Quote:
Originally Posted by ngcles
Hi Peter, Suzy & All,
Very good and interesting observations of a several nice pairs. Just thought I'd add my own notes on Gamma Leporis for comparison.
Gamma Leporis is an interesting star from many points of view. It is a nearby star only 29 light-years away and the primary is roughly solar-type (F6 dwarf) about 1.25 solar masses and about twice as bright, while the companion is K-type and about 0.8 solar-masses. It is not clear whether they are a true pair or merely share a common proper motion. If they are physically bound, the true separation is about 870 AU. The two share a similar motion to Sirius and are possibly connected to the URSA major moving group -- a loose association of stars that are not gravitationally bound as a true cluster but share a probable common origin and similar metallicity, age and motion around the galaxy. Moving groups are not clusters, but are the low-mass counterparts the the high-mass O-B stellar associations.
Think of a moving group as a bunch of cars moving along the expressway together all travelling at about the same speed in the same direction and all having an approximately similar destination. Alternately for a cluster, think of a bunch of people on the bus on the expressway. Not only are they all moving in the same direction at the same speed, but they are stuck together and don't move away from each other. In the case of a true cluster, gravity binds them together and makes escape difficult (like the walls of the bus).
This was my eyepiece impression of Gamma Lep with 25cm at x138 in 1998:
x138 21' TF x181 17' TF. Mags 3.8 6.4 Sep 96.7 PA 350. A very wide and not very interesting pair with a mags disparity of 3 mags . Both yellowish, B is deeper, A is light/pale yellow. In PA 345, sep by nearly 2'.
There have been many interpretations of the colour of this pair over the years with some observers thinking the secondary member looked greenish (possible contrast effect). Pairs (particularly bright ones) can produce many interesting "perceived" colours. But that's the way I saw it anyway.
Colour is a highly subjective thing for visual observers ...
Best,
Les D
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thanks les,as always love your reports.......i have one problem and it has been explained to me but i can't get my head around it p.a....and i use my sct and get completely confused which way to go to obtain that angle..
