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: 01-13 (93), 01-14 (93), 01-15 (93), 01-16 (93), 01-17 (93) — by astronomy; check the weather when the night is within four days.

2045-01-06astronomy score per night — click a bar for that night2045-02-04

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-01-06 Fri	18	—	unknown	02:15–06:10 (marginal, 3.92 h)	50.1° 05:45	11.38	83%	30.2°
2045-01-07 Sat	25	—	unknown	01:45–06:10 (marginal, 4.42 h)	50.1° 05:40	11.37	73%	16.8°
2045-01-08 Sun	36	—	unknown	01:30–06:10 (marginal, 4.67 h)	50.1° 05:35	11.35	63%	7.7°
2045-01-09 Mon	49	—	unknown	02:40–06:10 (good, 3.5 h)	50.1° 05:30	11.33	52%	14.4°
2045-01-10 Tue	63	—	unknown	02:00–06:10 (good, 4.17 h)	50.1° 05:30	11.32	42%	26.3°
2045-01-11 Wed	86	—	unknown	01:40–06:10 (good, 4.5 h)	50.1° 05:25	11.3	32%	38.5°
2045-01-12 Thu	91	—	unknown	01:35–06:10 (good, 4.58 h)	50.1° 05:20	11.28	23%	50.7°
2045-01-13 Fri	93	—	unknown	01:30–06:10 (good, 4.67 h)	50.1° 05:15	11.26	16%	62.7°
2045-01-14 Sat	93	—	unknown	01:25–06:10 (good, 4.75 h)	50.1° 05:15	11.24	9%	74.6°
2045-01-15 Sun	93	—	unknown	01:20–06:10 (good, 4.83 h)	50.1° 05:10	11.22	5%	86.4°
2045-01-16 Mon	93	—	unknown	01:20–06:10 (good, 4.83 h)	50.1° 05:05	11.19	2%	98.1°
2045-01-17 Tue	93	—	unknown	01:15–06:10 (good, 4.92 h)	50.1° 05:00	11.17	0%	109.9°
2045-01-18 Wed	93	—	unknown	01:10–06:10 (good, 5.0 h)	50.1° 04:55	11.15	0%	121.6°
2045-01-19 Thu	93	—	unknown	01:05–06:10 (good, 5.08 h)	50.1° 04:55	11.12	3%	133.3°
2045-01-20 Fri	93	—	unknown	01:00–06:10 (good, 5.17 h)	50.1° 04:50	11.1	7%	144.9°
2045-01-21 Sat	93	—	unknown	01:00–06:05 (good, 5.08 h)	50.1° 04:45	11.07	12%	156.5°
2045-01-22 Sun	93	—	unknown	00:55–06:05 (good, 5.17 h)	50.1° 04:40	11.05	19%	167.3°
2045-01-23 Mon	93	—	unknown	00:50–06:05 (good, 5.25 h)	50.1° 04:35	11.02	27%	172.0°
2045-01-24 Tue	93	—	unknown	00:45–06:05 (good, 5.33 h)	50.1° 04:35	10.99	37%	163.4°
2045-01-25 Wed	93	—	unknown	00:45–06:05 (good, 5.33 h)	50.1° 04:30	10.96	47%	151.3°
2045-01-26 Thu	93	—	unknown	00:45–06:05 (good, 5.33 h)	50.1° 04:25	10.93	58%	138.4°
2045-01-27 Fri	93	—	unknown	00:40–06:05 (good, 5.42 h)	50.1° 04:20	10.9	68%	124.9°
2045-01-28 Sat	93	—	unknown	00:45–06:05 (good, 5.33 h)	50.1° 04:15	10.87	78%	110.9°
2045-01-29 Sun	90	—	unknown	00:55–06:00 (good, 5.08 h)	50.1° 04:15	10.84	87%	96.5°
2045-01-30 Mon	66	—	unknown	02:40–06:00 (good, 3.33 h)	50.1° 04:10	10.81	94%	81.6°
2045-01-31 Tue	47	—	unknown	00:20–06:00 (marginal, 5.67 h)	50.1° 04:05	10.78	99%	66.6°
2045-02-01 Wed	31	—	unknown	00:45–06:00 (marginal, 5.25 h)	50.1° 04:00	10.74	100%	51.5°
2045-02-02 Thu	21	—	unknown	02:55–06:00 (marginal, 3.08 h)	50.1° 04:00	10.71	98%	36.6°
2045-02-03 Fri	19	—	unknown	02:45–05:55 (marginal, 3.17 h)	50.1° 03:55	10.68	94%	22.3°
2045-02-04 Sat	25	—	unknown	00:05–05:55 (marginal, 5.83 h)	50.1° 03:50	10.64	87%	10.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-01-06&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.