Automated Variable Star Observing and Photometric Processing at the

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Automated Variable Star Observing andPhotometric
Processing at the
Dave Lane (RASC, AAVSO and SMU Astronomy/Physics)
AR2007 July 1, 2007
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Abbey Ridge Observatory
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Goals

• To do differential variable star observations
  automatically, as specified by simple text files
  containing the parameters of the target fields
  and observing lists for the night
• To automatically calibrate, combine, and perform
  the aperture photometry (a processing pipeline)
  of a nights observations, as specified by simple
  text files containing the parameters of the
  target fields
• To participate in a variable star observing
  program using the above (therefore requiring
  minimal ongoing time commitment from me)
• To make the developed software tools generalized
  enough so that others could use them

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Abbey Ridge Auto Pilot

• Abbey Ridge Auto Pilot (ARAP) is the core
  software that automates my observatory and its
  data processing pipeline.
• Uses Daves Telescope Language (DTL), an
  observatory language that makes it very easy to
  control all observatory and processing functions
  using (nearly) plain English scripts
• It is entirely custom software (about 20,000
  lines) written in Borland Delphi (based on the
  Pascal language)
• Includes all commonly-available language features
  (if..then, goto, variables, subroutines, file
  i/o, simple math, etc.)
• Interfaces with telescope, focuser, and dome
  using the ASCOM standard
• Interfaces with the CCD camera using the
  scripting functions of MaxIm DL
• Includes many advanced features such as
  astronomical calculations (positions of sun,
  moon, planets, comets, asteroids,
  altitude/azimuth, airmass, Julian date, etc.)
• And it does plate solving, image calibrations,
  aperture photometry, uploading files to the
  internet, sending emails, etc.
• Currently has over 100 commands and growing

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Automated Variable Star Observing

• Two hours of shutter time/night are allocated to
  Turner/Majaess (rest is devoted to supernova
  searching as part of the Tim Puckett team)
• Fields to be observed are sent by the observer
  in a prescribed format
• Each field is specified by a unique identifier,
  the centre RA/Dec, exposure times, and number of
  exposures in each filter
• Observations are grouped in batch text files
  and sprinkled through the night
• After the dome closes darks, biases, and dome
  flats are automatically taken

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Automated Variable Star Observing(Observing
Process)

• For each field
• Is it clear? (park scope and wait if not)
• Is it fully dark?
• Is the field altitude gt 25 degrees?
• Is the field gt 25 degrees from the Moon?
• Is the field not too close to the meridian (ARO
  issue)
• Goto field, image field 30 seconds, solve plate,
  sync scope, and re-centre
• Take X exposures for Y seconds in each filter
• Update observing log
• Auto-focus once every hour
• Repeat for all objects in the batch
• Send email to observer

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Automated Variable Star Observing(e-mail log)

• 2007-05-08 223101 Start of observing log for
  early.txt
• 2007-05-08 223603 NGC2281 has been observed in
  V
• 2007-05-08 224528 NGC2281 has been observed in
  B
• 2007-05-08 225054 HD96x has been observed in V
  
• 2007-05-08 225737 HD96x has been observed in B
  
• 2007-05-08 230229 HD97x has been observed in V
  
• 2007-05-08 230913 HD97x has been observed in B
  
• 2007-05-08 233318 SAO15264e has been observed
  in V
• 2007-05-08 233922 HD96x has been observed in V
  
• 2007-05-08 234606 HD96x has been observed in B
• 2007-05-08 235822 End of observing log for
  early.txt
• 2007-05-08 235825 Start of observing log for
  later.txt
• 2007-05-08 235825 NGC2281 is too low at
  18.8470955936 degrees
• 2007-05-09 000653 HD96x has been observed in V
  
• 2007-05-09 001337 HD96x has been observed in B
  
• 2007-05-09 001903 HD97x has been observed in V
  
• 2007-05-09 003107 It has become cloudy,
  waiting for clear...
• 2007-05-09 010131 Clouds persisted - variable
  star group later.txt was aborted
• 2007-05-09 010131 End of observing log for
  later.txt

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Automated Processing Pipeline

• For each field appropriate parameters are
  determined ahead of time and included in a
  simply-formatted text file
• Reference, check, and other objects are selected
• Precise positions of selected stars are
  determined
• Appropriate initial aperture, gap, and sky
  annulus parameters are determined
• Which fields are processed is based on the
  successful observing log for the night

Gap
Aperture
Sky annulus
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Automated Processing Pipeline(parameter file
format)
Object_Name Next_Object_Line "Comment" Field_RA
Field_Dec V_Exptime Num_V_Exposures B_Exptime
Num_B_Exposures Do_Photometry_Flag (true or
false) Auto_Aperture_Ratio (0 if off)
Aperture_Radius Gap_Width Annulus_Thickness Object
_RA Object_Dec "Reference Name" Reference_RA
Reference_Dec Reference_V_Mag Reference_B_Mag Num
of Other objects "Name of Other1" Other1_RA
Other1_Dec "Name of Other2" Other2_RA Other2_Dec
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Automated Processing Pipeline(parameter file
example)
HD344787 29 "HD344787 - Possible Small-Amp Cep -
Vul" 19.72751 23.21037 18 20 -1 0 true 3.5 5 7
4 19.7248293 23.177951 "ref1" 19.723084 23.21062
11.74 -1 3 "Check2 (TYC 2139 01475 1)" 19.7300370
23.189212 "TYC 2139 02216 1" 19.7283125 23.269618
"Object2 (TYC 2139 01120 1)" 19.7312985
23.194615
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Automated Processing Pipeline(procedure)

• Master bias, dark, and flat images are prepared
• For each field
• Individual images are dark, bias, and flat frame
  calibrated
• Multiple images of the same field are registered
  and combined using the new Lane-Majaess clip
  algorithm
• Combined images are plate solved so that the
  x/y coordinates of specific stars can be easily
  found
• The reference stars FWHM is measured and used to
  set the photometry aperture for the frame based
  on a specified ratio (the gap is automatically
  adjusted to keep the annulus at a fixed
  position)
• Aperture photometry is performed on all stars of
  interest
• Differential magnitudes and other diagnostic data
  are written to an Excel-compatible file
• Repeat for each field
• E-mail observer a message with the processing
  summary
• Upload processed/combined images and photometry
  data to a web site

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Automated Processing Pipeline(status email)

• Variable star processing has completed - details
  are below
• This is the processing log for D\aroimages\200704
  01\variablestars\varlog.txt
• V photometry error for Berk59 in file
  Berk59-1V-LMAVE.fit
• B photometry error for Berk59 in file
  Berk59-1B-LMAVE.fit
• Plate solve error in file HIP56732e-1V-LMAVE.fit
• Plate solve error in file HIP56732e-1B-LMAVE.fit
• Plate solve error in file RTAur-1V-LMAVE.fit
• V photometry done for ABCam in file
  ABCam-1V-LMAVE.fit
• B photometry done for ABCam in file
  ABCam-1B-LMAVE.fit
• V photometry done for GSC3729-1127 in file
  GSC3729-1127-1V-LMAVE.fit
• B photometry done for GSC3729-1127 in file
  GSC3729-1127-1B-LMAVE.fit

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Automated Processing Pipeline(summary)

• The diagnostic data provides information that
  can be used to reject or qualify suspect data.
• This pipeline saves a great deal of work, but
  more importantly it takes most of the human
  error out of the equation and ensures that every
  observation is treated in a consistent fashion.
• We have used this capability to re-process all of
  the data collected last fall and the results were
  better than what was obtained by earlier manual
  processing.

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Some Sample Light Curves(built up over 1.5-4
months and phased)
Standard deviation of check star ranges from
0.009-0.017
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Usage Requirements

• Maxim DL/CCD (Diffraction Limited)
• PinPoint Astrometric Engine (DC3 Dreams)
• Abbey Ridge Auto-Pilot (me)
• ASCOM-compatible telescope, focuser, etc.
• FocusMax (Weber and Brady)
• Boltwood Cloud Sensor (optional)
• Windows 2000/XP

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Future Work

• Intelligent observation scheduling
• Output data also in AAVSO reporting format!

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The End
Special thanks to Doug George, Ajai Sehgal, Bob
Denny, Larry Weber, Steve Brady, Paul
Boltwood Co-conspirators Daniel Majaess and Dave
Turner

• Website www.davelane.ca/aro