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.

2038-01-02astronomy score per night — click a bar for that night2038-01-31

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2038-01-21 Thu	28	—	unknown	01:20–06:05 (marginal, 4.75 h)	50.1° 04:45	11.08	99%	53.7°
2038-01-22 Fri	19	—	unknown	02:55–06:05 (marginal, 3.17 h)	50.1° 04:40	11.05	96%	39.4°
2038-01-23 Sat	17	—	unknown	03:05–06:05 (marginal, 3.0 h)	50.1° 04:40	11.03	90%	24.9°
2038-01-24 Sun	23	—	unknown	00:50–06:05 (marginal, 5.25 h)	50.1° 04:35	11.0	82%	10.5°
2038-01-25 Mon	33	—	unknown	00:25–06:05 (marginal, 5.67 h)	50.1° 04:30	10.97	72%	4.0°
2038-01-26 Tue	48	—	unknown	00:10–06:05 (marginal, 5.92 h)	50.1° 04:25	10.94	61%	18.3°
2038-01-27 Wed	78	—	unknown	00:35–06:05 (good, 5.5 h)	50.1° 04:20	10.91	50%	32.4°
2038-01-28 Thu	87	—	unknown	00:30–06:05 (good, 5.58 h)	50.1° 04:20	10.88	39%	46.3°
2038-01-29 Fri	92	—	unknown	00:30–06:00 (good, 5.5 h)	50.1° 04:15	10.85	28%	60.0°
2038-01-30 Sat	93	—	unknown	00:25–06:00 (good, 5.58 h)	50.1° 04:10	10.82	19%	73.6°
2038-01-31 Sun	93	—	unknown	00:20–06:00 (good, 5.67 h)	50.1° 04:05	10.79	11%	86.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-01-02&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.