[Barrykgerdes]

Originally Posted by kitsuna

Hi all, just looking for a bit of advice.

I've recently bought all 3 volumes of Burnham's Celestial Handbook. I'm really enjoying it, but the books are quite old (1977 for my edition, AND YES THAT QUALIFIES AS OLD). As a result, all the RA and DEC coordinates are all recorded in epoch 1950. This makes it an interesting historical document, but not much good for actually finding celestial objects.

I'm vaguely aware that the difference between epochs occurs due to the movement of the earth and the difference between where the first point of Aries was in 1950 as apposed to 2000.

I'm wondering if anyone would be able to advise me how to convert the RA and DEC coords from epoch 1950 to 2000. Can this be done simply (as in, could a reasonable person do it in their head?) or does this require any complex calculations, or is there a calculator available somewhere.

Thanks guys.

Hi Adam
Yes as Gary says Precession makes a bigger change in Coords than most people realise.

Here is a little program in compiled basic from Peter Duffet Smith's book "Astronomy with your personal computer" that I wrote some time ago and just tidied it up a bit. You can enter any date and calculate precession for another date for the RA and DEC of an object.