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: 01-30 (93), 01-31 (93), 02-01 (93), 02-02 (93), 02-03 (93) — by astronomy; check the weather when the night is within four days.

2038-01-23astronomy score per night — click a bar for that night2038-02-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2038-02-01 Mon	93	—	unknown	00:15–06:00 (good, 5.75 h)	50.1° 04:05	10.75	6%	100.1°
2038-02-02 Tue	93	—	unknown	00:10–06:00 (good, 5.83 h)	50.1° 04:00	10.72	2%	113.1°
2038-02-03 Wed	93	—	unknown	00:10–06:00 (good, 5.83 h)	50.1° 03:55	10.69	0%	125.8°
2038-02-04 Thu	93	—	unknown	00:05–05:55 (good, 5.83 h)	50.1° 03:50	10.65	0%	138.4°
2038-02-05 Fri	93	—	unknown	00:00–05:55 (good, 5.92 h)	50.1° 03:45	10.62	3%	150.7°
2038-02-06 Sat	93	—	unknown	23:55–05:55 (good, 6.0 h)	50.1° 03:45	10.58	7%	162.8°
2038-02-07 Sun	93	—	unknown	23:50–05:55 (good, 6.08 h)	50.1° 03:40	10.55	13%	174.8°
2038-02-08 Mon	93	—	unknown	23:50–05:55 (good, 6.08 h)	50.1° 03:35	10.51	20%	173.3°
2038-02-09 Tue	93	—	unknown	23:45–05:50 (good, 6.08 h)	50.1° 03:30	10.47	28%	161.5°
2038-02-10 Wed	93	—	unknown	23:45–05:50 (good, 6.08 h)	50.1° 03:25	10.44	36%	149.7°
2038-02-11 Thu	93	—	unknown	23:40–05:50 (good, 6.17 h)	50.1° 03:25	10.4	46%	137.8°
2038-02-12 Fri	93	—	unknown	23:40–05:50 (good, 6.17 h)	50.1° 03:20	10.36	55%	125.7°
2038-02-13 Sat	93	—	unknown	23:40–05:45 (good, 6.08 h)	50.1° 03:15	10.32	65%	113.3°
2038-02-14 Sun	93	—	unknown	23:45–05:45 (good, 6.0 h)	50.1° 03:10	10.28	74%	100.6°
2038-02-15 Mon	90	—	unknown	00:20–05:45 (good, 5.42 h)	50.1° 03:10	10.24	83%	87.5°
2038-02-16 Tue	85	—	unknown	02:15–05:45 (good, 3.5 h)	50.1° 03:05	10.2	90%	73.9°
2038-02-17 Wed	49	—	unknown	23:20–05:40 (marginal, 6.33 h)	50.1° 03:00	10.16	96%	59.9°
2038-02-18 Thu	31	—	unknown	00:35–05:40 (marginal, 5.08 h)	50.1° 02:55	10.12	99%	45.4°
2038-02-19 Fri	18	—	unknown	03:40–05:40 (marginal, 2.0 h)	50.1° 02:50	10.08	100%	30.7°
2038-02-20 Sat	18	—	unknown	03:50–05:40 (marginal, 1.83 h)	50.1° 02:50	10.04	98%	15.8°
2038-02-21 Sun	21	—	unknown	23:05–05:35 (marginal, 6.5 h)	50.1° 02:45	10.0	92%	0.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-01-23&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.