Is it possible to guess your rising sign by tracing significant events in your life or by the characteristics of your personality or appearance? My mother doesnt have the foggiest idea of my time of birth and way back in '61 they never kept records of that type of information...

You can try putting either 6am or 12noon into astro.com to get your chart, but the moon sign and aspects plus Ascendant and MC are going to be wrong. So therefore, you are only going to get half the story.

Rectification is possibly, but it's time consuming --

Solar Arcs
Solar arcs are really simple, especially for beginners, just move the Angles, Asc, Desc, MC, IC 1' for each year of your life onto planets and vice versa. Not just used for rectification either. Under age 12 though these interpretations are directed towards family changes, maybe relocation, job changes, illnesses, additions to family etc. Another example is my Pluto is 28' Leo in 7th house and my Uranus is 3' Leo in same house to subtract these and you get age 25. That year my then husband and I had an almighty explosion (Uranus) and transformation (Pluto) of that marriage that started the demise and ultimate ending thereof....

Further research on solar arcs try these threads.
http://www.astrologyweekly.com/forum/showthread.php?t=12024&highlight=solar+arcs
http://www.astrologyweekly.com/forum/showthread.php?t=12958&highlight=solar+arcs
http://www.astrologyweekly.com/forum/showthread.php?t=6691&highlight=solar+arcs
http://www.aquamoonlight.co.uk/rectification.html
http://www.frankstar.com/solararc.htm
http://thezodiac.com/arcs.htm
http://www.donmc.com/Comparing%20Transits%20and%20Solar%20Arcs%20II.htm
http://en.mimi.hu/astrology/solar_arc_directions.html
http://en.wikipedia.org/wiki/Astrological_progression


Rectification of birth time
http://www.youtube.com/watch?v=KW0G2S2Ti4I
http://www.youtube.com/watch?v=OYMX9X2C1BQ&NR=1
• Transiting Pluto square, conj opp Asc, Desc, MC, IC
• If under 12’ when it conj an Angle then their age was under age 12 it’s parents adjustments. A death, change within father’s work, a separation, remarriage.
• Adults or teens, 1st job, identity transformation MC.
• Pluto conj Desc = death, health concerns, geographic, significant relationship or break up, but has to be ‘life transforming’
• Also try transiting Neptune, something dissolving, disappearing, confusing etc.
• Timings of transits… is it the 1st hit? More often it’s the middle retrograde hit… but could be the last direct hit also. 1’ =4minutes in time.