Sky Notes – September 2018

After spending the summer close to minimum, both Chi Cygni and Omicron Ceti (Mira) are on the rise. Both stars are expected to reach maximum brightness in early December. At their faintest, both stars are only visible in large telescopes, but over the course of the next couple of months they should be observable in binoculars. At maximum brightness, both stars can be seen with the naked eye from a dark site. Chi Ceti has a typical maximum brightness of around the fifth magnitude, while Mira usually reaches the third magnitude, so both stars should be visible in binoculars, even from a light polluted site.

Looking to the north-east the eclipsing binaries RZ Cas and Beta Per (Algol) are visible. There will be a favourable eclipse of RZ Cas on the 20th; with a mid-eclipse time of approximately 22:00 UT. Each eclipse lasts five hours; so the eclipse should be well underway by the time it gets dark. RZ Cas varies between magnitudes 6.4 and 7.8, so its variation can be followed with a modest pair of binoculars. There are no favourable eclipses of Algol in September.

If you want to try and observe any of these stars, the charts are on the website.