Guide to Z Ursae Majoris

A reliable variable star located in the ‘bowl’ of Ursa Major.


Z Ursae Majoris is a red giant star whose brightness variations are due to pulsations in its outer layers. Although it is classed as a semi-regular variable, Z UMa can be relied upon to produce a good amount of brightness variation on a regular basis.

Extreme brightness range 6.3 – 9.8
More typical range 6.9 – 8.7
Period of variation About 6 months (longer secondary period is also present)
Frequency of observation Worth checking a few times per month
Observe using 50mm binoculars will suffice for most of the time, but 60-80mm binoculars may be required during the deeper minima
Visibility Can be observed all year round. Circumpolar

The following charts show the location of Z Ursae Majoris.

You can follow the brightness changes of Z UMa by comparing its brightness with that of the lettered comparison stars.

The first shows the wide area view and labels the brighter comparison stars (A to D).

Wide angle finder chart for Z UMa

The second shows the fainter comparison stars.

Binocular chart for Z UMa