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: 04-09 (93), 04-10 (93), 04-11 (93), 04-12 (93), 04-13 (93) — by astronomy; check the weather when the night is within four days.

2029-04-09astronomy score per night — click a bar for that night2029-05-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-04-09 Mon	93	—	unknown	21:35–04:30 (good, 6.92 h)	50.2° 00:40	7.62	14%	149.8°
2029-04-10 Tue	93	—	unknown	21:40–04:25 (good, 6.75 h)	50.2° 00:35	7.56	8%	160.6°
2029-04-11 Wed	93	—	unknown	21:40–04:20 (good, 6.67 h)	50.2° 00:30	7.51	4%	169.0°
2029-04-12 Thu	93	—	unknown	21:40–04:20 (good, 6.67 h)	50.2° 00:25	7.45	1%	168.1°
2029-04-13 Fri	93	—	unknown	21:40–04:15 (good, 6.58 h)	50.2° 00:20	7.39	0%	159.0°
2029-04-14 Sat	93	—	unknown	21:45–04:10 (good, 6.42 h)	50.2° 00:20	7.33	1%	148.1°
2029-04-15 Sun	93	—	unknown	21:45–04:05 (good, 6.33 h)	50.2° 00:15	7.28	4%	136.7°
2029-04-16 Mon	93	—	unknown	21:45–04:00 (good, 6.25 h)	50.2° 00:10	7.22	8%	125.0°
2029-04-17 Tue	93	—	unknown	21:50–04:00 (good, 6.17 h)	50.2° 00:05	7.16	14%	113.0°
2029-04-18 Wed	93	—	unknown	21:50–03:55 (good, 6.08 h)	50.2° 00:05	7.1	22%	100.9°
2029-04-19 Thu	90	—	unknown	21:50–03:50 (good, 6.0 h)	50.2° 00:00	7.05	31%	88.5°
2029-04-20 Fri	87	—	unknown	21:50–03:45 (good, 5.92 h)	50.2° 23:55	6.99	40%	75.8°
2029-04-21 Sat	83	—	unknown	21:55–03:45 (good, 5.83 h)	50.2° 23:50	6.93	51%	62.9°
2029-04-22 Sun	75	—	unknown	23:00–03:40 (good, 4.67 h)	50.2° 23:45	6.87	62%	49.6°
2029-04-23 Mon	46	—	unknown	21:55–04:05 (marginal, 6.17 h)	50.2° 23:45	6.81	73%	36.0°
2029-04-24 Tue	32	—	unknown	22:00–03:50 (marginal, 5.83 h)	50.2° 23:40	6.75	82%	22.5°
2029-04-25 Wed	25	—	unknown	22:00–03:35 (marginal, 5.58 h)	50.2° 23:35	6.7	90%	11.3°
2029-04-26 Thu	21	—	unknown	22:00–03:20 (marginal, 5.33 h)	50.2° 23:30	6.64	96%	13.6°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-04-09&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.