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: 03-09 (93), 03-10 (93), 03-11 (93), 03-12 (93), 03-13 (93) — by astronomy; check the weather when the night is within four days.

2045-03-04astronomy score per night — click a bar for that night2045-04-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-03-04 Sat	25	—	unknown	22:20–05:20 (marginal, 7.0 h)	50.1° 02:00	9.49	96%	7.8°
2045-03-05 Sun	35	—	unknown	21:55–05:20 (marginal, 7.42 h)	50.1° 01:55	9.44	91%	17.2°
2045-03-06 Mon	73	—	unknown	22:05–22:30 (good, 0.42 h)	50.1° 01:50	9.4	84%	30.1°
2045-03-07 Tue	87	—	unknown	22:00–02:20 (good, 4.33 h)	50.1° 01:50	9.35	75%	42.9°
2045-03-08 Wed	92	—	unknown	22:00–04:40 (good, 6.67 h)	50.1° 01:45	9.3	66%	55.5°
2045-03-09 Thu	93	—	unknown	21:55–05:10 (good, 7.25 h)	50.1° 01:40	9.25	56%	67.8°
2045-03-10 Fri	93	—	unknown	21:50–05:10 (good, 7.33 h)	50.1° 01:35	9.2	46%	79.9°
2045-03-11 Sat	93	—	unknown	21:45–05:10 (good, 7.42 h)	50.1° 01:30	9.16	37%	91.7°
2045-03-12 Sun	93	—	unknown	21:40–05:05 (good, 7.42 h)	50.1° 01:30	9.11	28%	103.4°
2045-03-13 Mon	93	—	unknown	21:40–05:05 (good, 7.42 h)	50.1° 01:25	9.06	20%	115.1°
2045-03-14 Tue	93	—	unknown	21:35–05:00 (good, 7.42 h)	50.1° 01:20	9.01	13%	126.8°
2045-03-15 Wed	93	—	unknown	21:30–05:00 (good, 7.5 h)	50.1° 01:15	8.96	7%	138.6°
2045-03-16 Thu	93	—	unknown	21:25–05:00 (good, 7.58 h)	50.1° 01:15	8.91	3%	150.3°
2045-03-17 Fri	93	—	unknown	21:20–04:55 (good, 7.58 h)	50.1° 01:10	8.86	1%	161.8°
2045-03-18 Sat	93	—	unknown	21:20–04:55 (good, 7.58 h)	50.1° 01:05	8.8	0%	171.3°
2045-03-19 Sun	93	—	unknown	21:15–04:55 (good, 7.67 h)	50.1° 01:00	8.75	2%	168.5°
2045-03-20 Mon	93	—	unknown	21:10–04:50 (good, 7.67 h)	50.1° 00:55	8.7	5%	157.3°
2045-03-21 Tue	93	—	unknown	21:05–04:45 (good, 7.67 h)	50.1° 00:55	8.65	11%	144.8°
2045-03-22 Wed	93	—	unknown	21:05–04:40 (good, 7.58 h)	50.1° 00:50	8.6	18%	131.8°
2045-03-23 Thu	93	—	unknown	21:00–04:35 (good, 7.58 h)	50.1° 00:45	8.54	27%	118.5°
2045-03-24 Fri	93	—	unknown	21:05–04:35 (good, 7.5 h)	50.1° 00:40	8.49	38%	105.0°
2045-03-25 Sat	90	—	unknown	21:05–05:30 (good, 7.42 h)	50.1° 00:35	8.44	49%	91.2°
2045-03-26 Sun	85	—	unknown	22:25–05:25 (good, 7.0 h)	50.1° 01:35	8.39	60%	77.2°
2045-03-27 Mon	80	—	unknown	00:25–05:20 (good, 4.92 h)	50.1° 01:30	8.33	71%	63.1°
2045-03-28 Tue	57	—	unknown	21:40–05:35 (marginal, 7.92 h)	50.1° 01:25	8.28	81%	48.8°
2045-03-29 Wed	37	—	unknown	22:25–05:30 (marginal, 7.08 h)	50.1° 01:20	8.22	89%	34.6°
2045-03-30 Thu	27	—	unknown	00:40–05:20 (marginal, 4.67 h)	50.1° 01:20	8.17	95%	20.8°
2045-03-31 Fri	24	—	unknown	00:45–05:05 (marginal, 4.33 h)	50.1° 01:15	8.12	99%	9.1°
2045-04-01 Sat	26	—	unknown	21:25–04:55 (marginal, 7.5 h)	50.1° 01:10	8.06	100%	12.1°
2045-04-02 Sun	35	—	unknown	21:25–04:50 (marginal, 7.42 h)	50.1° 01:05	8.01	98%	24.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-03-04&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.