[vsnet-alert 10134] Re: U Gem unusual outburst?

[arne]

Gary Poyner wrote:
> I thought this was strange when I saw it in the AAVSO DB.
> I checked with several observers in the UK before updating
> CVnet (it was cloudy here) and John Toone observed U Gem
> at 14.9 on the evening of April 27, so no outburst!
> 
> 
> 
>>   According to AAVSO MyNewsFlash, U Gem is reported to be in outburst.
>> The object was caught in the rise on Apr. 26-27 at around mag 12.8.
>> It is a very queer outburst if this object remained at this brightness
>> for more than 20 hours.
>>
> 

As long as a CCD datapoint falls within the historical limits of
a CV, the first level of automatic prevalidation cannot
tag the point as discrepant - that requires a human looking at
the dataset to make that judgement.  As with all observations,
a confirming observation is wise before considering any outburst
is in progress - a discrepant point is just a good heads-up that
something might be happening.  In this case, we have fainter-than
observations prior to and after the 12.8 point, so either it had
to be a "flare" or else the observer made an error.  It was
the latter case for this point, and it will be modified shortly
based on information from the observer.

MyNewsFlash is a purely automatic system, useful to alert you
quickly when something is potentially happening.  It should *not*
be used by itself to trigger anything, including an alert posting
to a maillist, without further confirmation.  In this day of
rapid dissemination of information, we made the decision to pass
on all prevalidated data without human checking to make sure that
you get the most rapid notification.  If a CV is part of a
professional campaign, then we work closely with the researcher
to ensure that any trigger is based on careful analysis and
not just from MyNewsFlash.
Arne