What is sidereal?

[bloodhound31]

Any clues? My telescope is asking me for a % of sidereal. I hazard a guess that this is pretty important for tracking?

Standing by the scope awaiting answers.

Baz.

[Dennis]

Sidereal Rate (http://en.wikipedia.org/wiki/Sidereal_time) is the tracking rate relative to the fixed stars. A Sidereal Rate of x1 means your mount would make 1 complete revolution in a Sidereal Day of 23H 56M.


A mean Solar Day is 24 hours.
A mean Sidereal Day is 23H 56M, some 4 mins shorter.
For auto guiding, I generally use a correction speed of between x0.5 and x0.9 Sidereal Rate.
Tracking (as opposed to auto guiding) is usually x 1 Sidereal Rate.

Cheers

Dennis

[bloodhound31]

Thanks Dennis. Now I just have to work out how to apply it to my particular scope.

Baz.

[Dennis]

Hi Baz

By default, when I power up either my Vixen or Tak German Equatorial Mount, they track at the sidereal rate.

To change the tracking rate to e.g. Sun, Moon tracking, I have to select those options from the menu or make a button press.

If I am auto guiding, menu options and button presses allow me to adjust the guide star correction rate (not tracking rate) from x0.1 to x0.9 sidereal tracking rate.

Cheers

Dennis