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: 02-25 (93), 02-26 (93), 02-27 (93), 02-28 (93), 03-01 (93) — by astronomy; check the weather when the night is within four days.

2030-02-25astronomy score per night — click a bar for that night2030-03-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-02-25 Mon	93	—	unknown	22:40–05:30 (good, 6.83 h)	50.2° 02:30	9.82	40%	72.7°
2030-02-26 Tue	93	—	unknown	22:35–05:30 (good, 6.92 h)	50.2° 02:25	9.78	30%	86.4°
2030-02-27 Wed	93	—	unknown	22:35–05:30 (good, 6.92 h)	50.2° 02:20	9.74	20%	100.0°
2030-02-28 Thu	93	—	unknown	22:30–05:25 (good, 6.92 h)	50.2° 02:15	9.69	12%	113.4°
2030-03-01 Fri	93	—	unknown	22:25–05:25 (good, 7.0 h)	50.2° 02:10	9.65	6%	126.5°
2030-03-02 Sat	93	—	unknown	22:20–05:25 (good, 7.08 h)	50.2° 02:10	9.6	2%	139.4°
2030-03-03 Sun	93	—	unknown	22:20–05:20 (good, 7.0 h)	50.2° 02:05	9.55	0%	151.8°
2030-03-04 Mon	93	—	unknown	22:15–05:20 (good, 7.08 h)	50.2° 02:00	9.51	1%	163.2°
2030-03-05 Tue	93	—	unknown	22:10–05:20 (good, 7.17 h)	50.2° 01:55	9.46	3%	170.3°
2030-03-06 Wed	93	—	unknown	22:05–05:15 (good, 7.17 h)	50.2° 01:55	9.41	7%	165.4°
2030-03-07 Thu	93	—	unknown	22:00–05:15 (good, 7.25 h)	50.2° 01:50	9.37	13%	155.0°
2030-03-08 Fri	93	—	unknown	22:00–05:15 (good, 7.25 h)	50.2° 01:45	9.32	20%	143.8°
2030-03-09 Sat	93	—	unknown	21:55–05:10 (good, 7.25 h)	50.2° 01:40	9.27	28%	132.3°
2030-03-10 Sun	93	—	unknown	21:55–05:10 (good, 7.25 h)	50.2° 01:35	9.22	37%	120.7°
2030-03-11 Mon	93	—	unknown	21:55–05:10 (good, 7.25 h)	50.2° 01:35	9.17	46%	109.1°
2030-03-12 Tue	92	—	unknown	22:00–05:05 (good, 7.08 h)	50.2° 01:30	9.12	56%	97.2°
2030-03-13 Wed	90	—	unknown	22:05–05:05 (good, 7.0 h)	50.2° 01:25	9.07	65%	85.2°
2030-03-14 Thu	86	—	unknown	23:20–05:05 (good, 5.75 h)	50.2° 01:20	9.02	74%	72.9°
2030-03-15 Fri	82	—	unknown	01:40–05:00 (good, 3.33 h)	50.2° 01:15	8.97	83%	60.2°
2030-03-16 Sat	67	—	unknown	04:45–05:00 (good, 0.25 h)	50.2° 01:15	8.92	90%	47.2°
2030-03-17 Sun	34	—	unknown	23:25–05:00 (marginal, 5.58 h)	50.2° 01:10	8.87	96%	33.9°
2030-03-18 Mon	26	—	unknown	00:45–04:55 (marginal, 4.17 h)	50.2° 01:05	8.82	99%	20.8°
2030-03-19 Tue	25	—	unknown	21:35–04:55 (marginal, 7.33 h)	50.2° 01:00	8.77	100%	10.4°
2030-03-20 Wed	29	—	unknown	21:05–04:45 (marginal, 7.67 h)	50.2° 01:00	8.72	98%	14.2°
2030-03-21 Thu	53	—	unknown	21:05–21:10 (good, 0.08 h)	50.2° 00:55	8.67	93%	26.9°
2030-03-22 Fri	85	—	unknown	21:05–22:25 (good, 1.33 h)	50.2° 00:50	8.62	86%	41.0°
2030-03-23 Sat	91	—	unknown	21:00–02:35 (good, 5.58 h)	50.2° 00:45	8.56	77%	55.2°
2030-03-24 Sun	93	—	unknown	20:55–04:05 (good, 7.17 h)	50.2° 00:40	8.51	66%	69.3°
2030-03-25 Mon	93	—	unknown	20:50–04:15 (good, 7.42 h)	50.2° 00:40	8.46	55%	83.2°
2030-03-26 Tue	93	—	unknown	20:45–04:15 (good, 7.5 h)	50.2° 00:35	8.41	44%	96.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-02-25&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.