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BRT1267

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#1 WRAK

WRAK

    Apollo

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Posted 22 April 2014 - 03:21 PM

Did in the last week twice a short session in Leo with main target STF1450 - of special interest because not only one of the objects of the Haas project but also a target for observing the secondary sitting centered on the first diffraction ring with an aperture of 88mm - and failed twice with 140mm and 120mm although I resolved this double last year with 80mm. There is obviously no upper limit for the effects of bad seeing conditions.
Interesting side effect is the determination of current TML in the Regulus environment with the faint double BRT1267 as part of the close environment of Regulus (see attached map).
WDS lists BRT1267 with 4" +10,3/11,6mag - this parameters suggest 120mm for resolution under reasonable good conditions. With the 140mm refractor I had +11.9mag and with the 120mm refractor in another location with somewhat less light pollution I had +12.3mag as current TML - in both cases basically enough to resolve a +11.6mag secondary.
But both times I could easily resolve the primary but failed to resolve the secondary - given the not this good conditions this seems inconclusive but I tend to assume that the WDS magnitudes are a tad too optimistic. UCAC4 suggests +10.63/12.39mag and this values seem valid for me and suggest at least a 6" aperture for resolution.
Will try to resolve BRT1267 next time with a larger aperture means 235mm and try to estimate the magnitudes with the help of the faint stars nearby.
Wilfried

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