[vsnet-chat 3703] Delta Vel comments

[Fraser Farrell <fraser@trilobytes.com.au>]

It is natural to ask why wasn't this bright variable discovered years 
ago?, and I could answer with "the surrounding star fields are too 
distracting" or that "we are all busy looking at CVs" or some other glib 
excuse.

But instead, I think it is a case (yet again) of preconceived 
perceptions. The catalogue says it's mag 1.0 so it must be true. Even 
though it looks fainter than that mag 2.0 star nearby. Let's be candid, 
we have all suffered from this kind of self-delusion at least once!

A classic example would be V1016 Ori, which is one of the famous 
Trapezium stars in the heart of the Orion Nebula. This has been seen by 
millions of people since the invention of telescopes, yet its eclipsing 
nature was not announced until 1973. I am quite certain that many of its 
earlier eclipses were detected, and then dismissed without further 
thought as a faulty observation. 

I have seen this happen, even with experienced observers. A few years ago 
I attended a member's viewing night at the local astronomy club, at a 
time when V1016 Ori and its companion BM Ori were both in eclipse. 
Although I asked everyone throughout the evening about their impressions 
of the Trapezium, nobody noticed anything different about these stars 
until I commented later "let's see if that simultaneous eclipse in the 
Trapezium has finished". It hadn't, but after my comment they could all 
(suddenly) see the differences. Nowadays if there are eclipses of these 
stars in progress during our public astronomy nights, these same members 
will be sure to mention the event to our visitors :)

In a more general vein, how many astronomers who are not variable star 
observers even notice the many bright variables all over the place? They 
all know about Omicron Cet from reading general astronomy books, but how 
many have also "discovered" R Sct, Kappa Pav, X Sgr, Eta Aql, U Car ....?

Getting back to Delta Vel; I cannot recall any fadings of this star 
during my astronomical lifetime. But now if I do happen to be awake at 
4am during the next couple of months, I will certainly take a look at it.

I haven't seen Sebastian's choice of comparison stars yet. Were these 
posted to another vsnet list?


cheers,
Fraser Farrell

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