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: 02-10 (100), 02-11 (96), 02-12 (89), 02-26 (85), 02-25 (84) — by astronomy; check the weather when the night is within four days.

2035-02-10astronomy score per night — click a bar for that night2035-03-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-02-10 Sat	100	—	unknown	19:25–00:00 (good, 4.58 h)	72.5° 18:45	10.45	7%	66.7°
2035-02-11 Sun	96	—	unknown	19:25–23:55 (good, 4.5 h)	72.5° 18:45	10.41	14%	53.4°
2035-02-12 Mon	89	—	unknown	19:25–23:50 (good, 4.42 h)	72.5° 18:40	10.37	22%	40.1°
2035-02-13 Tue	76	—	unknown	19:25–23:45 (good, 4.33 h)	72.5° 18:35	10.33	32%	26.9°
2035-02-14 Wed	58	—	unknown	19:30–23:20 (good, 3.83 h)	72.5° 18:30	10.29	43%	14.7°
2035-02-15 Thu	41	—	unknown	20:00–20:45 (good, 0.75 h)	72.5° 18:25	10.25	54%	9.6°
2035-02-16 Fri	28	—	unknown	19:30–23:50 (marginal, 4.33 h)	72.5° 18:25	10.21	66%	19.1°
2035-02-17 Sat	20	—	unknown	19:30–23:30 (marginal, 4.0 h)	72.5° 18:20	10.17	76%	32.3°
2035-02-18 Sun	21	—	unknown	19:35–23:20 (marginal, 3.75 h)	72.5° 18:15	10.13	85%	46.1°
2035-02-19 Mon	26	—	unknown	19:35–23:20 (marginal, 3.75 h)	72.5° 18:10	10.09	92%	60.1°
2035-02-20 Tue	35	—	unknown	19:35–20:15 (good, 0.67 h)	72.5° 18:10	10.05	97%	74.1°
2035-02-21 Wed	47	—	unknown	19:35–21:35 (good, 2.0 h)	72.5° 18:05	10.01	100%	88.0°
2035-02-22 Thu	60	—	unknown	19:40–22:45 (good, 3.08 h)	72.5° 18:00	9.96	100%	101.6°
2035-02-23 Fri	73	—	unknown	19:40–22:55 (good, 3.25 h)	72.5° 17:55	9.92	97%	114.8°
2035-02-24 Sat	83	—	unknown	19:40–22:55 (good, 3.25 h)	72.5° 17:50	9.88	92%	127.7°
2035-02-25 Sun	84	—	unknown	19:40–22:50 (good, 3.17 h)	72.5° 17:50	9.83	86%	140.2°
2035-02-26 Mon	85	—	unknown	19:40–22:50 (good, 3.17 h)	72.5° 17:45	9.79	79%	152.1°
2035-02-27 Tue	82	—	unknown	19:45–22:50 (good, 3.08 h)	72.5° 17:40	9.75	70%	163.1°
2035-02-28 Wed	80	—	unknown	19:45–22:45 (good, 3.0 h)	72.5° 17:35	9.7	61%	170.5°
2035-03-01 Thu	77	—	unknown	19:45–22:45 (good, 3.0 h)	72.5° 17:30	9.66	52%	166.7°
2035-03-02 Fri	74	—	unknown	19:45–22:40 (good, 2.92 h)	72.5° 17:30	9.61	42%	156.8°
2035-03-03 Sat	72	—	unknown	19:50–22:35 (good, 2.75 h)	72.5° 17:25	9.56	33%	145.6°
2035-03-04 Sun	70	—	unknown	19:50–22:30 (good, 2.67 h)	72.5° 17:20	9.52	24%	134.0°
2035-03-05 Mon	67	—	unknown	19:50–22:30 (good, 2.67 h)	72.5° 17:15	9.47	17%	122.0°
2035-03-06 Tue	65	—	unknown	19:50–22:25 (good, 2.58 h)	72.5° 17:15	9.42	10%	109.8°
2035-03-07 Wed	61	—	unknown	19:55–22:20 (good, 2.42 h)	72.5° 17:10	9.38	5%	97.2°
2035-03-08 Thu	60	—	unknown	19:55–22:15 (good, 2.33 h)	72.5° 17:05	9.33	1%	84.2°
2035-03-09 Fri	57	—	unknown	19:55–22:10 (good, 2.25 h)	72.5° 17:00	9.28	0%	71.0°
2035-03-10 Sat	56	—	unknown	19:55–22:10 (good, 2.25 h)	72.5° 16:55	9.23	1%	57.5°
2035-03-11 Sun	52	—	unknown	20:00–22:05 (good, 2.08 h)	72.5° 16:55	9.18	5%	43.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-02-10&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.