Welcome to the L3 Harris Geospatial documentation center. Here you will find reference guides and help documents.
﻿
>  Docs Center  >  Libraries  >  ASTROLIB  >  CO_ABERRATION

CO_ABERRATION

## Name

CO_ABERRATION

## Purpose

Calculate changes to Ra and Dec due to "the effect of aberration",

## Explanation

as described in Meeus, Chap 23.

## Calling Sequence

co_aberration, jd, ra, dec, d_ra, d_dec, [EPS = ]

## Inputs

jd : Julian Date [scalar or vector]
ra, dec : Arrays (or scalars) of the ra and dec's in degrees
Note: if jd is a vector, ra and dec MUST be vectors of the same length.

## Outputs

d_ra, d_dec: the corrections to ra and dec due to aberration (must then
be added to ra and dec to get corrected values).

## Optional Input Keyword

eps : set this to the true obliquity of the ecliptic (in radians), or
it will be set for you if you don't know it (in that case, set it to
an empty variable).

## Example

Compute the change in RA and Dec of Theta Persei (RA = 2h46m,11.331s, Dec =
49d20',54.54" on 2028 Nov 13.19 TD
IDL> jdcnv,2028,11,13,.19*24,jd ;Get Julian date
IDL> co_aberration,jd,ten(2,46,11.331)*15,ten(49,20,54.54),d_ra,d_dec
==> d_ra = 30.045" d_dec = 6.697"

## Notes

These formula are from Meeus, Chapters 23. Accuracy is much better than 1
arcsecond.

## Revision History

Written, June 2002, Chris O'Dell, U. of Wisconsin
Fix error with vector input W. Landsman June 2009

© 2020 Harris Geospatial Solutions, Inc. |  Legal