FWAS Rising Star
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the FWAS Rising Star clear sky chart from 2005-11-06 to 2024-11-05.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	8% 5% 2 4 3 3 4 3 5% 7% 56%	101031
	Night	8% 4 1 4 3 3 3 3 5% 7% 59%	98137
Transparency	Day	28% 2 9% 24% 26% 11%	104875
	Night	26% 2 8% 23% 26% 14%	102420
Seeing	Day	9% 6% 22% 30% 24% 9%	15043
	Night	10% 6% 29% 38% 16% 1	24937

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	9% 6% 2 5% 3 2 3 3 3 5% 59%	2847
	11th to 20th	Day	7% 6% 2 3 2 2 3 3 4 6% 62%	2850
	21st to end	Day	14% 6% 2 4 4 3 3 3 4 5% 52%	3361
February	1st to 10th	Day	11% 5% 2 5% 3 3 3 4 5% 6% 53%	1900
	11th to 20th	Day	11% 8% 2 5% 3 2 3 3 3 6% 53%	1849
	21st to end	Day	14% 7% 2 4 3 2 2 2 4 4 56%	1570
March	1st to 10th	Day	12% 7% 2 4 3 3 3 3 6% 7% 52%	3270
	11th to 20th	Day	15% 6% 2 5% 4 4 3 3 5% 6% 47%	3480
	21st to end	Day	7% 5% 2 6% 4 4 5% 5% 6% 7% 50%	3814
April	1st to 10th	Day	8% 5% 2 5% 3 4 4 3 5% 8% 53%	2090
	11th to 20th	Day	12% 6% 2 5% 3 3 3 3 3 6% 53%	2230
	21st to end	Day	9% 5% 2 5% 4 3 3 3 4 5% 57%	2399
May	1st to 10th	Day	12% 5% 2 6% 5% 4 4 4 5% 5% 48%	4082
	11th to 20th	Day	14% 6% 2 6% 3 3 3 3 4 6% 51%	4082
	21st to end	Day	11% 5% 2 5% 5% 5% 4 4 5% 7% 46%	4477
June	1st to 10th	Day	5% 3 1 4 4 4 4 3 6% 8% 58%	2470
	11th to 20th	Day	4 3 1 4 4 3 4 4 5% 8% 60%	2470
	21st to end	Day	5% 3 1 3 4 3 4 4 7% 7% 57%	2470
July	1st to 10th	Day	4 3 1 5% 5% 5% 5% 4 6% 7% 55%	4120
	11th to 20th	Day	3 2 1 3 3 3 3 3 6% 9% 65%	4120
	21st to end	Day	4 3 1 4 4 4 4 4 6% 10% 57%	4465
August	1st to 10th	Day	1 2 1 2 2 2 3 3 4 7% 72%	4053
	11th to 20th	Day	4 2 1 3 3 3 3 3 6% 9% 63%	3726
	21st to end	Day	2 2 1 4 3 4 4 4 6% 9% 60%	4158
September	1st to 10th	Day	10% 4 1 5% 4 4 5% 3 5% 6% 53%	2090
	11th to 20th	Day	9% 5% 2 6% 4 4 4 4 5% 7% 50%	2090
	21st to end	Day	7% 4 1 4 3 3 4 3 5% 7% 59%	2090
October	1st to 10th	Day	5% 4 1 3 3 3 3 3 6% 5% 65%	2090
	11th to 20th	Day	9% 3 1 4 2 3 3 2 4 4 65%	2000
	21st to end	Day	11% 4 1 3 2 2 3 2 3 4 64%	2090
November	1st to 10th	Day	9% 6% 1 4 3 3 2 2 4 5% 60%	1802
	11th to 20th	Day	4 4 1 4 3 2 4 2 5% 7% 64%	1710
	21st to end	Day	12% 5% 2 5% 4 3 3 3 4 4 56%	1710
December	1st to 10th	Day	11% 6% 2 4 3 3 3 3 4 6% 54%	1710
	11th to 20th	Day	10% 4 2 5% 3 3 4 4 6% 6% 52%	2161
	21st to end	Day	11% 7% 1 4 3 2 3 2 3 4 59%	3135
January	1st to 10th	Night	12% 6% 2 4 2 2 2 2 3 5% 60%	4108
	11th to 20th	Night	9% 5% 1 3 2 2 2 1 3 4 66%	4120
	21st to end	Night	13% 7% 2 5% 3 3 3 3 4 5% 53%	4336
February	1st to 10th	Night	10% 6% 2 5% 3 3 3 3 3 5% 56%	2280
	11th to 20th	Night	12% 6% 1 5% 3 3 3 3 4 6% 54%	2218
	21st to end	Night	12% 6% 2 3 3 2 3 3 3 5% 58%	1884
March	1st to 10th	Night	9% 6% 2 6% 3 3 3 3 4 5% 54%	3588
	11th to 20th	Night	12% 6% 2 5% 4 2 3 4 6% 6% 50%	3480
	21st to end	Night	6% 6% 2 5% 4 4 4 4 7% 7% 52%	3817
April	1st to 10th	Night	5% 4 2 5% 4 3 3 4 5% 9% 56%	2090
	11th to 20th	Night	9% 6% 1 5% 5% 3 3 3 4 6% 53%	1895
	21st to end	Night	8% 5% 1 3 2 3 3 3 4 6% 62%	1777
May	1st to 10th	Night	16% 7% 2 4 3 3 4 3 4 6% 48%	2823
	11th to 20th	Night	8% 6% 2 5% 4 4 3 3 4 7% 54%	2823
	21st to end	Night	9% 4 2 4 3 3 4 4 6% 9% 53%	3090
June	1st to 10th	Night	3 2 1 4 2 4 4 3 7% 8% 62%	1710
	11th to 20th	Night	3 2 1 3 2 3 3 4 6% 9% 64%	1710
	21st to end	Night	3 3 1 3 3 3 2 4 6% 7% 65%	1710
July	1st to 10th	Night	4 2 1 3 3 3 3 3 5% 8% 65%	2850
	11th to 20th	Night	2 1 1 2 2 2 2 3 5% 11% 71%	2850
	21st to end	Night	3 3 1 3 2 4 3 4 6% 9% 61%	3098
August	1st to 10th	Night	1 1 1 2 2 2 2 2 4 7% 75%	2883
	11th to 20th	Night	3 2 1 2 3 2 3 2 5% 10% 66%	3113
	21st to end	Night	2 2 1 3 3 4 4 3 6% 10% 61%	3507
September	1st to 10th	Night	8% 4 1 4 3 3 4 4 5% 8% 55%	2090
	11th to 20th	Night	9% 4 2 4 3 3 4 3 6% 8% 53%	2090
	21st to end	Night	6% 3 1 3 3 3 4 3 5% 7% 61%	2090
October	1st to 10th	Night	5% 3 1 3 3 3 3 3 4 6% 67%	2090
	11th to 20th	Night	8% 4 1 4 2 2 3 3 3 5% 65%	2158
	21st to end	Night	10% 4 2 4 2 3 3 2 3 4 63%	2508
November	1st to 10th	Night	10% 5% 1 4 2 2 3 3 4 4 62%	2373
	11th to 20th	Night	4 3 1 4 2 3 4 3 3 5% 65%	2470
	21st to end	Night	13% 5% 2 4 3 3 3 2 5% 6% 54%	2470
December	1st to 10th	Night	9% 4 1 4 3 3 3 3 5% 7% 58%	2470
	11th to 20th	Night	9% 5% 2 5% 4 3 4 4 4 6% 53%	3036
	21st to end	Night	12% 6% 2 4 3 3 3 2 3 4 58%	4532

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	31% 1 4 15% 33% 15%	2848
	11th to 20th	Day	27% 1 5% 19% 34% 14%	2850
	21st to end	Day	37% 2 4 17% 29% 11%	3361
February	1st to 10th	Day	32% 2 5% 17% 24% 19%	1900
	11th to 20th	Day	36% 2 5% 21% 23% 14%	1859
	21st to end	Day	34% 2 4 12% 28% 21%	1570
March	1st to 10th	Day	35% 1 4 11% 28% 21%	3270
	11th to 20th	Day	41% 2 13% 15% 21% 9%	3480
	21st to end	Day	35% 2 9% 18% 24% 12%	3814
April	1st to 10th	Day	32% 2 9% 21% 20% 16%	2090
	11th to 20th	Day	34% 2 7% 18% 23% 16%	2230
	21st to end	Day	31% 2 7% 19% 30% 10%	2399
May	1st to 10th	Day	39% 2 8% 19% 19% 13%	4120
	11th to 20th	Day	37% 2 8% 19% 29% 5%	4086
	21st to end	Day	38% 3 12% 24% 14% 10%	4489
June	1st to 10th	Day	24% 4 15% 31% 22% 5%	2470
	11th to 20th	Day	23% 4 10% 32% 24% 7%	2470
	21st to end	Day	24% 4 11% 29% 23% 9%	2470
July	1st to 10th	Day	26% 4 13% 40% 16% 1	4056
	11th to 20th	Day	18% 2 15% 36% 26% 3	4051
	21st to end	Day	22% 4 12% 37% 23% 2	4325
August	1st to 10th	Day	13% 2 11% 32% 37% 5%	4039
	11th to 20th	Day	19% 3 14% 35% 26% 4	3762
	21st to end	Day	21% 4 17% 31% 23% 4	4157
September	1st to 10th	Day	33% 3 7% 22% 24% 10%	2090
	11th to 20th	Day	34% 4 9% 21% 24% 8%	2090
	21st to end	Day	26% 3 7% 22% 27% 16%	2090
October	1st to 10th	Day	13% 2 6% 14% 35% 30%	3480
	11th to 20th	Day	19% 2 6% 24% 27% 22%	3305
	21st to end	Day	18% 2 3 25% 37% 14%	3428
November	1st to 10th	Day	29% 2 7% 23% 26% 13%	1802
	11th to 20th	Day	23% 2 7% 24% 28% 16%	1710
	21st to end	Day	33% 2 4 21% 26% 15%	1710
December	1st to 10th	Day	33% 2 5% 18% 30% 12%	1710
	11th to 20th	Day	33% 2 7% 17% 25% 15%	2159
	21st to end	Day	32% 1 3 20% 28% 16%	3135
January	1st to 10th	Night	30% 1 3 17% 35% 15%	4108
	11th to 20th	Night	25% 1 4 21% 29% 21%	4120
	21st to end	Night	36% 2 5% 17% 26% 15%	4336
February	1st to 10th	Night	32% 2 6% 17% 23% 19%	2280
	11th to 20th	Night	33% 2 6% 16% 25% 18%	2218
	21st to end	Night	31% 2 4 15% 24% 24%	1884
March	1st to 10th	Night	33% 2 5% 13% 27% 20%	3588
	11th to 20th	Night	36% 1 12% 23% 17% 11%	3480
	21st to end	Night	32% 1 9% 22% 27% 8%	3817
April	1st to 10th	Night	27% 3 10% 22% 19% 20%	2090
	11th to 20th	Night	33% 3 8% 17% 22% 17%	1895
	21st to end	Night	25% 3 10% 24% 29% 10%	1777
May	1st to 10th	Night	40% 2 8% 21% 18% 12%	2850
	11th to 20th	Night	32% 2 11% 23% 24% 8%	2824
	21st to end	Night	30% 2 13% 28% 18% 9%	3099
June	1st to 10th	Night	20% 4 17% 34% 21% 4	1710
	11th to 20th	Night	17% 3 13% 34% 25% 8%	1710
	21st to end	Night	19% 3 11% 30% 27% 9%	1710
July	1st to 10th	Night	19% 4 13% 42% 20% 3	2805
	11th to 20th	Night	11% 2 11% 40% 31% 5%	2796
	21st to end	Night	18% 4 13% 38% 25% 2	2999
August	1st to 10th	Night	11% 2 10% 30% 42% 6%	2873
	11th to 20th	Night	16% 2 16% 37% 25% 4	3143
	21st to end	Night	19% 5% 21% 28% 23% 4	3507
September	1st to 10th	Night	27% 4 9% 24% 24% 12%	2090
	11th to 20th	Night	29% 4 12% 22% 22% 10%	2090
	21st to end	Night	24% 2 7% 24% 25% 18%	2090
October	1st to 10th	Night	12% 1 6% 16% 30% 36%	3480
	11th to 20th	Night	18% 2 7% 18% 34% 23%	3579
	21st to end	Night	20% 1 3 23% 38% 15%	4120
November	1st to 10th	Night	27% 2 6% 22% 25% 18%	2373
	11th to 20th	Night	23% 3 6% 23% 27% 18%	2470
	21st to end	Night	33% 2 6% 17% 27% 16%	2470
December	1st to 10th	Night	29% 2 7% 22% 27% 15%	2470
	11th to 20th	Night	34% 2 5% 16% 27% 17%	3037
	21st to end	Night	32% 2 3 16% 28% 19%	4532

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	10% 13% 39% 31% 7%	270
	11th to 20th	Day	13% 14% 28% 33% 9% 3	270
	21st to end	Day	12% 10% 41% 24% 12% 1	297
February	1st to 10th	Day	16% 12% 38% 26% 7% 1	270
	11th to 20th	Day	19% 11% 40% 25% 5%	270
	21st to end	Day	22% 9% 44% 21% 3 1	225
March	1st to 10th	Day	16% 13% 36% 30% 6%	270
	11th to 20th	Day	14% 12% 36% 28% 7% 2	270
	21st to end	Day	9% 13% 45% 25% 8%	297
April	1st to 10th	Day	10% 14% 40% 27% 8%	270
	11th to 20th	Day	14% 13% 46% 21% 6%	428
	21st to end	Day	12% 12% 41% 26% 9% 1	579
May	1st to 10th	Day	11% 10% 36% 34% 8%	653
	11th to 20th	Day	15% 6% 26% 32% 17% 4	675
	21st to end	Day	10% 5% 28% 36% 18% 3	734
June	1st to 10th	Day	6% 2 14% 42% 29% 7%	680
	11th to 20th	Day	4 1 18% 47% 24% 6%	680
	21st to end	Day	4 1 9% 35% 38% 13%	680
July	1st to 10th	Day	6% 1 4 31% 42% 16%	671
	11th to 20th	Day	3 1 3 27% 48% 18%	668
	21st to end	Day	2 1 2 26% 47% 22%	739
August	1st to 10th	Day	1 1 2 26% 48% 22%	651
	11th to 20th	Day	7% 1 3 26% 41% 22%	477
	21st to end	Day	4 1 4 25% 38% 28%	530
September	1st to 10th	Day	11% 1 6% 14% 38% 30%	300
	11th to 20th	Day	5% 2 4 21% 42% 26%	300
	21st to end	Day	10% 1 4 28% 33% 24%	300
October	1st to 10th	Day	5% 12% 35% 31% 17%	300
	11th to 20th	Day	9% 2 26% 36% 26% 2	300
	21st to end	Day	18% 7% 24% 25% 24% 2	330
November	1st to 10th	Day	14% 4 28% 34% 13% 6%	282
	11th to 20th	Day	7% 11% 28% 33% 17% 4	270
	21st to end	Day	16% 10% 34% 25% 12% 2	270
December	1st to 10th	Day	17% 7% 27% 31% 13% 4	270
	11th to 20th	Day	7% 13% 42% 28% 10%	270
	21st to end	Day	21% 7% 35% 27% 8% 1	297
January	1st to 10th	Night	11% 8% 37% 37% 7%	950
	11th to 20th	Night	14% 10% 33% 36% 7% 1	950
	21st to end	Night	13% 9% 36% 34% 8%	927
February	1st to 10th	Night	14% 9% 39% 32% 6%	760
	11th to 20th	Night	15% 8% 42% 30% 4	744
	21st to end	Night	16% 10% 49% 23% 3	628
March	1st to 10th	Night	14% 11% 43% 28% 4	679
	11th to 20th	Night	16% 8% 41% 30% 5%	570
	21st to end	Night	9% 10% 48% 29% 4	627
April	1st to 10th	Night	6% 11% 52% 26% 4	570
	11th to 20th	Night	11% 10% 49% 26% 4	563
	21st to end	Night	9% 8% 50% 26% 6%	570
May	1st to 10th	Night	10% 10% 44% 32% 4	570
	11th to 20th	Night	10% 4 39% 36% 11% 1	561
	21st to end	Night	8% 4 36% 41% 11% 1	617
June	1st to 10th	Night	3 3 22% 51% 19% 2	570
	11th to 20th	Night	4 2 28% 55% 12% 1	570
	21st to end	Night	5% 1 13% 52% 27% 1	570
July	1st to 10th	Night	6% 1 7% 52% 30% 3	555
	11th to 20th	Night	3 7% 53% 36% 1	552
	21st to end	Night	2 4 50% 42% 1	624
August	1st to 10th	Night	1 5% 50% 41% 3	567
	11th to 20th	Night	7% 1 3 45% 40% 4	564
	21st to end	Night	3 1 4 43% 46% 4	627
September	1st to 10th	Night	9% 1 8% 44% 35% 4	570
	11th to 20th	Night	10% 1 10% 42% 35% 1	570
	21st to end	Night	7% 1 12% 47% 32% 2	570
October	1st to 10th	Night	6% 2 19% 46% 26% 1	570
	11th to 20th	Night	9% 3 26% 46% 16% 1	638
	21st to end	Night	13% 6% 28% 36% 16% 1	836
November	1st to 10th	Night	12% 3 27% 41% 16%	853
	11th to 20th	Night	6% 7% 32% 41% 13% 1	950
	21st to end	Night	16% 7% 33% 33% 10% 1	950
December	1st to 10th	Night	12% 8% 32% 40% 8% 1	950
	11th to 20th	Night	15% 8% 34% 35% 7%	950
	21st to end	Night	12% 7% 38% 35% 7%	1045

Page generated at 2024-11-03 01:11:21. Version ac07

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