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: 01-13 (93), 01-14 (93), 01-15 (93), 01-16 (93), 01-17 (93) — by astronomy; check the weather when the night is within four days.

2044-12-21astronomy score per night — click a bar for that night2045-01-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-12-21 Wed	74	—	unknown	03:00–06:05 (good, 3.08 h)	50.1° 06:45	11.51	6%	112.8°
2044-12-22 Thu	76	—	unknown	02:55–06:10 (good, 3.25 h)	50.1° 06:45	11.51	11%	124.5°
2044-12-23 Fri	78	—	unknown	02:50–06:10 (good, 3.33 h)	50.1° 06:40	11.5	17%	136.1°
2044-12-24 Sat	80	—	unknown	02:50–06:10 (good, 3.33 h)	50.1° 06:35	11.5	25%	147.8°
2044-12-25 Sun	82	—	unknown	02:45–06:10 (good, 3.42 h)	50.1° 06:30	11.5	34%	159.3°
2044-12-26 Mon	84	—	unknown	02:40–06:10 (good, 3.5 h)	50.1° 06:25	11.49	44%	169.7°
2044-12-27 Tue	84	—	unknown	02:35–06:10 (good, 3.58 h)	50.1° 06:25	11.49	54%	170.7°
2044-12-28 Wed	86	—	unknown	02:35–06:10 (good, 3.58 h)	50.1° 06:20	11.48	64%	160.0°
2044-12-29 Thu	87	—	unknown	02:35–06:10 (good, 3.58 h)	50.1° 06:15	11.47	74%	147.2°
2044-12-30 Fri	86	—	unknown	02:35–06:10 (good, 3.58 h)	50.1° 06:10	11.47	83%	133.6°
2044-12-31 Sat	83	—	unknown	02:30–06:10 (good, 3.67 h)	50.1° 06:10	11.46	91%	119.4°
2045-01-01 Sun	64	—	unknown	02:40–06:10 (good, 3.5 h)	50.1° 06:05	11.45	96%	104.7°
2045-01-02 Mon	50	—	unknown	03:55–06:10 (good, 2.25 h)	50.1° 06:00	11.43	100%	89.7°
2045-01-03 Tue	36	—	unknown	06:00–06:10 (good, 0.17 h)	50.1° 05:55	11.42	100%	74.5°
2045-01-04 Wed	26	—	unknown	02:15–06:10 (marginal, 3.92 h)	50.1° 05:50	11.41	96%	59.4°
2045-01-05 Thu	20	—	unknown	02:20–06:10 (marginal, 3.83 h)	50.1° 05:50	11.4	91%	44.6°
2045-01-06 Fri	18	—	unknown	02:15–06:10 (marginal, 3.92 h)	50.1° 05:45	11.38	83%	30.2°
2045-01-07 Sat	25	—	unknown	01:45–06:10 (marginal, 4.42 h)	50.1° 05:40	11.37	73%	16.8°
2045-01-08 Sun	36	—	unknown	01:30–06:10 (marginal, 4.67 h)	50.1° 05:35	11.35	63%	7.7°
2045-01-09 Mon	49	—	unknown	02:40–06:10 (good, 3.5 h)	50.1° 05:30	11.33	52%	14.4°
2045-01-10 Tue	63	—	unknown	02:00–06:10 (good, 4.17 h)	50.1° 05:30	11.32	42%	26.3°
2045-01-11 Wed	86	—	unknown	01:40–06:10 (good, 4.5 h)	50.1° 05:25	11.3	32%	38.5°
2045-01-12 Thu	91	—	unknown	01:35–06:10 (good, 4.58 h)	50.1° 05:20	11.28	23%	50.7°
2045-01-13 Fri	93	—	unknown	01:30–06:10 (good, 4.67 h)	50.1° 05:15	11.26	16%	62.7°
2045-01-14 Sat	93	—	unknown	01:25–06:10 (good, 4.75 h)	50.1° 05:15	11.24	9%	74.6°
2045-01-15 Sun	93	—	unknown	01:20–06:10 (good, 4.83 h)	50.1° 05:10	11.22	5%	86.4°
2045-01-16 Mon	93	—	unknown	01:20–06:10 (good, 4.83 h)	50.1° 05:05	11.19	2%	98.1°
2045-01-17 Tue	93	—	unknown	01:15–06:10 (good, 4.92 h)	50.1° 05:00	11.17	0%	109.9°
2045-01-18 Wed	93	—	unknown	01:10–06:10 (good, 5.0 h)	50.1° 04:55	11.15	0%	121.6°
2045-01-19 Thu	93	—	unknown	01:05–06:10 (good, 5.08 h)	50.1° 04:55	11.12	3%	133.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-12-21&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.