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: 05-01 (93), 05-02 (93), 05-03 (93), 05-04 (93), 05-05 (93) — by astronomy; check the weather when the night is within four days.

2029-04-27astronomy score per night — click a bar for that night2029-05-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-04-27 Fri	22	—	unknown	22:05–03:10 (marginal, 5.08 h)	50.2° 23:25	6.58	99%	26.5°
2029-04-28 Sat	34	—	unknown	22:05–03:15 (marginal, 5.17 h)	50.2° 23:25	6.52	100%	40.8°
2029-04-29 Sun	76	—	unknown	22:05–23:30 (good, 1.42 h)	50.2° 23:20	6.46	97%	55.4°
2029-04-30 Mon	92	—	unknown	22:10–01:35 (good, 3.42 h)	50.2° 23:15	6.41	91%	69.7°
2029-05-01 Tue	93	—	unknown	22:10–02:40 (good, 4.5 h)	50.2° 23:10	6.35	84%	83.7°
2029-05-02 Wed	93	—	unknown	22:10–02:45 (good, 4.58 h)	50.2° 23:10	6.29	75%	97.2°
2029-05-03 Thu	93	—	unknown	22:15–02:45 (good, 4.5 h)	50.2° 23:05	6.23	65%	110.2°
2029-05-04 Fri	93	—	unknown	22:15–02:45 (good, 4.5 h)	50.2° 23:00	6.17	55%	122.8°
2029-05-05 Sat	93	—	unknown	22:15–02:45 (good, 4.5 h)	50.2° 22:55	6.12	45%	135.0°
2029-05-06 Sun	93	—	unknown	22:20–02:45 (good, 4.42 h)	50.2° 22:50	6.06	35%	146.7°
2029-05-07 Mon	93	—	unknown	22:20–02:40 (good, 4.33 h)	50.2° 22:50	6.0	26%	157.8°
2029-05-08 Tue	93	—	unknown	22:20–02:35 (good, 4.25 h)	50.2° 22:45	5.95	19%	167.2°
2029-05-09 Wed	93	—	unknown	22:25–02:30 (good, 4.08 h)	50.2° 22:40	5.89	12%	169.4°
2029-05-10 Thu	93	—	unknown	22:25–02:30 (good, 4.08 h)	50.2° 22:35	5.83	6%	161.7°
2029-05-11 Fri	93	—	unknown	22:25–02:25 (good, 4.0 h)	50.2° 22:30	5.78	3%	151.0°
2029-05-12 Sat	93	—	unknown	22:30–02:20 (good, 3.83 h)	50.2° 22:30	5.72	0%	139.6°
2029-05-13 Sun	92	—	unknown	22:30–02:15 (good, 3.75 h)	50.2° 22:25	5.67	0%	127.9°
2029-05-14 Mon	90	—	unknown	22:30–02:10 (good, 3.67 h)	50.2° 22:20	5.62	2%	116.0°
2029-05-15 Tue	87	—	unknown	22:35–02:10 (good, 3.58 h)	50.2° 22:15	5.56	5%	103.8°
2029-05-16 Wed	83	—	unknown	22:35–02:05 (good, 3.5 h)	50.2° 22:15	5.51	11%	91.4°
2029-05-17 Thu	78	—	unknown	22:35–02:00 (good, 3.42 h)	50.2° 22:10	5.46	18%	78.8°
2029-05-18 Fri	69	—	unknown	22:40–01:55 (good, 3.25 h)	50.2° 22:05	5.41	26%	66.0°
2029-05-19 Sat	60	—	unknown	22:40–01:55 (good, 3.25 h)	50.2° 22:00	5.36	36%	53.0°
2029-05-20 Sun	45	—	unknown	22:40–01:30 (good, 2.83 h)	50.2° 21:55	5.31	47%	39.9°
2029-05-21 Mon	33	—	unknown	22:40–02:15 (marginal, 3.58 h)	50.2° 21:55	5.26	58%	26.7°
2029-05-22 Tue	25	—	unknown	22:45–02:05 (marginal, 3.33 h)	50.2° 21:50	5.21	70%	14.6°
2029-05-23 Wed	19	—	unknown	22:45–01:50 (marginal, 3.08 h)	50.2° 21:45	5.16	80%	10.7°
2029-05-24 Thu	15	—	unknown	22:45–01:40 (marginal, 2.92 h)	50.2° 21:40	5.11	88%	20.9°
2029-05-25 Fri	14	—	unknown	22:50–01:30 (marginal, 2.67 h)	50.2° 21:35	5.07	95%	34.7°
2029-05-26 Sat	19	—	unknown	22:50–01:30 (marginal, 2.67 h)	50.2° 21:35	5.03	99%	49.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-04-27&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.