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Exoplanet Detection with an 8 LX200 Part 1
Preparation
The Aim
Position Now
Egress
Ingress
Mid Transit
Flux (or Mag)
Light from Host Star
Light from Control Star
UT Hours

• David Richards
• 2007-October

All pictures in this presentation are by the
author (unless specifically indicated) and were
taken with 8 LX200 / ST7e
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Exoplanet Challenge

• First exoplanet transit detection made in 1999 -
  HD 209458b
• HD 209458 (Osiris, 13 Pegasi ) Charbonneau et
  al 2000, Henry et al 2000 (from Hipparcos Images
  ?)
• Castellano et al (NASA Ames) demonstrated HD
  209458b transit detection with an 8 LX200
  telescope and ST7e CCD camera
• JAAVSO, Vol 33, No 1, 2004
• Same equipment as me !
• Same journal volume as a paper by D.Mais and
  myself on Mira variables !
• Led to a strong ambition to detect an Exoplanet
  for myself
• 14 more transiting exoplanets discovered
  2004-2007
• Its both feasible and now regularly proven that
  amateurs with CCD cameras and just moderately
  sized telescopes can detect transit events
• Ive made my own exoplanet detection attempts in
  2005 and 2006, but without firm success
• Requires ideal sky conditions and the highest
  possible precision (lt0.005 m)
• Im currently optimising my imaging setup and
  (with luck) hope to make a firm transit detection
  during the 2007/8 season.

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Table of Nearby Transiting Exoplanets (Jul 2007)
Note Most known transiting exoplanet sols are
visible from N. Hemisphere )
5 distant exoplanets (OGLE-TR-10,56,111,113,132)
in Sagittarius and Carina are not listed,
OGLE - Optical Gravitional Lensing Experiment
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My Own Equipment Setup
Meade 8 LX200 Goto Telescope
ST-7e CCD Camera
Equatorial Wedge
PermanentPier
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2005 Attempt HD 209458
60s exp (C Filter)
Planet HD 209458b around HD 209458 (Osiris)
Discovered in 1999 (followed up
1999-2004)Parent Sol is a 7.6 magnitude star in
PegasusOrbital period 3.52 days. Transit
duration 3 hours, Transit depth 0.0165 mag
Attempted Transit Observation in V Filters,
2005-08-08
Depth of magnitude dip being looked for
15s exposures (V Filter)
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2006 Attempt TrES-1
Av 3 x 20s exp (C Filter)
Planet TrES-1 around GSC 26521324 Jupiter sized
planet discovered in 2003-2004 (R.Alonso et
al)Sol 11.8 magnitude star in Lyra (lying at
500 ly distance)Orbital period 3.03 days.
Transit duration 2.5 hours, Transit depth
0.023 mag
Attempted Transit Observation in C Filters,
2006-08-08 / 09
30s exposures (C Filter)
End Transit(predicted)
Mid Transit(predicted)
Depth of magnitude dip being looked for
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Improving my chances

• Transit Opportunities - Dates/Times /Airmass
• Screening worksheet/charts
• Baseline Images for each candidate
• Central Image Positions, Reference Stars,
  Exposure Times
• Better Flat fields
• Not realistically feasible with current focuser,
  due to gravity droop on CCD camera(option to
  invest in new heavy duty focuser, but avoiding at
  this stage)
• Anti-Dew System
• New power source installed in early 2007 has
  fixed previous problem with dew heater
• Reduction in star drift / keep stars fixed on
  same pixels
• Improved Polar Alignment (aiming for less than 1
  arc min, current misalignment is 3.4 arc min )
• Guiding between frames with new script that is
  robust to passing cloud
• Robust Software / Procedures
• Software thats going to work on that one ideal
  night when conditions are perfect
• Focus / FWHM monitoring
• Script to monitor FWHM / sky brightness in
  realtime
• Better prediction of Clear Weather Good Seeing
• Weather forecasts / Jet Stream monitoring

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Screening Transit Opportunities
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Screening Transit Opportunities
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HD 189733 good candidate
in Vulpecula mag 7.67, transit depth 0.025
magref star mag 8.1
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Results from guiding between frames
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Practice Photometry (non exoplanet star)
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Weather
Total Cloud Cover Forecast for Sun Sept 2nd,
2300 (2 ½ days prior)
Total Cloud Cover on Sun Sept 2nd, 2300 (on
the day forecast)
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Latest Attempt WASP-1
Transit Depth of magnitude dip being looked for
(0.011 m)
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Pointing Accuracy during WASP-1 Transit Attempt,
2007-09-14
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How close ?
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HD 209458 opportunity, 2007-11-18
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HD 189733 opportunity, 2007-10-16
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