OfftheShelf Automation of a Small Optical Research Telescope

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Off-the-Shelf Automation of a Small Optical
Research Telescope
Presented at the 207th Meeting of the American
Astronomical Society
K. Phillip Nelson1, Ken P. Portock1, John H.
Simonetti1, Brain Dennison2, Greg A. Topasna3,
Jay Billings1, Philip J. DeSena1
1Physics Dept., Virginia Tech 2Physics Dept.,
UNCA 3Physics Dept., VMI
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Abstract
Automation of astronomical observatories is an
important part of modern research. Unmanned
observatories allow for repetitive observations
to be completed in an efficient and timely manner
that cannot be accomplished with a manually
operated system. However, observatory control
techniques appear in a variety of forms. Not all
automation requires high-end electronics,
sophisticated control mechanisms or expensive
components to operate. Using off-the-shelf
hardware and producing many of the components
in-house reduces the expense and gives the user a
better understanding of how the various
components will interact. Many of the
considerations of observing are the same from one
observatory to the next, although the techniques
used to solve these issues at one observatory may
not be suitable at another. Here, we describe
how some of the basic observing considerations
were handled in automating the Virginia Tech
Spectral-line Survey.
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Reasons to automate VTSS(or any observatory!)

• Repetitive (Multiple, extended exposures of same
  field)
• Flexible schedule (Cant observe during twilight
  or if moon is up)
• Increase productivity - decrease down-time
• Improve data quality

• Less travel to observatory
• Fewer unused nights (Due to early AM moonset,
  short observing window)
• Other time conflicts (Personal obligations,
  Illness, etc.)

• Remote location (No city lights)
• Repeat steps exactly (Reduces human error)
• Instrumentation is constant (Always use same
  camera, filter set)
• Data acquisition procedures dont change

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Components of an Automated Observatory

• Mount
• Telescope or Camera lens
• CCD
• Control software
• Environmental monitoring equipment
• Power recovery (or safe shut-down) equipment
  i.e., UPS
• Enclosure (dome or shed w/ roll-off roof)

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Types of Telescope Control

• Manual (MT) not robotic
• Computer Controlled (CT) PC controls mount,
  camera
• Robotic (RT)

• Dumb Mode (RT-M) User _at_ telescope PC
• Basic (RT-B) CT w/ scripting
• Remote Accessibility (RT-RA) Upload observing
  requests
• Real Time Interactivity (RT-RTI) Remote user
  interactivity

VTSS can be run in any robotic mode.
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A Typical Observing Session

• Simulation program (SLICARsim)
• Load field list onto observatory computer
• Run SLICAR, Polaris monitoring program

• Modified version of SLICAR
• Creates text file (e.g., 05_01_12.OBS) list of
  fields to observe
• File fields to observe calibration fields
  (known intensity)
• Entry RA DEC, field name, filter, exposure
  time (min.), no. exposures
• Example 05 56 00 -09 32 00 Orio10
  2 6 6
• Simulate an observing session
• Can field be seen (hour angle, altitude limits)?

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S L I C A R

• Spectral Line Imaging Camera Automation Routine
• Authors P. Nelson, K. Portock, J. Simonetti, B.
  Dennison
• Primary control program
• Language PERL
• Manual control (from menu by user) or automated
  (remote)
• Controls peripheral programs

• TheSky6 Mount/camera position
• CCDSoft Acquire save images, regulate
  temperature
• BASIC Stamp IIe Filter, focus, roof control
  (PBASIC routines)

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Control Flow
Polaris Monitor
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SLICAR Control Flow
Launch programs TheSky6, CCDSoft, PERL modules
Wait to start Observing time based on moonrise
twilight
Read .OBS file?
File not found
Read file
Clear or Cloudy? Check Polaris Monitor output file
Clouds
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Clear
Slew to coordinates
Select Filter
Focus
Expose Image multiple times
Shut down Wait until new close misc. programs
roof
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Off-the-shelf components

• FOCUS OPTICS
• Brass ring gear
• Stepper motor from PC disk drive
• Worm gear
• Noct-Nikkor lens (58mm, f1.2)
• Custom-designed filter wheel
• Ha, SII, Dual-band filters

• POLARIS MONITOR
• ST-5 Camera controller (SBIG)
• PVC pipe (camera housing)
• Mounting hardware brackets, shelf
• PERL code
• (by J. Simonetti P. Nelson)

• CONTROL SOFTWARE
• PERL compiler modules
• (free from internet)
• IBM PC (built by R. Link T. Heath)
• PERL and PBASIC codes
• (by K. Portock, P. Nelson)
• BASIC Stamp IIe (Parallax, Inc.)
• TheSky6 CCDSoft
• (Software Bisque)

• CAMERA MOUNT
• Losmandy Gemini LV3 mount
• 25-L LN2 supply dewar
• Mesh hose mechanical valves
• (LN2 flow regulation)
• Photometrics CCD (LN2 cooled)
• and
• ST-10 camera (SBIG air/H2O cooled)

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Mount (Gemini Losmandy)
Declination gear
Right Ascension gear
Ha and White light box flat-field correction
images

• Level 3 Software
• Run via Software Bisques TheSky6
• Manual control w/ hand paddle

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Focus
Noct-Nikkor lens f1.2, 58mm lens
Brass ring stabilize gear
Stepper Motor From PC floppy drive
Worm gear Focus rotations (200 steps/rev. of
stepper motor)
Brass gear 360 teeth
Precision 0.005o per step of motor backlash
0.001 5 steps)
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Enclosure w/ Roll-off Roof
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Polaris Brightness Monitor(Cloud Monitor)

• SBIG ST-5 CCD camera (320 x 240 CCD chip)
• Full diurnal motion of Polaris contained on CCD
  chip
• Measure of sky transparency (cloud cover)
• No moving parts (i.e., stationary mount)
• Sealed in PVC pipe, mounted to back of control
  room building
• Separate PERL program to control exposure and
  processing
• Images taken 1 min. intervals.
• 3x3 Median Binning of image no dark or
  flat-field images
• Important Output location of bright pixel,
  average amplitude
• 5-min running avg. determines clear/cloudy
  (Output read by SLICAR)

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Cloud Monitor (Polaris Monitor)
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Unbinned Polaris Image
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• References
• Advantages of Automated Observing with Small
  Telescopes, Eaton, J. A., Henry, G. W., Fekel, F.
  C., Tenn. St. Univ.
• Categories of Robotic Telescopes
  (http//www.phys-astro.sonoma.edu/observatory/robo
  scope/)
• Devices for Observatory Automation, Honeycutt, R.
  K., Adams, B. R., Swearingen, D. J., Kopp, W. R.,
  Publications of the Astronomical Society of the
  Pacific, June 1994
• Planning Your Observatory (http//www.opticalmecha
  nics.com/telescopes_and_observatories.htm)

Acknowledgments Construction, automation and
image acquisition analysis has been supported,
in part, by NSF grant AST-9319670 and a grant
from the Horton Foundation to Virginia Tech.
http//www.phys.vt.edu/halpha/