Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.naic.edu/~phil/hardware/byuPhasedAr/arcLenErr.html
Äàòà èçìåíåíèÿ: Fri Apr 30 21:11:01 2010
Äàòà èíäåêñèðîâàíèÿ: Fri Jun 25 22:38:52 2010
Êîäèðîâêà:
Ïîèñêîâûå ñëîâà: ðåëÿòèâèñòñêîå äâèæåíèå

byu phased array feed.

Arc length error

apr2010

28apr10: Errors in arclength using arclenth/sin(za)

The pointing pattern uses: daz = arclengthReq/sin(za) to move the azimuth. This is not a great circle arc. For small angles the error is not significant. The picture shows the angles and lengths:

The plots show the error vs za for different values of Daz (.ps) (.pdf)

Top: great circle offset - .17 degrees (10 amin). The error down to 1 deg za is less than 1 arcsecond.
Middle: great circle offset = .5 degree= 30 arcmin. The error at 3.5 deg za is1-2 asecs.
bottom: great circle offset=3 degrees (what green bank used). The error at 3.5 deg za is about 3 amin.
If we keep the offset to +/- 20 amin and za > 3.5 degrees then we shouldn't have any problem with the position error.

processing: x101/100407/byurot.pro

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