# OTHERtek2000 1.2m Offset Angle??

#### Captain Midnight

##### SatelliteGuys Pro
Original poster
I'm helping someone get his 1.2m polar mount offset 1.2m on the entire arc and I can't find the offset angle for this dish anywhere! Anyone know it? I know the Geosatpro 1.2m is offset 27.3 but I am not sure if they are the same dish mold. Tek2000 doesn't even send instructions or give the offset angle in their specs online.

Should I add the offset to the elevation and just add the declination only? I don't think I can add the declination and offset angles together on this mount..

Thoughts?

#### Attachments

• 20200514_190517.jpg
297.9 KB · Views: 243
• 20200514_190511.jpg
124.1 KB · Views: 253
Let's see the front of the dish. That's not a mount for an offset dish. It's a prime focus mount.

Captain Midnight
If the declination bolts are long enough to get about 30° (declination + offset ) you might use that mount but there would be a bind on the actuator.

Captain Midnight
This is the only photo of the front I have right now handy

Let's see the front of the dish. That's not a mount for an offset dish. It's a prime focus mount.
That's what I saw. Definitely a prime focus. And it was new to me to see that with an offset dish. I can't imagine trying to set this thing up blind.

if it's a flat faced dish, you can find the offset angle easily by calculating.
Forumula is:
cosinus(offsetangle) = width of the dish / height of the dish.

MfG,
A33

That's what I saw. Definitely a prime focus. And it was new to me to see that with an offset dish. I can't imagine trying to set this thing up blind.
A couple years ago I converted a prime focus mount for a 1.2m offset dish. This thread may help you figure out what to do for your situation.

A couple years ago I converted a prime focus mount for a 1.2m offset dish. This thread may help you figure out what to do for your situation.
I looked at that last night. I was just wondering if I could add the offset to the elevation, since the adjustment bolt is so much longer or if it can only be added to the declination to accurately track the arc.

if it's a flat faced dish, you can find the offset angle easily by calculating.
Forumula is:
cosinus(offsetangle) = width of the dish / height of the dish.

MfG,
A33
Should I use metric units?

if width and height are measured in the same units (metric or whatever), the offset angle has no unit except degrees.

if width and height are measured in the same units (metric or whatever), the offset angle has no unit except degrees.
Thanks. I was hoping to avoid math but that is inevitable LOL. That is width and length straight across or laid against the surface? I would think laid against the surface, but I want to ask while you are here. (I'm a H-H guy, so actuators on offset dishes is a new trick for me)

Measured in straight lines, so along the dish face.
But of course: only the paraboloid working area of the dish, so WITHOUT the dish rim (if it has a rim).
(All dish calculations only refer to the working area of the paraboloid; that's some kind of logical, don't you think?)

I was just wondering if I could add the offset to the elevation, since the adjustment bolt is so much longer or if it can only be added to the declination to accurately track the arc.

Adding offsetangle to DECLINATIONangle would be right, indeed.

Axis elevation should of course be left as what it is.

Preferably use: the 'modified angles'! And you'll have to do less tweaking.

greetz,
A33

Edit:
I was hoping to avoid math but that is inevitable LOL.
Does this help? : How did students find sine cosine and tangent before calculators? - Quora

Last edited:
Captain Midnight
BTW If the dish has a non-flat dish face (and is intended that way, so not a flat dish face dish which is warped ), the offset angle equation is somewhat more complicated, and needs four input measurements in total; that is, with the formula I derived recently for non-flat dish face dishes.

Greetz,
A33

After looking at the front of this dish I can see there is some offset built into the way the dish attaches to the mount. So you may actually get this adjusted correctly.

And (as so often the case) no mentioning if the hor and vert dimensions of the dish are inclusive or exclusive the rim.....
Dish specs are often not very precise.

And, BTW, I would also always check if the LNB holder is in fact at ( in fact, a bit behind) the focal point of the dish.
Can be calculated with only three input measures: height, width, and depth at the center of the dish (depth measure must be very precise!).

Greetz,
A33