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: 01-03 (93), 01-04 (93), 01-05 (93), 01-06 (93), 01-07 (93) — by astronomy; check the weather when the night is within four days.

2043-12-25astronomy score per night — click a bar for that night2044-01-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-12-25 Fri	63	—	unknown	02:45–06:10 (good, 3.42 h)	50.1° 06:35	11.5	25%	29.7°
2043-12-26 Sat	74	—	unknown	02:45–06:10 (good, 3.42 h)	50.1° 06:30	11.5	17%	41.4°
2043-12-27 Sun	82	—	unknown	02:40–06:10 (good, 3.5 h)	50.1° 06:25	11.49	11%	53.1°
2043-12-28 Mon	85	—	unknown	02:35–06:10 (good, 3.58 h)	50.1° 06:20	11.49	6%	64.8°
2043-12-29 Tue	86	—	unknown	02:30–06:10 (good, 3.67 h)	50.1° 06:20	11.48	2%	76.6°
2043-12-30 Wed	88	—	unknown	02:30–06:10 (good, 3.67 h)	50.1° 06:15	11.47	0%	88.4°
2043-12-31 Thu	90	—	unknown	02:25–06:10 (good, 3.75 h)	50.1° 06:10	11.46	0%	100.3°
2044-01-01 Fri	91	—	unknown	02:20–06:10 (good, 3.83 h)	50.1° 06:05	11.45	2%	112.4°
2044-01-02 Sat	92	—	unknown	02:15–06:10 (good, 3.92 h)	50.1° 06:05	11.44	6%	124.5°
2044-01-03 Sun	93	—	unknown	02:10–06:10 (good, 4.0 h)	50.1° 06:00	11.43	11%	136.8°
2044-01-04 Mon	93	—	unknown	02:10–06:10 (good, 4.0 h)	50.1° 05:55	11.42	18%	149.2°
2044-01-05 Tue	93	—	unknown	02:05–06:10 (good, 4.08 h)	50.1° 05:50	11.41	27%	161.6°
2044-01-06 Wed	93	—	unknown	02:00–06:10 (good, 4.17 h)	50.1° 05:45	11.39	37%	172.6°
2044-01-07 Thu	93	—	unknown	01:55–06:10 (good, 4.25 h)	50.1° 05:45	11.38	47%	169.2°
2044-01-08 Fri	93	—	unknown	01:50–06:10 (good, 4.33 h)	50.1° 05:40	11.36	58%	156.6°
2044-01-09 Sat	93	—	unknown	01:55–06:10 (good, 4.25 h)	50.1° 05:35	11.35	69%	142.8°
2044-01-10 Sun	93	—	unknown	01:55–06:10 (good, 4.25 h)	50.1° 05:30	11.33	80%	128.5°
2044-01-11 Mon	93	—	unknown	01:55–06:10 (good, 4.25 h)	50.1° 05:25	11.31	88%	113.8°
2044-01-12 Tue	70	—	unknown	02:10–06:10 (good, 4.0 h)	50.1° 05:25	11.29	95%	99.0°
2044-01-13 Wed	53	—	unknown	03:50–06:10 (good, 2.33 h)	50.1° 05:20	11.27	99%	84.0°
2044-01-14 Thu	38	—	unknown	01:30–06:10 (marginal, 4.67 h)	50.1° 05:15	11.25	100%	69.1°
2044-01-15 Fri	27	—	unknown	01:45–06:10 (marginal, 4.42 h)	50.1° 05:10	11.23	98%	54.5°
2044-01-16 Sat	19	—	unknown	02:25–06:10 (marginal, 3.75 h)	50.1° 05:10	11.21	94%	40.2°
2044-01-17 Sun	18	—	unknown	01:45–06:10 (marginal, 4.42 h)	50.1° 05:05	11.19	87%	26.5°
2044-01-18 Mon	25	—	unknown	01:10–06:10 (marginal, 5.0 h)	50.1° 05:00	11.17	79%	13.7°
2044-01-19 Tue	34	—	unknown	00:50–06:10 (marginal, 5.33 h)	50.1° 04:55	11.14	70%	6.1°
2044-01-20 Wed	47	—	unknown	00:40–06:10 (marginal, 5.5 h)	50.1° 04:50	11.12	60%	14.6°
2044-01-21 Thu	62	—	unknown	01:25–06:05 (good, 4.67 h)	50.1° 04:50	11.09	50%	26.3°
2044-01-22 Fri	85	—	unknown	00:55–06:05 (good, 5.17 h)	50.1° 04:45	11.07	41%	38.1°
2044-01-23 Sat	90	—	unknown	00:55–06:05 (good, 5.17 h)	50.1° 04:40	11.04	32%	49.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-12-25&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.