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 2018-10-27.

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%
16191
16%
51313
8%
16159
39%
16159
19%
34755

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%
780
18%
2716
8%
776
38%
776
17%
1786
January16th to endNight
17%
832
16%
2912
4%
832
32%
832
13%
1961
February1st to 15thNight
21%
764
14%
2466
6%
761
34%
761
14%
1749
February16th to endNight
20%
683
18%
2049
6%
683
35%
683
17%
1422
March1st to 15thNight
18%
780
14%
2304
5%
780
29%
780
14%
1694
March16th to endNight
26%
832
21%
2246
6%
832
37%
832
22%
1509
April1st to 15thNight
21%
768
16%
1936
4%
768
29%
768
19%
1424
April16th to endNight
23%
578
15%
1734
5%
578
31%
578
17%
1210
May1st to 15thNight
26%
585
15%
1755
8%
585
34%
585
17%
1249
May16th to endNight
28%
433
12%
1651
9%
432
37%
432
13%
1166
June1st to 15thNight
31%
390
10%
1440
7%
390
39%
390
14%
1034
June16th to endNight
40%
390
10%
1451
10%
390
46%
390
20%
951
July1st to 15thNight
47%
370
12%
1480
16%
370
52%
370
21%
904
July16th to endNight
50%
408
12%
1546
13%
386
55%
386
21%
962
August1st to 15thNight
45%
532
12%
1673
8%
530
49%
530
22%
1120
August16th to endNight
50%
684
19%
1926
10%
684
54%
684
33%
1181
September1st to 15thNight
44%
780
19%
2042
9%
780
49%
780
33%
1313
September16th to endNight
44%
777
26%
2145
16%
777
52%
777
32%
1324
October1st to 15thNight
36%
780
20%
2207
10%
780
46%
780
24%
1467
October16th to endNight
24%
816
15%
2647
6%
816
35%
816
17%
1824
November1st to 15thNight
31%
760
20%
2472
12%
760
43%
760
19%
1642
November16th to endNight
30%
792
20%
2590
11%
792
42%
792
18%
1702
December1st to 15thNight
20%
825
15%
2925
5%
825
33%
825
14%
2067
December16th to endNight
18%
852
17%
3000
5%
852
33%
852
13%
2094

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%34446%36%
52230
Night
17%7%25%424446%37%
51483
TransparencyDay
47%6%10%20%13%1
51918
Night
46%5%11%21%13%1
51313
SeeingDay
24%12%28%21%10%3
7458
Night
22%10%30%26%8%
16191

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%
1552
16th to endDay
14%9%35%43445%7%37%
1664
February1st to 15thDay
16%9%38%6%35%45%5%31%
1721
16th to endDay
13%12%35%6%35%45%6%32%
1710
March1st to 15thDay
18%10%35%6%34445%32%
1976
16th to endDay
14%7%35%5%3334442%
2330
April1st to 15thDay
18%8%35%6%24446%35%
2342
16th to endDay
21%6%25%433446%37%
2501
May1st to 15thDay
24%6%35%6%34345%31%
2527
16th to endDay
21%5%25%5%35%45%6%33%
2824
June1st to 15thDay
27%6%245%2445%6%29%
2844
16th to endDay
21%6%25%5%25%5%46%33%
2833
July1st to 15thDay
13%4247%36%6%6%7%37%
2730
16th to endDay
14%5%26%6%36%5%6%8%32%
2878
August1st to 15thDay
16%425%5%46%6%6%8%34%
2515
16th to endDay
12%41443445%7%46%
2626
September1st to 15thDay
13%4245%24446%46%
2247
16th to endDay
14%5%13423447%48%
2145
October1st to 15thDay
20%6%24424445%40%
2083
16th to endDay
20%7%36%424336%37%
1834
November1st to 15thDay
20%5%36%334446%37%
1716
16th to endDay
21%6%24423345%41%
1697
December1st to 15thDay
21%9%45%414445%33%
1365
16th to endDay
22%11%45%5%33445%30%
1570
January1st to 15thNight
14%9%35%435%5%46%38%
2716
16th to endNight
14%9%37%5%3445%6%35%
2912
February1st to 15thNight
12%9%48%6%35%5%5%6%31%
2465
16th to endNight
15%11%35%5%25%44437%
2049
March1st to 15thNight
18%10%35%5%25%5%3432%
2291
16th to endNight
16%6%35%423335%43%
2246
April1st to 15thNight
19%8%36%5%2443435%
1936
16th to endNight
24%6%25%423445%35%
1734
May1st to 15thNight
21%7%25%5%3445%6%33%
1755
16th to endNight
22%8%35%435%45%6%30%
1649
June1st to 15thNight
26%8%243345%46%30%
1440
16th to endNight
21%5%245%1335%8%38%
1451
July1st to 15thNight
14%425%5%245%5%10%39%
1560
16th to endNight
14%5%244245%5%10%39%
1642
August1st to 15thNight
14%5%25%6%345%6%7%38%
1683
16th to endNight
12%41442335%8%48%
1926
September1st to 15thNight
14%5%24423346%48%
2042
16th to endNight
14%424223346%50%
2145
October1st to 15thNight
18%6%2432445%7%40%
2207
16th to endNight
21%7%245%245%46%35%
2647
November1st to 15thNight
19%6%25%5%24347%37%
2472
16th to endNight
18%5%25%424346%41%
2590
December1st to 15thNight
22%10%35%42344433%
2925
16th to endNight
20%11%35%424345%33%
3000

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
47%6%11%18%14%2
1553
16th to endDay
45%5%12%21%13%1
1664
February1st to 15thDay
54%5%9%18%11%1
1724
16th to endDay
51%5%10%15%12%3
1710
March1st to 15thDay
55%49%16%12%2
1986
16th to endDay
43%48%18%19%4
2330
April1st to 15thDay
50%46%19%15%3
2342
16th to endDay
49%49%19%13%3
2501
May1st to 15thDay
54%47%18%12%2
2527
16th to endDay
50%6%9%19%12%1
2828
June1st to 15thDay
54%6%10%16%10%1
2844
16th to endDay
50%7%9%18%12%
2833
July1st to 15thDay
41%9%12%23%12%
2581
16th to endDay
46%8%13%20%10%
2711
August1st to 15thDay
44%9%14%24%6%
2501
16th to endDay
35%6%13%24%18%1
2626
September1st to 15thDay
38%6%10%25%17%1
2247
16th to endDay
35%5%9%30%19%1
2145
October1st to 15thDay
46%5%10%23%12%1
2083
16th to endDay
48%411%22%12%
1834
November1st to 15thDay
46%5%13%19%13%1
1716
16th to endDay
45%413%20%15%1
1697
December1st to 15thDay
51%6%10%20%10%
1365
16th to endDay
56%39%15%12%1
1570
January1st to 15thNight
45%5%12%22%12%1
2716
16th to endNight
48%5%9%19%14%2
2912
February1st to 15thNight
52%5%11%18%11%1
2466
16th to endNight
49%410%20%13%2
2049
March1st to 15thNight
54%5%7%18%11%2
2304
16th to endNight
43%410%17%19%4
2246
April1st to 15thNight
52%37%18%16%2
1936
16th to endNight
49%5%9%17%14%3
1734
May1st to 15thNight
50%6%7%18%14%1
1755
16th to endNight
53%6%11%17%10%1
1651
June1st to 15thNight
54%6%11%17%8%1
1440
16th to endNight
44%7%12%22%11%1
1451
July1st to 15thNight
40%7%15%24%11%
1480
16th to endNight
41%7%16%23%10%
1546
August1st to 15thNight
44%7%16%22%8%
1673
16th to endNight
33%6%16%27%15%
1926
September1st to 15thNight
36%5%12%29%15%1
2042
16th to endNight
34%5%9%33%15%1
2145
October1st to 15thNight
42%6%11%24%14%1
2207
16th to endNight
48%5%11%21%11%
2647
November1st to 15thNight
46%411%22%13%1
2472
16th to endNight
45%5%11%22%14%1
2590
December1st to 15thNight
53%5%9%20%10%
2925
16th to endNight
52%49%19%12%1
3000

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%14%37%15%5%
90
16th to endDay
25%25%33%14%2
96
February1st to 15thDay
29%16%28%21%3
255
16th to endDay
21%21%29%21%5%
291
March1st to 15thDay
30%17%32%15%4
330
16th to endDay
23%17%31%15%7%3
352
April1st to 15thDay
32%13%30%14%7%2
330
16th to endDay
28%13%33%13%7%3
319
May1st to 15thDay
35%14%23%16%7%2
348
16th to endDay
24%12%35%20%6%1
395
June1st to 15thDay
28%12%26%22%10%
489
16th to endDay
22%10%28%27%10%2
478
July1st to 15thDay
15%7%33%24%14%3
365
16th to endDay
16%6%31%26%12%5%
390
August1st to 15thDay
18%7%27%26%15%4
358
16th to endDay
15%9%23%26%17%7%
396
September1st to 15thDay
17%7%25%25%18%5%
375
16th to endDay
18%9%25%19%14%11%
374
October1st to 15thDay
25%12%22%21%14%3
356
16th to endDay
30%13%28%18%8%
323
November1st to 15thDay
25%10%29%22%10%2
280
16th to endDay
30%13%20%25%8%1
282
December1st to 15thDay
27%15%34%14%7%
90
16th to endDay
35%23%31%9%
96
January1st to 15thNight
20%13%35%26%3
780
16th to endNight
21%15%35%23%3
832
February1st to 15thNight
20%15%33%28%2
764
16th to endNight
22%14%34%23%4
683
March1st to 15thNight
29%12%35%19%3
780
16th to endNight
21%16%30%23%7%
832
April1st to 15thNight
26%13%33%21%4
768
16th to endNight
28%12%32%21%5%
578
May1st to 15thNight
26%12%30%24%6%
585
16th to endNight
22%8%34%28%4
433
June1st to 15thNight
27%5%29%31%6%
390
16th to endNight
20%328%36%10%
390
July1st to 15thNight
17%225%36%18%
370
16th to endNight
15%125%39%17%
408
August1st to 15thNight
15%425%36%17%
532
16th to endNight
15%325%35%18%2
684
September1st to 15thNight
16%428%33%15%1
780
16th to endNight
18%6%25%27%18%2
777
October1st to 15thNight
22%9%26%28%11%1
780
16th to endNight
27%12%31%21%6%
816
November1st to 15thNight
23%9%28%27%10%1
760
16th to endNight
22%12%28%26%8%1
792
December1st to 15thNight
28%11%33%21%4
825
16th to endNight
30%13%31%21%3
852
Page generated at 2018-10-28 08:41:06. Version ac04

Copyright 2018 A. Danko


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