Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Seven Sisters: 08-02 (35), 08-03 (35), 08-15 (35), 08-05 (33), 08-01 (32) — by astronomy; check the weather when the night is within four days.

2036-07-17astronomy score per night — click a bar for that night2036-08-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-07-17 Thu	3	—	unknown	03:50–04:05 (marginal, 0.25 h)	72.5° 09:25	5.11	36%	20.1°
2036-07-18 Fri	5	—	unknown	04:25–04:50 (marginal, 0.42 h)	72.5° 09:20	5.16	26%	10.3°
2036-07-19 Sat	7	—	unknown	04:15–04:55 (marginal, 0.67 h)	72.5° 09:15	5.2	17%	13.2°
2036-07-20 Sun	9	—	unknown	03:40–04:55 (marginal, 1.25 h)	72.5° 09:10	5.25	9%	25.5°
2036-07-21 Mon	11	—	unknown	04:00–04:10 (good, 0.17 h)	72.5° 09:05	5.3	3%	39.5°
2036-07-22 Tue	13	—	unknown	04:00–04:10 (good, 0.17 h)	72.5° 09:05	5.35	0%	54.2°
2036-07-23 Wed	15	—	unknown	03:55–04:10 (good, 0.25 h)	72.5° 09:00	5.4	0%	69.2°
2036-07-24 Thu	18	—	unknown	03:50–04:15 (good, 0.42 h)	72.5° 08:55	5.45	3%	84.2°
2036-07-25 Fri	19	—	unknown	03:45–04:15 (good, 0.5 h)	72.5° 08:50	5.5	9%	99.0°
2036-07-26 Sat	21	—	unknown	03:40–04:15 (good, 0.58 h)	72.5° 08:50	5.56	17%	113.5°
2036-07-27 Sun	24	—	unknown	03:40–04:20 (good, 0.67 h)	72.5° 08:45	5.61	27%	127.5°
2036-07-28 Mon	25	—	unknown	03:35–04:20 (good, 0.75 h)	72.5° 08:40	5.66	37%	140.9°
2036-07-29 Tue	26	—	unknown	03:30–04:20 (good, 0.83 h)	72.5° 08:35	5.72	48%	153.7°
2036-07-30 Wed	28	—	unknown	03:25–04:25 (good, 1.0 h)	72.5° 08:30	5.77	58%	165.0°
2036-07-31 Thu	30	—	unknown	03:20–04:25 (good, 1.08 h)	72.5° 08:30	5.82	68%	170.7°
2036-08-01 Fri	32	—	unknown	03:20–04:25 (good, 1.08 h)	72.5° 08:25	5.88	77%	163.9°
2036-08-02 Sat	35	—	unknown	03:15–04:30 (good, 1.25 h)	72.5° 08:20	5.94	85%	153.0°
2036-08-03 Sun	35	—	unknown	03:15–04:30 (good, 1.25 h)	72.5° 08:15	5.99	91%	141.5°
2036-08-04 Mon	32	—	unknown	03:15–04:30 (good, 1.25 h)	72.5° 08:10	6.05	96%	129.9°
2036-08-05 Tue	33	—	unknown	03:15–04:35 (good, 1.33 h)	72.5° 08:10	6.1	99%	118.3°
2036-08-06 Wed	29	—	unknown	03:15–04:35 (good, 1.33 h)	72.5° 08:05	6.16	100%	106.6°
2036-08-07 Thu	25	—	unknown	03:25–04:35 (good, 1.17 h)	72.5° 08:00	6.22	99%	95.0°
2036-08-08 Fri	22	—	unknown	04:20–04:40 (good, 0.33 h)	72.5° 07:55	6.27	97%	83.2°
2036-08-09 Sat	19	—	unknown	02:30–04:40 (marginal, 2.17 h)	72.5° 07:55	6.33	93%	71.4°
2036-08-10 Sun	16	—	unknown	02:30–04:40 (marginal, 2.17 h)	72.5° 07:50	6.39	87%	59.6°
2036-08-11 Mon	15	—	unknown	02:30–04:40 (marginal, 2.17 h)	72.5° 07:45	6.45	80%	47.6°
2036-08-12 Tue	16	—	unknown	02:25–04:45 (marginal, 2.33 h)	72.5° 07:40	6.5	71%	35.6°
2036-08-13 Wed	19	—	unknown	02:15–04:45 (marginal, 2.5 h)	72.5° 07:35	6.56	62%	23.6°
2036-08-14 Thu	26	—	unknown	04:30–04:45 (good, 0.25 h)	72.5° 07:35	6.62	51%	12.8°
2036-08-15 Fri	35	—	unknown	02:45–04:50 (good, 2.08 h)	72.5° 07:30	6.68	41%	10.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-07-17&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.