that´s me in thermal infrared

Graphical Display of Periodic Errors

 
date
(yy/mm/dd)
exp. time
(min/sec)
CCD / telescope Mount Remarks

Celestron 8 fork mount

Celestron 8 fork mount

00/09/29

150 x 2 sec

Starlight SX

C8 + Focal reducer
@ f /5.6

original Celestron 8
(orange) fork mount
(build 1982)

before azimuth correction

  • periodic error ± 30 arcsec

  • period about 5 ½ min

  • maximum unguided exposure time about 60 sec ( 1 out of 5)

Celestron 8 fork mount

Celestron 8 fork mount

00/10/07
250 x 2 sec

Starlight SX

C8 + Focal reducer
@ f /5.6

original Celestron 8
(orange) fork mount
(build 1982)

after azimuth correction

  • periodic error ± 30 arcsec

  • period about 5 ½ min

  • maximum unguided exposure time about 60 sec ( 1 out of 5)

 

Losmandy CG 11

Losmandy CG 11

00/10/19 165 x 2 sec

Starlight SX

C8 + Focal reducer
@ f /5.6

Losmandy CG 11

before azimuth correction

  • periodic error ± 3...6 arcsec

  • period about 30 ... 40 sec

  • maximum unguided exposure time about 10 sec ( 1 out of 10)

The deviation of the declination from a straight line is produced by the seeing which is always in the same order of 1 ... 2 arcsec for this short exposures.

The slope of the declination line is a measure for the misalignement of the polar axis in azimuth (the images were taken near the meridian).

The overall slope of the right ascension line is a measure for the incorrect speed of the mount. This is a special problem with the Celestron 8 fork mount with its modified Tuthill drive corrector (enlarged scope of minimal [about 20 Hz] and maximal [about 100 Hz] correction speed). The correct speed of 50 Hz can only be set by a potenziometer(?, regulator) without a notch(?) while observing the beat of a LED. When it shines with constant light you have reached 50 Hz.


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