On 1981 Jun 08 at UT01:48-02:45 B. Hobdell (St Petersberg, FL, USA, 10 and 4" reflectors) could hardly see Aristarchus crater, however at 01:48UT it brightened in blue for about 3 minutes. Then at 02:20UT there was a bright flash, and by 02:25UT the crater was very bright, but by 02:45UT it was no longer visible. Cameron 2006 catalog ID=144 and weight=0. The ALPO/BAA weight=1.
Linne 1867 Aug 06 UT 21:00? Observed by Buckingham (England?) "Crater in darkness, he saw a "rising oval spot". Other obs. saw it as a triang. Bold black spot pointing to earth, slowly diffused white & drift of white on slope of pyramid. (indep. confirmation?)" NASA catalog weight=5 and catalog ID #155. ALPO/BAA weight=2.
Near Ross D (23E, 12N) 1964 May 18 UT 03:54-04:53 Observed by Harris, Cross et al. (Whittler, CA, USA, 19" relector x720, 8" reflector x322, S=G) "White gas obscuration. Moved 20mph, decreased in extent. Phenom. repeated. Drawing." NASA catalog weight=5 (very high). NASA catalog ID 811.
On 2011 Oct 07 UT 21:45 Gassendi observed by P. Grego (St Dennis, UK,300m Newtonian, x150, seeing III, intermittent cloud) - whilst producing some sketches of the crater - observer noticed a faint point of light inside the shadow filled interior, two thirds of the way out from where the central peaks should have been, towards the SE rim. Some uncertainty in being sure about this spot and after interuption by cloud it was not seen later that evening. ALPO/BAA weight=1 to refelct uncertainty of observer.
M. Cook of Frimley, UK observed a brightening of the crater during this observing session. The cameron 2006 extended catalog ID=346 and weight=3. ALPO/BAA weight=2.