Zeta Ursa Majoris 

Tim Leese
Star: Zeta Ursa Majoris 
Date & Time: 19-November-2000 (20:45 UT) 
Seeing: 5 <1-10 Seeing Scale (10 best)>  
Location of site: Cheshire. UK 
53° 15' N –2º 33' W  
Site classification: Suburban  
Sky darkness: 4 <Limiting magnitude> 
Conditions: slight to moderate breeze, cold, cloud hopping. 
Binoculars: 12X50 Olympus 5.3deg FOV 
(hand held) 
 

 

Mizar and Alcor is probably one the most celebrated double star systems in the sky and was certainly the 
first double star system I learned to recognise through binoculars. Tonight they are located quite low down 
in the sky, being just above neighbours roof tops. Mizar scintillated in the darkness with its wide companion 
appearing to be a white colour. 
 

 
 

 
 
Stuart Anderson
Star: Zeta Ursa Majoris
Date & Time: 06 Jan 2001 22:42 UT
Seeing: 2-3 <1-10 Seeing Scale (10 best)>
Weather: Hazy, almost full moon
Location of site: Hamburg, Germany 
Lat/Long: 53 34 N, 9 59 E 
Site classification: Suburban sky 
Sky darkness: -- <Limiting magnitude> 
Binoculars: Vixen Ultima 9x63 
Magnification: 9x
Field of view: 5° 24'
Observing aids: Camera Tripod

 

Decided to take a look at this famous double, given the poor seeing conditions. Zeta was easy to locate and split from its listed companion, 80 Uma. Very large separation and bright magnitude of each member (2.3 and 4.0) made it very easy, even in a hazy moonlit sky.
 
No colour could be distinguished in 80 Uma, but zeta seemed to show a very slight 
yellowish colour. Zeta itself was not resolvable into components, as expected for this 
instrument.
 
The star SAO 28748 makes a small triangle with Zeta and 80 Uma. This is listed in 
SkyMap as having magnitude 7.6, and was *just* visible in with averted vision - but only 
just.
 
Est. PA is 90 degrees (they seem to lie in W-E direction).
Clouds are here again, must stop.