[vsnet-alert 4146] Re: EX Hya brighert? (Pearce)

[Taichi Kato <tkato>]

Re: [vsnet-alert 4142] Re: EX Hya brighert? (Pearce)

> Visual observers often seem unaware that this star is subject to both
> eclipses at about 98 minute intervals and white dwarf spin period
> fluctuations with a period of 67 minutes. The amplitude of the latter is
> usually between 0.3 and 0.7 magnitudes but I have seen it larger on a few
> occasions. On one occasion in 1968 it was almost flarelike. 

    For observers interested in eclipse observations, I prensent the
ephemeris (a bit old, though).

    HJD 2437699.94179 + 0.068233846 E

    Past visual and photographic observers didn't completely neglect eclipses
of such an interesting object.  An example can be found in VSOLJ Variable
Star Bulletin 3, 9 (1987), where photographic and visual time-resolved
photometry of the 1987 May outburst is presented.  Eclipses were easily
detectable, and they got remarkably broader during the outburst.
The network between observers is far exceedingly better than that time,
and we are looking forward to receiving the next early announcement of the
detection of outburst, and words of successful observations!

Regards,
Taichi Kato

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