Angle of polar mount in Dublin ?

Capt'n Midnight

I want to setup a pole with a few dishes on it, non-motorised so I can leave dishes pointing at the usual suspects whilst having the option to point them elsewhere easily enough. - Anyone know a site that does these angles ?



What angle should the pole be at from vertical (elevation)
should it lean North South or what Azimuth should I use.




I remember finding stuff about this before and the the angle is a compromise because the tracking arc is slightly different to the arc the satellites are seen to be on.

seano

As regards the pole.

90 degrees from the ground.

In otherwords straight right angle. pointing to the heavens.


I hope you find other useful information in one of these links


http://www.satellite-calculations.com/

http://www.ctiinfo.com/SatControl/ComTrack/InclinedOrbitTutorial/satgeomt.htm

http://repairfaq.cis.upenn.edu/sam/icets/satellte.htm

and finally More then you need to know about satelliet

Capt'n Midnight

seano wrote:

As regards the pole.
90 degrees from the ground.
In otherwords straight right angle. pointing to the heavens.

You're missing the point - I won't be using rotators or actuators the dishes will be clamped straight to the pole. The dishes will be set for 0 degrees as the pole will supply the angle.

From the links above [ Thanks ] I get http://www.satellite-calculations.com/Satellite/lookangles.htm
Declination from horizontal plane (is this the right one ?)
Angle SAT
28.53 12.2
28.77 turksat 1c
28.63 astra 2
28.49 thor 2-3
29.41 direct inc 0.8

So does the pole just have to lean back north south at an angle of about 28 degrees with minor adjustments to get the strongest signal at the edges and centre of the rotation around it ?

seano

You are right i missed the point,
You can use a straight pole and fix an arc onto it

Unless you are handy a diseqc moter is cheaper.

Zaphod

A dish mounted on a pole is not a polar mount. A polar mount is a specific type of mount where the dish tracks the Clarke Belt - it raises the dish as you approach true south, and lowers it as you move away. They were originally based on the mounts used on telescopes to track the "movement" of the stars.

A dish attached to a pole would more correctly be referred to as an az/el mount (azimuth/elevation). The pole is always straight.

The angle you need to check up for each sat is therefore the elevation angle based on your location. From the sat calc site the elevation for Astra 28E is 21.475, Astra 19E 24.800 and Thor 0.8W is 28.926. As you can see, unless you are using a curved pole, you won't be able to accommodate the different elevations. So you'll have to adjust the settings on the dishes themselves.

FWIW the declination angle is specific to "modified polarmounts" - it's an extra angle which takes account of the curvature of the Earth the further you move away from the equator.

http://www.arrowe.com/polarmount.html
http://www.freewebs.com/bealach/html/mount.html