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Total Lunar Eclipse

Total Lunar Eclipse. March 2007 Simon Dawes CMHAS. Site. Sex. Hya. P1 20:18:11 UT U1 21:30:22 UT. 19:48 – 22:35. Thought you would get away without some maths…. Why are the Images so poor?. Dawes Limit of Camera Lens = 2.4” Moon angular size ~ 1800” Therefore 1800/2.4 = 750

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Total Lunar Eclipse

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  1. Total Lunar Eclipse March 2007Simon Dawes CMHAS

  2. Site Sex Hya www.itslifejim.btinternet.co.uk

  3. www.itslifejim.btinternet.co.uk

  4. www.itslifejim.btinternet.co.uk

  5. P1 20:18:11 UTU1 21:30:22 UT www.itslifejim.btinternet.co.uk

  6. 19:48 – 22:35 www.itslifejim.btinternet.co.uk

  7. Thought you would get away without some maths… www.itslifejim.btinternet.co.uk

  8. Why are the Images so poor? • Dawes Limit of Camera Lens = 2.4” • Moon angular size ~ 1800” • Therefore 1800/2.4 = 750 • Double sampling = 1500 pixels • So I should be able to support a Lunar image of 1500x1500 pixels… www.itslifejim.btinternet.co.uk

  9. However… 23 Pixels www.itslifejim.btinternet.co.uk

  10. Therefore… • The image is smeared out by the lack of tracking and seeing conditions(px res = 2”, 2s exp = 30arc” = 15 px) • 1500/15 = 100 Pixels • So an Image 100x100 pixels should be enough to capture all the information… www.itslifejim.btinternet.co.uk

  11. 800 pixels 100 pixels www.itslifejim.btinternet.co.uk

  12. Original 800x800 www.itslifejim.btinternet.co.uk

  13. 800x800 recovered from 100x100 www.itslifejim.btinternet.co.uk

  14. Conclusions • The maths does describe the optical performance quite well. • To take decent images of the moon at the maximum resolution you do need to track the sky. • I need a dew heater! • To create high quality time lapse video you need to take images more regularly than every ten minutes for a lunar Eclipse (estimate every minute) www.itslifejim.btinternet.co.uk

  15. Thank You www.itslifejim.btinternet.co.uk

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