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: 12-19 (69), 12-18 (68), 12-17 (67), 12-16 (65), 12-15 (62) — by astronomy; check the weather when the night is within four days.

2047-11-20astronomy score per night — click a bar for that night2047-12-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-11-20 Wed	20	—	unknown	05:05–05:40 (good, 0.58 h)	50.1° 08:50	11.09	16%	99.5°
2047-11-21 Thu	21	—	unknown	05:00–05:45 (good, 0.75 h)	50.1° 08:50	11.12	25%	113.4°
2047-11-22 Fri	23	—	unknown	04:55–05:45 (good, 0.83 h)	50.1° 08:45	11.14	35%	126.8°
2047-11-23 Sat	24	—	unknown	04:55–05:45 (good, 0.83 h)	50.1° 08:40	11.17	46%	139.5°
2047-11-24 Sun	26	—	unknown	04:50–05:45 (good, 0.92 h)	50.1° 08:35	11.19	56%	151.7°
2047-11-25 Mon	28	—	unknown	04:45–05:45 (good, 1.0 h)	50.1° 08:30	11.21	65%	162.7°
2047-11-26 Tue	29	—	unknown	04:40–05:50 (good, 1.17 h)	50.1° 08:30	11.23	74%	169.8°
2047-11-27 Wed	31	—	unknown	04:40–05:50 (good, 1.17 h)	50.1° 08:25	11.25	82%	165.9°
2047-11-28 Thu	33	—	unknown	04:35–05:50 (good, 1.25 h)	50.1° 08:20	11.27	89%	156.0°
2047-11-29 Fri	33	—	unknown	04:40–05:50 (good, 1.17 h)	50.1° 08:15	11.29	94%	145.0°
2047-11-30 Sat	29	—	unknown	04:35–05:50 (good, 1.25 h)	50.1° 08:10	11.31	98%	133.6°
2047-12-01 Sun	30	—	unknown	04:35–05:55 (good, 1.33 h)	50.1° 08:10	11.33	100%	122.0°
2047-12-02 Mon	27	—	unknown	04:40–05:55 (good, 1.25 h)	50.1° 08:05	11.35	100%	110.3°
2047-12-03 Tue	24	—	unknown	04:55–05:55 (good, 1.0 h)	50.1° 08:00	11.36	98%	98.5°
2047-12-04 Wed	20	—	unknown	05:50–05:55 (good, 0.08 h)	50.1° 07:55	11.38	95%	86.6°
2047-12-05 Thu	17	—	unknown	03:55–05:55 (marginal, 2.0 h)	50.1° 07:55	11.39	90%	74.6°
2047-12-06 Fri	15	—	unknown	03:55–05:55 (marginal, 2.0 h)	50.1° 07:50	11.41	83%	62.4°
2047-12-07 Sat	15	—	unknown	03:50–06:00 (marginal, 2.17 h)	50.1° 07:45	11.42	74%	50.1°
2047-12-08 Sun	16	—	unknown	03:45–06:00 (marginal, 2.25 h)	50.1° 07:40	11.43	65%	37.7°
2047-12-09 Mon	20	—	unknown	03:30–06:00 (marginal, 2.5 h)	50.1° 07:35	11.44	55%	25.3°
2047-12-10 Tue	27	—	unknown	04:40–06:00 (good, 1.33 h)	50.1° 07:35	11.45	44%	14.0°
2047-12-11 Wed	36	—	unknown	04:00–06:00 (good, 2.0 h)	50.1° 07:30	11.46	33%	10.8°
2047-12-12 Thu	45	—	unknown	03:50–06:00 (good, 2.17 h)	50.1° 07:25	11.47	22%	20.8°
2047-12-13 Fri	53	—	unknown	03:35–06:00 (good, 2.42 h)	50.1° 07:20	11.48	14%	34.3°
2047-12-14 Sat	60	—	unknown	03:30–06:05 (good, 2.58 h)	50.1° 07:15	11.48	6%	48.7°
2047-12-15 Sun	62	—	unknown	03:25–06:05 (good, 2.67 h)	50.1° 07:15	11.49	2%	63.5°
2047-12-16 Mon	65	—	unknown	03:25–06:05 (good, 2.67 h)	50.1° 07:10	11.5	0%	78.3°
2047-12-17 Tue	67	—	unknown	03:20–06:05 (good, 2.75 h)	50.1° 07:05	11.5	1%	93.1°
2047-12-18 Wed	68	—	unknown	03:15–06:05 (good, 2.83 h)	50.1° 07:00	11.5	5%	107.5°
2047-12-19 Thu	69	—	unknown	03:10–06:05 (good, 2.92 h)	50.1° 07:00	11.51	12%	121.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-11-20&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.