RabbitEye Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the RabbitEye Observatory clear sky chart from 2005-11-05 to 2017-10-06.

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
50%
15884
22%
47129
15%
15845
58%
15845
28%
29645

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
33%
716
22%
2327
10%
716
48%
716
22%
1430
January16th to endNight
31%
768
23%
2496
13%
768
45%
768
24%
1513
February1st to 15thNight
31%
703
22%
2133
11%
700
44%
700
25%
1348
February16th to endNight
32%
631
24%
1866
12%
631
45%
631
28%
1147
March1st to 15thNight
37%
720
28%
1980
15%
720
49%
720
34%
1188
March16th to endNight
40%
768
22%
2112
11%
768
49%
768
32%
1293
April1st to 15thNight
43%
718
24%
1976
14%
718
51%
718
35%
1194
April16th to endNight
49%
660
29%
1747
17%
660
56%
660
41%
1007
May1st to 15thNight
59%
539
24%
1620
15%
539
65%
539
36%
944
May16th to endNight
63%
561
20%
1684
14%
561
66%
561
29%
1051
June1st to 15thNight
67%
540
14%
1620
10%
540
69%
540
26%
1065
June16th to endNight
69%
540
12%
1620
11%
540
70%
540
24%
1081
July1st to 15thNight
70%
510
13%
1530
11%
510
71%
510
25%
1028
July16th to endNight
72%
564
10%
1595
9%
531
73%
531
23%
1101
August1st to 15thNight
74%
539
13%
1609
12%
536
74%
536
23%
1113
August16th to endNight
63%
674
13%
1922
13%
674
64%
674
20%
1404
September1st to 15thNight
64%
720
16%
1980
14%
720
65%
720
24%
1367
September16th to endNight
58%
717
17%
1980
16%
717
60%
717
24%
1384
October1st to 15thNight
54%
684
27%
1959
23%
684
60%
684
33%
1207
October16th to endNight
56%
704
32%
2112
27%
704
65%
704
35%
1202
November1st to 15thNight
52%
700
30%
2101
24%
700
61%
700
35%
1202
November16th to endNight
41%
720
27%
2324
18%
720
55%
720
30%
1331
December1st to 15thNight
41%
720
23%
2340
16%
720
50%
720
24%
1459
December16th to endNight
40%
768
23%
2496
18%
768
50%
768
22%
1586

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
11%5%25%6%35%5%6%7%39%
48059
Night
10%5%25%4345%5%8%44%
47329
TransparencyDay
41%8%11%17%15%6%
47760
Night
35%7%12%18%16%8%
47132
SeeingDay
12%6%19%24%23%13%
5740
Night
12%6%22%32%21%3
15892

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
12%5%25%4245%5%7%43%
1611
16th to endDay
16%5%24424345%45%
1728
February1st to 15thDay
14%5%345%24446%44%
1723
16th to endDay
14%5%24413335%50%
1606
March1st to 15thDay
10%5%24434346%50%
1980
16th to endDay
12%5%36%42445%5%46%
2111
April1st to 15thDay
10%5%24424446%50%
1972
16th to endDay
8%5%2443446%7%47%
2220
May1st to 15thDay
7%4246%35%6%5%9%44%
2331
16th to endDay
9%5%25%7%46%6%6%8%37%
2431
June1st to 15thDay
9%5%36%6%5%7%7%7%9%30%
2340
16th to endDay
7%5%26%7%5%7%9%9%10%28%
2340
July1st to 15thDay
9%6%36%7%5%7%9%8%11%25%
2340
16th to endDay
8%5%37%9%5%9%7%8%10%23%
2465
August1st to 15thDay
10%6%38%7%5%8%8%8%10%21%
2340
16th to endDay
13%6%37%8%5%8%7%8%9%21%
2265
September1st to 15thDay
11%6%37%8%46%5%7%8%29%
1980
16th to endDay
13%8%37%6%46%6%6%7%29%
1980
October1st to 15thDay
14%5%24434346%46%
1797
16th to endDay
8%43432335%5%54%
1760
November1st to 15thDay
10%423423346%55%
1757
16th to endDay
10%5%24324345%53%
1634
December1st to 15thDay
13%7%36%424346%43%
1620
16th to endDay
14%7%25%43345%6%41%
1728
January1st to 15thNight
11%6%25%42445%6%44%
2327
16th to endNight
14%6%24323346%46%
2496
February1st to 15thNight
14%5%25%433445%46%
2127
16th to endNight
12%5%25%424446%48%
1866
March1st to 15thNight
8%3144235%5%7%52%
1980
16th to endNight
9%5%24424336%52%
2112
April1st to 15thNight
9%31342445%6%52%
1976
16th to endNight
7%4223245%6%8%54%
1747
May1st to 15thNight
7%223325%5%7%7%52%
1619
16th to endNight
6%325%5%35%6%5%9%45%
1682
June1st to 15thNight
8%425%5%25%8%10%14%33%
1620
16th to endNight
5%5%25%5%37%8%8%14%34%
1620
July1st to 15thNight
6%425%5%46%8%9%12%35%
1620
16th to endNight
35%36%7%48%7%8%12%33%
1703
August1st to 15thNight
5%326%6%47%8%10%13%30%
1620
16th to endNight
10%5%27%6%46%7%8%11%29%
1922
September1st to 15thNight
8%5%26%6%35%5%7%11%36%
1980
16th to endNight
13%6%25%5%45%5%6%8%35%
1980
October1st to 15thNight
12%6%14323445%50%
1959
16th to endNight
8%424423335%56%
2112
November1st to 15thNight
9%41432335%7%53%
2101
16th to endNight
12%5%24323346%52%
2324
December1st to 15thNight
12%6%35%424437%45%
2340
16th to endNight
13%7%35%5%2345%7%41%
2496

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
38%5%9%17%18%10%
1612
16th to endDay
40%37%16%21%10%
1728
February1st to 15thDay
41%47%14%21%11%
1725
16th to endDay
37%36%16%24%11%
1606
March1st to 15thDay
34%48%21%20%9%
1980
16th to endDay
39%5%11%15%19%8%
2112
April1st to 15thDay
34%5%8%20%20%9%
1972
16th to endDay
33%6%11%19%20%9%
2220
May1st to 15thDay
34%7%12%21%19%5%
2331
16th to endDay
41%9%11%19%14%2
2435
June1st to 15thDay
44%11%15%18%9%
2340
16th to endDay
44%13%16%16%8%
2340
July1st to 15thDay
45%14%19%15%41
2201
16th to endDay
49%13%18%13%4
2310
August1st to 15thDay
51%13%17%12%4
2327
16th to endDay
53%14%14%13%4
2265
September1st to 15thDay
48%11%13%13%10%1
1980
16th to endDay
50%10%10%13%13%2
1980
October1st to 15thDay
38%5%8%16%19%11%
1797
16th to endDay
30%47%16%25%15%
1760
November1st to 15thDay
30%37%19%24%14%
1757
16th to endDay
33%48%18%23%12%
1634
December1st to 15thDay
42%5%8%19%16%8%
1620
16th to endDay
42%6%9%20%13%7%
1728
January1st to 15thNight
39%5%8%16%21%9%
2327
16th to endNight
38%48%12%23%12%
2496
February1st to 15thNight
40%46%15%18%14%
2136
16th to endNight
37%48%16%19%14%
1866
March1st to 15thNight
29%7%11%20%19%11%
1980
16th to endNight
34%411%18%21%10%
2112
April1st to 15thNight
30%6%8%22%20%11%
1976
16th to endNight
26%5%12%22%22%10%
1747
May1st to 15thNight
28%7%14%22%19%7%
1620
16th to endNight
33%10%13%26%13%2
1684
June1st to 15thNight
34%13%20%21%9%
1620
16th to endNight
35%14%22%18%8%
1620
July1st to 15thNight
36%13%21%23%41
1530
16th to endNight
37%15%22%19%4
1595
August1st to 15thNight
36%16%24%17%4
1609
16th to endNight
43%14%19%17%3
1922
September1st to 15thNight
40%11%18%15%11%1
1980
16th to endNight
42%10%14%16%12%3
1980
October1st to 15thNight
35%5%11%17%19%10%
1959
16th to endNight
31%47%15%24%16%
2112
November1st to 15thNight
31%47%17%24%14%
2101
16th to endNight
33%48%16%22%14%
2324
December1st to 15thNight
39%6%11%17%17%7%
2340
16th to endNight
41%5%8%20%14%8%
2496

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
22%16%32%14%5%8%
90
16th to endDay
19%29%29%12%9%
96
February1st to 15thDay
18%24%32%21%3
90
16th to endDay
11%20%43%21%2
107
March1st to 15thDay
11%15%33%22%16%
270
16th to endDay
13%10%32%20%18%4
288
April1st to 15thDay
15%15%21%24%18%4
270
16th to endDay
8%5%26%25%20%13%
270
May1st to 15thDay
8%8%30%23%18%10%
288
16th to endDay
9%316%26%26%18%
331
June1st to 15thDay
13%111%25%26%23%
315
16th to endDay
11%19%25%28%24%
315
July1st to 15thDay
6%6%22%35%29%
305
16th to endDay
9%8%21%37%22%
326
August1st to 15thDay
13%6%25%33%20%
313
16th to endDay
14%17%21%26%28%
332
September1st to 15thDay
15%213%21%29%16%
315
16th to endDay
17%212%27%28%12%
314
October1st to 15thDay
18%226%25%20%6%
278
16th to endDay
9%5%20%30%28%5%
272
November1st to 15thDay
14%8%26%28%17%4
265
16th to endDay
6%12%40%25%10%3
104
December1st to 15thDay
13%14%45%17%7%1
90
16th to endDay
20%13%31%26%7%1
96
January1st to 15thNight
15%15%30%27%9%
720
16th to endNight
17%13%33%28%6%
768
February1st to 15thNight
19%12%31%29%6%
704
16th to endNight
15%12%34%32%5%
631
March1st to 15thNight
12%12%34%32%8%
720
16th to endNight
12%10%33%31%12%
768
April1st to 15thNight
12%8%31%35%10%
718
16th to endNight
9%6%31%38%14%
660
May1st to 15thNight
7%5%23%42%19%1
540
16th to endNight
8%215%34%33%4
563
June1st to 15thNight
9%12%38%33%5%
540
16th to endNight
7%11%37%35%9%
540
July1st to 15thNight
8%10%30%39%11%
510
16th to endNight
417%35%42%7%
564
August1st to 15thNight
7%6%32%43%10%
539
16th to endNight
14%8%27%38%11%
674
September1st to 15thNight
10%19%30%40%7%
720
16th to endNight
16%112%32%31%4
717
October1st to 15thNight
15%421%29%25%3
684
16th to endNight
11%6%20%33%25%2
704
November1st to 15thNight
13%5%22%37%19%1
700
16th to endNight
13%10%30%27%16%
720
December1st to 15thNight
14%10%28%30%14%1
720
16th to endNight
17%11%26%31%13%
768
Page generated at 2017-10-07 14:07:44. Version ac04

Copyright 2017 A. Danko


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