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.

2037-12-09astronomy score per night — click a bar for that night2038-01-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-12-09 Wed	53	—	unknown	03:50–06:00 (good, 2.17 h)	50.1° 07:35	11.45	10%	109.2°
2037-12-10 Thu	55	—	unknown	03:45–06:00 (good, 2.25 h)	50.1° 07:30	11.46	17%	122.1°
2037-12-11 Fri	57	—	unknown	03:40–06:00 (good, 2.33 h)	50.1° 07:25	11.47	25%	134.7°
2037-12-12 Sat	57	—	unknown	03:35–06:00 (good, 2.42 h)	50.1° 07:25	11.47	34%	146.9°
2037-12-13 Sun	60	—	unknown	03:30–06:05 (good, 2.58 h)	50.1° 07:20	11.48	44%	159.0°
2037-12-14 Mon	62	—	unknown	03:30–06:05 (good, 2.58 h)	50.1° 07:15	11.49	53%	170.8°
2037-12-15 Tue	65	—	unknown	03:25–06:05 (good, 2.67 h)	50.1° 07:10	11.49	62%	177.3°
2037-12-16 Wed	66	—	unknown	03:20–06:05 (good, 2.75 h)	50.1° 07:05	11.5	71%	165.5°
2037-12-17 Thu	67	—	unknown	03:15–06:05 (good, 2.83 h)	50.1° 07:05	11.5	79%	153.5°
2037-12-18 Fri	67	—	unknown	03:20–06:05 (good, 2.75 h)	50.1° 07:00	11.5	87%	141.4°
2037-12-19 Sat	67	—	unknown	03:20–06:05 (good, 2.75 h)	50.1° 06:55	11.51	93%	129.0°
2037-12-20 Sun	58	—	unknown	03:20–06:05 (good, 2.75 h)	50.1° 06:50	11.51	97%	116.3°
2037-12-21 Mon	49	—	unknown	03:25–06:05 (good, 2.67 h)	50.1° 06:50	11.51	100%	103.4°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-12-09&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.