Reply to thread

Message

<blockquote data-quote="a33" data-source="post: 1069733" data-attributes="member: 332642">I have to correct myself on the previous post, I discovered. So I add again to this old topic.Though in general a rotation circle can be made to follow an ellips (as is the case with the offset dish example, that I gave), in the specific case of the Clarke Belt and a single-axis motor setup on the earth's surface it cannot, I discovered.Recently I did the mathematical checking if the 'modified angles' perfectly track the arc, and the answer is alas NO. So I was wrong, in my earlier assumption. <img src="https://www.satellites.co.uk/styles/default/xenforo/smilies/sad.png"&nbsp; class="smilie" loading="lazy" alt=":(" title="Sad&nbsp; &nbsp; :(" data-shortname=":(" />I had expected a perfect match, due to what I understood about cones, circles and ellipses. However I tested if the modified angles, when perfectly aligned to the due south and the opposite satellite (at 180 degrees), hit exactly the arc at plus or minus 90 rotating degrees from south, using the forward axis tilt of the modified angles (so that the 90 degrees rotation sees a greater part of the satellite arc, than the 90 degrees rotation with an axis parallel to the earth axis).My calculations indicate: At 90 degree rotation, the modified angle looks a little bit UNDER the clarke belt; with a maximum (at latitude about 35 degrees) of a little under 0.04 degrees.I'm not sure what modified angles are the best compromise to use, now. I've used the '0-180 degrees fit' till now, some use the '0-90 degrees fit' I believe, but also the '0-horizon fit' could be good, or even a fit from 0 to only halfway or two-thirds towards horizon might be better (with 0 = clarke belt zenith).It is all about just some hundredths of degrees, but maybe I'll check and calculate someday…greetz,A33</blockquote>

[QUOTE="a33, post: 1069733, member: 332642"] I have to correct myself on the previous post, I discovered. So I add again to this old topic. Though [I]in general[/I] a rotation circle can be made to follow an ellips (as is the case with the offset dish example, that I gave), in [I]the specific case[/I] of the Clarke Belt and a single-axis motor setup on the earth's surface it cannot, I discovered. Recently I did the mathematical checking if the 'modified angles' perfectly track the arc, and the answer is alas NO. So I was wrong, in my earlier assumption. :( I had expected a perfect match, due to what I understood about cones, circles and ellipses. However I tested if the modified angles, when perfectly aligned to the due south and the opposite satellite (at 180 degrees), hit exactly the arc at plus or minus 90 rotating degrees from south, using the forward axis tilt of the modified angles (so that the 90 degrees rotation sees a greater part of the satellite arc, than the 90 degrees rotation with an axis parallel to the earth axis). My calculations indicate: At 90 degree rotation, the modified angle looks a little bit UNDER the clarke belt; with a maximum (at latitude about 35 degrees) of a little under 0.04 degrees. I'm not sure what modified angles are the best compromise to use, now. I've used the '0-180 degrees fit' till now, some use the '0-90 degrees fit' I believe, but also the '0-horizon fit' could be good, or even a fit from 0 to only halfway or two-thirds towards horizon might be better (with 0 = clarke belt zenith). It is all about just some hundredths of degrees, but maybe I'll check and calculate someday… greetz, A33 [/QUOTE]

Verification