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Exoplanet Detection with an 8” LX200 : Part 1 : Preparation

Exoplanet Detection with an 8” LX200 : Part 1 : Preparation. The Aim. Position Now. Egress. Mid Transit. Ingress. David Richards 2007-October. Flux (or Mag). Light from Host Star. Light from Control Star. UT Hours.

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Exoplanet Detection with an 8” LX200 : Part 1 : Preparation

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  1. Exoplanet Detection with an 8” LX200 :Part 1 : Preparation The Aim Position Now Egress Mid Transit Ingress David Richards 2007-October Flux (or Mag) Light from Host Star Light from Control Star UT Hours All pictures in this presentation are by the author (unless specifically indicated) and were taken with 8” LX200 / ST7e

  2. 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 • It’s both feasible and now regularly proven that amateurs with CCD cameras and just moderately sized telescopes can detect transit events • I’ve made my own exoplanet detection attempts in 2005 and 2006, but without firm success • Requires ideal sky conditions and the highest possible precision (<0.005 m) • I’m currently optimising my imaging setup and (with luck) hope to make a firm transit detection during the 2007/8 season.

  3. 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 ]

  4. My Own Equipment & Setup Meade 8” LX200 Goto Telescope ST-7e CCD Camera Equatorial Wedge PermanentPier

  5. 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)

  6. 2006 Attempt – TrES-1 Av 3 x 20s exp (C Filter) Planet TrES-1 around GSC 2652:1324 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

  7. 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 that’s 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

  8. Screening Transit Opportunities

  9. Screening Transit Opportunities

  10. HD 189733 – good candidate in Vulpecula mag +7.67, transit depth 0.025 magref star mag +8.1

  11. Results from guiding between frames

  12. Practice Photometry (non exoplanet star)

  13. Total Cloud Cover Forecast for Sun Sept 2nd, 23:00 (2 ½ days prior) Total Cloud Cover on Sun Sept 2nd, 23:00 (on the day forecast) Weather

  14. Latest Attempt : WASP-1 Transit Depth of magnitude dip being looked for (0.011 m)

  15. Pointing Accuracy during WASP-1 Transit Attempt, 2007-09-14

  16. How close ?

  17. HD 209458 opportunity, 2007-11-18

  18. HD 189733 opportunity, 2007-10-16

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