P mount

[RT-Cat]

Construction of a Polar Mount
I have been thinking of building a polar mount for my 1.2M Prodelin dish and putting a good mover on it. Research has brought up some questions that the pros here could answer. Just to see if I have this correct.
Elevation – The entire dish moves up or down.
Declination – Best explanation I can come up with would be the dish “fixed” at the bottom and the top moved away from the mount.
Now if this is correct, do both prime focus and offset dishes require a declination setting?
If they do, why can't this amount of “movement” be calculated into the construction of the mount?
I have stated that due to there is no adjustment on my BUD for declination. Built into the mount?
I have found several designs. Some really wild, but they worked.
Any thoughts?

 

[FaT Air]

>> Elevation – The entire dish moves up or down << Polar elevation will raise/lower dish. Declination will raise/lower dish without affecting polar elevation.

>>Now if this is correct, do both prime focus and offset dishes require a declination setting? <<
Declination is the difference in the polar axis elevation angle, (90° from the Latitude angle) and the angle , from the horizon, to "Look at the satellite. (90° from the dish face angle)
The required declination angle for a prime focus is only a few degrees to "look" at the Clark Belt. With a BUD it's easiest to measure the dish face and the Latitude angle.
The dish face angle for an offset can be calculated as: the required declination plus the offset angle.
(I hope that wasn't confusing)

>> I have stated that due to there is no adjustment on my BUD for declination. Built into the mount? << There has to be, or you wouldn't tract the Clark Belt (arc) I think it may be like an Orbitron, The dish attaches to the mount via a tube. This tube is attached to the dish at an angle. The amount of "UP/DN" declination is determined by spinning the dish tube within the mount tube. (The little bit of E-W movement is irrelevant) "spinclination" in the manufacturers terms

 

[RT-Cat]

>> Elevation – The entire dish moves up or down << Polar elevation will raise/lower dish. Declination will raise/lower dish without affecting polar elevation.

OK Got that.

The dish face angle for an offset can be calculated as: the required declination plus the offset angle.
(I hope that wasn't confusing)

Nope, got that, too.

>> I have stated that due to there is no adjustment on my BUD for declination. Built into the mount? << There has to be, or you wouldn't tract the Clark Belt (arc) I think it may be like an Orbitron, The dish attaches to the mount via a tube. This tube is attached to the dish at an angle. The amount of "UP/DN" declination is determined by spinning the dish tube within the mount tube. (The little bit of E-W movement is irrelevant) "spinclination" in the manufacturers terms

Yes, it is an orbitron. And it does mount as you stated. Been too long since I installed to remember the adjustment. Must have done it cuz it works.
Thanks for info.

 

[Pixl]

Ted,

I wish we had talked about polar mounts when you were here last week. Since you had a H-H motor on order I didn't think to offer you a polar mount I had in the back barn.
Anyhow I'm told that dishes sold in Michigan were figured to be at or around 45 degN. The elevation and N. Latitude are a wash at 45 deg and they welded the declanation at about 7 deg forward nod of the dish into the mounts. Look at your polar mount. Above the polar rotating bolt are usually ears that reach out to the dish frame. The top one is probably longer than the bottom one by a small amount. This nods the dish down AFTER polar rotation has been accomplished. Now all you do is add the offset of your dish (usually about 22 deg) to the declination of 7 for a total of 29 deg.
Using hinges at the bottom and threaded rods at the top you can lean the dish out 29 deg and walk it in or out as needed.

 

[RT-Cat]

Oh well, I expected the motor could handle that dish, so.....
Interesting about the dish calculation. I will take a careful look at my bud and check that out. The hinge at the bottom and rod at top was one of the ideas I found in my research. Lots of different ideas out there.

T.

 

[RT-Cat]

Look at your polar mount. Above the polar rotating bolt are usually ears that reach out to the dish frame. The top one is probably longer than the bottom one by a small amount. This nods the dish down AFTER polar rotation has been accomplished.

Yes, the top bolt ear is a little longer than the bottom.

T.

 

[Magic Static]

The AJAK uses selective mounting holes on the dish ring for setting declination