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: 03-30 (93), 03-31 (93), 04-01 (93), 04-02 (93), 04-03 (93) — by astronomy; check the weather when the night is within four days.

2043-03-25astronomy score per night — click a bar for that night2043-04-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-03-25 Wed	22	—	unknown	21:05–04:20 (marginal, 7.25 h)	50.1° 00:40	8.47	100%	5.7°
2043-03-26 Thu	29	—	unknown	20:40–04:15 (marginal, 7.58 h)	50.1° 00:35	8.41	98%	16.1°
2043-03-27 Fri	53	—	unknown	20:45–20:50 (good, 0.08 h)	50.1° 00:30	8.36	95%	27.8°
2043-03-28 Sat	84	—	unknown	20:40–21:55 (good, 1.25 h)	50.1° 00:25	8.31	90%	39.5°
2043-03-29 Sun	90	—	unknown	21:35–02:15 (good, 4.67 h)	50.1° 01:25	8.25	84%	51.3°
2043-03-30 Mon	93	—	unknown	21:35–04:05 (good, 6.5 h)	50.1° 01:20	8.2	76%	63.1°
2043-03-31 Tue	93	—	unknown	21:30–04:45 (good, 7.25 h)	50.1° 01:15	8.14	68%	74.9°
2043-04-01 Wed	93	—	unknown	21:25–04:50 (good, 7.42 h)	50.1° 01:10	8.09	58%	87.0°
2043-04-02 Thu	93	—	unknown	21:25–04:50 (good, 7.42 h)	50.1° 01:10	8.03	49%	99.2°
2043-04-03 Fri	93	—	unknown	21:25–04:50 (good, 7.42 h)	50.1° 01:05	7.98	38%	111.8°
2043-04-04 Sat	93	—	unknown	21:30–04:50 (good, 7.33 h)	50.1° 01:00	7.92	29%	124.8°
2043-04-05 Sun	93	—	unknown	21:30–04:50 (good, 7.33 h)	50.1° 00:55	7.87	19%	138.1°
2043-04-06 Mon	93	—	unknown	21:30–04:45 (good, 7.25 h)	50.1° 00:50	7.81	11%	151.9°
2043-04-07 Tue	93	—	unknown	21:35–04:40 (good, 7.08 h)	50.1° 00:50	7.76	5%	165.9°
2043-04-08 Wed	93	—	unknown	21:35–04:35 (good, 7.0 h)	50.1° 00:45	7.7	1%	175.3°
2043-04-09 Thu	93	—	unknown	21:35–04:30 (good, 6.92 h)	50.1° 00:40	7.64	0%	162.9°
2043-04-10 Fri	93	—	unknown	21:35–04:30 (good, 6.92 h)	50.1° 00:35	7.59	2%	148.1°
2043-04-11 Sat	93	—	unknown	21:40–04:25 (good, 6.75 h)	50.1° 00:30	7.53	7%	133.1°
2043-04-12 Sun	93	—	unknown	21:40–04:20 (good, 6.67 h)	50.1° 00:30	7.47	14%	118.3°
2043-04-13 Mon	93	—	unknown	21:40–04:15 (good, 6.58 h)	50.1° 00:25	7.41	23%	103.8°
2043-04-14 Tue	89	—	unknown	21:45–04:10 (good, 6.42 h)	50.1° 00:20	7.36	34%	89.6°
2043-04-15 Wed	84	—	unknown	21:45–04:10 (good, 6.42 h)	50.1° 00:15	7.3	45%	75.9°
2043-04-16 Thu	75	—	unknown	21:45–04:05 (good, 6.33 h)	50.1° 00:15	7.24	55%	62.5°
2043-04-17 Fri	62	—	unknown	00:30–03:30 (good, 3.0 h)	50.1° 00:10	7.18	66%	49.6°
2043-04-18 Sat	43	—	unknown	21:50–04:20 (marginal, 6.5 h)	50.1° 00:05	7.13	75%	36.9°
2043-04-19 Sun	30	—	unknown	21:50–04:10 (marginal, 6.33 h)	50.1° 00:00	7.07	83%	24.6°
2043-04-20 Mon	24	—	unknown	21:50–03:55 (marginal, 6.08 h)	50.1° 23:55	7.01	90%	12.7°
2043-04-21 Tue	20	—	unknown	21:55–03:45 (marginal, 5.83 h)	50.1° 23:55	6.95	95%	4.5°
2043-04-22 Wed	20	—	unknown	21:55–03:30 (marginal, 5.58 h)	50.1° 23:50	6.89	98%	13.1°
2043-04-23 Thu	23	—	unknown	21:55–03:20 (marginal, 5.42 h)	50.1° 23:45	6.84	100%	24.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-03-25&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.