Local Newspaper Report

written by Mike Lewis

General Information

These reports appear in the last Thursday of the month (before our monthly meeting held on the first Thursday of the month) editions of the 'Clacton and Frinton Gazette' and the 'Harwich and Manningtree Standard' in their 'Neighbourhood News' sections

The Brightest Stars Part I

by David Pugh

5th October 2017

The number of stars visible in the northern and southern hemisphere is around 6,000 where the faintest stars visible are magnitude 6. The modern scale of magnitude is logarithmic where magnitude 6 is one hundred times dimmer than magnitude 1. The brightest star visible on this scale is the Sun at -26 and dimmist visble with bhe Huble telescope is +28.

The brightest stars 20 to 11 are classed according to apparent magnitude although many astronomers use a scale based on absolute magnitude which is the magnitude at a fixed distance of one parsec (3.26 light years).

Number 20 on this list is Deneb apparent magnitude 1.25 at a distance of 2,600 light years and about 196,000 times brighter than the Sun and is blue in colour. Other stars in this list are as follows:-

Fomelhaut, Pollux, Spica, Natares, Aldebaran, Acrux, Altair, Hadar and no. 11 is Beteljeuse. This star at 640 light years and magitude of around 0.04 and is a red giant star.

All the stars listed can be found on a Herzsprung Russell diagram where stars are classified according to luninosities versus effective temperature.