Moonbows 2015 Lower Yosemite Fall

MOONBOW PREDICTIONS FOR 2015

LOWER YOSEMITE FALL 

        

            Texas State group              moonbow: Robert Stavers

OBSERVING LOCATION:

VIEWING AREA, TERRACE AT THE WEST END OF THE BRIDGE NEAR THE BASE OF LOWER YOSEMITE FALL

 

DATE

IN

2015

TIMES

(PACIFIC

DAYLIGHT

TIME)

LUNAR

PHASE

 

REMARKS

April 3

(Fri)

8:10pm

(Fri)

to

10:00pm

(Fri)

100%

 

moonbow is already in progress when sky gets dark enough at about 8:10pm

April 4

(Sat)

8:55pm

(Sat)

to

11:35pm

(Sat)

99%

waning

 

night of

April 5-6

(Sun-Mon)

9:45pm

(Sun)

to

12:45am

(Mon)

97%

waning

 

May 1

(Fri)

8:40pm

(Fri)

to

9:20pm

(Fri)

96%

waxing

moonbow is already in progress when sky gets dark enough at about 8:40pm

May 2

(Sat)

8:40pm

(Sat)

to

10:35pm

(Sat)

99%

waxing

moonbow is already in progress when sky gets dark enough at about 8:40pm

May 3

(Sun)

8:40pm

(Sun)

to

11:40pm

(Sun)

100%

moonbow is already in progress when sky gets dark enough at about 8:40pm;

later that evening:  BRIGHT MOONBOW

(full Moon occurs at 8:42pm PDT on May 3)

 

night of

May 4-5

(Mon-Tues)

10:35pm

(Mon)

to

12:45am

(Tues)

99%

waning

 

night of

May 5-6

(Tues-Wed)

11:55pm

(Tues)

to

1:50am

(Wed)

95%

waning

 

May 31

(Sun)

9:05pm

(Sun)

to

10:35pm

(Sun)

98%

waxing

moonbow is already in progress when sky gets dark enough at about 9:05pm

June 1

(Mon)

9:45pm

(Mon)

to

11:35pm

(Mon)

100%

 

night of

June 2-3

(Tues-Wed)

10:50pm

(Tues)

to

12:35am

(Wed)

99%

waning

 

night of

June 3-4

(Wed-Thurs)

11:50pm

(Wed)

to

1:35am

(Thurs)

97%

waning

 

June 29

(Mon)

9:15pm

(Mon)

to

10:25pm

(Mon)

96%

waxing

moonbow is already in progress when sky gets dark enough at about 9:15pm

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

June 30

(Tues)

9:40pm

(Tues)

to

11:20pm

(Tues)

99%

waxing

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

night of

July 1-2

(Wed-Thurs)

10:30pm

(Wed)

to

12:15am

(Thurs)

100%

 

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

night of

July 2-3

(Thurs-Fri)

11:05pm

(Thurs)

to

1:05am

(Fri)

98%

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.