On 2012-12-09 I detected a remarkable transient in low resolution spectra of DNTau using the Star Analyser.
88 x 20 sec spectra show a rise in total flux (4000-7500A) of ~130% in just 6 minutes, followed by a rapid drop over the following 6 minutes and a continuing slow fall over the next 40 minutes to ~20% of the initial level. The flux increase was greatest at the blue end (a 300% increase at 4500A)
These changes would have easily been detected in using photometry but were very rapid and may have been hidden by averaging sub exposures. I would be interested to hear from any photometrists who have seen similar transients in any of the campaign target stars
More details of the spectra here
http://www.threehillsobservatory.co.uk/ ... ra_42a.htm 
and a description of the technique used here
http://www.threehillsobservatory.co.uk/ ... tra_42.htm