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: 02-26 (93), 02-27 (93), 02-28 (93), 03-01 (93), 03-14 (93) — by astronomy; check the weather when the night is within four days.

2031-02-26astronomy score per night — click a bar for that night2031-03-27

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-02-26 Wed	93	—	unknown	22:40–05:30 (good, 6.83 h)	50.2° 02:25	9.79	29%	141.9°
2031-02-27 Thu	93	—	unknown	22:40–05:30 (good, 6.83 h)	50.2° 02:20	9.75	38%	130.0°
2031-02-28 Fri	93	—	unknown	22:35–05:25 (good, 6.83 h)	50.2° 02:15	9.7	48%	118.2°
2031-03-01 Sat	93	—	unknown	22:40–05:25 (good, 6.75 h)	50.2° 02:15	9.66	57%	106.5°
2031-03-02 Sun	92	—	unknown	22:45–05:25 (good, 6.67 h)	50.2° 02:10	9.61	66%	94.8°
2031-03-03 Mon	90	—	unknown	23:15–05:20 (good, 6.08 h)	50.2° 02:05	9.56	75%	83.1°
2031-03-04 Tue	86	—	unknown	00:45–05:20 (good, 4.58 h)	50.2° 02:00	9.52	83%	71.3°
2031-03-05 Wed	82	—	unknown	03:25–05:20 (good, 1.92 h)	50.2° 02:00	9.47	89%	59.3°
2031-03-06 Thu	45	—	unknown	22:25–05:15 (marginal, 6.83 h)	50.2° 01:55	9.42	95%	47.2°
2031-03-07 Fri	31	—	unknown	00:30–05:15 (marginal, 4.75 h)	50.2° 01:50	9.38	98%	35.0°
2031-03-08 Sat	25	—	unknown	01:45–05:15 (marginal, 3.5 h)	50.2° 01:45	9.33	100%	22.8°
2031-03-09 Sun	24	—	unknown	00:30–05:10 (marginal, 4.67 h)	50.2° 01:40	9.28	99%	11.9°
2031-03-10 Mon	27	—	unknown	21:50–05:10 (marginal, 7.33 h)	50.2° 01:40	9.23	96%	10.3°
2031-03-11 Tue	37	—	unknown	21:30–05:10 (marginal, 7.67 h)	50.2° 01:35	9.18	91%	20.8°
2031-03-12 Wed	81	—	unknown	21:45–22:25 (good, 0.67 h)	50.2° 01:30	9.14	84%	33.7°
2031-03-13 Thu	88	—	unknown	21:40–02:20 (good, 4.67 h)	50.2° 01:25	9.09	75%	47.1°
2031-03-14 Fri	93	—	unknown	21:35–04:25 (good, 6.83 h)	50.2° 01:20	9.04	65%	60.9°
2031-03-15 Sat	93	—	unknown	21:30–04:50 (good, 7.33 h)	50.2° 01:20	8.99	54%	74.7°
2031-03-16 Sun	93	—	unknown	21:25–04:55 (good, 7.5 h)	50.2° 01:15	8.94	42%	88.7°
2031-03-17 Mon	93	—	unknown	21:25–04:55 (good, 7.5 h)	50.2° 01:10	8.89	31%	102.7°
2031-03-18 Tue	93	—	unknown	21:20–04:55 (good, 7.58 h)	50.2° 01:05	8.84	21%	116.7°
2031-03-19 Wed	93	—	unknown	21:15–04:55 (good, 7.67 h)	50.2° 01:05	8.78	13%	130.6°
2031-03-20 Thu	93	—	unknown	21:10–04:50 (good, 7.67 h)	50.2° 01:00	8.73	6%	144.3°
2031-03-21 Fri	93	—	unknown	21:10–04:45 (good, 7.58 h)	50.2° 00:55	8.68	2%	157.5°
2031-03-22 Sat	93	—	unknown	21:05–04:45 (good, 7.67 h)	50.2° 00:50	8.63	0%	168.7°
2031-03-23 Sun	93	—	unknown	21:00–04:40 (good, 7.67 h)	50.2° 00:45	8.58	1%	169.1°
2031-03-24 Mon	93	—	unknown	20:55–04:35 (good, 7.67 h)	50.2° 00:45	8.52	4%	158.6°
2031-03-25 Tue	93	—	unknown	20:55–04:30 (good, 7.58 h)	50.2° 00:40	8.47	8%	146.6°
2031-03-26 Wed	93	—	unknown	20:50–04:25 (good, 7.58 h)	50.2° 00:35	8.42	15%	134.4°
2031-03-27 Thu	93	—	unknown	20:45–04:25 (good, 7.67 h)	50.2° 00:30	8.36	22%	122.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-02-26&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.