____________________________________________________________________ LOGISTICS: Phone # of VLBA ops 505 835 7250 and VLBA_xx ! carry phone list ! or use lookup -f online Combination lock #'s: ! main gate of VLBA_xx ! building door ! vertex room ____________________________________________________________________ MIRROR MOUNT, HARDWARE connections. Set rotation to desired position around feed circle ==> NEED TO KNOW 3mm rotation position, it is on elevation axis, and count from there. Align post 'vertical' i.e. so laser spot is on crosshair in middle of subreflector. (Rotate laser to ensure seating correct) Align horn/mirror so as to put 'horizontal' laser beam onto crosshair. (Stick optical mirror to RF mirror) Connect WR75 inputs of amplifier to horn. ALIGN POLARIZATION CORRECTLY. GET PARALLACTIC ANGLE FROM VSAT LOG. E.G. GE-4 (current favourite sat ellite) radiates vertical linear polarization and has parang= -10deg at PT. Thus the polarization of receiving amplifier/ waveguide should be 10deg CCW from vertical, as at left. \ or the END-ON view from back of amplifier should have | the long axis of the w/g perpendicular to that, or \ 10deg CCW from horizontal, as at right . ____ | ____/ \ _____/ | amplifier WR75 input SMA out to small grey box, whose output is type-N connector to heliax. Inside vertex room: Disconnect VLBA 2cm inputs, connect holo 2cm to converters RCP gets main antenna (for peakup, channel 1 =BBC1 is used) Connect 15v; Outside bulkhead: Check if 4-band guys have stolen holo inputs for their signals - reconnect holo inputs if so: 1/4" heliax from feed cone; ignore 1/4" hlax from quad'pod. 3/8" heliax from apex reference horn. ON FEEDCONE & ON APEX: SET POLARIZATION ANGLE OF MAIN (AND reference if reqd) feeds. AT VLBA RACK: Connect ethernet, DAQ card to HUYGEN. Connect BBC front panel monitor points to DAQ input. ENSURE MAIN SIGNAL IS IN CHAN 0 = BBC#1. This is to peakup on the main antenna beam (Else edit the .crd file to put in peakchan 2 instead of peakchan 1.) ____________________________________________________________________ MISCELLANEOUS: ETHERNET TO HUYGEN From: James Robnett Subject:[HelpDesk #3843] given to gmartin by jrobnett Date: Wed, 28 Nov 2001 cc: vdhawan, mrevnell Could you change huygen's hostname to huygen-pt it's domain should be changed to vlba.nrao.edu from aoc.nrao.edu, this will be in the /etc/sysconfig/network and /etc/sysconfig/scripts/ifcfg-eth0 files From now on huygen is the name at the aoc, huygen-pt, huygen-mk etc is it's name at a give site. james ---- Forwarded Message -- Done. I somehow missed noticing this last Wednesday. 146.88.101.21 is now huygen-pt.vlba.nrao.edu. I assume Mike Revnell was involved as I had reserved that address for him. George ____________________________________________________________________ SATELLITE TRACKING ____________________________________________________________________ ON HUYGEN cd /gabor/satrk makeraster ! optional, or use files **.sch makes a file raster.sch for vsat inputs: d n m p where d=FOV_deg, n=n_rows, m=mins_per_rowscan, p=peakpoint_every_p_scans? e.g. 2.5 50 4 4 output in file raster.sch ## If there are scans in the .sch file which have ## scan duration between 2 and 4 minutes ## and have iqual = 0 ## then a "peakchan=1" is inserted in that scan ## in the vsat output file (see below) ## to peak up the pointing. Standard rasters exist already: e.g. raz.sch, uses inputs 2.5 50 4 4 & makes a raster with: total time 3.9hr; 3' step in el. 0.625 deg/min az slew rate; 2.5deg square raster (current favourite) rel.sch =slew in el; rest as above. ss.sch =satellite on boresight ## get satellite ephemeris (2-line elements, TLE's) from web site: http://celestrak.com/NORAD/elements/geo.txt save in file /gabor/satrk/geo.txt get_tle ! extract TLE format to small files one per satellite. ! read messages carefully to ensure latest ephemeris is ! extracted. NOW run ./vsnl to generate VLBA control file. ## to compile vsat under solaris: ## f77 vsat.f -o vsat /home/pingora/cwalker/code/slalib/NEW/source/libsla.a ## above is old for reference only ## ## NOW use f77 -o vsat vsat_new_sunOS.f ! for SUN ## e.g. paso or jansky ## OR ELSE ON HUYGEN USE: ## g77 -fno-automatic -o vsnl vsat_new_linux.f ./vsnl ! prepare schedule for satellite obs ephemeris file ........ ge4 ! eph ge4 ! file for satellite TLE. schedule file ......... ss.sch ! sch ss.sch ! file for scan, raster etc. part1 file ............ part1.12198 ! part1 part1.12198 ! file for setup root for output files . holo ! root holo ! names of output file(s) site .................. pt ! site pt ! list, or ALL date [dd/mm/yyyy] ....... 24/7/2002 ! date 24/07/2002 ut [decimal hours] .... 16.00000 ! ut 0.1 ! start UT (scans from **.sch) reference antenna ? ... NO ! ref NO ! e.g. ! YES=stare at source, ! no raster, even if **.sch ! specifies it. inp ! view inputs go ! generates output ! output filename is of form: root.site, ! log appended to file vsat.log Make file with scans on boresight; ./vsnl sch ss.sch go ! output VLBA antenna control file is e.g. holo.pt ON JANSKY: PUT VLBA CONTROL FILE ONTO JANSKY. ssh jansky -l vlbaops password cd /home/jansky3/vlbaops/OBS cp /home/aakash/kudre/VLBA/satrk/holo.pt . INFORM vlba operator 505 835 7250 to start file and point antenna. STILL ON JANSKY: start antenna monitor/control screens. xpt ! start screens to control/monitor vlba PT ACU ! monitor az,el,error, stow/point etc. OBS ! monitor scans, skip lines, etc. CLOCK ! for UT MODULE BBC 1,2 ! monitor/set TP levels FR ! to adjust focus/rotation FR PEAKPOINT CROSS or RASTER ! to find pointing offsets Start observation on boresight; OBS screen Find satellite pointing; PEAKPOINT etc. Peakup pointing/focus/rotation for beam from holography feed. NOTE DOWN POINTING OFFSETS AND FOCUS/ROTATION, PUT INTO sed script munge.sed in next step. BACK ON HUYGEN: Make 2 new files, one on boresight; one a raster starting 1hr later. ./vsnl sch ss.sch ! all boresight scans go ./vsnl raz.sch ! raster scans incl. autopeak go sadd file2 file1 ! concatenate file2 to file1; ! remove header lines from file2 ! Put in previously measured pointing, ! focus, rotation offsets. munge file1 ! See old files munge_focxx_rotyy ! edit & copy to munge.sed ! Then run script munge. get_scans file1 ! makes auxiliary files: ! file1.start_stop = for flagging data, later ! file1.filestop = human readable stop times ! file1.cronin = times for crontab to break files on HUYGEN emacs file1.cronin ! edit crontab file - optional. ## This part not necessary if satelite tracking is generated on HUYGEN ## (files are already in place) ## ftp ftp.aoc.nrao.edu ## vdhawan password ## cd /var/spool/ftp/pub/staff/vdhawan ## get f2.cronin ! cron job start/stop times for ## ! file start/stop file1.cronin is automatically copied to /root/v2/holo if satrk files were generated on huygen. BACK ON JANSKY at the monitor/control antenna screens Start again on boresight, file1; OBS; PEAKPOINT, etc. After peakup, skip ahead into raster file2, 30min or so BEFORE IT STARTS. ENSURE SIGNALS ARE STRONG. ____________________________________________________________________ DATA AQUISITION on HUYGEN username root password ! login /etc/rc.d/rc.pietown ! to setup ethernet for PT. telnet vlbapt ! from HUYGEN, telnet to VLBAPT __________________________________________________________________________ on VLBAPT (VxWorks) username vlbaops password ld p2 ! extract cross-cor spectra to file p2 holo_run ! Split data into boresight + raster. ! use bore.p2 for calibration ! of the raster data in holo.p2 ## file holo_run looks like this: ## sort data file into time order - else flags and data are not in step ## and flagging will fail. ## /bin/sort -k1,1 -n p22 >! p2 ## now run holo_fix = various corrections & flagging /home/aakash2/holo/holo_fix <! vsl __________________________________________________________________________ REFERENCE POINTING OFFSETS DURING RUN extract with SARA/CPK ssh jansky -l vlbaops ! login to a sun solaris box - VLBA software ! is sun only. sara typ= CPK utt date etc outfile date # reference pointing offsets: ## run grepcpk after which the ## file C has data: ut, aznom, elnom, azof, elof (arcmin) convert to degr awk '{ print $1, $4-$2, $5-$3 }' C >! cpk __________________________________________________________________________ ## write out corrections from XMGR intp files CAZ, CEL, Camp, Cphas; ## correct the holo.p2 output in subsequent runs of holo_run to try ## different x,y offsets etc. results in FITS area for reading in by HOLGR. ## paste caz cel camp cphas | awk ' substr($1,1,1)!="@"&&$1!="&"&&($1-$3+$5-$7)^2<=.01{ print $1, $2, $4, $6-30, $8 }' >! temp paste holo.p2 temp | awk '($1-$6)^2<=0.01&&$1>=6.0&&$1<=9.9 { print $2-$7, $3-$8, $4-$9, $5-$10 }' >! $AK1/H1JUN15 paste holo.p2 temp | awk '($6-$1)^2<=0.01&&$1>=7.5&&$1<=11.5{ print $2-$7, $3-$8, $4-$9, $5-$10 }' >! $AK1/H2JUN15 paste holo.p2 temp | awk '($6-$1)^2<=0.01&&$1>=3.5&&$1<=11.5{ print $2-$7, $3-$8, $4-$9, $5-$10 }' >! $AK1/H3JUN15 __________________________________________________________________________ AIPS: recompiling, private versions, etc. setenv RAPAIPS=/home/okanagan/rperley/aipscode setenv VHOLO=/home/aakash2/holo cd /home/aakash2/holo cp HOLGR.FOR . cp HOLGR.HLP . source /home/AIPS/LOGIN.CSH $CDTST LIBS $APGNOT [DEBUG] > HOLGR.OPT edit HOLGR.FOR HOLGR.HLP COMLNK HOLGR HOLGR.OPT [DEBUG NOOPT] setenv VHOLO `pwd` ! or setenv VHOLO=/home/aakash2/holo setenv RAPAIPS=/home/okanagan/rperley/aipscode aips [debug=gdb] ! start aips version 'VHOLO' ! pick up private versions __________________________________________________________________________ RUNNING AIPS ON HUYGEN cd /gabor/aips source LOGIN.SCH aips AIPS 1: Found in Version=RAPAIPS AIPS 1: HOLGR: Task to read and process holography visibility data AIPS 1: Adverbs Values Comments AIPS 1: ---------------------------------------------------------------- AIPS 1: INFILE 'AK1:HMAR13 ' AIPS 1: Input data file name. AIPS 1: OUTNAME 'HMAR13 ' Output image name. AIPS 1: OUTDISK 2 Output disk number. AIPS 1: UVTAPER 0 0 Data tapering: (1) type, AIPS 1: (2) width in cells to 0.5 AIPS 1: OPTYPE 'SUBR' Telescope type: 'PFOC' prime AIPS 1: focus, 'SUBR' subreflector AIPS 1: FACTOR 6.2 Magnification AIPS 1: APARM 12.198 49.4 Operating parameters. AIPS 1: 25 3.51 1: Frequency (GHz). AIPS 1: 8.85 *rest 0 2: Satellite elevation, deg. AIPS 1: Use -1 for sidereal obj. AIPS 1: 3: Antenna diameter, m. AIPS 1: 4: Subreflector diameter, m. AIPS 1: 5: Focal length, m. AIPS 1: 6: Disabled AIPS 1: 7: Disabled AIPS 1: 8: Disabled AIPS 1: 9: 10000 * Ref ant. + AIPS 1: 100 * target ant. + IF#. AIPS 1: 10: Stokes (RR=1, LL=2) AIPS 1: (9) and (10) used only AIPS 1: if INFILE is not of form AIPS 1: 'AREA:FILE' AIPS 1: BPARM 30 256 Data reduction parameters. AIPS 1: 0 0 1: Required map size, m. AIPS 1: 0 -1 2: No. of pixels on a side AIPS 1: -1.75 -12.5 of the output map (power AIPS 1: 0 1 of 2, maximum 512). AIPS 1: 3: Min. antenna scan angle AIPS 1: 4: Max. antenna scan angle AIPS 1: 0 => all data used. AIPS 1: <0 => circular maximum. AIPS 1: 5: Amplitude scaling factor AIPS 1: 6: Fourier transform sign AIPS 1: 7: Minimum antenna aperture AIPS 1: < 0 => circular min. AIPS 1: 8: Maximum antenna aperture AIPS 1: < 0 => Circular max. AIPS 1: (7,8) used for focus and AIPS 1: pointing calculations. AIPS 1: 9: Correction control flags: AIPS 1: read the HELP! AIPS 1: 10: >0 => logarithmic ampl. AIPS 1: <0 => linear amplitudes. AIPS 1: CPARM *all 0 Parameters for the gridding AIPS 1: operation (see HELP). AIPS 1: DPARM 1 1 Output maps, >0 => Save this. AIPS 1: 1 1 1,2: Regridded amplitude and AIPS 1: 1 1 phase of the observed AIPS 1: 1 1 antenna beam pattern. AIPS 1: 1 8 3: Weights used in the AIPS 1: regridding procedure. AIPS 1: 4,5: Derived amplitude and AIPS 1: phase of the grading. AIPS 1: 6,7: Amplitude and phase of AIPS 1: the point-spread func. AIPS 1: 8: Focus model corrections AIPS 1: 9: Surface deviation map. AIPS 1: 10: Antenna power pattern AIPS 1: (See HELP!) __________________________________________________________________________ Explanation of HOLGR in AIPS version 31DEC99 HOLGR Type: Task Use: HOLGR processes holography data. It Fourier transforms the complex antenna pattern and to produce the complex voltage distribution in the aperture plane of the antenna. Data defining the amplitude and phase of the antenna pattern is obtained from a file. The input data consists of four free format ASCII encoded values per record: 1) Azimuth offset from source (degrees) 2) Elevation offset from source (degrees) 3) Amplitude (Volts or dB) 4) Phase (degrees) HOLGR can compute and apply a variety of corrections to the data: 1) The offset of the antenna vertex from the intersection of the azimuth and elevation axes. Such an offset produces a ramp in the antenna pattern phase. 2) A pointing offset. This produces a ramp in the aperture voltage distribution function. 3) The offset of the antenna feed. This produces a characteristic signature in the aperture voltage distribution function. Computation of the above corrections is predicated on reliable phase unwrapping; that is removing phase jumps of 360 degrees from the antenna pattern phase (for 1), or aperture voltage distribution function (for 2 and 3). HOLGR can reliably remove closed areas of phase discontinuities but does not attempt to resolve unclosed areas (see EXPLAIN). HOLGR provides a choice of Fourier transforms, either DFT (direct) or FFT (fast). For the FFT, the antenna pattern data may be interpolated onto a regular grid using a variety of interpolation functions specified in CPARM. Up to ten different AIPS image files will be produced according to the options specified in DPARM. In the following description, (x,y) are distances in the antenna aperture plane and (l,m) are the corresponding direction cosines. Do "EXPLAIN HOLGR" for a fuller description of the coordinate systems used. Adverbs: INFILE......Input visibility file name in the form AREA:FILE, where AREA is a directory logical name or environment variable, and FILE is an operating system specific file name. If INFILE = 'ANT' or is blank, then INFILE will be set to 'FITS:HOLOnn-mmssii' where nn is the moving antenna number and mm is the reference antenna number (= 0 if more than one reference antenna is used), ss is the Stokes, and ii is the IF. If INFILE contains only a logical name, as INFILE = 'AREA:', then 'AREA:HOLOnn-mmssii' will be used. The values of nn, mm, ss, and ii come from APARMs (9) and (10). OUTNAME.....Output image name (12 characters). If the last 7 characters are blank, they are set to 'nn-mmss'. OUTDISK.....Output disk number. UVTAPER.....Tapering of data during the gridding process: (1) Type: 1 Gaussian, 2 Exponential, 3 Linear (2) Radius in cells for taper of 0.5. 0 => N/3. (Remember that the max radius of the data must be < N/2 just to avoid aliasing.) OPTYPE......The model used for removing the effects of primary focus offset. 'PFOC' = Prime Focus. 'SUBR' = Cassegrain system. FACTOR......The magnification. Used only if OPTYPE = 'SUBR' Operating parameters: all are required (NO defaults). APARM(1)....Observing frequency (GHz). APARM(2)....Satellite elevation, degrees. Set = -1. for VLA data (true l,m); set = +1. for sky az,el; set = actual elevation for true az,el APARM(3)....Antenna diameter, in metres. Used only for blanking the phase map and computing the gain. APARM(4)....Subreflector diameter, in metres. Used only for blanking the phase map and computing the gain. APARM(5)....Focal length, in metres. This is used in correcting for the focus and feed offset, and in computing the surface deviation map. APARM(6-8)..Offset of the antenna vertex in (x,y,z) from the intersection of the azimuth and elevation axes, in metres. APARM(9)....10000 * Reference antenna number + 100 * 2nd (moving) antenna number + IF number. Used only for default names (i.e., if INFILE = 'AREA:') APARM(10)...Stokes ID (1 - 4 => RR, LL, RL, LR). Used only for default names (i.e., if INFILE = 'AREA:') Data reduction control parameters. BPARM(1)....Required map size, in metres. BPARM(2)....Number of pixels on a side of the output map (power of 2, maximum 512). BPARM(3,4)..Range of |l| and |m| to use for transform. BPARM(5)....Scaling factor for the input amplitudes. BPARM(6)....Fourier transform control. If negative, the phase read from the data file is negated. If the absolute value is 2, a direct Fourier transform will be done, otherwise, an FFT. BPARM(7,8)..Range of |x| and |y| used in correcting for pointing, focus, and feed offset. Negative values denote a range of SQRT(x*x + y*y). See also BPARM(9). BPARM(9)....Decimal encoded control parameters 1: Inhibit the "phase closure" part of the phase unwrapping of the antenna pattern (A_PHA) map. 2: Inhibit all phase unwrapping of A_PHA. 10: inhibit determination of a phase ramp in the l-m data and use APARM(6,7,8) instead, 100: Inhibit the "phase closure" part of the phase unwrapping of the antenna aperture (V_PHA) map. 200: Inhibit all phase unwrapping of V_PHA. 1000: inhibit correction for pointing, focus, and feed offset. 2000: inhibit focus and feed offset (but solve for pointing). 4000: Disable the zero phase offset term. BPARM(10)...Switch for logarithmic or linear data >= 0 for logarithmic data (as for PKS) < 0 for linear data (for the VLA). Regridding parameters. CPARM(1)....Type of interpolation to apply in gridding 'l'. 1: Pillbox, (don't use for regularly sampled data) 2: Exponential, 3: Sinc, 4: Sinc*Exponential, 5: Spheroidal (default). NEGATE to obtain natural weighting. (default = uniform) CPARM(2)....Support radius in l, in cells. CPARM(3-5)..Parameters defining the interpolation function in 'l'. Do HELP UVnTYPE for n=1,2,3,4,5. CPARM(6-10).Corresponding parameters for 'm'. Output option flags. The particular map will be stored if the associated DPARM is greater than zero. If all are <= 0, DPARM(4,5) will both be set to 1. DPARM(1,2)..Regridded amplitude and phase of the observed antenna beam voltage pattern (A_AMP, A_PHA). DPARM(3)....Weights used in the regridding procedure (WGT) - includes the weights for uniform (vs natural) weighting. DPARM(4,5)..Derived amplitude and phase of the aperture voltage distribution, (V_AMP, V_PHA). The focus model, if requested, will be removed from the phase image. DPARM(6,7)..Amplitude and phase of the point-spread function. This indicates the blurring in the derived aperture voltage map (P_AMP, P_PHA). DPARM(8)....Map of the phase corrections removed by the focus model (MODEL). DPARM(9)....Map of the surface deviations of the antenna (V_DEV). Units are in metres. The focus offset model, if requested, will be removed. DPARM(10)...The interpolated antenna power pattern (A_PWR). Explanation of HOLGR in AIPS version 31DEC99 Set it = to the desired interpolation factor, with anything >0 and < 2 => 2. Must be a power of 2 <= 2048 / NPIX, where NPIX = BPARM(2). Additional data reduction parameters. XPARM(1,2)..Cross-talk correction; a constant offset may arise in the observed antenna beam voltage pattern due to cross-talk between the signals from the reference and target antennas. This produces a spike of the specified amplitude and phase at the centre of the aperture voltage distribution map. XPARM(3-6)..Offset beam correction; large maps may sometimes encompass a nearby satellite which appears as an offset beam in the A_AMP map. This may be removed during data gridding by specifying the azimuth and elevation offsets (deg), and the amplitude factor and phase offset (deg). Uniform weighting must be used. XPARM(7)....Amplitude threshhold for unwrapping the V_PHA map. Pixels in the V_PHA map with corresponding amplitude in the V_AMP map below this threshhold will be treated as being blank for the purpose of phase unwrapping only. __________________________________________________________________________ HOLGR: Process antenna holography data. Author: Mark Calabretta Related tasks: HOLSR Coordinate systems: Antenna aperture coordinates are described by a right-handed system, (x,y,z), centred on the point of intersection of the azimuth and elevation axes. The xy-plane is parallel to the aperture plane; the x-axis is parallel to the elevation axis and increases to the right as the dish is seen from above. The y-axis increases towards the top of the dish; the z-axis points skyward more-or-less along the optical axis. (l,m,n) are the direction cosines which correspond to the (x,y,z) coordinates. Note that the (l,m) plane is projected onto the sky with the l-axis in the direction of decreasing azimuth and the n-axis towards increasing elevation. It is therefore left-handed as seen from the earth. The azimuth and elevation offsets in the data file refer to the position of the telescope beam on the sky. A POSITIVE azimuth offset samples a point in the antenna pattern at a NEGATIVE azimuth offset and this corresponds to a POSITIVE value of l. A POSITIVE elevation offset samples a point in the antenna pattern at a NEGATIVE elevation offset and this corresponds to a NEGATIVE value of m. If the satellite is at (Az0,El0) and the antenna is pointing at (Az,El) the (l,m,n) coordinates are l = sin(Az-Az0)*cos(El0) m = -cos(Az-Az0)*cos(El0)*sin(El) + sin(El0)*cos(El) n = cos(Az-Az0)*cos(El0)*cos(El) + sin(El0)*sin(El) Phase unwrapping: The algorithm used for phase unwrapping is based on an equivalence operator defined such that two pixels are equivalent iff there is a path between them which does not cross a discontinuity. The path is restricted to horizontal and vertical steps between neighbouring pixels. A discontinuity is defined as a phase step of greater than 180 degrees. This equivalence operator partitions the phase map into a number of equivalence classes referred to as "patches". Adjacent patches can be made equal to each other via the addition or subtraction of an integral multiple 360 degrees. While the algorithm is reliable it does not attempt to resolve open-ended discontinuities. The extent to which phase unwrapping succeeds can be judged by the "phase unwrapping index" reported before and after HOLGR attempts to unwrap a phase map. This consists of a simple count of the total number discontinuous boundaries between neighbouring pixels. In the "phase closure" part of the unwrapping algorithm these open-ended discontinuities are reduced to the shortest path connecting the end-points. __________________________________________________________________________