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: 01-22 (93), 01-23 (93), 01-24 (93), 01-25 (93), 01-26 (93) — by astronomy; check the weather when the night is within four days.

2047-01-22astronomy score per night — click a bar for that night2047-02-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-01-22 Tue	93	—	unknown	00:55–06:05 (good, 5.17 h)	50.1° 04:45	11.06	11%	78.8°
2047-01-23 Wed	93	—	unknown	00:55–06:05 (good, 5.17 h)	50.1° 04:40	11.03	5%	92.2°
2047-01-24 Thu	93	—	unknown	00:50–06:05 (good, 5.25 h)	50.1° 04:35	11.0	1%	105.3°
2047-01-25 Fri	93	—	unknown	00:45–06:05 (good, 5.33 h)	50.1° 04:30	10.98	0%	118.2°
2047-01-26 Sat	93	—	unknown	00:40–06:05 (good, 5.42 h)	50.1° 04:25	10.95	1%	130.8°
2047-01-27 Sun	93	—	unknown	00:35–06:05 (good, 5.5 h)	50.1° 04:25	10.92	4%	143.0°
2047-01-28 Mon	93	—	unknown	00:35–06:05 (good, 5.5 h)	50.1° 04:20	10.89	8%	154.7°
2047-01-29 Tue	93	—	unknown	00:30–06:00 (good, 5.5 h)	50.1° 04:15	10.86	14%	165.1°
2047-01-30 Wed	93	—	unknown	00:25–06:00 (good, 5.58 h)	50.1° 04:10	10.82	22%	170.2°
2047-01-31 Thu	93	—	unknown	00:20–06:00 (good, 5.67 h)	50.1° 04:10	10.79	30%	164.2°
2047-02-01 Fri	93	—	unknown	00:15–06:00 (good, 5.75 h)	50.1° 04:05	10.76	39%	153.9°
2047-02-02 Sat	93	—	unknown	00:15–06:00 (good, 5.75 h)	50.1° 04:00	10.73	48%	142.7°
2047-02-03 Sun	93	—	unknown	00:15–06:00 (good, 5.75 h)	50.1° 03:55	10.69	58%	131.1°
2047-02-04 Mon	93	—	unknown	00:15–05:55 (good, 5.67 h)	50.1° 03:50	10.66	67%	119.2°
2047-02-05 Tue	93	—	unknown	00:20–05:55 (good, 5.58 h)	50.1° 03:50	10.62	76%	106.9°
2047-02-06 Wed	91	—	unknown	00:30–05:55 (good, 5.42 h)	50.1° 03:45	10.59	84%	94.3°
2047-02-07 Thu	87	—	unknown	02:00–05:55 (good, 3.92 h)	50.1° 03:40	10.55	91%	81.2°
2047-02-08 Fri	55	—	unknown	04:20–05:55 (good, 1.58 h)	50.1° 03:35	10.52	96%	67.8°
2047-02-09 Sat	39	—	unknown	00:05–05:50 (marginal, 5.75 h)	50.1° 03:30	10.48	99%	54.0°
2047-02-10 Sun	26	—	unknown	01:45–05:50 (marginal, 4.08 h)	50.1° 03:30	10.44	100%	40.0°
2047-02-11 Mon	21	—	unknown	03:00–05:50 (marginal, 2.83 h)	50.1° 03:25	10.41	98%	26.2°
2047-02-12 Tue	24	—	unknown	23:45–05:50 (marginal, 6.08 h)	50.1° 03:20	10.37	92%	13.7°
2047-02-13 Wed	31	—	unknown	23:20–05:45 (marginal, 6.42 h)	50.1° 03:15	10.33	85%	10.9°
2047-02-14 Thu	46	—	unknown	23:00–05:45 (marginal, 6.75 h)	50.1° 03:15	10.29	76%	21.7°
2047-02-15 Fri	83	—	unknown	23:20–03:50 (good, 4.5 h)	50.1° 03:10	10.25	65%	35.1°
2047-02-16 Sat	90	—	unknown	23:20–05:45 (good, 6.42 h)	50.1° 03:05	10.21	54%	48.7°
2047-02-17 Sun	93	—	unknown	23:15–05:40 (good, 6.42 h)	50.1° 03:00	10.17	43%	62.3°
2047-02-18 Mon	93	—	unknown	23:10–05:40 (good, 6.5 h)	50.1° 02:55	10.13	32%	75.7°
2047-02-19 Tue	93	—	unknown	23:05–05:40 (good, 6.58 h)	50.1° 02:55	10.09	22%	88.9°
2047-02-20 Wed	93	—	unknown	23:00–05:40 (good, 6.67 h)	50.1° 02:50	10.04	14%	101.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-01-22&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.