b2j: B1950 to J2000 coordinate conversion

In astroFns: Astronomy: Time and Position Functions, Misc. Utilities

B1950 to J2000 coordinate conversion

Description

Precession from B1950 to J2000

Usage

b2j(ra = "17h42m29.3076s", dec = "-28d59m18.484s")

Arguments

ra	B1950 Right ascention (string)
dec	B1950 Declination (string)

Details

Enter positions as text strings with fields separated by characters d, h, m, s, a colon, or a comma, e.g. '17, 42, 28', '-28h43m03s', or '- 28 :43 : 3'. Spaces are removed in input conversion. Trailing missing values are taken as zero. The code uses an approximate formula for precession; spot checks give results accurate within a few tenths of an arcsecond.

Value

List with strings in:

ra2000	J2000 Right ascension
dec2000	J2000 Declination

Note

Calculation based on power-law expansion of exact function.

Author(s)

Andrew Harris

References

Explanatory supplement to the Astronomical Almanac, Seidelmann (ed.), c.~1992, chapter 3.213

See Also

j2b. See dms2rad, hms2rad for input conversions.

Examples

b2j()
b2j(ra='17, 43', dec='-28, 47, 30')
b2j(ra='17, 43', dec=' -  28,  47, 30')
b2j(ra='17h43m', dec='-28d47m30s')
tmp <- b2j(ra='17, 43', dec=' -  28,  47, 30')
str(tmp)
tmp

astroFns documentation built on May 9, 2022, 1:05 a.m.