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CCD Images - Session 205 (2007-08-18)

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Objects Session Notes
Bullet WASP-1 (GSC 2265:107 ) - Parent Star to Exosolar Planet
Bullet Astrometric & Photometric Monitoring
- SS Cyg (Dwarf Nova)
- BL Lac (Blazar)
- Session duration 0.9 hr, cut short by deteriorating sky conditions
- CCD operation of -15 degC (at 75% average cooling). .
- main objective was to acquire replacement  baseline images of specific exosolar planet host star WASP-1
- secondary objective was to acquire images of selected variable stars and nearby stars for ongoing photometric and astrometric  monitoring.
(due to sky conditions in what only possible to acquire images of BL Lac & SS Cyg before the session was halted)
- it had also be hoped to perform further polar alignment checks using Drift Method, but cloud/poor sky opacity below 40 deg inclination prevented this task.
- More Notes
-

WASP-1 (GSC 2265:107) - Parent Star to Exosolar Planet

Baseline images of WASP-1 parent star (GSC 2265:107) as part of a project to attempt to detect the transit of an exosolar planet using my 8" LX200 scope. 

WASP-1  (GSC 2265:107) (Andromeda)
Image
Annotated CCD Image 
3 x 45 sec exposure (median combine), 2x2 binning, C Filter
2007-08-18 00:20h UT (#205011-15)
 
Reference Stars
Image
Annotated CCD Image 
60 sec exposure, 2x2 binning, R Filter
2007-08-18 00:24h UT (#205017)

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WASP-2 (GSC 522:1199)  - Parent Star to Exosolar Planet

Baseline images of WASP-2 parent star (GSC 522:1199) were acquired as part of a project to attempt to detect the transit of an exosolar planet using my 8" LX200 scope. WASP-2b was recently discussed to orbit this star. 

WASP-2 (GSC 522:1199)  (Delphinus)
Image
Annotated CCD Image 
3 x 60 sec exposure (median combine), 2x2 binning, C Filter
2007-08-14 00:32h UT (#203232-36)
 
Reference Stars
Image
Annotated CCD Image 
45 sec exposure, 2x2 binning, R Filter
2007-08-14 00:30h UT (#204233)

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Polar Alignment Check

Polar Alignment Check was made by taking a two baseline/check image pairs separated by 3 minutes (one for a point Due South at Dec 0 deg and a second point approximately Due West and around Dec 16 deg). Results were as follows :

    South Sky Point :  Northwards Drift at a rate of 1.64 arc secs/min 
        (equivalent to Polar Misalignment of 6.28 arc mins in Azimuth, 
         scope's polar axis needs turning clockwise by 6.28 arc mins)

    West Sky Point :  Northwards Drift at a rate of 0.81 arc secs/min 
        (equivalent to Polar Misalignment of 3.11 arc mins in Inclination
         scope's polar axis needs raising by 3.11 arc mins)

Polar alignment is not off by far, but benefits would come from improving it. 
  Aim is to improve Polar Alignment to allow longer image exposures (for gallery image) and to help reduce errors associated with high precision photometry of exoplanet transits. The later will require stars to be maintained on the CCD images at the the same pixel location. Autoguiding between frames will be utilised to help maintain stars at fixed positions, but precise polar alignment will help reduce errors associated with small but still significant field rotation.  Too help ensure the operation goes smoothly, further checks will be made, ahead of making a final Polar Alignment Refinement attempt. 

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Astrometric and Photometric Monitoring

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This Web Page: CCD Images - Session 205 (2007-08-18)
Last Updated : 2015-05-16
Site Owner : David Richards
Home Page : David's Astronomy Web Site