JCMT Pointing

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	General topics : current performance, problems, fact sheet
	Catalog : a caution re extended sources
	Pointing model : data acquisition and handling
	Inclinometry - measuring track irregularities
	Other things affecting pointing - e.g. : refraction, seeing
	Pointing Documents : including recent reports
	Pointing of other mm/sub-mm telescopes
	Time issues

Latest News: (rmsdaz, rmsdel) = (1.2", 1.6")     (FE=RxA,   N=17)

General Topics

• General description of the pointing of the JCMT
• Latest Fact Sheet - the latest dedicated pointing run, and links to previous runs
• PROBLEMS - old and new
• History -
  • . . . of events affecting pointing
  • . . . of residuals with SCUBA and the heterodyne FEs
• Pointing catalog - blazars, UCHIIs, line sources.
  • Notes on Individual sources
  • Upgrade to J2000 - The case of the blazars
  • Distribution of blazars
  • (Optical) Finding charts for AGN
  • ICRS - the International Celestial Reference System; the foundation of all these positions.

THE POINTING MODEL

• The 7 parameters of the basic model - their algorithmic forms and illustrations showing their effects on the pointing residuals.
  • Parameter Derivation : A comparison of FIT9 with TPOINT
  • Clock errors, and how to check the ASM clock.

• Data Acquisition
  • Pointing run tactics
  • The LOGGER task
  • TPOINT data format
  • Observational considerations
  • Discrete pointing observations
    • The heterodyne FIVEPOINT command
    • Heterodyne spectral line pointing
    • The SCUBA POINTING command
      • - The benefits of on-line REMSKY
  • Continuous Tracking Experiments
    • Heterodyne tracking using fives
    • SCUBA tracking using map16.t

• How to Plot JCMT Pointing Data

• Data Processing
  • The analysis of JCMT pointing data is done with TPOINT
    (try here or here if the local .ps version doesn't work).
    The use of TPOINT is also described by Pat Wallace at his commercial website.
  • Single pointings may be used to update the collimations.

• Updating the model

Inclinometry - what it is, and where you do it. Example data, and the track model.

• Trouble-shooting
• Taking data
  • locally
  • remotely
  • transit-inclinometry -- see the transit step archive.
  • Protocols & safety instructions to accompany remote inclinometry activities
• Format of inclinometry output
• How to reduce inclinometry data and install a new track model.
• Azimuths of wheel-joint interactions
• Prediction of pointing errors from track model parameters (F1,F2,F3)
• Roll
• Yaw
• Constructing a hybrid model
• Strain gauge data

Other quantities affecting pointing :

• Refraction
• thermal effects
• SMU & TMU alignment
• Water Vapour Meter archive (since ~ Feb 2004)
• Opacity archive and Opacity & Seeing GUI
• Seeing analysis by Jason Stevens (1995)

Documents

• Pointing Project Documents
• Search for documents on 'pointing' in JACdocs on 01 Nov 2000
• Annual Reports
  • 1996             1997
• Reports to the JCMT Board
  • 1997 April             1997 October            
    1998 October            
    1999 April             1999 October            
    2000 April             2000 October
    2002 October        
    2003 April             2003 October        
    2004 March           2004 September        
    2005 April             2005 October        
• Occasional Pointing Reports
  • 1996           1997           1998           1999          
  • 2000           2001           2002           2003          
  • 2004           2005          

• Pat Wallace's TPOINT program - and a comparison with FIT9.

• CSO
• SEST
• IRAM 30m - see A.Greve et al, 1996, A&ASuppl. 115,379.
• HHT - 1" rms absolute.
• OVRO - Array pointing, by Steve Scott (1993).
• AST/RO at the South Pole (requires access to electronic PASP).
• KOSMA (in German)
• LMT

Time

• IERS central Bureau
• Clock errors, and how to check the ASM clock.
• NIST page on time
• IRIG-B coding of time signal
• The U.S. Naval Observatory - keepers of the Master Clock.
• The IERS product Bulletin A provides UT1-UTC for updating the TCS pointing model. Predictions for the upcoming month or so have been used in the past with no noticeable loss of pointing accuracy. Updating THI.tide any more frequently would be tedious. I also receive this file by email once a week or so - see the main IERS page for their Request form.
  See also How to get UT1-UTC.
  
• For other Earth rotation parameters see the IERS Earth Orientation Parameters product centre. (eg Click on 'EOP combined series' then Series of the current year').
• Watch the USNO pages or IERS for announcements/status of Leap Seconds.