Double Stars - Ursa Major

  • Note:

    All images are at 1:1 scale taken with the same equipment (120mm refractor, 1000mm FL, Canon 450D DSLR) and same magnification unless stated. The Canon 450D gives equivilent to a 12mm EP, giving a mangnification factor of approximatly 80x. This means that the split between all stars can be compared against each other. Exposure times and ISO levels are adjusted to give best image of both components but on average they are 4 seconds at ISO 400


  • 22:46 UTC      06-02-2013

    Zeta UMA (Mizar)

    A little confusing information with this double as the split is more commonly of Mizar and Alcor which has a split of around 11.5' (arc minutes), but Mizar has its own double. This image is of Mizar Aa and Mizar Ab, with a 14.5" (arc second) separation, it is an easy split. Magnitudes of 2.4 and 4.0 make this a bright double for imaging.
    Trawling through the internet, there seems to be a lot of sites that indicate this is Mizar and Alcor, which caused me a lot of confusion.
    Details: Constellation: Ursa Major    RA: 13h 23' 55.4"    Dec: +54° 55' 31.5"    PA: 152º     Separation: 14.4"

  • 23:01 UTC      06-02-2013

    STF 1520

    Similar magnitudes of 6.6 and 7.9 with almost 13" separation made this an easy target and a nice easy split.
    Details: Constellation: Ursa Major    RA: 11h 16m 3.9s    Dec: +52° 46' 35.8"    PA: 344º     Separation: 12.7"


  • 23:05 UTC      06-02-2013

    STF 1415

    Another easy pair, magnitudes of 6.7 and 7.3 with a nice wide 17" separation.
    Details: Constellation: Ursa Major    RA: 10h 17m 50.5s    Dec: +71° 03' 38.0"    PA: 167º     Separation: 16.7"



  • 23:10 UTC      06-02-2013

    STF 1544

    Magnitudes of 7.2 and 8.2 with almost 13" separation, similar to STF 1520, but slightly dimmer, just as easy to split.
    Details: Constellation: Ursa Major    RA: 11h 31m 18.6s    Dec: +59° 42' 3.3"    PA: 90º     Separation: 12.4"


  • 23:16 UTC      06-02-2013

    STF 1427

    Magnitudes of 7.5 and 8.0 with a 9" separation, nice and easy but appeared to be strangely dim, of course when I looked outside, I found I was looking through the clouds, but I did get them.
    Details: Constellation: Ursa Major    RA: 10h 22m 0.0s    Dec: +43° 54' 11.5"    PA: 214°     Separation: 9.4"