Don Olson in Yosemite       
         Don Olson                    Russell Doescher, Roger Sinnott (Sky & Telescope)      Moonbow  May 11, 2006
   Department of Physics             Kellie Beicker, Ashley Ralph, and Don Olson           Photo by Robert Stavers
   Texas State University                at the Lower Yosemite Fall Viewing Area               www.galleriehare.com

MOONBOW PREDICTIONS FOR 2010

LOWER YOSEMITE FALL
based on the methods described in this article:
       "Moonbows over Yosemite," Sky & Telescope, May 2007
related story:
          http://www.txstate.edu/news/news_releases/news_archive/2007/04/Moonbow041207.html

visual observers generally report that moonbows appear "white," "gray," or "silvery"
but time-exposure photographs reveal the full palette of colors


MOONBOW PREDICTIONS FOR 2010
LOWER YOSEMITE FALL
 
OBSERVING LOCATION:
VIEWING AREA, TERRACE AT THE WEST END OF THE BRIDGE
NEAR THE BASE OF LOWER YOSEMITE FALL
  

DATE
IN
2010

TIMES
(PACIFIC
DAYLIGHT
TIME)

LUNAR
PHASE
 

REMARKS

March 28
(Sun)

8:00pm
(Sun)
to
9:00pm
(Sun)

99%
waxing

moonbow is already in progress when sky gets dark enough at about 8:00pm

March 29
(Mon)

8:22pm
(Mon)
to
11:10pm
(Mon)

100%
 

possibly brightest moonbow for 2010
(depending on snowmelt runoff)
moonbow appears just as Moon rises into sky
between Half Dome and Mount Starr King
(full Moon occurs at 7:25pm PDT on March 29)

night of
March 30-31
(Tues-Wed)

9:26pm
(Tues)
to
12:45am
(Wed)

98%
waning

moonbow appears just as Moon rises into sky
between Half Dome and Mount Starr King

April 26
(Mon)

8:30pm
(Mon)
to
10:15pm
(Mon)

98%
waxing

moonbow is already in progress when sky gets dark enough at about 8:30pm

April 27
(Tues)

9:45pm
(Tues)
to
11:40pm
(Tues)

100%

bright moonbow
(full Moon occurs at 5:18am PDT on April 28)

night of
April 28-29
(Wed-Thurs)

11:15pm
(Wed)
to
12:55am
(Thurs)

99%
waning

 

night of
April 29-30
(Thurs-Fri)

12:38am
(Fri)
to
2:00am
(Fri)

96%
waning

moonbow appears just as Moon clears south rim of valley between Moran Point and Sentinel Dome

May 25
(Tues)

9:00pm
(Tues)
to
10:35pm
(Tues)

96%
waxing

moonbow is already in progress when sky gets dark enough at about 9:00pm

May 26
(Wed)

10:18pm
(Wed)
to
11:45pm
(Wed)

99%
waxing

moonbow appears just as Moon clears south rim of valley between Moran Point and Sentinel Dome

night of
May 27-28
(Thurs-Fri)

11:25pm
(Thurs)
to
12:50am
(Fri)

100%

moonbow appears just as Moon clears south rim of valley near Sentinel Dome
 

night of
May 28-29
(Fri-Sat)

12:19am
(Sat)
to
1:45am
(Sat)

98%
waning

moonbow appears just as Moon clears south rim of valley near Sentinel Dome

night of
May 29-30
(Sat-Sun)

1:06am
(Sun)
to
2:30am
(Sun)

94%
waning

moonbow appears just as Moon clears south rim of valley near Sentinel Dome

June 23
(Wed)

9:15pm
(Wed)
to
10:30pm
(Wed)

95%
waxing

moonbow appears just as Moon clears south rim of valley near Sentinel Dome
(brightness and duration depend on snow season and snowmelt runoff)

June 24
(Thurs)

10:12pm
(Thurs)
to
11:30pm
(Thurs)

98%
waxing

moonbow appears just as Moon clears south rim of valley near Sentinel Dome
(brightness and duration depend on snow season and snowmelt runoff)

night of
June 25-26
(Fri-Sat)

11:02pm
(Fri)
to
12:20am
(Sat)

100%

possibly brightest moonbow for 2010
(depending on snowmelt runoff)
moonbow appears just as Moon clears south rim of valley near Sentinel Dome
(partial lunar eclipse begins at 3:17am PDT
  on June 26)

night of
June 26-27
(Sat-Sun)

11:40pm
(Sat)
to
1:00am
(Sun)

99%
waning

(brightness and duration depend on snow season and snowmelt runoff)

night of
June 27-28
(Sun-Mon)

12:05am
(Mon)
to
1:35am
(Mon)

97%
waning

(brightness and duration depend on snow season and snowmelt runoff)

 
CONDITIONS REQUIRED TO OBSERVE A MOONBOW IN LOWER YOSEMITE FALL
for observers at the viewing area, the terrace just west of the bridge near the base of Lower Yosemite Fall
 
1.  bright moonlight (nearly-full Moon)
2.  Moon risen above the south rim of the valley (so moonlight can strike Lower Yosemite Fall)
3.  sufficient mist and spray (during snowmelt runoff season: April, May, June, sometimes July)
4.  clear skies
5.  dark skies (Sun more than 9 degrees below the horizon)
6.  geometry (the angle between the “anti-lunar direction” [observer’s shadow cast by the moonlight] and the
     direction toward the base of Lower Yosemite Fall must be near the “rainbow angle” of 42 degrees)
 
NOTE
If the snowmelt runoff is unusually strong, then moonbows could appear earlier and last longer than the predicted times. 
If the snowmelt runoff is unusually weak, then moonbows would be visible for shorter intervals than the predicted times.

NOTE
Feedback from photographers / observers regarding the accuracy of our predictions is welcomed
by Don Olson at
dolson@txstate.edu

 

 

 

LINKS

 

Texas State University Honors Program
http://www.txstate.edu/honors/

Sky & Telescope

http://www.skyandtelescope.com/

 

Don Olson, Physics Department, Texas State University

http://uweb.txstate.edu/~do01/

 

Marilynn Olson, English Department, Texas State University

http://www.english.txstate.edu/people-contacts/faculty/olson.html

 

Christopher Olson, JD, Hawaii Lawyer, Oahu Lawyer, Oahu, Hawaii
http://hawaiiattorneyonline.com/