I think you read correctly Patrick. The two recommendations are in conflict. The one in the readme is consistent with how I numbered the UCAC2 stars and how IOTA uses them. I will forward this question to them, Dave Herald in particular.
I'm pretty sure IOTA used the 2UCAC notation. In fact it's the only one I've seen used. I remember updating my conversion program: http://www.tungstentech.com/Articles/Occultations/UCAC2identifiersforCartesduCiel/tabid/62/Default.aspx as the first version used UCAC2 which was pointed out is wrong. It now uses 2UCAC. Sander Patrick Chevalley wrote: > > > From what I understand I already found tree different way to identify > an UCAC3 star :-( > We need to clarify this point before to build a search index. > > From the UCAC3 readme 3i) : > http://ad.usno.navy.mil/ucac/readme_u3.html > <http://ad.usno.navy.mil/ucac/readme_u3.html> > 1- the last 4 bytes of the zone files contain the MPOS number. This > number spans the range of 3 to 140051297 > 2- ID = n0 + running star number in zone z "3UCAC100200300". n0 is the > largest star ID number of the previous zone. The star ID number runs > from 000000001 to 100766420. > > From Vizier Note (1): > http://cdsarc.u-strasbg.fr/viz-bin/Cat?I/315#sRM3.1 > <http://cdsarc.u-strasbg.fr/viz-bin/Cat?I/315#sRM3.1> > 3- 3UC"zzz-nnnnnnn", where zzz is the zone number and nnnnnn a 6-digit > running number in the zone. "3UC180-000007" > > Can someone with better english can clarify the UCAC3 readme 3i). it > is quite confuse for me. > > Also, do anyone know which identifier will be used the most frequently > by people using UCAC2 now? by IOTA? for SN chart? > > Patrick > >
