Saturday 30 April 2022

Should it be called pi or Fl18 UMi


Should a star be labelled with its Bayer label i.e. its Greek letter or should it have just its Flamsteed number.

The star Flamsteed 18 Ursa Minor is also pi Umi or struve 1989 which indicates it is a double star.

Star atlas 2000 shows the star as 18 rather than pi and of further interest in the star atlas 2000 catalogue it is neither shown as 18 or pi but by just its HD number which is HD141652 for pi 1 and HD 139777 for pi 2. Pi 2 is the brighter of the two components. I have no idea what is going on here.

I have checked numerous double star catalogues for struve 1898 i.e. pi Umi and as you might expert I discover a wife range of observations for the brightness of this pi or 18 Umi.

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