Difficult doubles as means of guaging seeing?

[Stonius]

Following on from the doubles thread, I've been looking for some challenging doubles that could be used as a more exact indicator of seeing than just kinda estimating how much the stars are twinkling.

Does anyone have favourite test stars that they use specifically for this purpose?

Best,
Markus

[bigjoe]

Hi Markus ..Yes I do VIZ..RIGEL or Upsilon Carinae in Summer..If I can't easily split them at medium/high mag...150x in my 130mm Apo...then I wont attempt other difficult targets that night, mainly Sirius,32, 52 Orionis.

Same goes in Winter ..I use Porrima in Virgo, Izar in Bootes..if they split then its over to Antares and the incredible DOUBLE DOUBLE..JABBAH ETC.

....
Otherwise theres always Acrux, h3945, Theta Indi, Iota Cancri ..Cor Caroli, Gamma Volantis , Velorum, Arietis, Delphinus, Leporis and Leonis; as they're always easy here in Sydney.



PS: Porrima needs around 1 to 2 Arc Sec seeing at worst ..All of the above make sensational viewing.

bigjoe.

[Stonius]

Ah thank you! I had discounted Bootes double because I figure theyre getting too low to the horizon for me here in Melbourne.

Best,
Markus