Comets

Project Aims

• to determine the orbital parameters (and their associated uncertainties) of a set of comets from astrometric measurements
• to determine the structure of the targetted comets (e.g. size, brightness)
• to determine the brightness limit for studies of comets with the AstroLab telescopes/CCDs

Project Notes

1. Learn how to use the telescope and CCD system efficiently

   • Attend the observing training sessions
   • Undertake the CyberSky "Patterns of motion in the Sky" exercise to refresh your understanding of the apparent movement of objects in the night sky
   • Study the provided reference material on the telescope, CCD and the software

2. Research background material

   • Understand the aims of the project
   • Study the Web-based information linked from the provided References page
   • Revise the material covered in the "Observational Techniques" part of Level-2 "Stars and Galaxies" module
   • Read Chapter 7 (Astrometry) of "The Handbook of Astronomical Image Processing" by Berry and Burnell
   • Search out additional sources of information

3. Plan your project

   • Select at least two suitable comets
   • Determine when they can be best observed
   • Estimate the likely exposure times required for your targets
   • How many observations will you need?
   • Plan your project write-up; consult the DUO online Report Format Guide and Marking Criteria

4. Write-up the "Introduction and Background" sections of your project

5. Understand how astrometric measurements are made

   • Measure the positions of a few comets on archival CCD images
   • Study Herbert Raab's paper on "Detecting and Measuring faint Point Sources with a CCD"   (local copy)
   • Assess the random and systematic uncertainties in your astrometric measurements
   • Write-up your conclusions for your report

6. Observe your targets regularly, as the weather permits, during the term and measure their astrometric positions relative to stars on the CCD images

   • Ideally you will be able to observe your target comets on about seven separate occasions during the term
   • On the best Moonless nights try longer exposures in order to measure the fainter structures, e.g. the tail
   • How do your measured positions depend on the choice of stars used to define the astrometric mapping?
   • How do your measured comet positions compare with those given by JPL's HORIZONS System?
   • Write-up your results and conclusions

7. Use the find_orb programme for orbit determination

   • Demonstrate that find_orb gives reliable results
   • Assess the random and systematic uncertainties of find_orb
   • Determine the orbital parameters (and their uncertainties) of your targets
   • Compare your values to the recognised values
   • Research other methods for orbital determination
   • Write-up your results and conclusions

8. Determine structure (e.g. size, brightness, appearance) of your comets

   • How does the brightness and size of the comets change during the observation period and is this as expected?
   • How do your results compare with those reported on the Web?
   • Write-up your conclusions
9. Make observations of a few faint comets to assess the brightness limit of the experiment

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jrl

2020-Jun-17 13:46:07 UTC