Brahmand Darshan Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Brahmand Darshan Observatory clear sky chart from 2005-11-06 to 2024-11-08.

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	12% 6% 2 6% 4 4 5% 4 6% 8% 44%	101113
	Night	12% 6% 2 5% 4 3 4 3 5% 7% 49%	98084
Transparency	Day	36% 7% 12% 20% 18% 7%	104843
	Night	33% 6% 12% 20% 19% 10%	102481
Seeing	Day	13% 7% 19% 26% 26% 10%	14925
	Night	14% 7% 25% 35% 18% 2	24778

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	16% 9% 2 5% 3 3 3 4 5% 6% 45%	2847
	11th to 20th	Day	18% 6% 2 5% 2 3 3 2 4 6% 50%	2850
	21st to end	Day	22% 10% 4 6% 3 2 2 2 4 8% 38%	3135
February	1st to 10th	Day	21% 9% 3 7% 3 3 3 3 4 6% 38%	1854
	11th to 20th	Day	21% 8% 2 5% 4 4 3 2 3 6% 41%	1849
	21st to end	Day	20% 7% 2 5% 4 3 4 3 4 5% 44%	1665
March	1st to 10th	Day	16% 9% 3 7% 6% 4 5% 3 5% 7% 34%	3436
	11th to 20th	Day	19% 8% 3 7% 6% 5% 5% 4 6% 6% 31%	3480
	21st to end	Day	15% 8% 3 7% 4 4 4 3 5% 7% 40%	3814
April	1st to 10th	Day	14% 8% 3 8% 5% 4 5% 4 4 7% 39%	2090
	11th to 20th	Day	15% 8% 3 7% 5% 4 4 4 5% 6% 39%	2163
	21st to end	Day	12% 7% 2 7% 4 4 4 4 6% 6% 44%	2280
May	1st to 10th	Day	18% 9% 3 8% 5% 5% 5% 4 6% 7% 30%	4070
	11th to 20th	Day	13% 7% 2 6% 5% 4 5% 4 6% 6% 42%	4082
	21st to end	Day	9% 6% 2 7% 6% 6% 7% 5% 9% 10% 33%	4477
June	1st to 10th	Day	5% 4 2 6% 5% 5% 6% 5% 8% 10% 44%	2470
	11th to 20th	Day	5% 4 1 5% 4 5% 5% 5% 8% 10% 48%	2470
	21st to end	Day	5% 5% 3 6% 6% 6% 7% 6% 8% 10% 38%	2470
July	1st to 10th	Day	8% 4 1 5% 5% 4 5% 4 8% 10% 46%	4120
	11th to 20th	Day	5% 5% 2 7% 5% 5% 5% 4 9% 11% 41%	4120
	21st to end	Day	12% 8% 3 7% 5% 5% 6% 5% 7% 9% 32%	4465
August	1st to 10th	Day	2 1 1 2 3 3 3 3 5% 8% 69%	4104
	11th to 20th	Day	3 2 1 3 3 4 4 5% 7% 12% 55%	4017
	21st to end	Day	5% 4 2 6% 4 5% 6% 5% 8% 10% 45%	3936
September	1st to 10th	Day	5% 5% 2 6% 5% 6% 6% 5% 6% 9% 44%	2090
	11th to 20th	Day	11% 6% 2 8% 6% 5% 5% 4 6% 7% 41%	2090
	21st to end	Day	6% 4 2 6% 5% 5% 5% 5% 5% 7% 52%	2090
October	1st to 10th	Day	5% 4 2 5% 3 4 4 3 5% 7% 59%	2025
	11th to 20th	Day	12% 5% 2 4 3 3 3 3 5% 5% 55%	1900
	21st to end	Day	13% 4 2 4 3 3 3 2 3 5% 58%	2090
November	1st to 10th	Day	11% 6% 2 6% 4 4 5% 4 5% 6% 47%	1928
	11th to 20th	Day	11% 6% 2 7% 4 3 3 3 4 6% 52%	1900
	21st to end	Day	18% 8% 3 5% 4 4 4 3 4 5% 42%	1730
December	1st to 10th	Day	15% 8% 3 6% 3 4 3 3 4 6% 45%	1710
	11th to 20th	Day	18% 7% 2 6% 5% 4 3 3 4 5% 42%	2161
	21st to end	Day	16% 8% 3 6% 3 4 3 3 4 4 47%	3135
January	1st to 10th	Night	18% 6% 2 4 3 3 3 3 3 5% 50%	4108
	11th to 20th	Night	18% 6% 2 4 2 2 2 2 3 3 56%	4120
	21st to end	Night	22% 8% 2 6% 4 3 3 2 4 6% 40%	4532
February	1st to 10th	Night	20% 7% 3 5% 4 4 3 2 4 5% 43%	2341
	11th to 20th	Night	20% 8% 2 5% 2 3 3 2 3 4 46%	2218
	21st to end	Night	21% 7% 2 5% 4 3 4 2 5% 5% 43%	1786
March	1st to 10th	Night	20% 9% 3 7% 4 4 4 3 4 6% 35%	3419
	11th to 20th	Night	21% 8% 3 8% 5% 4 4 3 5% 6% 33%	3480
	21st to end	Night	14% 9% 2 6% 4 4 4 3 5% 5% 45%	3817
April	1st to 10th	Night	12% 6% 2 6% 4 3 4 3 6% 7% 46%	2090
	11th to 20th	Night	13% 5% 3 5% 4 4 4 3 5% 8% 45%	1965
	21st to end	Night	14% 6% 2 4 4 4 4 3 5% 6% 47%	1900
May	1st to 10th	Night	20% 8% 3 7% 5% 3 4 3 5% 8% 34%	2831
	11th to 20th	Night	11% 6% 2 7% 4 4 4 4 5% 7% 46%	2823
	21st to end	Night	10% 6% 2 7% 5% 5% 5% 4 8% 9% 40%	3090
June	1st to 10th	Night	5% 3 1 5% 2 3 3 4 7% 11% 55%	1710
	11th to 20th	Night	3 3 1 3 3 3 3 4 6% 11% 60%	1710
	21st to end	Night	3 4 2 5% 4 5% 5% 5% 8% 11% 49%	1710
July	1st to 10th	Night	4 3 1 4 5% 5% 5% 4 7% 13% 50%	2850
	11th to 20th	Night	2 4 2 5% 4 4 4 4 7% 12% 53%	2850
	21st to end	Night	10% 7% 3 7% 5% 4 5% 4 7% 11% 38%	3098
August	1st to 10th	Night	1 1 1 2 2 2 2 5% 9% 74%	2836
	11th to 20th	Night	3 2 1 3 2 3 4 3 8% 12% 59%	2819
	21st to end	Night	3 3 1 4 4 4 5% 5% 8% 11% 52%	3715
September	1st to 10th	Night	5% 5% 2 6% 5% 4 4 5% 6% 8% 51%	2090
	11th to 20th	Night	9% 6% 2 6% 5% 5% 5% 3 6% 6% 46%	2090
	21st to end	Night	7% 3 1 5% 3 3 3 3 6% 8% 57%	2090
October	1st to 10th	Night	4 3 2 5% 3 3 3 2 4 7% 64%	2133
	11th to 20th	Night	11% 4 1 4 2 3 2 3 5% 5% 60%	2280
	21st to end	Night	12% 5% 2 4 3 3 3 2 3 4 61%	2508
November	1st to 10th	Night	12% 5% 2 5% 3 3 3 3 5% 6% 54%	2311
	11th to 20th	Night	9% 6% 2 5% 4 4 4 3 4 7% 52%	2280
	21st to end	Night	17% 7% 2 5% 4 3 4 3 5% 5% 46%	2446
December	1st to 10th	Night	16% 8% 3 5% 4 3 3 3 4 6% 45%	2470
	11th to 20th	Night	16% 9% 3 5% 4 3 4 3 4 6% 43%	3036
	21st to end	Night	16% 7% 2 5% 3 3 3 2 4 5% 51%	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	37% 6% 7% 17% 22% 10%	2848
	11th to 20th	Day	36% 3 7% 19% 28% 6%	2850
	21st to end	Day	48% 4 4 13% 20% 11%	3135
February	1st to 10th	Day	48% 5% 6% 12% 18% 11%	1854
	11th to 20th	Day	46% 3 7% 16% 18% 10%	1859
	21st to end	Day	43% 5% 8% 15% 17% 13%	1665
March	1st to 10th	Day	46% 9% 9% 13% 19% 5%	3436
	11th to 20th	Day	50% 9% 10% 11% 15% 6%	3480
	21st to end	Day	42% 6% 10% 16% 21% 5%	3814
April	1st to 10th	Day	45% 7% 6% 17% 14% 11%	2090
	11th to 20th	Day	44% 7% 9% 14% 18% 9%	2163
	21st to end	Day	38% 6% 10% 18% 21% 6%	2280
May	1st to 10th	Day	48% 11% 12% 14% 10% 5%	4108
	11th to 20th	Day	39% 9% 10% 17% 23% 3	4086
	21st to end	Day	38% 13% 14% 25% 10% 1	4489
June	1st to 10th	Day	31% 10% 15% 27% 15% 2	2470
	11th to 20th	Day	28% 9% 17% 24% 17% 4	2470
	21st to end	Day	37% 10% 15% 24% 12% 2	2470
July	1st to 10th	Day	30% 7% 27% 31% 5%	4056
	11th to 20th	Day	33% 8% 18% 25% 14% 1	4051
	21st to end	Day	44% 9% 18% 22% 6%	4325
August	1st to 10th	Day	14% 5% 14% 40% 26% 1	4090
	11th to 20th	Day	19% 7% 30% 34% 9% 2	4056
	21st to end	Day	31% 11% 20% 23% 13% 1	3935
September	1st to 10th	Day	35% 10% 12% 21% 15% 7%	2090
	11th to 20th	Day	40% 9% 13% 15% 17% 5%	2090
	21st to end	Day	30% 8% 11% 20% 17% 14%	2090
October	1st to 10th	Day	15% 4 7% 12% 21% 41%	3363
	11th to 20th	Day	20% 4 6% 16% 34% 20%	3140
	21st to end	Day	24% 5% 5% 21% 31% 15%	3428
November	1st to 10th	Day	35% 7% 9% 17% 21% 10%	1928
	11th to 20th	Day	33% 5% 10% 17% 22% 12%	1900
	21st to end	Day	45% 5% 7% 15% 19% 10%	1730
December	1st to 10th	Day	40% 5% 10% 17% 19% 8%	1710
	11th to 20th	Day	43% 6% 7% 13% 22% 10%	2159
	21st to end	Day	40% 4 6% 13% 26% 10%	3135
January	1st to 10th	Night	36% 5% 7% 18% 21% 13%	4108
	11th to 20th	Night	34% 3 6% 17% 28% 12%	4120
	21st to end	Night	45% 5% 5% 14% 21% 10%	4532
February	1st to 10th	Night	44% 4 5% 12% 19% 15%	2341
	11th to 20th	Night	42% 4 6% 15% 19% 13%	2218
	21st to end	Night	44% 4 8% 13% 16% 15%	1786
March	1st to 10th	Night	47% 7% 10% 12% 18% 6%	3419
	11th to 20th	Night	51% 7% 9% 15% 13% 6%	3480
	21st to end	Night	40% 7% 9% 14% 22% 8%	3817
April	1st to 10th	Night	36% 7% 10% 18% 17% 13%	2090
	11th to 20th	Night	37% 6% 11% 16% 17% 13%	1965
	21st to end	Night	36% 6% 10% 19% 22% 7%	1900
May	1st to 10th	Night	46% 9% 11% 18% 11% 5%	2858
	11th to 20th	Night	34% 8% 12% 20% 21% 4	2824
	21st to end	Night	35% 11% 15% 26% 12% 1	3099
June	1st to 10th	Night	21% 8% 20% 29% 21% 2	1710
	11th to 20th	Night	18% 8% 18% 32% 19% 5%	1710
	21st to end	Night	27% 7% 19% 29% 16% 2	1710
July	1st to 10th	Night	26% 8% 29% 32% 5%	2805
	11th to 20th	Night	24% 8% 21% 33% 13%	2796
	21st to end	Night	38% 9% 23% 23% 7%	2999
August	1st to 10th	Night	8% 5% 16% 41% 27% 2	2826
	11th to 20th	Night	17% 7% 30% 35% 11% 1	2846
	21st to end	Night	24% 11% 23% 28% 13% 2	3715
September	1st to 10th	Night	27% 10% 19% 22% 15% 7%	2090
	11th to 20th	Night	35% 9% 15% 19% 16% 7%	2090
	21st to end	Night	24% 6% 15% 20% 20% 14%	2090
October	1st to 10th	Night	13% 4 7% 15% 18% 42%	3562
	11th to 20th	Night	16% 3 4 20% 32% 25%	3779
	21st to end	Night	21% 3 5% 21% 32% 18%	4120
November	1st to 10th	Night	31% 6% 10% 21% 21% 12%	2311
	11th to 20th	Night	34% 5% 9% 19% 20% 13%	2280
	21st to end	Night	40% 4 9% 15% 19% 13%	2446
December	1st to 10th	Night	40% 5% 8% 20% 18% 10%	2470
	11th to 20th	Night	42% 5% 7% 11% 21% 14%	3037
	21st to end	Night	36% 5% 6% 14% 28% 10%	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	23% 13% 31% 24% 7% 2	270
	11th to 20th	Day	26% 11% 31% 23% 7% 2	270
	21st to end	Day	21% 15% 35% 20% 9%	297
February	1st to 10th	Day	27% 16% 32% 18% 7%	270
	11th to 20th	Day	28% 18% 30% 18% 5%	270
	21st to end	Day	26% 20% 37% 14% 3	225
March	1st to 10th	Day	23% 15% 35% 19% 8%	270
	11th to 20th	Day	19% 16% 40% 18% 6% 1	270
	21st to end	Day	19% 14% 40% 19% 8%	297
April	1st to 10th	Day	20% 16% 37% 23% 4	270
	11th to 20th	Day	22% 14% 30% 22% 11% 1	361
	21st to end	Day	17% 11% 33% 27% 10% 2	460
May	1st to 10th	Day	15% 10% 35% 29% 10% 1	641
	11th to 20th	Day	13% 8% 26% 33% 16% 4	675
	21st to end	Day	11% 4 25% 36% 20% 4	734
June	1st to 10th	Day	5% 3 13% 36% 32% 11%	680
	11th to 20th	Day	7% 1 12% 41% 32% 8%	680
	21st to end	Day	7% 1 13% 26% 38% 15%	680
July	1st to 10th	Day	6% 2 8% 27% 40% 17%	671
	11th to 20th	Day	3 1 3 29% 43% 20%	668
	21st to end	Day	6% 1 5% 23% 47% 19%	739
August	1st to 10th	Day	3 4 18% 53% 22%	676
	11th to 20th	Day	6% 2 19% 52% 21%	654
	21st to end	Day	8% 2 4 17% 39% 32%	399
September	1st to 10th	Day	4 1 5% 24% 35% 30%	300
	11th to 20th	Day	8% 6% 23% 37% 26%	300
	21st to end	Day	7% 2 7% 26% 39% 20%	300
October	1st to 10th	Day	3 1 13% 33% 37% 13%	300
	11th to 20th	Day	12% 4 20% 31% 24% 9%	300
	21st to end	Day	22% 9% 21% 20% 20% 8%	330
November	1st to 10th	Day	14% 7% 20% 33% 19% 6%	291
	11th to 20th	Day	16% 10% 23% 34% 14% 3	270
	21st to end	Day	23% 13% 29% 21% 11% 2	270
December	1st to 10th	Day	20% 8% 28% 26% 13% 6%	270
	11th to 20th	Day	25% 14% 30% 23% 7% 1	270
	21st to end	Day	22% 11% 33% 22% 10% 1	297
January	1st to 10th	Night	20% 10% 30% 33% 7%	950
	11th to 20th	Night	23% 10% 29% 29% 8%	950
	21st to end	Night	20% 10% 31% 32% 6%	1045
February	1st to 10th	Night	22% 13% 33% 27% 4	821
	11th to 20th	Night	26% 10% 32% 28% 3	744
	21st to end	Night	25% 14% 38% 20% 2	530
March	1st to 10th	Night	21% 10% 40% 25% 4	570
	11th to 20th	Night	18% 11% 38% 27% 7%	570
	21st to end	Night	14% 10% 44% 28% 4	627
April	1st to 10th	Night	15% 10% 41% 31% 4	570
	11th to 20th	Night	15% 11% 34% 33% 7%	563
	21st to end	Night	16% 11% 37% 28% 9% 1	570
May	1st to 10th	Night	12% 11% 40% 30% 6% 1	570
	11th to 20th	Night	13% 4 31% 38% 13% 1	561
	21st to end	Night	8% 4 28% 43% 16% 1	617
June	1st to 10th	Night	6% 2 15% 47% 27% 3	570
	11th to 20th	Night	3 1 22% 50% 22% 2	570
	21st to end	Night	4 1 12% 45% 33% 5%	570
July	1st to 10th	Night	4 2 6% 45% 37% 5%	555
	11th to 20th	Night	3 1 7% 47% 37% 4	552
	21st to end	Night	4 2 6% 49% 36% 4	624
August	1st to 10th	Night	1 1 4 50% 41% 3	567
	11th to 20th	Night	5% 4 46% 41% 4	564
	21st to end	Night	5% 7% 34% 48% 7%	627
September	1st to 10th	Night	6% 1 9% 34% 43% 7%	570
	11th to 20th	Night	12% 1 6% 34% 42% 5%	570
	21st to end	Night	7% 1 11% 36% 38% 5%	570
October	1st to 10th	Night	5% 2 12% 44% 31% 7%	613
	11th to 20th	Night	12% 3 21% 40% 22% 1	760
	21st to end	Night	13% 7% 26% 31% 19% 2	836
November	1st to 10th	Night	13% 3 25% 37% 20% 1	771
	11th to 20th	Night	12% 8% 27% 38% 14% 1	760
	21st to end	Night	20% 9% 28% 29% 14% 1	926
December	1st to 10th	Night	21% 7% 28% 31% 13%	950
	11th to 20th	Night	23% 11% 28% 31% 7%	950
	21st to end	Night	21% 9% 30% 31% 9% 1	1045

Page generated at 2024-11-05 07:15:51. Version ac07

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