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: 02-26 (82), 02-25 (80), 02-27 (80), 02-28 (79), 03-01 (77) — by astronomy; check the weather when the night is within four days.

2043-02-17astronomy score per night — click a bar for that night2043-03-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-02-17 Tue	28	—	unknown	19:30–23:45 (marginal, 4.25 h)	72.6° 18:20	10.17	64%	15.4°
2043-02-18 Wed	18	—	unknown	19:35–23:25 (marginal, 3.83 h)	72.6° 18:15	10.13	74%	29.2°
2043-02-19 Thu	19	—	unknown	19:35–23:15 (marginal, 3.67 h)	72.5° 18:10	10.09	83%	42.8°
2043-02-20 Fri	23	—	unknown	19:35–23:15 (marginal, 3.67 h)	72.5° 18:10	10.05	90%	56.3°
2043-02-21 Sat	30	—	unknown	19:35–23:20 (marginal, 3.75 h)	72.6° 18:05	10.0	96%	69.6°
2043-02-22 Sun	40	—	unknown	19:40–20:55 (good, 1.25 h)	72.6° 18:00	9.96	99%	82.6°
2043-02-23 Mon	52	—	unknown	19:40–22:05 (good, 2.42 h)	72.5° 17:55	9.92	100%	95.5°
2043-02-24 Tue	63	—	unknown	19:40–22:45 (good, 3.08 h)	72.5° 17:50	9.88	99%	108.1°
2043-02-25 Wed	80	—	unknown	19:40–22:50 (good, 3.17 h)	72.5° 17:50	9.83	96%	120.5°
2043-02-26 Thu	82	—	unknown	19:40–22:45 (good, 3.08 h)	72.6° 17:45	9.79	91%	132.7°
2043-02-27 Fri	80	—	unknown	19:45–22:45 (good, 3.0 h)	72.6° 17:40	9.74	85%	144.8°
2043-02-28 Sat	79	—	unknown	19:45–22:50 (good, 3.08 h)	72.5° 17:35	9.7	78%	156.7°
2043-03-01 Sun	77	—	unknown	19:45–22:45 (good, 3.0 h)	72.5° 17:35	9.65	70%	168.5°
2043-03-02 Mon	75	—	unknown	19:45–22:40 (good, 2.92 h)	72.6° 17:30	9.61	60%	179.6°
2043-03-03 Tue	72	—	unknown	19:50–22:35 (good, 2.75 h)	72.6° 17:25	9.56	51%	167.7°
2043-03-04 Wed	70	—	unknown	19:50–22:30 (good, 2.67 h)	72.6° 17:20	9.51	41%	155.6°
2043-03-05 Thu	67	—	unknown	19:50–22:30 (good, 2.67 h)	72.5° 17:15	9.47	32%	143.3°
2043-03-06 Fri	65	—	unknown	19:50–22:25 (good, 2.58 h)	72.5° 17:15	9.42	23%	130.6°
2043-03-07 Sat	61	—	unknown	19:55–22:20 (good, 2.42 h)	72.6° 17:10	9.37	15%	117.5°
2043-03-08 Sun	60	—	unknown	19:55–22:15 (good, 2.33 h)	72.6° 17:05	9.33	8%	104.0°
2043-03-09 Mon	58	—	unknown	19:55–22:10 (good, 2.25 h)	72.6° 17:00	9.28	3%	90.0°
2043-03-10 Tue	56	—	unknown	19:55–22:10 (good, 2.25 h)	72.5° 16:55	9.23	0%	75.7°
2043-03-11 Wed	52	—	unknown	20:00–22:05 (good, 2.08 h)	72.5° 16:55	9.18	0%	61.1°
2043-03-12 Thu	51	—	unknown	20:00–22:00 (good, 2.0 h)	72.6° 16:50	9.13	3%	46.3°
2043-03-13 Fri	46	—	unknown	20:00–21:55 (good, 1.92 h)	72.6° 16:45	9.08	9%	31.5°
2043-03-14 Sat	39	—	unknown	20:00–21:45 (good, 1.75 h)	72.5° 16:40	9.03	17%	16.8°
2043-03-15 Sun	30	—	unknown	20:05–21:35 (good, 1.5 h)	72.5° 16:40	8.98	27%	2.3°
2043-03-16 Mon	23	—	unknown	20:05–21:20 (good, 1.25 h)	72.6° 16:35	8.93	38%	12.0°
2043-03-17 Tue	17	—	unknown	20:05–22:00 (marginal, 1.92 h)	72.6° 16:30	8.88	49%	26.0°
2043-03-18 Wed	13	—	unknown	20:05–21:50 (marginal, 1.75 h)	72.6° 16:25	8.83	60%	39.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-02-17&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.