[vsnet-chat 3654] Re: re Overobserving

[crawl@zoom.co.uk]

At 08:11 30/09/00 +1200, Stan Walker wrote:

>By the way, John, I found a consistent period of about 63 days in 8000
>visual measures of R CrA (or one of those stars). Probably an orbital
>signature but when I mentioned this the visual people wouldn't believe it.
>Quite puzzling. Why do they observe the star if they don't credit the
>analyses?

I was quite well chuffed with myself a few years ago when I found the
orbital signature of T CrB in visual data, only to find out that J Bailey
had already done a damn good job of analysing this a quarter century
earlier!  This periodicity, though admittedly about 227 days if memory
serves, was found visually [as opposed to pep].

T CrB is a case in point too... ...it also suffers from some "tramlines"
with the folded lightcurve... why? because a sufficient number of people
are recording it at "minimum", which is always the same value to them.  I
rarely ever saw it at the same mag two nights running [it tends to flicker
a bit as well].  Of course, suitably available adjacent sequence stars help
in situations like this.

And, whether folk believe it or not, if you merge BAAVSS, AFOEV, VSOLJ and
probably HKK observations of GK Per and ditch the outburst data, only
keeping the "quiessence" stuff, you can recover a 1.99 day period quite
easily via DFT, and get an interesting looking near sinusoidal folded
lightcurve... ...of course you do have the weighting from all them CV folk
who post their obs to every archive going...

...but it must be admitted, I already knew the orbital period of GK Per
when I started, so I precluded my period search range to less than a few
days, as opposed to between say 0.1 and 1000 days.

But a very good point that Stan makes is that variable star observations
shouldn't just be reported in order to be stored away in some "holy of
holies" receptacle of an archive somewhere... ...they need analysing.  Lack
of publishing venues probably put some folk off, but I personally find it
easier to analyse summat than it is to think up a title for a paper, let
alone write one!!!!!!!!!!

Cheers

John

PS you're not sure it's R CrA then???

PPS I forgot to say earlier, good title by the way!

PPPS Stan, BEWARE of sparrows bearing salmonella, apparently...!!!!

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