Buckeyestargazer Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Buckeyestargazer Observatory clear sky chart from 2005-11-06 to 2024-11-03.

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	13% 9% 3 8% 5% 4 4 4 6% 8% 36%	101171
	Night	14% 10% 4 8% 5% 4 4 4 5% 6% 36%	97869
Transparency	Day	46% 6% 12% 22% 13% 2	100962
	Night	48% 6% 11% 21% 13% 2	97750
Seeing	Day	16% 11% 29% 25% 14% 5%	15747
	Night	18% 10% 30% 30% 12% 1	25574

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	15% 15% 10% 13% 6% 4 5% 4 5% 5% 18%	2527
	11th to 20th	Day	14% 14% 7% 15% 8% 6% 5% 6% 7% 4 14%	2530
	21st to end	Day	23% 24% 6% 10% 5% 3 3 3 4 5% 15%	2783
February	1st to 10th	Day	16% 15% 4 11% 6% 6% 4 3 4 6% 25%	1835
	11th to 20th	Day	14% 11% 5% 9% 6% 5% 4 4 5% 7% 31%	1848
	21st to end	Day	16% 14% 5% 10% 4 4 5% 3 6% 6% 27%	1570
March	1st to 10th	Day	18% 15% 5% 8% 4 4 4 3 5% 5% 30%	3120
	11th to 20th	Day	11% 8% 4 8% 5% 4 5% 4 6% 8% 37%	3284
	21st to end	Day	18% 11% 5% 12% 6% 5% 5% 4 5% 7% 23%	4098
April	1st to 10th	Day	16% 11% 3 8% 5% 4 4 4 6% 7% 31%	2280
	11th to 20th	Day	17% 10% 3 6% 4 4 3 4 5% 7% 36%	2254
	21st to end	Day	20% 9% 3 6% 4 4 4 4 5% 7% 34%	2428
May	1st to 10th	Day	18% 7% 3 6% 5% 5% 5% 4 6% 8% 34%	4082
	11th to 20th	Day	14% 7% 3 5% 4 4 4 4 5% 9% 40%	4129
	21st to end	Day	8% 6% 2 6% 4 4 4 4 6% 9% 45%	4824
June	1st to 10th	Day	10% 5% 2 6% 5% 5% 5% 4 6% 8% 44%	2660
	11th to 20th	Day	8% 5% 2 6% 4 4 5% 4 7% 8% 45%	2660
	21st to end	Day	10% 6% 2 7% 5% 5% 6% 4 7% 9% 39%	2660
July	1st to 10th	Day	12% 7% 2 7% 6% 5% 5% 5% 7% 10% 35%	4440
	11th to 20th	Day	7% 4 2 5% 5% 5% 4 4 7% 10% 47%	4440
	21st to end	Day	8% 6% 3 7% 5% 5% 5% 4 7% 8% 42%	4813
August	1st to 10th	Day	7% 5% 2 6% 5% 4 5% 4 6% 9% 47%	4184
	11th to 20th	Day	8% 5% 2 6% 4 5% 5% 4 6% 8% 47%	3852
	21st to end	Day	7% 4 2 6% 4 4 4 4 6% 9% 49%	4180
September	1st to 10th	Day	10% 5% 2 6% 4 5% 4 4 6% 8% 47%	2280
	11th to 20th	Day	10% 6% 2 5% 4 4 4 4 6% 8% 48%	2109
	21st to end	Day	11% 7% 2 7% 5% 4 4 5% 6% 10% 41%	2090
October	1st to 10th	Day	11% 7% 3 7% 3 4 4 4 5% 7% 46%	2090
	11th to 20th	Day	18% 7% 3 8% 4 5% 4 4 6% 7% 36%	1871
	21st to end	Day	19% 9% 3 8% 5% 5% 6% 4 5% 6% 30%	1881
November	1st to 10th	Day	12% 8% 3 6% 4 4 3 4 6% 7% 43%	1690
	11th to 20th	Day	18% 11% 3 8% 4 4 4 4 5% 7% 32%	1710
	21st to end	Day	18% 11% 3 9% 5% 4 4 3 5% 5% 33%	1710
December	1st to 10th	Day	16% 15% 4 10% 6% 4 4 4 5% 6% 26%	1558
	11th to 20th	Day	13% 15% 5% 13% 6% 5% 4 3 5% 6% 24%	1918
	21st to end	Day	23% 22% 7% 13% 5% 4 3 3 4 4 13%	2783
January	1st to 10th	Night	16% 17% 8% 11% 6% 4 4 3 4 4 22%	4428
	11th to 20th	Night	15% 20% 8% 13% 6% 4 5% 4 6% 4 15%	4440
	21st to end	Night	23% 17% 7% 11% 5% 4 3 3 4 4 19%	4880
February	1st to 10th	Night	16% 14% 4 9% 6% 5% 3 2 5% 6% 29%	2343
	11th to 20th	Night	14% 11% 3 7% 6% 4 4 3 5% 8% 35%	2218
	21st to end	Night	20% 13% 3 8% 4 4 4 4 4 5% 31%	1884
March	1st to 10th	Night	17% 11% 4 8% 4 4 4 3 4 6% 35%	3733
	11th to 20th	Night	10% 6% 2 6% 5% 4 4 4 5% 7% 46%	3675
	21st to end	Night	19% 9% 4 9% 5% 5% 5% 4 5% 6% 28%	3562
April	1st to 10th	Night	14% 9% 2 7% 5% 5% 5% 4 5% 7% 37%	1900
	11th to 20th	Night	19% 8% 3 7% 4 4 4 3 4 6% 39%	1875
	21st to end	Night	17% 8% 3 8% 6% 4 4 4 5% 6% 36%	1750
May	1st to 10th	Night	16% 7% 4 7% 5% 5% 4 4 6% 8% 34%	2813
	11th to 20th	Night	17% 7% 3 6% 4 3 4 3 6% 7% 40%	2764
	21st to end	Night	11% 7% 2 7% 5% 5% 4 4 5% 6% 44%	2743
June	1st to 10th	Night	9% 5% 2 5% 3 3 4 4 7% 9% 48%	1520
	11th to 20th	Night	7% 6% 1 7% 4 4 5% 5% 6% 9% 46%	1520
	21st to end	Night	10% 6% 2 7% 5% 5% 4 5% 6% 8% 42%	1520
July	1st to 10th	Night	10% 5% 2 6% 5% 5% 5% 4 6% 9% 44%	2530
	11th to 20th	Night	6% 4 2 6% 4 3 4 4 5% 7% 55%	2530
	21st to end	Night	5% 5% 2 6% 5% 5% 6% 5% 7% 9% 45%	2750
August	1st to 10th	Night	7% 5% 2 6% 4 5% 5% 5% 7% 9% 46%	2733
	11th to 20th	Night	8% 5% 2 5% 4 4 5% 4 6% 7% 52%	2974
	21st to end	Night	9% 4 2 5% 4 4 4 4 6% 7% 51%	3476
September	1st to 10th	Night	10% 5% 2 5% 4 4 4 3 4 6% 53%	1900
	11th to 20th	Night	8% 4 1 5% 3 3 4 4 7% 7% 54%	2052
	21st to end	Night	10% 6% 2 6% 4 4 5% 3 6% 8% 45%	2090
October	1st to 10th	Night	11% 5% 2 6% 3 4 3 3 5% 6% 51%	2090
	11th to 20th	Night	17% 9% 2 6% 3 3 3 3 4 6% 43%	2304
	21st to end	Night	20% 9% 2 7% 4 3 4 3 5% 6% 37%	2717
November	1st to 10th	Night	12% 8% 3 6% 4 4 4 3 6% 6% 42%	2433
	11th to 20th	Night	14% 10% 3 9% 4 5% 5% 4 6% 7% 34%	2470
	21st to end	Night	19% 10% 4 7% 5% 4 5% 4 5% 6% 33%	2470
December	1st to 10th	Night	16% 14% 5% 8% 5% 4 4 4 5% 6% 29%	2619
	11th to 20th	Night	16% 14% 4 10% 6% 5% 4 4 4 6% 27%	3279
	21st to end	Night	24% 19% 6% 10% 6% 4 4 3 4 5% 15%	4884

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	66% 5% 12% 12% 5%	2528
	11th to 20th	Day	70% 5% 8% 11% 6%	2530
	21st to end	Day	72% 4 8% 13% 3	2783
February	1st to 10th	Day	61% 4 12% 15% 7% 1	1835
	11th to 20th	Day	52% 5% 10% 23% 9% 1	1858
	21st to end	Day	56% 6% 12% 18% 6% 2	1570
March	1st to 10th	Day	55% 7% 8% 19% 9% 1	3120
	11th to 20th	Day	43% 6% 10% 30% 9% 1	3284
	21st to end	Day	60% 7% 14% 16% 3	4098
April	1st to 10th	Day	50% 6% 11% 21% 12%	2280
	11th to 20th	Day	48% 5% 9% 23% 12% 3	2254
	21st to end	Day	48% 6% 13% 18% 12% 2	2428
May	1st to 10th	Day	46% 8% 11% 25% 8% 1	4120
	11th to 20th	Day	41% 8% 12% 28% 10% 1	4133
	21st to end	Day	34% 7% 11% 23% 23% 2	4837
June	1st to 10th	Day	36% 7% 11% 25% 17% 3	2660
	11th to 20th	Day	35% 8% 10% 23% 20% 3	2660
	21st to end	Day	38% 9% 15% 19% 16% 3	2660
July	1st to 10th	Day	44% 5% 13% 21% 14% 3	4371
	11th to 20th	Day	32% 5% 16% 29% 17% 1	4365
	21st to end	Day	39% 5% 16% 17% 19% 3	4662
August	1st to 10th	Day	34% 5% 15% 29% 16% 1	4169
	11th to 20th	Day	34% 5% 12% 32% 16% 1	3891
	21st to end	Day	32% 5% 13% 26% 20% 4	4179
September	1st to 10th	Day	35% 7% 12% 24% 17% 4	2280
	11th to 20th	Day	32% 7% 11% 25% 21% 3	2109
	21st to end	Day	39% 6% 11% 24% 19% 2	2090
October	1st to 10th	Day	37% 7% 11% 24% 18% 2	2090
	11th to 20th	Day	47% 4 11% 23% 15% 1	1871
	21st to end	Day	54% 5% 11% 20% 9% 1	1881
November	1st to 10th	Day	39% 6% 15% 23% 14% 2	1690
	11th to 20th	Day	52% 5% 11% 22% 9% 1	1710
	21st to end	Day	56% 3 11% 21% 8% 1	1710
December	1st to 10th	Day	60% 5% 13% 16% 6%	1558
	11th to 20th	Day	61% 5% 11% 19% 4	1915
	21st to end	Day	77% 5% 8% 7% 3	2783
January	1st to 10th	Night	64% 6% 11% 14% 5%	4428
	11th to 20th	Night	71% 4 10% 11% 4	4440
	21st to end	Night	69% 4 9% 13% 5%	4880
February	1st to 10th	Night	58% 4 10% 17% 9% 1	2343
	11th to 20th	Night	50% 5% 11% 21% 11% 1	2219
	21st to end	Night	55% 6% 9% 18% 10% 2	1884
March	1st to 10th	Night	49% 7% 11% 23% 10% 1	3733
	11th to 20th	Night	37% 6% 10% 27% 17% 2	3675
	21st to end	Night	54% 6% 14% 20% 5%	3562
April	1st to 10th	Night	45% 6% 12% 22% 14% 1	1900
	11th to 20th	Night	47% 5% 7% 21% 17% 3	1875
	21st to end	Night	48% 6% 10% 19% 14% 3	1750
May	1st to 10th	Night	47% 7% 10% 22% 13% 1	2840
	11th to 20th	Night	42% 7% 13% 26% 11%	2765
	21st to end	Night	39% 7% 10% 18% 23% 4	2751
June	1st to 10th	Night	31% 7% 13% 27% 20% 2	1520
	11th to 20th	Night	34% 7% 11% 23% 21% 3	1520
	21st to end	Night	38% 8% 15% 21% 15% 3	1520
July	1st to 10th	Night	37% 5% 14% 25% 13% 5%	2490
	11th to 20th	Night	29% 4 13% 24% 28% 2	2482
	21st to end	Night	33% 6% 17% 20% 20% 5%	2662
August	1st to 10th	Night	34% 6% 15% 29% 16% 1	2724
	11th to 20th	Night	31% 5% 14% 29% 21% 1	3001
	21st to end	Night	32% 4 11% 30% 19% 3	3476
September	1st to 10th	Night	32% 6% 12% 24% 20% 6%	1900
	11th to 20th	Night	27% 6% 8% 29% 26% 4	2052
	21st to end	Night	36% 6% 9% 26% 19% 3	2090
October	1st to 10th	Night	34% 5% 10% 27% 22% 1	2090
	11th to 20th	Night	43% 4 10% 24% 18% 2	2304
	21st to end	Night	48% 5% 10% 23% 13% 1	2717
November	1st to 10th	Night	42% 5% 10% 25% 17% 2	2433
	11th to 20th	Night	49% 5% 12% 22% 10% 1	2470
	21st to end	Night	52% 4 12% 23% 8%	2470
December	1st to 10th	Night	56% 5% 13% 18% 8%	2619
	11th to 20th	Night	58% 7% 11% 18% 6% 1	3281
	21st to end	Night	72% 5% 10% 9% 4	4884

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% 14% 33% 24% 6% 1	270
	11th to 20th	Day	23% 19% 36% 15% 5% 1	270
	21st to end	Day	24% 18% 33% 20% 5%	297
February	1st to 10th	Day	20% 20% 37% 18% 5%	270
	11th to 20th	Day	23% 18% 35% 20% 4	270
	21st to end	Day	24% 19% 40% 14% 4	225
March	1st to 10th	Day	23% 21% 36% 17% 3	270
	11th to 20th	Day	20% 18% 35% 19% 7%	342
	21st to end	Day	27% 16% 30% 20% 6% 1	506
April	1st to 10th	Day	24% 13% 32% 22% 7% 1	460
	11th to 20th	Day	21% 17% 32% 16% 11% 2	452
	21st to end	Day	24% 14% 32% 20% 8% 2	460
May	1st to 10th	Day	22% 13% 30% 22% 10% 3	463
	11th to 20th	Day	21% 8% 30% 23% 15% 3	509
	21st to end	Day	13% 9% 29% 26% 16% 7%	734
June	1st to 10th	Day	12% 8% 28% 29% 19% 5%	680
	11th to 20th	Day	11% 6% 32% 29% 19% 4	680
	21st to end	Day	12% 8% 31% 31% 13% 5%	680
July	1st to 10th	Day	9% 5% 21% 31% 20% 13%	671
	11th to 20th	Day	10% 5% 24% 30% 21% 10%	668
	21st to end	Day	9% 3 24% 34% 22% 8%	739
August	1st to 10th	Day	9% 3 18% 30% 26% 13%	541
	11th to 20th	Day	11% 4 21% 29% 25% 11%	479
	21st to end	Day	11% 3 15% 34% 28% 9%	539
September	1st to 10th	Day	11% 6% 20% 33% 23% 7%	490
	11th to 20th	Day	10% 4 16% 28% 27% 14%	490
	21st to end	Day	14% 10% 24% 24% 19% 9%	490
October	1st to 10th	Day	13% 8% 29% 30% 16% 5%	490
	11th to 20th	Day	18% 21% 26% 25% 10% 1	329
	21st to end	Day	29% 15% 36% 16% 4 1	330
November	1st to 10th	Day	15% 12% 37% 25% 9% 3	276
	11th to 20th	Day	21% 19% 34% 17% 7% 1	270
	21st to end	Day	27% 11% 39% 20% 3	270
December	1st to 10th	Day	18% 20% 37% 18% 6%	270
	11th to 20th	Day	19% 19% 40% 19% 4 1	270
	21st to end	Day	26% 22% 36% 14% 2	297
January	1st to 10th	Night	22% 15% 36% 22% 5%	950
	11th to 20th	Night	23% 15% 37% 21% 4 1	950
	21st to end	Night	22% 14% 34% 25% 4	1045
February	1st to 10th	Night	23% 13% 38% 23% 3	823
	11th to 20th	Night	21% 14% 35% 25% 4	743
	21st to end	Night	26% 15% 36% 19% 2	628
March	1st to 10th	Night	21% 13% 37% 23% 6%	760
	11th to 20th	Night	17% 12% 40% 25% 6%	760
	21st to end	Night	23% 11% 33% 26% 6%	684
April	1st to 10th	Night	17% 13% 39% 24% 6% 1	570
	11th to 20th	Night	23% 8% 35% 26% 7% 1	563
	21st to end	Night	20% 11% 33% 28% 8% 1	570
May	1st to 10th	Night	20% 7% 34% 29% 9% 1	570
	11th to 20th	Night	19% 5% 27% 35% 14% 1	561
	21st to end	Night	12% 4 23% 40% 20% 2	617
June	1st to 10th	Night	10% 4 22% 45% 18%	570
	11th to 20th	Night	11% 3 28% 40% 17% 1	570
	21st to end	Night	11% 3 25% 41% 18% 1	570
July	1st to 10th	Night	8% 2 14% 45% 25% 5%	555
	11th to 20th	Night	8% 3 19% 38% 28% 4	552
	21st to end	Night	5% 2 16% 46% 30% 1	624
August	1st to 10th	Night	7% 2 9% 49% 30% 4	567
	11th to 20th	Night	9% 1 13% 41% 31% 5%	564
	21st to end	Night	8% 2 17% 38% 32% 3	627
September	1st to 10th	Night	12% 4 17% 37% 27% 4	570
	11th to 20th	Night	9% 3 19% 37% 29% 4	722
	21st to end	Night	13% 6% 24% 32% 22% 3	760
October	1st to 10th	Night	14% 5% 25% 36% 19% 1	760
	11th to 20th	Night	22% 13% 28% 27% 9%	760
	21st to end	Night	25% 11% 31% 25% 7%	836
November	1st to 10th	Night	18% 12% 36% 23% 10% 1	749
	11th to 20th	Night	20% 18% 33% 24% 6%	760
	21st to end	Night	23% 14% 34% 23% 6%	760
December	1st to 10th	Night	24% 15% 35% 22% 3	909
	11th to 20th	Night	23% 12% 35% 25% 4	950
	21st to end	Night	30% 14% 33% 20% 3	1045

Page generated at 2024-10-31 02:39:21. Version ac07

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