Mancamp Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mancamp Observatory clear sky chart from 2005-11-06 to 2024-11-10.

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	18% 8% 3 7% 5% 4 5% 4 6% 7% 35%	101143
	Night	18% 9% 3 7% 4 4 4 4 5% 6% 36%	97997
Transparency	Day	46% 7% 11% 21% 13% 2	104668
	Night	47% 6% 12% 21% 13% 2	102562
Seeing	Day	24% 15% 30% 20% 9% 2	15237
	Night	23% 11% 31% 27% 8% 1	23914

By Month

Percentage Cloud Cover NE (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	15% 8% 2 7% 5% 5% 5% 5% 6% 7% 35%	2517
	11th to 20th	Day	16% 8% 3 7% 6% 5% 4 4 5% 8% 34%	2520
	21st to end	Day	14% 12% 3 8% 5% 5% 5% 4 5% 6% 33%	2772
February	1st to 10th	Day	16% 10% 3 7% 5% 5% 4 3 6% 6% 34%	1653
	11th to 20th	Day	12% 10% 3 9% 7% 5% 5% 3 6% 5% 34%	1833
	21st to end	Day	14% 12% 4 6% 5% 6% 5% 4 6% 6% 34%	1570
March	1st to 10th	Day	23% 13% 3 7% 4 4 5% 3 4 4 29%	3116
	11th to 20th	Day	16% 9% 3 8% 5% 5% 5% 4 5% 5% 35%	3410
	21st to end	Day	23% 10% 3 6% 4 3 3 2 5% 6% 34%	3926
April	1st to 10th	Day	20% 11% 3 7% 5% 3 3 3 4 6% 34%	2280
	11th to 20th	Day	18% 7% 2 6% 5% 4 5% 4 5% 7% 38%	2360
	21st to end	Day	22% 9% 3 8% 5% 5% 4 3 4 5% 32%	2470
May	1st to 10th	Day	23% 9% 3 7% 5% 5% 5% 4 5% 7% 28%	4106
	11th to 20th	Day	19% 7% 3 8% 6% 6% 6% 4 6% 7% 29%	4198
	21st to end	Day	15% 6% 2 6% 5% 5% 5% 4 7% 9% 35%	4837
June	1st to 10th	Day	24% 7% 2 6% 4 4 5% 4 7% 8% 29%	2731
	11th to 20th	Day	17% 7% 2 5% 5% 5% 5% 4 5% 7% 38%	2850
	21st to end	Day	24% 7% 3 6% 5% 4 4 4 6% 6% 31%	2714
July	1st to 10th	Day	14% 6% 2 7% 5% 5% 5% 4 7% 9% 35%	4440
	11th to 20th	Day	12% 5% 2 6% 5% 4 6% 5% 7% 9% 38%	4440
	21st to end	Day	18% 7% 2 6% 5% 4 5% 4 6% 8% 35%	4814
August	1st to 10th	Day	15% 6% 3 8% 5% 6% 5% 4 7% 9% 32%	4171
	11th to 20th	Day	17% 10% 3 8% 4 5% 5% 4 6% 8% 32%	4045
	21st to end	Day	11% 5% 2 5% 4 4 5% 4 6% 9% 44%	4372
September	1st to 10th	Day	11% 5% 2 5% 5% 3 4 3 6% 8% 47%	2240
	11th to 20th	Day	13% 5% 1 4 3 4 4 4 5% 7% 51%	2090
	21st to end	Day	17% 5% 2 5% 4 4 3 4 6% 8% 43%	2090
October	1st to 10th	Day	19% 7% 3 6% 5% 5% 4 4 4 6% 38%	2090
	11th to 20th	Day	18% 7% 3 5% 3 5% 4 3 5% 7% 41%	1815
	21st to end	Day	24% 9% 3 7% 4 3 4 2 4 5% 34%	1881
November	1st to 10th	Day	16% 6% 2 6% 3 4 5% 3 5% 6% 42%	1752
	11th to 20th	Day	21% 6% 2 5% 3 4 4 5% 6% 7% 38%	1710
	21st to end	Day	21% 8% 2 5% 4 3 3 3 4 6% 42%	1626
December	1st to 10th	Day	22% 12% 3 6% 4 3 4 4 4 5% 33%	1330
	11th to 20th	Day	23% 10% 3 5% 4 4 3 3 4 6% 36%	1668
	21st to end	Day	24% 12% 2 6% 4 4 5% 4 6% 5% 28%	2706
January	1st to 10th	Night	15% 10% 3 7% 4 4 5% 3 5% 6% 37%	4429
	11th to 20th	Night	13% 10% 4 10% 5% 5% 5% 5% 6% 7% 28%	4440
	21st to end	Night	17% 11% 4 10% 5% 4 5% 4 5% 5% 30%	4884
February	1st to 10th	Night	14% 10% 4 8% 6% 5% 4 5% 6% 6% 32%	2526
	11th to 20th	Night	11% 12% 4 7% 5% 5% 5% 4 5% 5% 39%	2228
	21st to end	Night	14% 10% 3 7% 4 5% 5% 4 5% 6% 37%	1884
March	1st to 10th	Night	27% 11% 3 5% 4 4 4 3 4 5% 30%	3724
	11th to 20th	Night	14% 11% 4 9% 5% 6% 5% 4 6% 6% 31%	3548
	21st to end	Night	24% 11% 2 7% 4 4 4 4 6% 7% 28%	3704
April	1st to 10th	Night	20% 12% 3 7% 4 3 4 2 4 5% 36%	1900
	11th to 20th	Night	18% 7% 2 7% 5% 5% 4 5% 5% 6% 37%	1768
	21st to end	Night	25% 8% 2 7% 4 3 3 3 5% 6% 34%	1710
May	1st to 10th	Night	22% 9% 3 6% 4 4 5% 4 6% 7% 31%	2834
	11th to 20th	Night	18% 10% 3 9% 5% 5% 5% 4 6% 7% 28%	2724
	21st to end	Night	16% 6% 2 7% 4 4 5% 4 6% 7% 40%	2738
June	1st to 10th	Night	25% 7% 2 6% 4 4 5% 4 5% 7% 33%	1439
	11th to 20th	Night	17% 7% 3 5% 4 4 4 5% 6% 8% 39%	1330
	21st to end	Night	24% 7% 3 5% 5% 3 4 3 6% 7% 33%	1455
July	1st to 10th	Night	12% 6% 2 6% 5% 5% 6% 5% 7% 10% 36%	2520
	11th to 20th	Night	15% 6% 2 7% 5% 4 4 3 6% 8% 40%	2520
	21st to end	Night	14% 6% 2 5% 4 4 4 4 6% 9% 41%	2739
August	1st to 10th	Night	20% 8% 3 7% 4 5% 5% 4 5% 6% 32%	2725
	11th to 20th	Night	14% 9% 3 7% 5% 4 5% 3 6% 7% 34%	2782
	21st to end	Night	11% 6% 2 6% 4 4 5% 3 6% 8% 45%	3281
September	1st to 10th	Night	13% 5% 2 6% 3 4 3 4 5% 7% 49%	1939
	11th to 20th	Night	16% 6% 2 4 3 2 3 3 4 6% 51%	2090
	21st to end	Night	17% 6% 2 5% 3 4 3 3 5% 7% 45%	2090
October	1st to 10th	Night	18% 7% 2 7% 4 4 4 5% 5% 6% 38%	2090
	11th to 20th	Night	17% 7% 2 5% 4 5% 5% 3 5% 7% 40%	2363
	21st to end	Night	24% 9% 2 5% 4 3 4 4 5% 7% 34%	2717
November	1st to 10th	Night	17% 7% 2 7% 4 4 3 3 5% 7% 41%	2531
	11th to 20th	Night	18% 6% 2 6% 5% 4 4 3 5% 7% 40%	2470
	21st to end	Night	17% 7% 2 6% 4 4 5% 4 5% 7% 39%	2550
December	1st to 10th	Night	21% 11% 3 6% 5% 4 4 4 5% 5% 31%	2850
	11th to 20th	Night	22% 9% 2 6% 4 4 4 3 5% 5% 37%	3531
	21st to end	Night	23% 10% 3 6% 4 3 4 3 5% 5% 34%	4944

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	44% 8% 12% 24% 11% 1	2518
	11th to 20th	Day	46% 8% 11% 23% 11% 2	2520
	21st to end	Day	49% 8% 12% 17% 13% 1	2772
February	1st to 10th	Day	50% 6% 9% 19% 13% 3	1653
	11th to 20th	Day	50% 6% 10% 18% 13% 3	1842
	21st to end	Day	50% 6% 10% 17% 11% 5%	1570
March	1st to 10th	Day	59% 5% 8% 11% 14% 3	3119
	11th to 20th	Day	48% 7% 9% 19% 13% 3	3410
	21st to end	Day	51% 4 6% 15% 19% 4	3926
April	1st to 10th	Day	53% 4 8% 17% 14% 4	2280
	11th to 20th	Day	45% 6% 9% 22% 15% 2	2360
	21st to end	Day	54% 5% 7% 17% 13% 3	2470
May	1st to 10th	Day	54% 9% 10% 18% 9% 1	4120
	11th to 20th	Day	51% 10% 13% 16% 9% 1	4202
	21st to end	Day	41% 10% 13% 20% 15% 1	4837
June	1st to 10th	Day	52% 7% 12% 20% 8% 1	2731
	11th to 20th	Day	44% 7% 12% 20% 15% 2	2850
	21st to end	Day	52% 9% 11% 17% 10% 1	2714
July	1st to 10th	Day	43% 7% 14% 23% 12%	4370
	11th to 20th	Day	40% 8% 15% 27% 10%	4365
	21st to end	Day	46% 6% 12% 21% 14%	4661
August	1st to 10th	Day	47% 8% 14% 25% 6%	4157
	11th to 20th	Day	49% 6% 15% 23% 7%	4084
	21st to end	Day	35% 7% 14% 25% 17% 2	4372
September	1st to 10th	Day	35% 7% 13% 27% 17% 1	2240
	11th to 20th	Day	33% 5% 9% 30% 20% 2	2090
	21st to end	Day	39% 6% 11% 28% 15% 1	2090
October	1st to 10th	Day	50% 6% 11% 20% 12% 1	3480
	11th to 20th	Day	36% 5% 11% 29% 17% 1	2992
	21st to end	Day	39% 3 14% 21% 19% 3	3081
November	1st to 10th	Day	42% 6% 14% 22% 15% 2	1752
	11th to 20th	Day	44% 6% 10% 20% 16% 3	1710
	21st to end	Day	45% 4 16% 22% 12% 1	1626
December	1st to 10th	Day	54% 5% 9% 20% 11% 1	1330
	11th to 20th	Day	50% 5% 9% 19% 15% 3	1668
	21st to end	Day	57% 5% 10% 17% 8% 3	2706
January	1st to 10th	Night	46% 7% 13% 23% 10% 1	4429
	11th to 20th	Night	50% 8% 14% 15% 10% 2	4440
	21st to end	Night	53% 8% 8% 18% 12% 2	4884
February	1st to 10th	Night	50% 6% 12% 17% 12% 3	2526
	11th to 20th	Night	46% 5% 11% 20% 16% 3	2230
	21st to end	Night	47% 5% 10% 20% 14% 4	1884
March	1st to 10th	Night	57% 4 10% 15% 10% 4	3734
	11th to 20th	Night	51% 8% 10% 19% 10% 2	3549
	21st to end	Night	55% 3 7% 15% 17% 3	3704
April	1st to 10th	Night	52% 4 8% 18% 16% 3	1900
	11th to 20th	Night	47% 6% 9% 21% 17% 1	1768
	21st to end	Night	51% 5% 11% 17% 14% 3	1710
May	1st to 10th	Night	48% 9% 16% 18% 8% 1	2840
	11th to 20th	Night	51% 10% 12% 17% 8% 2	2725
	21st to end	Night	41% 8% 16% 20% 14% 1	2739
June	1st to 10th	Night	51% 7% 11% 21% 9% 1	1439
	11th to 20th	Night	43% 6% 15% 22% 12% 2	1330
	21st to end	Night	50% 8% 13% 18% 9% 1	1455
July	1st to 10th	Night	41% 7% 19% 21% 11%	2480
	11th to 20th	Night	44% 4 15% 28% 9%	2472
	21st to end	Night	39% 8% 15% 26% 12% 1	2651
August	1st to 10th	Night	52% 7% 13% 21% 6%	2715
	11th to 20th	Night	47% 6% 18% 18% 10%	2809
	21st to end	Night	37% 7% 15% 24% 15% 2	3281
September	1st to 10th	Night	34% 7% 14% 30% 16%	1939
	11th to 20th	Night	34% 5% 9% 32% 17% 2	2090
	21st to end	Night	39% 6% 10% 29% 14% 2	2090
October	1st to 10th	Night	46% 5% 13% 22% 13% 1	3480
	11th to 20th	Night	36% 6% 10% 28% 19% 1	3925
	21st to end	Night	40% 4 12% 26% 15% 2	4467
November	1st to 10th	Night	43% 5% 12% 25% 14% 1	2531
	11th to 20th	Night	44% 5% 10% 23% 15% 3	2470
	21st to end	Night	44% 6% 14% 21% 13% 2	2550
December	1st to 10th	Night	54% 6% 9% 20% 11% 1	2850
	11th to 20th	Night	49% 5% 9% 18% 17% 1	3532
	21st to end	Night	51% 6% 11% 19% 11% 1	4944

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	32% 16% 33% 14% 5%	180
	11th to 20th	Day	32% 16% 33% 12% 4 2	180
	21st to end	Day	21% 20% 35% 20% 5%	198
February	1st to 10th	Day	30% 18% 29% 19% 4	313
	11th to 20th	Day	26% 24% 32% 16% 2	449
	21st to end	Day	24% 21% 32% 20% 3	382
March	1st to 10th	Day	27% 19% 33% 16% 5%	460
	11th to 20th	Day	28% 21% 32% 15% 3 1	460
	21st to end	Day	29% 20% 29% 14% 6% 2	506
April	1st to 10th	Day	35% 19% 27% 13% 6% 1	460
	11th to 20th	Day	30% 18% 31% 13% 6% 2	452
	21st to end	Day	31% 20% 29% 13% 4 2	460
May	1st to 10th	Day	33% 17% 25% 18% 5% 2	463
	11th to 20th	Day	22% 17% 34% 18% 7% 1	487
	21st to end	Day	21% 17% 33% 21% 6% 1	529
June	1st to 10th	Day	24% 13% 31% 21% 8% 2	561
	11th to 20th	Day	22% 13% 27% 23% 13% 3	680
	21st to end	Day	26% 13% 28% 21% 11% 2	544
July	1st to 10th	Day	20% 11% 32% 24% 12% 2	485
	11th to 20th	Day	16% 7% 37% 24% 12% 4	484
	21st to end	Day	16% 8% 36% 26% 10% 4	532
August	1st to 10th	Day	15% 9% 29% 29% 15% 3	486
	11th to 20th	Day	17% 10% 28% 26% 13% 5%	479
	21st to end	Day	14% 12% 30% 26% 13% 5%	539
September	1st to 10th	Day	16% 11% 28% 25% 16% 4	490
	11th to 20th	Day	19% 9% 26% 23% 14% 10%	490
	21st to end	Day	18% 11% 29% 23% 14% 5%	490
October	1st to 10th	Day	22% 15% 23% 23% 12% 4	490
	11th to 20th	Day	26% 13% 28% 18% 12% 2	393
	21st to end	Day	34% 12% 27% 18% 9%	429
November	1st to 10th	Day	26% 13% 28% 23% 8% 2	392
	11th to 20th	Day	31% 12% 30% 19% 7% 1	370
	21st to end	Day	30% 19% 22% 22% 7% 1	366
December	1st to 10th	Day	33% 12% 34% 14% 7%	180
	11th to 20th	Day	34% 17% 35% 9% 4	180
	21st to end	Day	30% 20% 28% 16% 4 2	198
January	1st to 10th	Night	22% 13% 36% 25% 3	760
	11th to 20th	Night	26% 16% 31% 24% 4	760
	21st to end	Night	17% 17% 37% 24% 4	836
February	1st to 10th	Night	23% 17% 30% 27% 3	760
	11th to 20th	Night	20% 18% 38% 20% 3	743
	21st to end	Night	22% 13% 36% 27% 3	628
March	1st to 10th	Night	26% 14% 34% 24% 2	760
	11th to 20th	Night	23% 16% 32% 23% 6%	760
	21st to end	Night	26% 16% 31% 21% 6% 1	836
April	1st to 10th	Night	29% 15% 30% 22% 3	760
	11th to 20th	Night	22% 15% 35% 22% 5%	644
	21st to end	Night	31% 12% 33% 20% 4	570
May	1st to 10th	Night	27% 12% 29% 28% 5%	570
	11th to 20th	Night	24% 13% 32% 24% 7% 1	512
	21st to end	Night	20% 7% 34% 34% 5%	411
June	1st to 10th	Night	26% 6% 32% 31% 6%	380
	11th to 20th	Night	19% 6% 28% 36% 11%	380
	21st to end	Night	26% 3 30% 34% 7%	380
July	1st to 10th	Night	18% 3 29% 36% 14%	370
	11th to 20th	Night	18% 2 22% 42% 15% 1	368
	21st to end	Night	16% 3 25% 40% 16% 1	416
August	1st to 10th	Night	16% 4 23% 41% 16% 1	506
	11th to 20th	Night	16% 4 28% 36% 15% 1	562
	21st to end	Night	17% 6% 23% 36% 16% 2	719
September	1st to 10th	Night	14% 5% 32% 32% 16% 1	760
	11th to 20th	Night	19% 7% 24% 30% 17% 4	760
	21st to end	Night	20% 8% 28% 28% 15% 1	760
October	1st to 10th	Night	21% 9% 25% 31% 14% 1	760
	11th to 20th	Night	21% 12% 30% 26% 10% 1	760
	21st to end	Night	31% 12% 28% 25% 5%	836
November	1st to 10th	Night	23% 11% 31% 27% 7% 1	779
	11th to 20th	Night	23% 11% 30% 26% 9% 1	760
	21st to end	Night	24% 15% 28% 27% 6% 1	796
December	1st to 10th	Night	29% 10% 33% 22% 6%	850
	11th to 20th	Night	27% 14% 33% 22% 5%	850
	21st to end	Night	29% 14% 30% 23% 3	852

Page generated at 2024-11-07 06:55:42. Version ac07

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