Declination Angle

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I have been trying to find the true declination angle of my location.

Dish pointer tells me every thing else, but I can't see a declination angle.

At the moment I have it set to 6.7° as advised by another member on the group.

But I am just trying to find this on a website.
 
Deduct the offset angle from the elevation and tweak from there, I had to use a modified angle for the 1224 to get it right.
 
martin-f said:
Deduct the offset angle from the elevation and tweak from there, I had to use a modified angle for the 1224 to get it right.
Click to expand...
Do you mean from the sat elevation eg 3w 31.8° - declination or do you mean from 50.9° my latitude?

I am using a polar mount.
 
I never bother with measuring declination. Inclination of the polar mount, yes but then adjust declination of the dish to the best possible signal.
 
So when setting the polar mount to the right angle, do I measure it:
image.webp
Like this above to equal my latitude 50.9° or like the photo below?
image.webp
 
So I should set the polar mount to 50.9° like the top photo,

Then set the dish to 3W

31.8-6.7-21.3=3.8°

So dish face to 3.8°?
 
I use elevation angle, 90-latitude=elevation angle. In your case it should be 39.1, which isn't far off your 38.4 figure.. nudge it slightly higher.
 
I just do what Alex does in around about way, if the pm has been stripped down I will set my latitude to what it should be the deduct 22.6 from 29 6.4 at my location and tilt the dish to peak the signal maybe a little tweak on the latitude,

I am unsure if you need to use a modified angle on that mount ? if so you will find the modified angle here.
decang.webp
 
Chris1979 said:
So I should set the polar mount to 50.9° like the top photo,

Then set the dish to 3W

31.8-6.7-21.3=3.8°

So dish face to 3.8°?
Click to expand...

The angles mentioned are fixed - they don't change with satellites. Satellite elevation relative to the dish does, yes, but this is handled by the polar mount itself when it moves east and west.
 
Captain Jack said:
The angles mentioned are fixed - they don't change with satellites. Satellite elevation relative to the dish does, yes, but this is handled by the polar mount itself when it moves east and west.
Click to expand...
Like you say, I will use the 90-50.9=39.1° on the polar mount.

When I get a chance to pop out and swap the dishes I will adjust it then.

Thanks guys, for your help :-)
 
Will not go very deep in details, but elevation and declination not only angles present in the polar-mounted system…. Of course, for the offset antenna there is offset angle. But, there is one additional angle, which is usually less than 1*, could be called “Correction angle”.
 
But, if we decide to go little bit deeper than @Chris1979 has set elevation of his dish rightly. And that is because of this small Correction angle (will abbreviate it "Y") which becomes bigger if you go more North. For location Lat 50,9* this angle is about 0,7*.
And if you wish (and we usually wish) to set Elevation (El) correctly than this angle should be taken into account, especially for bigger dishes.
To calculate proper El we should use formula: El=90-Lat-Y that means 38,4*- exactly how it is shown on picture #2 in Post#7
This could be topic for our weekend discussions BTW. ;)
 
I can not find proper site in English, but you CJ should understand this if you read carefully here and here.
Correction angle for you is also little bit smaller than 0,7* ScreenHunter_471 Sep. 04 18.31.webp
 

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Thanks Martin and Rimant. I seem to remember Huevos talking about this as well so this will be extra important for the 1.8m dish (1m one probably won't care all that much). And I completely forgot about it...

Rimant, R3 and Rorb are constants at 6378km at 42233km, making a ratio of 6.622? The rest looks easy enough (with a calculator!).
 
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