SAO numbers clarified

I wanted to clarify the matter with the SAO catalogue numbers now used RASC Observer's Handbook for the coloured double stars.

The table below notes the differences in SAO numbers. Where:

• list - the list the star is shown in, either in the handbook proper (main) or the downloaded supplemental sheet.
• OH - Observer's Handbook entry
• ST - SkyTools 3 Professional entry

star	list	OH	ST	notes
ο Dra	main	31219	31218	Both stars searchable in SIMBAD. SAO catalogues reports this as a deleted duplicate.
Σ1604	supp	157112	157111	SkyTools says 157112 is the C star.
δ Crv	supp	157322	157323	SkyTools says 157322 is the B star.
ρ Her	supp	66000	66001	Wikipedia says 66000 is the B star and 66001 is A.
α Cru	supp	251903	251904	SkyTools says 251903 is the C star.
γ Cru	supp	239791	240019	SkyTools says 239791 refers to delta Cru, a completely different star.

For the most part, where the SAO numbers are different, the other quoted number still gets one in the neighbourhood. In other words, the SAO number refers to another star within the double or multiple star system. And someone using the number in a telescope hand controller or in software should land at the correct location.

The entry for gamma Crucis however appeared more severe, referring to a completely different star. I interpreted this as an error and reported it.

See the original observation blog post. The OH team corrected the error.