44074.794982 MHz 61,431 44074.867441 MHz note that we're using 24.41 KHz channels, i.e., 0.02441 MHz so these diffs are (wrt 61429) 61,426 44074.794982 -0.07755 or -3.1 channels 61,431 44074.867441 +0.045115 or +1.8 channels Checking the VLA logs: 61426 file was started on 26 aug at 11:20 IAT or ~ 2:50 LST 61431 file was started on 31 aug at 15:30 IAT Or ~ 7:20 LST Now, go back to dopset, using the right day AND the right time: 61,426 44074.792525 61,431 44074.869091 from these I subtract the sky freq that was put into the observe file (i.e.,44074.872532 and 44074.822326 MHz) which gives me differences of: 61,426: -0.080007 = -3.27 channels 61,431: +0.046765 = +1.91 channels Do a SPLIT w/ calib Run CVEL w/ these inputs: aparm -17600 64 0 1 4.4069E10 430000 which shows on-screen as: For August 26: AIPS 1: CVEL Task to shift spectral line data to a given velocity AIPS 1: Adverbs Values Comments AIPS 1: ---------------------------------------------------------------- AIPS 1: INNAME '05391+35453' Input UV file name (name) AIPS 1: INCLASS 'SPLIT' Input UV file name (class) AIPS 1: INSEQ 1 Input UV file name (seq. #) AIPS 1: INDISK 2 Input UV file disk unit # AIPS 1: OUTNAME 'AUG26' Output UV file name (name) AIPS 1: OUTCLASS ' ' Output UV file name (class) AIPS 1: OUTSEQ 0 Output UV file name (seq. #) AIPS 1: OUTDISK 2 Output UV file disk unit # AIPS 1: SOURCES *all ' ' Source list to shift, other AIPS 1: sources will be passed AIPS 1: unshifted. Ignored for AIPS 1: single source files. AIPS 1: '*' or ' ' => all; AIPS 1: QUAL -1 Source qualifier to shift, AIPS 1: Sources with other quals AIPS 1: will be passed unshifted. AIPS 1: -1 => no selection by qual AIPS 1: TIMERANG *all 0 Time range to shift AIPS 1: SELBAND -1 Bandwidth to select (kHz) AIPS 1: SELFREQ -1 Frequency to select (MHz) AIPS 1: FREQID 1 Freq. ID to select (1 only) AIPS 1: SUBARRAY 0 Subarray, 0=>1 AIPS 1: FLAGVER 0 Flag table version AIPS 1: DOBAND -1 If >0 apply bandpass cal. AIPS 1: Method used depends on value AIPS 1: of DOBAND (see HELP file). AIPS 1: BPVER -1 Bandpass table version AIPS 1: GAINUSE 2 CL table version which AIPS 1: contains the time/antenna AIPS 1: dependent frequency offsets. AIPS 1: 0 => 1. AIPS 1: AIPS 1: APARMS(1:6) will define the AIPS 1: velocity parameters needed AIPS 1: for single source files. The AIPS 1: parameters you define here AIPS 1: will override any of those AIPS 1: set with ALTDEF. If any of AIPS 1: APARM(1)-(6) are set CVEL AIPS 1: will assume all are set. AIPS 1: These are ignored in the case AIPS 1: of multi-source files, you AIPS 1: should use SETJY for them. AIPS 1: APARM -17600 64 (1) => for single source file AIPS 1: 0 1 the velocity of a given AIPS 1: 4.407E+10 430000 pixel (m/s). AIPS 1: *rest 0 (2) => the pixel to which AIPS 1: APARM(1) refers. AIPS 1: (3) defines the velocity type AIPS 1: 0 => LSR, 1 => HELIO AIPS 1: (4) the velocity definition: AIPS 1: 0 => optical, 1 => radio AIPS 1: (5) aparms 5 & 6 define the AIPS 1: rest frequency of the AIPS 1: line in Hz; the value AIPS 1: used is the sum of AIPS 1: APARM(5) + APARM(6). AIPS 1: See helpfile. AIPS 1: (7) not used now AIPS 1: (8) if > 0 then do not print AIPS 1: messages about large AIPS 1: channel shifts, used if AIPS 1: deliberately want a large AIPS 1: shift. AIPS 1: (9) 0 => not smooth spectra AIPS 1: while shifting AIPS 1: >0 => smooth AC spectra AIPS 1: by Hanning AIPS 1: >1 => smooth XC spectra AIPS 1: by Hanning also AIPS 1: (10) 0 = trust CVEL AIPS 1: 1 = Earth center AIPS 1: 2 = Low antenna AIPS 1: 3 = High antenna AIPS 1: BADDISK *all 0 Disks to avoid for scratch comput> CVEL 1: Task CVEL (release of 31DEC13) begins comput> CVEL 1: You are using a non-standard program comput> CVEL 1: WARNING: CVEL may produce incorrect answers on files that comput> CVEL 1: have, at any time, been SPLIT; see HELP comput> CVEL 1: Create AUG26 .CVEL . 1 (UV) on disk 2 cno 7 comput> CVEL 1: Doing no flagging on the UV data comput> CVEL 1: QINIT: did a GET of 5120 Kwords, OFF 17462291317039 comput> CVEL 1: Will use velocity and frequency information from APARMS comput> CVEL 1: Velocity type is LSR comput> CVEL 1: Velocity definition is RADIO comput> CVEL 1: Rest frequency = 44069.429688 MHz comput> CVEL 1: Ref. pixel for new velocity is 64.00 comput> CVEL 1: New velocity at given pixel is -17.6000 km/s comput> CVEL 1: Scan 1 Source 05391+35 0/ 11 38 02 - 0/ 11 38 53 Shifting comput> CVEL 1: Ant: 1 IF#: 1 Average shift = 3.32124 comput> CVEL 1: Ant: 2 IF#: 1 Average shift = 3.32146 comput> CVEL 1: Ant: 4 IF#: 1 Average shift = 3.32106 comput> CVEL 1: Ant: 6 IF#: 1 Average shift = 3.32110 comput> CVEL 1: Ant: 7 IF#: 1 Average shift = 3.32130 comput> CVEL 1: Ant: 8 IF#: 1 Average shift = 3.32113 comput> CVEL 1: Ant: 9 IF#: 1 Average shift = 3.32147 comput> CVEL 1: Ant: 10 IF#: 1 Average shift = 3.32151 comput> CVEL 1: Ant: 12 IF#: 1 Average shift = 3.32124 comput> CVEL 1: Ant: 13 IF#: 1 Average shift = 3.32126 comput> CVEL 1: Ant: 14 IF#: 1 Average shift = 3.32129 comput> CVEL 1: Ant: 15 IF#: 1 Average shift = 3.32122 comput> CVEL 1: Ant: 16 IF#: 1 Average shift = 3.32114 comput> CVEL 1: Ant: 17 IF#: 1 Average shift = 3.32116 comput> CVEL 1: Ant: 18 IF#: 1 Average shift = 3.32124 comput> CVEL 1: Ant: 19 IF#: 1 Average shift = 3.32119 comput> CVEL 1: Ant: 20 IF#: 1 Average shift = 3.32124 comput> CVEL 1: Ant: 22 IF#: 1 Average shift = 3.32123 comput> CVEL 1: Ant: 23 IF#: 1 Average shift = 3.32153 comput> CVEL 1: Ant: 24 IF#: 1 Average shift = 3.32118 comput> CVEL 1: Ant: 25 IF#: 1 Average shift = 3.32121 comput> CVEL 1: Ant: 26 IF#: 1 Average shift = 3.32124 comput> CVEL 1: Scan 2 Source 05391+35 0/ 11 40 07 - 0/ 11 40 58 Shifting comput> CVEL 1: Ant: 1 IF#: 1 Average shift = 3.33225 ... *-----------------------*--------------------------*-------------------------* For August 31: AIPS 1: CVEL Task to shift spectral line data to a given velocity AIPS 1: Adverbs Values Comments AIPS 1: ---------------------------------------------------------------- AIPS 1: INNAME '05391+35453' Input UV file name (name) AIPS 1: INCLASS 'SPLIT' Input UV file name (class) AIPS 1: INSEQ 3 Input UV file name (seq. #) AIPS 1: INDISK 2 Input UV file disk unit # AIPS 1: OUTNAME 'AUG31' Output UV file name (name) AIPS 1: APARM -17600 64 (1) => for single source file AIPS 1: 0 1 the velocity of a given AIPS 1: 4.407E+10 430000 pixel (m/s). AIPS 1: *rest 0 (2) => the pixel to which comput> CVEL 1: Task CVEL (release of 31DEC13) begins comput> CVEL 1: You are using a non-standard program comput> CVEL 1: WARNING: CVEL may produce incorrect answers on files that comput> CVEL 1: have, at any time, been SPLIT; see HELP comput> CVEL 1: Create AUG31 .CVEL . 1 (UV) on disk 2 cno 27 comput> CVEL 1: Doing no flagging on the UV data comput> CVEL 1: QINIT: did a GET of 5120 Kwords, OFF 17480537821487 comput> CVEL 1: Will use velocity and frequency information from APARMS comput> CVEL 1: Velocity type is LSR comput> CVEL 1: Velocity definition is RADIO comput> CVEL 1: Rest frequency = 44069.429688 MHz comput> CVEL 1: Ref. pixel for new velocity is 64.00 comput> CVEL 1: New velocity at given pixel is -17.6000 km/s comput> CVEL 1: Scan 1 Source 05391+35 0/ 15 47 37 - 0/ 15 48 23 Shifting comput> CVEL 1: Ant: 1 IF#: 1 Average shift = -1.88731 comput> CVEL 1: Ant: 2 IF#: 1 Average shift = -1.88696 comput> CVEL 1: Ant: 4 IF#: 1 Average shift = -1.88745 comput> CVEL 1: Ant: 5 IF#: 1 Average shift = -1.88728 comput> CVEL 1: Ant: 6 IF#: 1 Average shift = -1.88743 comput> CVEL 1: Ant: 7 IF#: 1 Average shift = -1.88738 comput> CVEL 1: Ant: 8 IF#: 1 Average shift = -1.88741 comput> CVEL 1: Ant: 9 IF#: 1 Average shift = -1.88737 comput> CVEL 1: Ant: 10 IF#: 1 Average shift = -1.88716 comput> CVEL 1: Ant: 11 IF#: 1 Average shift = -1.88729 comput> CVEL 1: Ant: 12 IF#: 1 Average shift = -1.88734 comput> CVEL 1: Ant: 13 IF#: 1 Average shift = -1.88736 comput> CVEL 1: Ant: 14 IF#: 1 Average shift = -1.88720 comput> CVEL 1: Ant: 15 IF#: 1 Average shift = -1.88732 comput> CVEL 1: Ant: 16 IF#: 1 Average shift = -1.88739 comput> CVEL 1: Ant: 17 IF#: 1 Average shift = -1.88737 comput> CVEL 1: Ant: 18 IF#: 1 Average shift = -1.88733 comput> CVEL 1: Ant: 19 IF#: 1 Average shift = -1.88736 comput> CVEL 1: Ant: 20 IF#: 1 Average shift = -1.88732 comput> CVEL 1: Ant: 21 IF#: 1 Average shift = -1.88731 comput> CVEL 1: Ant: 22 IF#: 1 Average shift = -1.88733 comput> CVEL 1: Ant: 23 IF#: 1 Average shift = -1.88713 comput> CVEL 1: Ant: 24 IF#: 1 Average shift = -1.88734 comput> CVEL 1: Ant: 25 IF#: 1 Average shift = -1.88733 comput> CVEL 1: Ant: 26 IF#: 1 Average shift = -1.88735 comput> CVEL 1: Scan 2 Source 05391+35 0/ 15 49 48 - 0/ 15 50 38 Shifting comput> CVEL 1: Ant: 1 IF#: 1 Average shift = -1.87186 ... *-----------------------*--------------------------*-------------------------* Seems that CVEL and the predictions from the DOPSET tool agree well! But then: I image the Aug26 data and find that pixel 64 has: Skypos: 44074.873 MHZ IPOL Skypos: -17.6 KM/S IPOL I image the Aug31 data and find that pixel 64 has: Skypos: 44074.822 MHZ IPOL Skypos: -17.6 KM/S IPOL ************************************************************** The questions are: - Why the velocity in channel 64 is still the same as in the working plan? - Is it correct to expect a slight difference in the velocity of channel 64 owing to the doppler effect? - The CVEL inputs are okay? - Is it still channel 64 the reference? or - Do I have to put another channel? **************************************************************