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Old 02-10-2018, 11:06 AM
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big-blue is offline
Join Date: Jun 2006
Location: Adelaide
Posts: 51
I keep an eye on a number of close doubles as a guide to seeing quality. One of my regulars is Beta Muscae, which I looked up in the list provided by Nick. I noticed that separation is given as a very tight 0.8" which surprised me as I have split it cleanly with an ETX-125 on a good night, and I do not think the ETX is that good !

Looking up other references via Google, there is a range of separations all the way from 0.8" up to 1.6" and the upper end reflects my experience.

How can there be such a range of reported separations, given that its period is quite long and the separation has not changed much in the last 50 years (even tho PA might have changed) ?

See attached diagram picked off the web (And the web is never wrong is it !?)
Or are modern authors still quoting the 1880 separation ;-)

I do not mean to criticise the provided list, as I have already printed it out as an observing reference. ( & thankyou Nick for providing it)

Just wondering how precision measurements can be reported so differently.

Thoughts ?

Last edited by big-blue; 02-10-2018 at 11:18 AM. Reason: image attached
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