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I do tend to get carried away, I still find it fascinating that time is a totally human invention, calendars and such are simply what we choose to say they are. This is why no one can agree on how to come to the current time. What I just to like about astronomy where the endless arguments over mundane things, like how long an astronomical second should be.

Well back to the subject of guns in another tread….

jimlongley wrote:

mcub wrote:Well if you want to get serious move to Local Side Real Time.


It verys by Log. Lat. and Elevation !!

sidereal, one word, not two.

Sidereal time, calculated from the apparant motion of the vernal equinox, relates only to longitude, not lattitude or elevation. Sidereal time, is by definition, local to the meridean, but is the same all the way along that meridean.

You may be referring to "True Local Time" which may also be referred to as "Solar Time" and "Apparant Solar Time" according to who you are talking to, an astronomer, an astrologer, or someone else who has need or interest in determining the apparant time at any particular location on the face of the earth. The term "True Local Time" is primarily used by astrologers and does use a spherical geometric calculation based on sidereal time, lattitude, and elevation.

BY definition yes, but to align a telescope the apparent angle to the horizon is offset by elevation in relation to scopes distance to the earth’s rotational axis. Hence the higher your elevation, the greater the adjustment for the parallax error from the theoretical horizon to the actual one. Naturally as you move "UP" or "Down" if in the southern hemisphere, in latitude, the closer to the axis you become. Since all star charts are based on RA/DEC to the theoretical horizon at sea level on the equator, most astronomers offset sidereal time with LAT & LON and Elevation. It is simply easier than adjusting the RA/DEC for your location every time you want to center your CCD on a new object.

Remember it is called Local, as it is based on concept the clock starts when the target star "Shows on the horizon"

Perhaps it have been more accurate for me to have said try using LocalSide real time,

Also my spell checker forces the words apart when I copy and paste.

Well if you want to get serious move to Local Side Real Time.


It verys by Log. Lat. and Elevation !!