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: 03-11 (52), 03-12 (50), 03-13 (47), 03-14 (46), 03-15 (43) — by astronomy; check the weather when the night is within four days.

2045-03-11astronomy score per night — click a bar for that night2045-04-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-03-11 Sat	52	—	unknown	20:00–22:00 (good, 2.0 h)	72.6° 16:50	9.16	37%	142.6°
2045-03-12 Sun	50	—	unknown	20:00–22:00 (good, 2.0 h)	72.6° 16:50	9.11	28%	130.8°
2045-03-13 Mon	47	—	unknown	20:00–21:55 (good, 1.92 h)	72.6° 16:45	9.06	20%	119.0°
2045-03-14 Tue	46	—	unknown	20:00–21:50 (good, 1.83 h)	72.6° 16:40	9.01	13%	107.1°
2045-03-15 Wed	43	—	unknown	20:05–21:45 (good, 1.67 h)	72.6° 16:35	8.96	7%	95.2°
2045-03-16 Thu	41	—	unknown	20:05–21:45 (good, 1.67 h)	72.6° 16:30	8.91	3%	83.1°
2045-03-17 Fri	39	—	unknown	20:05–21:40 (good, 1.58 h)	72.6° 16:30	8.86	1%	70.9°
2045-03-18 Sat	37	—	unknown	20:05–21:35 (good, 1.5 h)	72.6° 16:25	8.8	0%	58.4°
2045-03-19 Sun	35	—	unknown	20:10–21:30 (good, 1.33 h)	72.6° 16:20	8.75	2%	45.8°
2045-03-20 Mon	33	—	unknown	20:10–21:25 (good, 1.25 h)	72.6° 16:15	8.7	5%	32.9°
2045-03-21 Tue	29	—	unknown	20:10–21:20 (good, 1.17 h)	72.6° 16:10	8.65	11%	19.9°
2045-03-22 Wed	24	—	unknown	20:10–21:10 (good, 1.0 h)	72.6° 16:10	8.6	18%	6.7°
2045-03-23 Thu	19	—	unknown	20:15–21:00 (good, 0.75 h)	72.6° 16:05	8.54	27%	7.0°
2045-03-24 Fri	14	—	unknown	20:15–20:35 (good, 0.33 h)	72.6° 16:00	8.49	38%	20.6°
2045-03-25 Sat	11	—	unknown	20:15–21:30 (marginal, 1.25 h)	72.6° 15:55	8.44	49%	34.5°
2045-03-26 Sun	9	—	unknown	21:15–22:20 (marginal, 1.08 h)	72.6° 16:50	8.39	60%	48.5°
2045-03-27 Mon	8	—	unknown	21:20–22:15 (marginal, 0.92 h)	72.6° 16:50	8.33	71%	62.8°
2045-03-28 Tue	8	—	unknown	21:20–22:15 (marginal, 0.92 h)	72.6° 16:45	8.28	81%	77.3°
2045-03-29 Wed	9	—	unknown	21:20–22:15 (marginal, 0.92 h)	72.6° 16:40	8.22	89%	91.8°
2045-03-30 Thu	10	—	unknown	21:20–21:25 (good, 0.08 h)	72.6° 16:35	8.17	95%	106.3°
2045-03-31 Fri	10	—	unknown	21:25–21:35 (good, 0.17 h)	72.6° 16:35	8.12	99%	120.7°
2045-04-01 Sat	9	—	unknown	21:25–21:30 (good, 0.08 h)	72.6° 16:30	8.06	100%	135.0°
2045-04-02 Sun	9	—	unknown	21:25–21:30 (good, 0.08 h)	72.6° 16:25	8.01	98%	148.9°
2045-04-03 Mon	8	—	unknown	20:55–22:00 (marginal, 1.08 h)	72.6° 16:20	7.95	94%	162.5°
2045-04-04 Tue	7	—	unknown	20:55–21:55 (marginal, 1.0 h)	72.6° 16:15	7.89	88%	175.6°
2045-04-05 Wed	6	—	unknown	20:55–21:25 (marginal, 0.5 h)	72.6° 16:15	7.84	81%	171.4°
2045-04-06 Thu	5	—	unknown	21:30–21:50 (marginal, 0.33 h)	72.6° 16:10	7.78	72%	158.9°
2045-04-07 Fri	3	—	unknown	21:00–21:15 (marginal, 0.25 h)	72.6° 16:05	7.73	63%	146.7°
2045-04-08 Sat	3	—	unknown	21:00–21:10 (marginal, 0.17 h)	72.6° 16:00	7.67	54%	134.7°
2045-04-09 Sun	2	—	unknown	21:00–21:10 (marginal, 0.17 h)	72.6° 15:55	7.61	44%	122.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-03-11&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.