[AZ-Observing] Izar split with SMALL aperture
- From: "Spencer, Darrell" <DSpencer@xxxxxxx>
- To: <az-observing@xxxxxxxxxxxxx>
- Date: Wed, 16 Jun 2010 14:22:44 -0700
Having spent a fair amount of time on Izar at the North Rim Star Party last
week and showing a few folks this fine double (using a C8), I got home and was
compelled to return to it with MUCH smaller glass. I have enjoyed the tight
pair quite a number of times in the past. Although my logs show several
observations of a clean split, none were using instruments of less than 76mm.
Izar, or Epsilon Boötis, is noted as a double system with a 2.4 mag primary and
a 4.2 mag secondary. Separation is listed at 2.9". But, even with
suboptimal seeing, I am happy to report that I've now notched a confirmed split
using a couple of old achromats in 50mm (f12) and 60mm (f17) configurations.
Using the 60, (a fine old Royal), actually caused a bit more trouble than the
smaller scope as the companion insisted on riding almost squarely on top of a
somewhat unstable diffraction ring. (I'm surprised I managed to grab it at
all, but its "apparent" blue-greenish color gave it away and presented as an
off-color "bump" in the ring!).
The 50 (a decent Towa unit) moved the diffraction ring out a bit and, to my
eye, actually made the observation easier - although the color was a bit less
pronounced.
I'm now on a quest to see just how low these little tools will go.
(Hey, it passes the evening hours and North Phoenix skies are no place to go
stalking Sharpless nebulosity).
Darrell Spencer
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