Bickel Radio Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bickel Radio Observatory clear sky chart from 2005-11-05 to 2017-09-22.

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 TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(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

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
43%
15794
24%
47011
15%
15748
51%
15748
31%
28333

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
24%
899
24%
2327
8%
895
35%
895
26%
1530
January16th to endNight
24%
960
26%
2496
7%
960
36%
960
30%
1566
February1st to 15thNight
22%
880
19%
2288
4%
876
32%
876
27%
1504
February16th to endNight
21%
636
23%
1898
6%
636
34%
636
25%
1174
March1st to 15thNight
29%
540
22%
1980
12%
540
41%
540
20%
1247
March16th to endNight
29%
576
16%
2112
11%
576
38%
576
18%
1380
April1st to 15thNight
31%
539
24%
1810
12%
539
47%
539
30%
1011
April16th to endNight
32%
540
21%
1800
13%
540
46%
540
25%
1122
May1st to 15thNight
41%
540
19%
1657
15%
540
50%
540
27%
1056
May16th to endNight
51%
563
19%
1619
15%
561
57%
561
30%
1038
June1st to 15thNight
69%
540
22%
1440
17%
540
72%
540
47%
815
June16th to endNight
70%
540
27%
1440
19%
540
74%
540
47%
800
July1st to 15thNight
73%
510
17%
1515
17%
510
74%
510
37%
881
July16th to endNight
82%
564
26%
1594
28%
531
85%
531
47%
827
August1st to 15thNight
79%
539
25%
1610
29%
536
79%
536
41%
879
August16th to endNight
76%
573
25%
1896
30%
573
78%
573
38%
1012
September1st to 15thNight
67%
540
27%
1800
29%
540
71%
540
34%
1005
September16th to endNight
61%
551
29%
1896
26%
551
67%
551
35%
1017
October1st to 15thNight
50%
660
29%
1980
21%
660
56%
660
36%
1131
October16th to endNight
44%
704
29%
2112
17%
704
53%
704
35%
1210
November1st to 15thNight
39%
700
32%
2115
17%
700
53%
700
36%
1177
November16th to endNight
31%
840
25%
2460
12%
840
42%
840
27%
1511
December1st to 15thNight
28%
900
20%
2520
8%
900
38%
900
26%
1642
December16th to endNight
24%
960
22%
2646
8%
960
36%
960
23%
1798

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 ForecastData
Points
Cloud CoverDay
12%6%25%5%2445%7%42%
47853
Night
11%5%24423447%48%
47206
TransparencyDay
40%5%12%24%15%2
47553
Night
35%411%26%18%3
47011
SeeingDay
13%7%22%28%21%6%
5836
Night
14%9%28%30%15%1
15795

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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
14%6%25%424235%48%
1611
16th to endDay
12%7%35%422346%45%
1728
February1st to 15thDay
13%8%36%6%23336%41%
1575
16th to endDay
13%9%46%5%33435%39%
1584
March1st to 15thDay
14%8%46%424336%39%
1980
16th to endDay
19%9%25%5%34346%33%
2110
April1st to 15thDay
14%7%35%423445%44%
2137
16th to endDay
19%8%36%424445%34%
2160
May1st to 15thDay
18%6%26%5%2445%6%37%
2291
16th to endDay
12%5%27%6%35%5%6%6%37%
2493
June1st to 15thDay
9%4245%35%45%9%45%
2520
16th to endDay
5%3135%35%6%7%10%47%
2520
July1st to 15thDay
9%5%246%36%6%7%9%38%
2350
16th to endDay
7%3245%46%5%8%10%41%
2466
August1st to 15thDay
8%3245%35%6%7%10%40%
2340
16th to endDay
6%425%7%36%5%6%9%42%
2304
September1st to 15thDay
12%5%25%435%45%6%44%
2160
16th to endDay
8%6%25%425%5%47%47%
1862
October1st to 15thDay
13%5%2432234452%
1650
16th to endDay
12%5%14322336%53%
1760
November1st to 15thDay
12%6%13212445%54%
1740
16th to endDay
17%7%24422237%46%
1497
December1st to 15thDay
16%7%35%424346%41%
1440
16th to endDay
14%11%35%424347%37%
1575
January1st to 15thNight
13%6%25%423345%46%
2327
16th to endNight
10%5%35%423345%49%
2496
February1st to 15thNight
12%8%25%423236%46%
2278
16th to endNight
11%7%3443435%5%46%
1898
March1st to 15thNight
16%7%36%413446%42%
1980
16th to endNight
17%7%35%434445%38%
2112
April1st to 15thNight
11%413423446%52%
1810
16th to endNight
15%6%35%32446%7%42%
1800
May1st to 15thNight
15%425%423446%45%
1656
16th to endNight
12%42433445%10%43%
1617
June1st to 15thNight
5%32341437%9%54%
1440
16th to endNight
4213435%35%9%57%
1440
July1st to 15thNight
6%3144345%6%9%49%
1605
16th to endNight
321333346%11%55%
1702
August1st to 15thNight
5%333345%5%9%54%
1620
16th to endNight
42234345%5%8%53%
1896
September1st to 15thNight
9%42442345%7%51%
1800
16th to endNight
8%414423348%54%
1896
October1st to 15thNight
11%413423345%54%
1980
16th to endNight
12%5%2332334456%
2112
November1st to 15thNight
10%5%23323335%57%
2115
16th to endNight
14%7%24313335%48%
2460
December1st to 15thNight
18%7%25%32345%7%40%
2520
16th to endNight
15%9%35%424346%39%
2646

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
39%211%25%18%2
1612
16th to endDay
40%312%28%13%2
1728
February1st to 15thDay
44%313%24%12%1
1576
16th to endDay
47%37%24%13%3
1584
March1st to 15thDay
46%39%21%15%4
1980
16th to endDay
50%5%12%18%11%
2112
April1st to 15thDay
42%313%21%18%1
2137
16th to endDay
51%410%19%11%2
2160
May1st to 15thDay
46%5%12%21%12%
2291
16th to endDay
43%7%15%22%11%1
2497
June1st to 15thDay
35%6%13%28%15%
2520
16th to endDay
29%7%17%28%13%2
2520
July1st to 15thDay
39%8%13%25%11%1
2211
16th to endDay
33%6%17%28%13%1
2311
August1st to 15thDay
34%8%15%24%16%
2326
16th to endDay
35%6%13%22%15%6%
2304
September1st to 15thDay
38%5%10%23%15%6%
2160
16th to endDay
36%5%8%28%18%3
1862
October1st to 15thDay
35%210%25%21%4
1650
16th to endDay
32%38%30%18%6%
1760
November1st to 15thDay
32%48%27%20%7%
1740
16th to endDay
41%29%20%23%2
1497
December1st to 15thDay
44%310%25%15%1
1440
16th to endDay
46%410%20%15%2
1575
January1st to 15thNight
40%39%24%20%2
2327
16th to endNight
37%211%28%17%2
2496
February1st to 15thNight
40%311%26%14%2
2288
16th to endNight
38%313%24%17%2
1898
March1st to 15thNight
43%5%8%21%17%4
1980
16th to endNight
47%49%24%12%1
2112
April1st to 15thNight
32%412%26%21%4
1810
16th to endNight
39%5%11%25%15%2
1800
May1st to 15thNight
40%5%12%22%17%1
1657
16th to endNight
36%7%17%23%12%2
1619
June1st to 15thNight
23%5%17%30%21%1
1440
16th to endNight
22%6%14%31%19%4
1440
July1st to 15thNight
28%7%15%27%18%2
1515
16th to endNight
21%5%15%37%18%
1594
August1st to 15thNight
25%6%15%30%20%1
1610
16th to endNight
25%7%15%24%21%6%
1896
September1st to 15thNight
31%5%10%27%18%6%
1800
16th to endNight
29%5%10%25%25%3
1896
October1st to 15thNight
32%311%23%24%6%
1980
16th to endNight
31%38%27%20%7%
2112
November1st to 15thNight
29%38%27%22%7%
2115
16th to endNight
38%36%25%21%3
2460
December1st to 15thNight
42%312%23%16%1
2520
16th to endNight
46%210%22%13%4
2646

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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
23%20%38%14%3
90
16th to endDay
12%32%33%16%5%
96
February1st to 15thDay
13%18%52%13%2
90
16th to endDay
22%17%37%17%6%
81
March1st to 15thDay
24%17%38%16%2
90
16th to endDay
22%21%36%13%5%
96
April1st to 15thDay
17%14%34%25%7%
256
16th to endDay
25%8%34%21%8%1
270
May1st to 15thDay
19%9%31%25%11%2
428
16th to endDay
15%8%31%27%13%3
517
June1st to 15thDay
9%417%34%25%7%
495
16th to endDay
8%122%37%22%7%
495
July1st to 15thDay
12%211%37%27%7%
475
16th to endDay
6%17%26%37%18%
515
August1st to 15thDay
11%11%31%35%9%
493
16th to endDay
11%19%31%37%8%
344
September1st to 15thDay
11%38%30%34%11%
315
16th to endDay
8%421%27%29%8%
138
October1st to 15thDay
8%6%28%35%15%4
90
16th to endDay
15%5%29%38%9%2
96
November1st to 15thDay
12%7%27%37%13%1
90
16th to endDay
28%22%26%14%7%
90
December1st to 15thDay
18%15%40%16%5%3
90
16th to endDay
18%19%41%15%4
96
January1st to 15thNight
19%18%34%22%5%
900
16th to endNight
14%17%40%23%3
960
February1st to 15thNight
17%16%41%22%2
880
16th to endNight
15%16%42%22%2
636
March1st to 15thNight
21%11%34%27%4
540
16th to endNight
19%11%34%26%7%
576
April1st to 15thNight
14%12%38%28%5%
539
16th to endNight
18%9%36%27%7%
540
May1st to 15thNight
16%432%32%12%
540
16th to endNight
14%325%37%17%1
563
June1st to 15thNight
6%216%45%27%1
540
16th to endNight
5%115%45%30%2
540
July1st to 15thNight
6%110%42%34%3
510
16th to endNight
3436%47%6%
564
August1st to 15thNight
7%16%35%43%5%
539
16th to endNight
7%9%42%34%4
573
September1st to 15thNight
12%210%34%34%5%
540
16th to endNight
10%318%36%26%5%
551
October1st to 15thNight
12%427%31%19%3
660
16th to endNight
15%8%29%33%12%
704
November1st to 15thNight
11%10%34%29%13%
700
16th to endNight
20%12%33%24%9%
840
December1st to 15thNight
22%12%33%25%5%
900
16th to endNight
21%13%35%24%3
960
Page generated at 2017-09-23 05:43:46. Version ac04

Copyright 2017 A. Danko


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