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: 01-11 (93), 01-12 (93), 01-13 (93), 01-14 (93), 01-15 (93) — by astronomy; check the weather when the night is within four days.

2048-01-05astronomy score per night — click a bar for that night2048-02-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2048-01-05 Sun	21	—	unknown	02:10–06:10 (marginal, 4.0 h)	50.1° 05:50	11.41	79%	28.0°
2048-01-06 Mon	28	—	unknown	01:50–06:10 (marginal, 4.33 h)	50.1° 05:45	11.39	70%	16.4°
2048-01-07 Tue	39	—	unknown	01:30–06:10 (marginal, 4.67 h)	50.1° 05:45	11.38	59%	10.1°
2048-01-08 Wed	52	—	unknown	02:20–06:10 (good, 3.83 h)	50.1° 05:40	11.36	48%	17.5°
2048-01-09 Thu	74	—	unknown	01:50–06:10 (good, 4.33 h)	50.1° 05:35	11.35	37%	30.0°
2048-01-10 Fri	88	—	unknown	01:45–06:10 (good, 4.42 h)	50.1° 05:30	11.33	26%	43.6°
2048-01-11 Sat	93	—	unknown	01:40–06:10 (good, 4.5 h)	50.1° 05:25	11.31	17%	57.8°
2048-01-12 Sun	93	—	unknown	01:35–06:10 (good, 4.58 h)	50.1° 05:25	11.29	9%	72.2°
2048-01-13 Mon	93	—	unknown	01:35–06:10 (good, 4.58 h)	50.1° 05:20	11.27	3%	86.7°
2048-01-14 Tue	93	—	unknown	01:30–06:10 (good, 4.67 h)	50.1° 05:15	11.25	0%	101.1°
2048-01-15 Wed	93	—	unknown	01:25–06:10 (good, 4.75 h)	50.1° 05:10	11.23	0%	115.3°
2048-01-16 Thu	93	—	unknown	01:20–06:10 (good, 4.83 h)	50.1° 05:10	11.21	3%	129.2°
2048-01-17 Fri	93	—	unknown	01:15–06:10 (good, 4.92 h)	50.1° 05:05	11.19	8%	142.5°
2048-01-18 Sat	93	—	unknown	01:15–06:10 (good, 4.92 h)	50.1° 05:00	11.16	14%	155.1°
2048-01-19 Sun	93	—	unknown	01:10–06:10 (good, 5.0 h)	50.1° 04:55	11.14	22%	165.9°
2048-01-20 Mon	93	—	unknown	01:05–06:10 (good, 5.08 h)	50.1° 04:50	11.12	31%	169.7°
2048-01-21 Tue	93	—	unknown	01:00–06:05 (good, 5.08 h)	50.1° 04:50	11.09	41%	162.2°
2048-01-22 Wed	93	—	unknown	01:00–06:05 (good, 5.08 h)	50.1° 04:45	11.06	50%	151.5°
2048-01-23 Thu	93	—	unknown	01:00–06:05 (good, 5.08 h)	50.1° 04:40	11.04	60%	140.2°
2048-01-24 Fri	93	—	unknown	00:55–06:05 (good, 5.17 h)	50.1° 04:35	11.01	69%	128.7°
2048-01-25 Sat	93	—	unknown	00:55–06:05 (good, 5.17 h)	50.1° 04:30	10.98	77%	117.1°
2048-01-26 Sun	93	—	unknown	01:00–06:05 (good, 5.08 h)	50.1° 04:30	10.95	84%	105.4°
2048-01-27 Mon	91	—	unknown	01:25–06:05 (good, 4.67 h)	50.1° 04:25	10.92	91%	93.5°
2048-01-28 Tue	66	—	unknown	02:50–06:05 (good, 3.25 h)	50.1° 04:20	10.89	96%	81.3°
2048-01-29 Wed	50	—	unknown	04:55–06:00 (good, 1.08 h)	50.1° 04:15	10.86	99%	69.0°
2048-01-30 Thu	37	—	unknown	00:40–06:00 (marginal, 5.33 h)	50.1° 04:15	10.83	100%	56.5°
2048-01-31 Fri	27	—	unknown	01:25–06:00 (marginal, 4.58 h)	50.1° 04:10	10.8	99%	43.8°
2048-02-01 Sat	20	—	unknown	02:55–06:00 (marginal, 3.08 h)	50.1° 04:05	10.77	96%	31.1°
2048-02-02 Sun	23	—	unknown	00:30–06:00 (marginal, 5.5 h)	50.1° 04:00	10.74	90%	18.9°
2048-02-03 Mon	30	—	unknown	00:05–06:00 (marginal, 5.92 h)	50.1° 03:55	10.7	83%	10.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2048-01-05&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.