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: 01-12 (93), 01-13 (93), 01-14 (93), 01-15 (93), 01-16 (93) — by astronomy; check the weather when the night is within four days.

2037-01-08astronomy score per night — click a bar for that night2037-02-06

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-01-08 Thu	50	—	unknown	02:15–06:10 (good, 3.92 h)	50.2° 05:35	11.35	48%	15.2°
2037-01-09 Fri	66	—	unknown	01:45–06:10 (good, 4.42 h)	50.2° 05:30	11.34	37%	28.7°
2037-01-10 Sat	85	—	unknown	01:40–06:10 (good, 4.5 h)	50.2° 05:30	11.32	27%	42.0°
2037-01-11 Sun	91	—	unknown	01:35–06:10 (good, 4.58 h)	50.2° 05:25	11.3	19%	55.0°
2037-01-12 Mon	93	—	unknown	01:35–06:10 (good, 4.58 h)	50.2° 05:20	11.28	11%	67.7°
2037-01-13 Tue	93	—	unknown	01:30–06:10 (good, 4.67 h)	50.2° 05:15	11.26	6%	80.3°
2037-01-14 Wed	93	—	unknown	01:25–06:10 (good, 4.75 h)	50.2° 05:10	11.24	2%	92.7°
2037-01-15 Thu	93	—	unknown	01:20–06:10 (good, 4.83 h)	50.2° 05:10	11.22	0%	104.9°
2037-01-16 Fri	93	—	unknown	01:20–06:10 (good, 4.83 h)	50.2° 05:05	11.2	0%	117.0°
2037-01-17 Sat	93	—	unknown	01:15–06:10 (good, 4.92 h)	50.2° 05:00	11.17	2%	129.0°
2037-01-18 Sun	93	—	unknown	01:10–06:10 (good, 5.0 h)	50.2° 04:55	11.15	6%	140.9°
2037-01-19 Mon	93	—	unknown	01:05–06:10 (good, 5.08 h)	50.2° 04:55	11.12	11%	152.7°
2037-01-20 Tue	93	—	unknown	01:00–06:10 (good, 5.17 h)	50.2° 04:50	11.1	17%	164.5°
2037-01-21 Wed	93	—	unknown	01:00–06:05 (good, 5.08 h)	50.2° 04:45	11.07	25%	176.4°
2037-01-22 Thu	93	—	unknown	00:55–06:05 (good, 5.17 h)	50.2° 04:40	11.05	34%	171.6°
2037-01-23 Fri	93	—	unknown	00:50–06:05 (good, 5.25 h)	50.2° 04:35	11.02	43%	159.5°
2037-01-24 Sat	93	—	unknown	00:50–06:05 (good, 5.25 h)	50.2° 04:35	10.99	53%	147.1°
2037-01-25 Sun	93	—	unknown	00:50–06:05 (good, 5.25 h)	50.2° 04:30	10.96	63%	134.3°
2037-01-26 Mon	93	—	unknown	00:45–06:05 (good, 5.33 h)	50.2° 04:25	10.93	73%	121.1°
2037-01-27 Tue	93	—	unknown	00:50–06:05 (good, 5.25 h)	50.2° 04:20	10.9	82%	107.4°
2037-01-28 Wed	92	—	unknown	01:15–06:05 (good, 4.83 h)	50.2° 04:15	10.87	90%	93.3°
2037-01-29 Thu	63	—	unknown	03:05–06:00 (good, 2.92 h)	50.2° 04:15	10.84	96%	78.7°
2037-01-30 Fri	44	—	unknown	00:30–06:00 (marginal, 5.5 h)	50.2° 04:10	10.81	99%	63.7°
2037-01-31 Sat	28	—	unknown	01:05–06:00 (marginal, 4.92 h)	50.2° 04:05	10.78	100%	48.5°
2037-02-01 Sun	18	—	unknown	03:40–06:00 (marginal, 2.33 h)	50.2° 04:00	10.75	97%	33.3°
2037-02-02 Mon	18	—	unknown	02:30–06:00 (marginal, 3.5 h)	50.2° 04:00	10.71	92%	18.2°
2037-02-03 Tue	24	—	unknown	00:05–06:00 (marginal, 5.92 h)	50.2° 03:55	10.68	84%	3.4°
2037-02-04 Wed	37	—	unknown	23:45–05:55 (marginal, 6.17 h)	50.2° 03:50	10.64	74%	11.1°
2037-02-05 Thu	53	—	unknown	23:30–05:55 (marginal, 6.42 h)	50.2° 03:45	10.61	64%	25.1°
2037-02-06 Fri	83	—	unknown	23:55–05:55 (good, 6.0 h)	50.2° 03:40	10.57	53%	38.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-01-08&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.