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: 01-27 (93), 01-28 (93), 02-09 (93), 02-10 (93), 02-11 (93) — by astronomy; check the weather when the night is within four days.

2045-01-27astronomy score per night — click a bar for that night2045-02-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-01-27 Fri	93	—	unknown	00:40–06:05 (good, 5.42 h)	50.1° 04:20	10.9	68%	124.9°
2045-01-28 Sat	93	—	unknown	00:45–06:05 (good, 5.33 h)	50.1° 04:15	10.87	78%	110.9°
2045-01-29 Sun	90	—	unknown	00:55–06:00 (good, 5.08 h)	50.1° 04:15	10.84	87%	96.5°
2045-01-30 Mon	66	—	unknown	02:40–06:00 (good, 3.33 h)	50.1° 04:10	10.81	94%	81.6°
2045-01-31 Tue	47	—	unknown	00:20–06:00 (marginal, 5.67 h)	50.1° 04:05	10.78	99%	66.6°
2045-02-01 Wed	31	—	unknown	00:45–06:00 (marginal, 5.25 h)	50.1° 04:00	10.74	100%	51.5°
2045-02-02 Thu	21	—	unknown	02:55–06:00 (marginal, 3.08 h)	50.1° 04:00	10.71	98%	36.6°
2045-02-03 Fri	19	—	unknown	02:45–05:55 (marginal, 3.17 h)	50.1° 03:55	10.68	94%	22.3°
2045-02-04 Sat	25	—	unknown	00:05–05:55 (marginal, 5.83 h)	50.1° 03:50	10.64	87%	10.1°
2045-02-05 Sun	35	—	unknown	23:45–05:55 (marginal, 6.17 h)	50.1° 03:45	10.61	78%	10.8°
2045-02-06 Mon	51	—	unknown	23:25–05:55 (marginal, 6.5 h)	50.1° 03:40	10.57	69%	22.4°
2045-02-07 Tue	83	—	unknown	23:50–05:25 (good, 5.58 h)	50.1° 03:40	10.54	59%	35.0°
2045-02-08 Wed	90	—	unknown	23:50–05:50 (good, 6.0 h)	50.1° 03:35	10.5	48%	47.4°
2045-02-09 Thu	93	—	unknown	23:45–05:50 (good, 6.08 h)	50.1° 03:30	10.46	39%	59.6°
2045-02-10 Fri	93	—	unknown	23:40–05:50 (good, 6.17 h)	50.1° 03:25	10.42	30%	71.6°
2045-02-11 Sat	93	—	unknown	23:35–05:50 (good, 6.25 h)	50.1° 03:20	10.39	21%	83.4°
2045-02-12 Sun	93	—	unknown	23:30–05:50 (good, 6.33 h)	50.1° 03:20	10.35	14%	95.2°
2045-02-13 Mon	93	—	unknown	23:30–05:45 (good, 6.25 h)	50.1° 03:15	10.31	8%	106.9°
2045-02-14 Tue	93	—	unknown	23:25–05:45 (good, 6.33 h)	50.1° 03:10	10.27	4%	118.5°
2045-02-15 Wed	93	—	unknown	23:20–05:45 (good, 6.42 h)	50.1° 03:05	10.23	1%	130.3°
2045-02-16 Thu	93	—	unknown	23:15–05:45 (good, 6.5 h)	50.1° 03:05	10.19	0%	142.0°
2045-02-17 Fri	93	—	unknown	23:10–05:40 (good, 6.5 h)	50.1° 03:00	10.15	1%	153.7°
2045-02-18 Sat	93	—	unknown	23:10–05:40 (good, 6.5 h)	50.1° 02:55	10.11	4%	164.9°
2045-02-19 Sun	93	—	unknown	23:05–05:40 (good, 6.58 h)	50.1° 02:50	10.07	8%	172.2°
2045-02-20 Mon	93	—	unknown	23:00–05:40 (good, 6.67 h)	50.1° 02:45	10.02	14%	165.9°
2045-02-21 Tue	93	—	unknown	22:55–05:35 (good, 6.67 h)	50.1° 02:45	9.98	22%	154.3°
2045-02-22 Wed	93	—	unknown	22:55–05:35 (good, 6.67 h)	50.1° 02:40	9.94	32%	141.8°
2045-02-23 Thu	93	—	unknown	22:55–05:35 (good, 6.67 h)	50.1° 02:35	9.9	42%	128.7°
2045-02-24 Fri	93	—	unknown	22:50–05:30 (good, 6.67 h)	50.1° 02:30	9.85	53%	115.3°
2045-02-25 Sat	92	—	unknown	22:55–05:30 (good, 6.58 h)	50.1° 02:25	9.81	64%	101.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-01-27&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.