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: 02-19 (95), 02-20 (95), 02-21 (94), 02-18 (93), 02-22 (92) — by astronomy; check the weather when the night is within four days.

2041-02-15astronomy score per night — click a bar for that night2041-03-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-02-15 Fri	51	—	unknown	19:30–21:35 (good, 2.08 h)	72.5° 18:25	10.23	100%	85.8°
2041-02-16 Sat	65	—	unknown	19:30–22:45 (good, 3.25 h)	72.5° 18:20	10.19	99%	97.7°
2041-02-17 Sun	77	—	unknown	19:35–23:10 (good, 3.58 h)	72.5° 18:20	10.15	97%	109.6°
2041-02-18 Mon	93	—	unknown	19:35–23:15 (good, 3.67 h)	72.5° 18:15	10.11	93%	121.6°
2041-02-19 Tue	95	—	unknown	19:35–23:15 (good, 3.67 h)	72.5° 18:10	10.07	87%	133.7°
2041-02-20 Wed	95	—	unknown	19:35–23:10 (good, 3.58 h)	72.5° 18:05	10.03	80%	146.0°
2041-02-21 Thu	94	—	unknown	19:35–23:15 (good, 3.67 h)	72.5° 18:00	9.98	71%	158.5°
2041-02-22 Fri	92	—	unknown	19:40–23:10 (good, 3.5 h)	72.5° 18:00	9.94	61%	171.0°
2041-02-23 Sat	91	—	unknown	19:40–23:05 (good, 3.42 h)	72.5° 17:55	9.9	51%	174.4°
2041-02-24 Sun	88	—	unknown	19:40–23:00 (good, 3.33 h)	72.5° 17:50	9.85	40%	161.6°
2041-02-25 Mon	86	—	unknown	19:40–22:55 (good, 3.25 h)	72.5° 17:45	9.81	29%	147.7°
2041-02-26 Tue	83	—	unknown	19:45–22:55 (good, 3.17 h)	72.5° 17:40	9.77	20%	133.4°
2041-02-27 Wed	80	—	unknown	19:45–22:50 (good, 3.08 h)	72.5° 17:40	9.72	11%	118.7°
2041-02-28 Thu	78	—	unknown	19:45–22:45 (good, 3.0 h)	72.5° 17:35	9.68	5%	103.7°
2041-03-01 Fri	76	—	unknown	19:45–22:40 (good, 2.92 h)	72.5° 17:30	9.63	1%	88.5°
2041-03-02 Sat	72	—	unknown	19:50–22:40 (good, 2.83 h)	72.5° 17:25	9.58	0%	73.4°
2041-03-03 Sun	70	—	unknown	19:50–22:35 (good, 2.75 h)	72.5° 17:25	9.54	3%	58.4°
2041-03-04 Mon	65	—	unknown	19:50–22:30 (good, 2.67 h)	72.5° 17:20	9.49	8%	43.8°
2041-03-05 Tue	58	—	unknown	19:50–22:25 (good, 2.58 h)	72.5° 17:15	9.45	15%	29.6°
2041-03-06 Wed	48	—	unknown	19:50–22:10 (good, 2.33 h)	72.5° 17:10	9.4	23%	16.0°
2041-03-07 Thu	38	—	unknown	19:55–22:00 (good, 2.08 h)	72.5° 17:05	9.35	33%	3.8°
2041-03-08 Fri	29	—	unknown	19:55–21:15 (good, 1.33 h)	72.5° 17:05	9.3	43%	10.8°
2041-03-09 Sat	21	—	unknown	19:55–22:30 (marginal, 2.58 h)	72.5° 17:00	9.25	53%	23.1°
2041-03-10 Sun	16	—	unknown	19:55–22:15 (marginal, 2.33 h)	72.5° 16:55	9.21	62%	35.2°
2041-03-11 Mon	14	—	unknown	20:00–22:10 (marginal, 2.17 h)	72.5° 16:50	9.16	71%	47.2°
2041-03-12 Tue	15	—	unknown	20:00–22:05 (marginal, 2.08 h)	72.5° 16:45	9.11	80%	59.0°
2041-03-13 Wed	16	—	unknown	20:00–22:05 (marginal, 2.08 h)	72.5° 16:45	9.06	86%	70.8°
2041-03-14 Thu	19	—	unknown	20:00–22:05 (marginal, 2.08 h)	72.5° 16:40	9.01	92%	82.6°
2041-03-15 Fri	22	—	unknown	20:05–20:45 (good, 0.67 h)	72.5° 16:35	8.96	96%	94.5°
2041-03-16 Sat	27	—	unknown	20:05–21:20 (good, 1.25 h)	72.5° 16:30	8.91	99%	106.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-02-15&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.