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: 05-30 (50), 05-31 (42), 06-01 (32), 06-13 (30), 06-14 (30) — by astronomy; check the weather when the night is within four days.

2044-05-30astronomy score per night — click a bar for that night2044-06-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-05-30 Mon	50	—	unknown	22:55–01:10 (good, 2.25 h)	50.1° 21:15	4.85	20%	62.5°
2044-05-31 Tue	42	—	unknown	22:55–00:55 (good, 2.0 h)	50.1° 21:15	4.81	30%	48.3°
2044-06-01 Wed	32	—	unknown	23:00–00:40 (good, 1.67 h)	50.1° 21:10	4.77	41%	34.5°
2044-06-02 Thu	25	—	unknown	23:00–23:35 (good, 0.58 h)	50.1° 21:05	4.74	52%	21.4°
2044-06-03 Fri	19	—	unknown	23:00–01:15 (marginal, 2.25 h)	50.1° 21:00	4.7	62%	9.8°
2044-06-04 Sat	15	—	unknown	23:00–01:05 (marginal, 2.08 h)	50.1° 20:55	4.67	72%	8.5°
2044-06-05 Sun	12	—	unknown	23:05–00:55 (marginal, 1.83 h)	50.1° 20:55	4.64	80%	19.2°
2044-06-06 Mon	10	—	unknown	23:05–00:45 (marginal, 1.67 h)	50.1° 20:50	4.62	88%	31.0°
2044-06-07 Tue	11	—	unknown	23:05–00:45 (marginal, 1.67 h)	50.1° 20:45	4.59	93%	43.0°
2044-06-08 Wed	14	—	unknown	23:05–00:45 (marginal, 1.67 h)	50.1° 20:40	4.56	97%	54.9°
2044-06-09 Thu	16	—	unknown	23:05–00:50 (marginal, 1.75 h)	50.1° 20:35	4.54	99%	66.7°
2044-06-10 Fri	19	—	unknown	23:10–23:25 (good, 0.25 h)	50.1° 20:35	4.52	100%	78.5°
2044-06-11 Sat	22	—	unknown	23:10–23:55 (good, 0.75 h)	50.1° 20:30	4.5	98%	90.3°
2044-06-12 Sun	25	—	unknown	23:10–00:00 (good, 0.83 h)	50.1° 20:25	4.48	95%	102.0°
2044-06-13 Mon	30	—	unknown	23:10–00:05 (good, 0.92 h)	50.1° 20:20	4.47	90%	113.8°
2044-06-14 Tue	30	—	unknown	23:10–00:05 (good, 0.92 h)	50.1° 20:20	4.46	84%	125.7°
2044-06-15 Wed	29	—	unknown	23:10–00:05 (good, 0.92 h)	50.1° 20:15	4.45	76%	137.6°
2044-06-16 Thu	27	—	unknown	23:10–00:00 (good, 0.83 h)	50.1° 20:10	4.44	68%	149.6°
2044-06-17 Fri	26	—	unknown	23:10–00:00 (good, 0.83 h)	50.1° 20:05	4.43	58%	161.6°
2044-06-18 Sat	25	—	unknown	23:10–23:55 (good, 0.75 h)	50.1° 20:00	4.42	48%	172.1°
2044-06-19 Sun	23	—	unknown	23:15–23:50 (good, 0.58 h)	50.1° 20:00	4.42	37%	169.0°
2044-06-20 Mon	22	—	unknown	23:15–23:45 (good, 0.5 h)	50.1° 19:55	4.42	27%	156.5°
2044-06-21 Tue	20	—	unknown	23:15–23:40 (good, 0.42 h)	50.1° 19:50	4.42	17%	142.8°
2044-06-22 Wed	18	—	unknown	23:15–23:40 (good, 0.42 h)	50.1° 19:45	4.43	9%	128.4°
2044-06-23 Thu	16	—	unknown	23:15–23:35 (good, 0.33 h)	50.1° 19:40	4.43	4%	113.6°
2044-06-24 Fri	15	—	unknown	23:15–23:30 (good, 0.25 h)	50.1° 19:40	4.44	1%	98.6°
2044-06-25 Sat	14	—	unknown	23:15–23:25 (good, 0.17 h)	50.1° 19:35	4.45	0%	83.4°
2044-06-26 Sun	12	—	unknown	23:15–23:20 (good, 0.08 h)	50.1° 19:30	4.46	4%	68.3°
2044-06-27 Mon	11	—	unknown	23:15–23:20 (good, 0.08 h)	50.1° 19:25	4.48	9%	53.6°
2044-06-28 Tue	10	—	unknown	22:20–23:45 (marginal, 1.42 h)	50.1° 19:25	4.49	17%	39.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-05-30&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.