Etscorn Campus Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Etscorn Campus Observatory clear sky chart from 2005-11-06 to 2024-01-11.

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
62%
23945
33%
74534
24%
23894
72%
23894
48%
36125

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 10thNight
60%
756
36%
2457
28%
756
73%
756
51%
1132
January11th to 20thNight
54%
724
35%
2352
27%
724
67%
724
51%
1077
January21st to endNight
54%
792
38%
2574
26%
792
71%
792
50%
1176
February1st to 10thNight
54%
720
36%
2336
25%
720
70%
720
55%
1013
February11th to 20thNight
48%
701
34%
2098
21%
700
63%
700
47%
1054
February21st to endNight
43%
592
39%
1776
20%
592
64%
592
54%
824
March1st to 10thNight
48%
720
39%
1980
19%
720
64%
720
54%
988
March11th to 20thNight
53%
720
36%
1980
19%
720
65%
720
53%
999
March21st to endNight
47%
770
37%
2156
17%
770
64%
770
51%
1070
April1st to 10thNight
46%
540
37%
1800
20%
540
68%
540
53%
774
April11th to 20thNight
44%
533
38%
1777
21%
533
66%
533
51%
766
April21st to endNight
45%
540
39%
1800
23%
540
70%
540
51%
786
May1st to 10thNight
54%
540
33%
1800
25%
540
69%
540
53%
793
May11th to 20thNight
61%
531
29%
1705
23%
531
69%
531
44%
851
May21st to endNight
62%
583
34%
1746
26%
582
72%
582
58%
788
June1st to 10thNight
69%
540
32%
1468
25%
540
73%
540
51%
765
June11th to 20thNight
70%
540
36%
1440
26%
540
76%
540
60%
708
June21st to endNight
73%
540
21%
1589
20%
540
74%
540
41%
867
July1st to 10thNight
72%
525
18%
1575
17%
525
72%
525
31%
943
July11th to 20thNight
79%
522
19%
1566
18%
522
79%
522
32%
926
July21st to endNight
77%
591
17%
1674
17%
558
77%
558
29%
1042
August1st to 10thNight
80%
537
17%
1647
17%
534
80%
534
34%
951
August11th to 20thNight
79%
534
22%
1778
25%
534
79%
534
32%
1027
August21st to endNight
83%
594
23%
1980
27%
594
84%
594
38%
1071
September1st to 10thNight
77%
540
26%
1800
27%
540
79%
540
36%
980
September11th to 20thNight
77%
540
37%
1800
36%
540
80%
540
42%
910
September21st to endNight
75%
652
35%
2028
28%
652
80%
652
52%
964
October1st to 10thNight
68%
720
33%
2160
24%
720
74%
720
49%
1087
October11th to 20thNight
71%
720
41%
2160
27%
720
80%
720
62%
959
October21st to endNight
69%
792
43%
2376
27%
792
79%
792
62%
1040
November1st to 10thNight
71%
740
46%
2220
30%
740
82%
740
69%
918
November11th to 20thNight
71%
821
43%
2341
30%
821
79%
821
70%
1008
November21st to endNight
58%
950
39%
2470
23%
950
68%
950
54%
1299
December1st to 10thNight
59%
950
38%
2610
23%
950
69%
950
55%
1315
December11th to 20thNight
53%
949
33%
3123
21%
948
65%
948
44%
1549
December21st to endNight
53%
886
25%
4392
27%
874
66%
874
38%
1705

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
331332445%8%64%
74580
Night
331342445%7%64%
75114
TransparencyDay
19%47%19%28%23%
74306
Night
20%47%18%28%22%
74909
SeeingDay
5%8%23%32%24%8%
13524
Night
5%424%43%22%2
23961

By Month

Percentage Cloud Cover SW (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 10thDay
231342446%8%63%
1708
11th to 20thDay
3313322345%71%
1620
21st to endDay
3313423347%67%
1782
February1st to 10thDay
2413223247%69%
1624
11th to 20thDay
4324424445%64%
1749
21st to endDay
2323212347%72%
1480
March1st to 10thDay
432332446%8%61%
1977
11th to 20thDay
3323323346%67%
1980
21st to endDay
1322323447%69%
2200
April1st to 10thDay
221222345%7%71%
2160
11th to 20thDay
4312223446%70%
2131
21st to endDay
2212313346%74%
2160
May1st to 10thDay
2111323447%71%
2160
11th to 20thDay
33135%245%5%6%63%
2185
21st to endDay
2112213347%73%
2530
June1st to 10thDay
12133245%6%9%65%
2484
11th to 20thDay
221222335%6%73%
2520
21st to endDay
5%3234345%6%8%57%
2359
July1st to 10thDay
5%2135%46%7%8%10%49%
2340
11th to 20thDay
3324445%8%9%11%47%
2340
21st to endDay
32246%5%7%8%9%13%41%
2545
August1st to 10thDay
42135%5%7%8%9%12%44%
2280
11th to 20thDay
43245%35%6%9%11%48%
2123
21st to endDay
4314445%6%8%9%52%
2376
September1st to 10thDay
6%3245%35%6%6%8%53%
2160
11th to 20thDay
5%3133245%6%8%59%
2160
21st to endDay
3212323346%71%
1926
October1st to 10thDay
4213423447%66%
1800
11th to 20thDay
3112222235%78%
1800
21st to endDay
321111232480%
1980
November1st to 10thDay
2112112338%76%
1859
11th to 20thDay
2212213246%76%
1817
21st to endDay
5%21333435%6%66%
1710
December1st to 10thDay
432322235%7%68%
1567
11th to 20thDay
33134245%5%8%62%
1926
21st to endDay
332322346%8%65%
3062
January1st to 10thNight
331332345%7%66%
2457
11th to 20thNight
4323323336%69%
2352
21st to endNight
3412323346%68%
2574
February1st to 10thNight
2322323337%70%
2336
11th to 20thNight
442342435%6%63%
2098
21st to endNight
2312412447%68%
1776
March1st to 10thNight
4313323347%67%
1980
11th to 20thNight
3324323435%67%
1980
21st to endNight
4413324345%69%
2156
April1st to 10thNight
22123245%47%69%
1800
11th to 20thNight
3313323346%70%
1777
21st to endNight
3213323347%69%
1800
May1st to 10thNight
231222345%6%70%
1800
11th to 20thNight
4323425%5%5%7%60%
1705
21st to endNight
1113313447%71%
1746
June1st to 10thNight
331442445%8%62%
1468
11th to 20thNight
231232346%7%68%
1440
21st to endNight
4425%425%47%9%53%
1589
July1st to 10thNight
5%425%6%46%6%6%11%43%
1620
11th to 20thNight
3325%7%47%7%9%14%39%
1620
21st to endNight
3435%7%46%9%10%12%37%
1773
August1st to 10thNight
33246%47%8%10%12%41%
1656
11th to 20thNight
44246%46%7%9%10%44%
1778
21st to endNight
32145%35%7%9%13%47%
1980
September1st to 10thNight
5%3146%447%7%9%50%
1800
11th to 20thNight
5%3144245%5%8%58%
1800
21st to endNight
421332345%6%67%
2028
October1st to 10thNight
421343445%8%63%
2160
11th to 20thNight
321222223476%
2160
21st to endNight
321221234476%
2376
November1st to 10thNight
311112346%77%
2220
11th to 20thNight
1212212236%78%
2341
21st to endNight
6%322322235%69%
2470
December1st to 10thNight
5%313322346%68%
2610
11th to 20thNight
43134245%6%9%60%
3271
21st to endNight
432342335%6%66%
4617

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 10thDay
19%37%26%37%9%
1709
11th to 20thDay
17%26%22%41%12%
1620
21st to endDay
19%36%21%37%15%
1782
February1st to 10thDay
17%26%20%33%22%
1624
11th to 20thDay
23%4417%30%22%
1759
21st to endDay
15%3213%38%29%
1480
March1st to 10thDay
21%45%15%32%24%
1977
11th to 20thDay
20%3316%32%27%
1980
21st to endDay
15%35%17%36%24%
2200
April1st to 10thDay
14%3415%35%31%
2160
11th to 20thDay
16%3312%29%37%
2134
21st to endDay
14%2414%36%30%
2160
May1st to 10thDay
14%3412%30%37%
2160
11th to 20thDay
21%47%14%26%28%
2188
21st to endDay
12%36%12%25%42%
2530
June1st to 10thDay
15%47%19%24%32%
2484
11th to 20thDay
13%3310%22%50%
2520
21st to endDay
23%5%6%15%23%28%
2359
July1st to 10thDay
26%8%12%18%17%19%
2276
11th to 20thDay
24%10%15%25%17%10%
2271
21st to endDay
29%10%19%27%12%3
2404
August1st to 10thDay
26%10%17%24%15%7%
2265
11th to 20thDay
28%7%14%23%18%10%
2123
21st to endDay
24%9%13%25%21%8%
2376
September1st to 10thDay
27%5%10%20%21%17%
2160
11th to 20thDay
20%6%10%18%23%23%
2160
21st to endDay
15%35%18%34%25%
1926
October1st to 10thDay
19%48%17%25%26%
1800
11th to 20thDay
13%2310%32%39%
1800
21st to endDay
12%2319%41%23%
1980
November1st to 10thDay
10%2321%39%24%
1859
11th to 20thDay
12%2423%38%21%
1817
21st to endDay
21%35%18%36%18%
1710
December1st to 10thDay
17%25%31%31%13%
1567
11th to 20thDay
22%210%28%28%9%
1924
21st to endDay
17%37%22%34%18%
3062
January1st to 10thNight
19%37%23%36%12%
2457
11th to 20thNight
20%26%20%41%12%
2352
21st to endNight
19%35%18%41%14%
2574
February1st to 10thNight
17%25%21%31%24%
2336
11th to 20thNight
23%35%19%28%23%
2098
21st to endNight
17%2412%35%29%
1776
March1st to 10thNight
19%2416%32%27%
1980
11th to 20thNight
20%25%15%32%27%
1980
21st to endNight
19%2416%32%26%
2156
April1st to 10thNight
16%3311%37%30%
1800
11th to 20thNight
16%3413%25%38%
1777
21st to endNight
17%3412%34%30%
1800
May1st to 10thNight
16%4411%28%37%
1800
11th to 20thNight
23%49%14%23%28%
1706
21st to endNight
14%46%13%20%44%
1746
June1st to 10thNight
21%48%16%19%32%
1468
11th to 20thNight
16%3410%18%49%
1440
21st to endNight
27%5%10%15%16%27%
1589
July1st to 10thNight
32%8%13%19%16%11%
1575
11th to 20thNight
29%10%18%21%14%7%
1566
21st to endNight
33%11%21%23%11%2
1674
August1st to 10thNight
29%9%21%24%11%7%
1647
11th to 20thNight
31%8%19%19%14%9%
1778
21st to endNight
24%9%19%24%16%8%
1980
September1st to 10thNight
27%7%14%19%18%14%
1800
11th to 20thNight
23%5%11%17%19%24%
1800
21st to endNight
19%46%15%30%27%
2028
October1st to 10thNight
21%49%17%23%27%
2160
11th to 20thNight
14%2312%26%42%
2160
21st to endNight
13%3417%36%28%
2376
November1st to 10thNight
10%3320%38%26%
2220
11th to 20thNight
11%1419%37%28%
2341
21st to endNight
20%3418%36%20%
2470
December1st to 10thNight
19%35%23%35%15%
2610
11th to 20thNight
22%38%24%33%10%
3272
21st to endNight
20%35%22%34%16%
4617

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 10thDay
6%7%28%49%10%
270
11th to 20thDay
6%6%28%43%15%1
240
21st to endDay
38%43%28%16%1
264
February1st to 10thDay
5%9%27%42%13%3
240
11th to 20thDay
10%11%36%37%6%
240
21st to endDay
9%19%35%29%5%3
198
March1st to 10thDay
6%20%36%27%9%1
417
11th to 20thDay
8%19%30%29%11%3
420
21st to endDay
9%24%36%22%9%1
462
April1st to 10thDay
5%16%40%26%10%3
420
11th to 20thDay
7%23%36%23%10%1
412
21st to endDay
7%17%35%30%10%1
420
May1st to 10thDay
417%33%30%13%2
423
11th to 20thDay
210%33%31%18%5%
448
21st to endDay
212%36%31%18%1
485
June1st to 10thDay
2420%40%30%5%
594
11th to 20thDay
2417%41%30%6%
630
21st to endDay
6%215%37%30%9%
469
July1st to 10thDay
318%32%38%18%
446
11th to 20thDay
41323%41%28%
444
21st to endDay
21223%42%30%
487
August1st to 10thDay
315%24%43%23%
447
11th to 20thDay
426%29%41%18%
437
21st to endDay
5%15%25%44%19%
495
September1st to 10thDay
6%28%30%40%14%
450
11th to 20thDay
413%36%38%9%
450
21st to endDay
45%17%33%33%10%
332
October1st to 10thDay
35%22%29%31%9%
270
11th to 20thDay
7%5%17%38%27%7%
270
21st to endDay
8%6%15%38%24%8%
297
November1st to 10thDay
5%9%24%40%18%3
270
11th to 20thDay
37%17%43%25%4
270
21st to endDay
6%11%34%32%16%3
270
December1st to 10thDay
5%7%37%38%13%1
270
11th to 20thDay
412%33%39%12%
270
21st to endDay
9%8%37%36%9%
297
January1st to 10thNight
4427%48%16%1
760
11th to 20thNight
5%434%41%15%1
724
21st to endNight
5%6%32%43%14%1
792
February1st to 10thNight
4432%44%14%1
720
11th to 20thNight
6%6%36%43%9%1
704
21st to endNight
48%42%41%5%
592
March1st to 10thNight
5%7%37%41%10%
720
11th to 20thNight
5%6%31%43%14%1
720
21st to endNight
6%9%35%41%9%
770
April1st to 10thNight
26%41%43%8%
540
11th to 20thNight
49%41%38%8%
533
21st to endNight
48%40%40%8%
540
May1st to 10thNight
4436%48%9%
540
11th to 20thNight
5%325%46%20%
531
21st to endNight
2327%53%14%
584
June1st to 10thNight
3218%55%22%
540
11th to 20thNight
3220%52%22%
540
21st to endNight
5%29%51%31%1
540
July1st to 10thNight
6%17%39%44%4
525
11th to 20thNight
3232%55%6%
522
21st to endNight
33423%58%9%
591
August1st to 10thNight
31326%58%10%
537
11th to 20thNight
425%30%56%4
534
21st to endNight
21433%54%6%
594
September1st to 10thNight
5%17%41%43%3
540
11th to 20thNight
7%18%46%36%3
540
21st to endNight
4113%48%31%2
652
October1st to 10thNight
5%318%49%24%1
720
11th to 20thNight
3318%54%20%2
720
21st to endNight
5%320%41%27%3
792
November1st to 10thNight
4222%49%23%1
740
11th to 20thNight
2321%50%22%2
821
21st to endNight
7%6%26%39%21%2
950
December1st to 10thNight
6%329%46%15%
950
11th to 20thNight
6%5%32%45%12%
950
21st to endNight
5%432%48%10%1
893
Page generated at 2024-01-08 09:14:18. Version ac07

Copyright 2024 Attilla Danko


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