Mancamp Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mancamp Observatory clear sky chart from 2005-11-05 to 2017-09-18.

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
29%
14778
16%
46923
8%
14746
39%
14746
19%
31878

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
25%
720
18%
2506
9%
716
38%
716
17%
1648
January16th to endNight
17%
768
17%
2688
4%
768
33%
768
13%
1805
February1st to 15thNight
22%
704
14%
2273
5%
701
33%
701
14%
1616
February16th to endNight
21%
631
18%
1893
6%
631
35%
631
17%
1319
March1st to 15thNight
19%
720
15%
2127
5%
720
31%
720
15%
1541
March16th to endNight
27%
768
20%
2073
7%
768
37%
768
22%
1392
April1st to 15thNight
21%
709
16%
1787
4%
709
29%
709
19%
1314
April16th to endNight
23%
540
16%
1620
5%
540
32%
540
17%
1128
May1st to 15thNight
26%
540
14%
1620
7%
540
33%
540
16%
1166
May16th to endNight
28%
399
11%
1521
9%
398
36%
398
13%
1087
June1st to 15thNight
30%
360
9%
1329
6%
360
37%
360
13%
966
June16th to endNight
40%
360
10%
1339
10%
360
46%
360
20%
880
July1st to 15thNight
45%
340
10%
1360
14%
340
50%
340
20%
851
July16th to endNight
49%
376
12%
1418
12%
354
55%
354
21%
880
August1st to 15thNight
45%
500
12%
1571
8%
498
49%
498
22%
1047
August16th to endNight
49%
631
20%
1777
11%
631
53%
631
33%
1093
September1st to 15thNight
43%
720
17%
1885
8%
720
48%
720
33%
1218
September16th to endNight
45%
669
26%
1847
15%
669
53%
669
33%
1127
October1st to 15thNight
34%
660
21%
1867
10%
660
44%
660
24%
1239
October16th to endNight
24%
704
15%
2285
6%
704
35%
704
18%
1598
November1st to 15thNight
32%
700
20%
2277
12%
700
44%
700
20%
1508
November16th to endNight
30%
728
19%
2391
10%
728
41%
728
18%
1590
December1st to 15thNight
21%
750
15%
2700
5%
750
33%
750
14%
1906
December16th to endNight
18%
781
16%
2769
5%
781
32%
781
13%
1959

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
18%6%25%5%3445%6%36%
47862
Night
18%7%25%424446%37%
47093
TransparencyDay
47%6%10%20%12%1
47550
Night
47%5%11%21%12%1
46923
SeeingDay
24%12%28%21%10%3
6054
Night
22%10%30%26%8%
14778

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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
16%7%35%5%35%45%7%34%
1432
16th to endDay
14%9%35%43445%7%37%
1536
February1st to 15thDay
15%9%38%7%45%35%5%31%
1585
16th to endDay
13%12%35%5%35%5%5%6%32%
1580
March1st to 15thDay
17%10%35%5%3445%5%34%
1823
16th to endDay
15%7%35%5%3344442%
2151
April1st to 15thDay
18%8%35%6%24445%36%
2161
16th to endDay
21%6%25%433446%37%
2340
May1st to 15thDay
25%6%36%6%34345%29%
2332
16th to endDay
23%5%25%5%25%45%6%32%
2602
June1st to 15thDay
27%6%245%2445%6%28%
2625
16th to endDay
22%6%25%5%25%5%46%32%
2615
July1st to 15thDay
14%4247%36%6%6%7%35%
2520
16th to endDay
14%5%26%6%37%5%6%8%32%
2654
August1st to 15thDay
15%4245%46%6%6%8%34%
2365
16th to endDay
12%4244345%5%7%45%
2423
September1st to 15thDay
14%4245%24446%45%
2074
16th to endDay
15%412323447%49%
1838
October1st to 15thDay
21%5%245%34445%39%
1763
16th to endDay
20%8%36%424335%36%
1587
November1st to 15thDay
20%5%35%334347%37%
1581
16th to endDay
21%6%24424345%41%
1566
December1st to 15thDay
22%10%344145%45%32%
1260
16th to endDay
22%11%45%433445%30%
1449
January1st to 15thNight
14%9%35%435%5%46%38%
2506
16th to endNight
14%9%36%5%3445%5%36%
2688
February1st to 15thNight
12%9%48%6%45%5%5%6%31%
2272
16th to endNight
15%10%45%5%25%44437%
1893
March1st to 15thNight
18%9%35%5%25%5%3434%
2114
16th to endNight
16%6%35%423336%43%
2073
April1st to 15thNight
19%8%36%5%2443436%
1787
16th to endNight
23%6%15%433445%36%
1620
May1st to 15thNight
22%7%25%5%3445%5%32%
1620
16th to endNight
23%8%35%435%45%6%28%
1519
June1st to 15thNight
27%8%244345%46%29%
1329
16th to endNight
21%5%245%1335%8%38%
1339
July1st to 15thNight
15%5%25%5%245%5%10%37%
1440
16th to endNight
14%5%25%425%5%5%10%39%
1514
August1st to 15thNight
14%5%25%6%35%5%5%6%39%
1581
16th to endNight
12%41442335%8%48%
1777
September1st to 15thNight
14%5%24324346%49%
1885
16th to endNight
14%324223346%51%
1847
October1st to 15thNight
19%6%2432445%7%40%
1867
16th to endNight
21%7%25%5%245%46%34%
2285
November1st to 15thNight
19%6%25%5%24347%37%
2277
16th to endNight
18%5%25%424346%40%
2391
December1st to 15thNight
21%10%35%42344434%
2700
16th to endNight
21%11%35%424345%31%
2769

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
46%6%11%19%14%2
1433
16th to endDay
45%5%12%21%13%1
1536
February1st to 15thDay
54%5%9%18%10%1
1588
16th to endDay
51%5%10%16%12%3
1580
March1st to 15thDay
52%49%17%12%2
1833
16th to endDay
44%49%18%18%4
2151
April1st to 15thDay
49%46%19%16%3
2161
16th to endDay
48%49%19%13%3
2340
May1st to 15thDay
56%47%18%11%2
2332
16th to endDay
51%7%9%19%11%1
2606
June1st to 15thDay
55%6%11%16%8%
2625
16th to endDay
50%7%10%18%12%
2615
July1st to 15thDay
43%9%13%23%10%
2371
16th to endDay
46%8%14%20%9%
2487
August1st to 15thDay
43%9%14%24%7%
2351
16th to endDay
36%6%13%24%18%1
2423
September1st to 15thDay
39%6%10%26%16%1
2074
16th to endDay
34%5%8%30%20%
1838
October1st to 15thDay
46%5%10%22%13%1
1763
16th to endDay
49%5%11%21%11%
1587
November1st to 15thDay
46%5%13%19%13%1
1581
16th to endDay
46%412%19%14%1
1566
December1st to 15thDay
52%6%10%19%9%
1260
16th to endDay
57%49%16%11%1
1449
January1st to 15thNight
46%5%12%23%11%1
2506
16th to endNight
48%5%9%19%14%2
2688
February1st to 15thNight
52%5%11%18%10%1
2273
16th to endNight
49%410%19%13%2
1893
March1st to 15thNight
52%5%8%18%11%2
2127
16th to endNight
43%410%18%18%4
2073
April1st to 15thNight
52%46%18%16%2
1787
16th to endNight
49%5%9%17%14%3
1620
May1st to 15thNight
51%6%7%18%13%1
1620
16th to endNight
54%6%10%17%9%1
1521
June1st to 15thNight
55%6%11%17%8%1
1329
16th to endNight
44%7%13%21%11%
1339
July1st to 15thNight
42%7%16%23%10%
1360
16th to endNight
41%7%17%22%10%
1418
August1st to 15thNight
44%6%15%23%9%
1571
16th to endNight
33%6%16%27%14%
1777
September1st to 15thNight
36%5%11%30%14%1
1885
16th to endNight
33%5%9%34%16%1
1847
October1st to 15thNight
43%5%11%23%14%1
1867
16th to endNight
49%5%11%22%10%
2285
November1st to 15thNight
46%5%11%22%13%1
2277
16th to endNight
46%5%11%22%13%1
2391
December1st to 15thNight
53%5%9%21%10%
2700
16th to endNight
54%49%19%11%
2769

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
26%11%36%20%5%
60
16th to endDay
23%21%31%20%3
64
February1st to 15thDay
26%17%28%23%4
209
16th to endDay
20%20%29%23%6%
239
March1st to 15thDay
28%18%31%16%5%
270
16th to endDay
23%18%29%16%7%4
288
April1st to 15thDay
30%11%30%15%7%2
270
16th to endDay
27%15%33%11%7%4
270
May1st to 15thDay
37%12%23%15%8%2
288
16th to endDay
26%12%32%20%6%1
331
June1st to 15thDay
28%12%25%21%10%
420
16th to endDay
21%8%29%28%10%2
410
July1st to 15thDay
17%8%35%20%15%3
305
16th to endDay
15%7%31%27%12%5%
326
August1st to 15thDay
17%8%28%26%14%4
313
16th to endDay
15%10%22%25%17%7%
332
September1st to 15thDay
19%7%25%24%17%5%
315
16th to endDay
20%8%22%18%16%13%
262
October1st to 15thDay
26%14%17%19%17%4
246
16th to endDay
28%11%30%19%10%
240
November1st to 15thDay
24%11%28%22%10%2
235
16th to endDay
32%13%18%24%8%1
237
December1st to 15thDay
31%11%33%16%6%
60
16th to endDay
34%20%34%10%
64
January1st to 15thNight
20%13%34%27%3
720
16th to endNight
21%16%35%23%2
768
February1st to 15thNight
19%16%32%28%2
704
16th to endNight
22%15%33%23%4
631
March1st to 15thNight
28%12%35%20%3
720
16th to endNight
21%16%29%23%7%
768
April1st to 15thNight
25%14%33%21%5%
709
16th to endNight
27%13%32%21%5%
540
May1st to 15thNight
27%12%29%24%6%
540
16th to endNight
23%8%33%29%5%
399
June1st to 15thNight
28%5%29%30%6%
360
16th to endNight
20%328%36%10%
360
July1st to 15thNight
18%225%34%18%
340
16th to endNight
15%126%39%17%
376
August1st to 15thNight
15%426%37%16%
500
16th to endNight
16%325%35%17%2
631
September1st to 15thNight
16%5%28%33%14%1
720
16th to endNight
18%6%26%27%19%2
669
October1st to 15thNight
23%10%26%26%12%1
660
16th to endNight
27%12%31%22%5%
704
November1st to 15thNight
23%8%29%28%9%1
700
16th to endNight
23%12%27%26%8%1
728
December1st to 15thNight
28%10%34%22%4
750
16th to endNight
31%12%31%21%3
781
Page generated at 2017-09-19 07:32:22. Version ac04

Copyright 2017 A. Danko


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