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.

2037-12-22astronomy score per night — click a bar for that night2038-01-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-12-22 Tue	40	—	unknown	04:30–06:10 (good, 1.67 h)	50.1° 06:45	11.51	100%	90.1°
2037-12-23 Wed	30	—	unknown	06:05–06:10 (good, 0.08 h)	50.1° 06:40	11.5	98%	76.7°
2037-12-24 Thu	23	—	unknown	02:50–06:10 (marginal, 3.33 h)	50.1° 06:35	11.5	94%	63.0°
2037-12-25 Fri	19	—	unknown	02:55–06:10 (marginal, 3.25 h)	50.1° 06:30	11.5	87%	49.1°
2037-12-26 Sat	17	—	unknown	02:50–06:10 (marginal, 3.33 h)	50.1° 06:30	11.49	78%	35.1°
2037-12-27 Sun	22	—	unknown	02:30–06:10 (marginal, 3.67 h)	50.1° 06:25	11.49	68%	21.1°
2037-12-28 Mon	31	—	unknown	02:10–06:10 (marginal, 4.0 h)	50.1° 06:20	11.48	57%	6.9°
2037-12-29 Tue	43	—	unknown	03:05–06:10 (good, 3.08 h)	50.1° 06:15	11.48	46%	7.2°
2037-12-30 Wed	57	—	unknown	02:40–06:10 (good, 3.5 h)	50.1° 06:10	11.47	35%	21.3°
2037-12-31 Thu	72	—	unknown	02:20–06:10 (good, 3.83 h)	50.1° 06:10	11.46	24%	35.4°
2038-01-01 Fri	85	—	unknown	02:20–06:10 (good, 3.83 h)	50.1° 06:05	11.45	15%	49.5°
2038-01-02 Sat	92	—	unknown	02:15–06:10 (good, 3.92 h)	50.1° 06:00	11.44	8%	63.4°
2038-01-03 Sun	93	—	unknown	02:10–06:10 (good, 4.0 h)	50.1° 05:55	11.43	3%	77.2°
2038-01-04 Mon	93	—	unknown	02:05–06:10 (good, 4.08 h)	50.1° 05:55	11.41	0%	90.8°
2038-01-05 Tue	93	—	unknown	02:00–06:10 (good, 4.17 h)	50.1° 05:50	11.4	0%	104.2°
2038-01-06 Wed	93	—	unknown	02:00–06:10 (good, 4.17 h)	50.1° 05:45	11.39	2%	117.3°
2038-01-07 Thu	93	—	unknown	01:55–06:10 (good, 4.25 h)	50.1° 05:40	11.37	6%	130.0°
2038-01-08 Fri	93	—	unknown	01:50–06:10 (good, 4.33 h)	50.1° 05:35	11.36	12%	142.5°
2038-01-09 Sat	93	—	unknown	01:45–06:10 (good, 4.42 h)	50.1° 05:35	11.34	18%	154.8°
2038-01-10 Sun	93	—	unknown	01:40–06:10 (good, 4.5 h)	50.1° 05:30	11.32	26%	166.8°
2038-01-11 Mon	93	—	unknown	01:40–06:10 (good, 4.5 h)	50.1° 05:25	11.3	35%	178.7°
2038-01-12 Tue	93	—	unknown	01:35–06:10 (good, 4.58 h)	50.1° 05:20	11.28	44%	169.5°
2038-01-13 Wed	93	—	unknown	01:30–06:10 (good, 4.67 h)	50.1° 05:15	11.27	54%	157.6°
2038-01-14 Thu	93	—	unknown	01:30–06:10 (good, 4.67 h)	50.1° 05:15	11.24	63%	145.7°
2038-01-15 Fri	93	—	unknown	01:30–06:10 (good, 4.67 h)	50.1° 05:10	11.22	72%	133.5°
2038-01-16 Sat	93	—	unknown	01:30–06:10 (good, 4.67 h)	50.1° 05:05	11.2	81%	121.1°
2038-01-17 Sun	93	—	unknown	01:35–06:10 (good, 4.58 h)	50.1° 05:00	11.18	88%	108.3°
2038-01-18 Mon	89	—	unknown	01:55–06:10 (good, 4.25 h)	50.1° 05:00	11.15	94%	95.2°
2038-01-19 Tue	58	—	unknown	03:30–06:10 (good, 2.67 h)	50.1° 04:55	11.13	98%	81.7°
2038-01-20 Wed	42	—	unknown	01:05–06:10 (marginal, 5.08 h)	50.1° 04:50	11.11	100%	67.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-12-22&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.