[Prev][Next][Index][Thread]

Re: (IAAC) Burnham's Stars



Well, since we're getting serious about this, :-) I took a look in the WDS database I downloaded from the web and imported into Access 2000 and found 3 records for WDSNum 02039N4220. Here is a field breakdown for them:

CatNum      Components      Last Obs.   PA        Sep      Mag1    Mag2    Class
STF 205     ASBC               2001           64         9.8       2.31      5.02      K3IIb
BAR  22     AD                    1898           245       27.9     5.1        15        K3IIb
STT   38     BC                    2000           103       0.2       5.1        6.3      B8VNAOV

Note that the PA and Sep info is from the last observation (listed). Also note that the spectral class listing for the first two entries is K3IIb. The data bible provided by the USNO states that the spectral types of two components are provided where space permits. It also says "See the Introduction for discussion." Unfortunately, the Bible introduction does not seem to be available on the USNO website. At least I could not find it after a brief search 5 minutes ago. Anyway, I don't know how they're formatting multiple spectral type entries.

From this information, it seems possible that the spectral type is being reported in applications like MegaStar and StarMap Pro only for the third entry.

One halfway suspects that the problem arises from the fact that amateur astronomers have become so focused on more "glamourous" deep-sky objects (like galaxies) that software designers haven't spent much time sorting out the admittedly complex doublestar catalog issues. Thank you Mr. Dobson!  :-)

Fiske
Kansas City

PS: I also checked Cartes du Ciel (the amazing free starmap software available on the internet) and found that the Almach doublestar info reported STF 205 A-BC and listed the primary as a spectral type K3IIb. It's been some months since I was messing about with it, but I did spend some time generating WDS data files for one of my starmap applications and it might have been Cartes du Ciel. (Can't recall specifically.) Anyway, if I did generate WDS files for this program, I might well have eliminated duplicate data entries from the file to fix reference problems. This could account for why the STF 205 entry appears in Cartes du Ciel on my computer.

Follow-Ups: