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 3C 273: 04-25 (93), 04-26 (93), 04-27 (93), 04-28 (93), 04-29 (93) — by astronomy; check the weather when the night is within four days.

2036-04-25astronomy score per night — click a bar for that night2036-05-24

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-04-25 Fri	93	—	unknown	22:00–03:25 (good, 5.42 h)	50.2° 23:35	6.68	0%	155.6°
2036-04-26 Sat	93	—	unknown	22:00–03:20 (good, 5.33 h)	50.2° 23:30	6.62	0%	142.0°
2036-04-27 Sun	93	—	unknown	22:05–03:20 (good, 5.25 h)	50.2° 23:25	6.56	3%	128.1°
2036-04-28 Mon	93	—	unknown	22:05–03:15 (good, 5.17 h)	50.2° 23:20	6.5	8%	114.1°
2036-04-29 Tue	93	—	unknown	22:05–03:10 (good, 5.08 h)	50.2° 23:20	6.45	15%	99.9°
2036-04-30 Wed	91	—	unknown	22:10–03:05 (good, 4.92 h)	50.2° 23:15	6.39	25%	85.7°
2036-05-01 Thu	86	—	unknown	22:10–03:00 (good, 4.83 h)	50.2° 23:10	6.33	35%	71.4°
2036-05-02 Fri	81	—	unknown	22:10–03:00 (good, 4.83 h)	50.2° 23:05	6.27	46%	57.2°
2036-05-03 Sat	53	—	unknown	22:35–02:30 (good, 3.92 h)	50.2° 23:05	6.21	58%	43.1°
2036-05-04 Sun	35	—	unknown	22:15–03:15 (marginal, 5.0 h)	50.2° 23:00	6.16	69%	29.1°
2036-05-05 Mon	26	—	unknown	22:15–03:05 (marginal, 4.83 h)	50.2° 22:55	6.1	78%	15.2°
2036-05-06 Tue	19	—	unknown	22:20–02:45 (marginal, 4.42 h)	50.2° 22:50	6.04	87%	1.9°
2036-05-07 Wed	15	—	unknown	22:20–02:30 (marginal, 4.17 h)	50.2° 22:45	5.99	93%	12.3°
2036-05-08 Thu	15	—	unknown	22:20–02:10 (marginal, 3.83 h)	50.2° 22:45	5.93	98%	25.7°
2036-05-09 Fri	21	—	unknown	22:25–02:15 (marginal, 3.83 h)	50.2° 22:40	5.87	100%	38.9°
2036-05-10 Sat	31	—	unknown	22:25–02:30 (marginal, 4.08 h)	50.2° 22:35	5.82	99%	51.8°
2036-05-11 Sun	43	—	unknown	22:25–23:35 (good, 1.17 h)	50.2° 22:30	5.76	97%	64.5°
2036-05-12 Mon	71	—	unknown	22:30–01:05 (good, 2.58 h)	50.2° 22:25	5.71	93%	76.9°
2036-05-13 Tue	80	—	unknown	22:30–01:50 (good, 3.33 h)	50.2° 22:25	5.65	87%	89.1°
2036-05-14 Wed	84	—	unknown	22:30–01:55 (good, 3.42 h)	50.2° 22:20	5.6	80%	101.2°
2036-05-15 Thu	84	—	unknown	22:35–02:00 (good, 3.42 h)	50.2° 22:15	5.55	72%	113.1°
2036-05-16 Fri	84	—	unknown	22:35–02:00 (good, 3.42 h)	50.2° 22:10	5.49	63%	124.9°
2036-05-17 Sat	84	—	unknown	22:35–02:00 (good, 3.42 h)	50.2° 22:10	5.44	54%	136.8°
2036-05-18 Sun	81	—	unknown	22:40–01:55 (good, 3.25 h)	50.2° 22:05	5.39	45%	148.8°
2036-05-19 Mon	79	—	unknown	22:40–01:50 (good, 3.17 h)	50.2° 22:00	5.34	35%	160.9°
2036-05-20 Tue	77	—	unknown	22:40–01:50 (good, 3.17 h)	50.2° 21:55	5.29	26%	173.2°
2036-05-21 Wed	74	—	unknown	22:45–01:45 (good, 3.0 h)	50.2° 21:50	5.24	18%	173.8°
2036-05-22 Thu	73	—	unknown	22:45–01:40 (good, 2.92 h)	50.2° 21:50	5.19	10%	160.8°
2036-05-23 Fri	71	—	unknown	22:45–01:35 (good, 2.83 h)	50.2° 21:45	5.15	5%	147.3°
2036-05-24 Sat	69	—	unknown	22:45–01:30 (good, 2.75 h)	50.2° 21:40	5.1	1%	133.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-04-25&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.