Angular Separation

Proxima Centauri has the epoch J2000.0 coordinates (α,δ) = (14h29m42.95s, −62◦40046.100). Alpha Centauri has J2000.0 coordinates of (α,δ) = (14h39m36.50s, −60◦50002.300). What is the angular separation of these two stars? You need the formula for angular separation (not in lecture notes): (∆θ)2 = (∆αcosδ)2 + (∆δ)2.

1. You're really at the point where you need to use latex, or to put up a photo. This is hard to read.

2. I'm not familiar with this formula, but I don't see how to apply it. You have two deltas, but the formula only has one. Surely a formula for angular separation must work on the angular position of both stars?

Formula refers to both ∆α and ∆δ, surely?

[If you think about the position being determined in spherical coordinates it's reasonably clear what's going on, especially if you know the given formula is only valid for small deltas].

I've copied it from the questions, that's how it appears on my sheet.

Plus, that was my thinking exactly, hence why I'm so confused!!

I have emailed my lecturer but no reply yet.

You're right. Eyesight problem. I'm tired.


Right. This certainly can't be the full formula.

Ok thank you.

However when i put my numbers in i don't get the answer the online calculators get. I've attached a photo of my working. I've tried to include all the formulas i used but i had to write them squished up so i hope you can make sense of it.