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: 01-17 (93), 01-18 (93), 01-19 (93), 01-20 (93), 01-21 (93) — by astronomy; check the weather when the night is within four days.

2048-01-17astronomy score per night — click a bar for that night2048-02-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2048-02-04 Tue	41	—	unknown	23:45–05:55 (marginal, 6.17 h)	50.1° 03:55	10.67	74%	15.0°
2048-02-05 Wed	65	—	unknown	00:00–00:15 (good, 0.25 h)	50.1° 03:50	10.63	63%	27.0°
2048-02-06 Thu	86	—	unknown	00:00–05:55 (good, 5.92 h)	50.1° 03:45	10.6	52%	40.3°
2048-02-07 Fri	92	—	unknown	23:55–05:55 (good, 6.0 h)	50.1° 03:40	10.56	41%	54.0°
2048-02-08 Sat	93	—	unknown	23:50–05:55 (good, 6.08 h)	50.1° 03:35	10.53	30%	67.9°
2048-02-09 Sun	93	—	unknown	23:45–05:50 (good, 6.08 h)	50.1° 03:35	10.49	20%	81.9°
2048-02-10 Mon	93	—	unknown	23:45–05:50 (good, 6.08 h)	50.1° 03:30	10.45	12%	96.0°
2048-02-11 Tue	93	—	unknown	23:40–05:50 (good, 6.17 h)	50.1° 03:25	10.41	5%	109.9°
2048-02-12 Wed	93	—	unknown	23:35–05:50 (good, 6.25 h)	50.1° 03:20	10.38	2%	123.7°
2048-02-13 Thu	93	—	unknown	23:30–05:50 (good, 6.33 h)	50.1° 03:20	10.34	0%	137.1°
2048-02-14 Fri	93	—	unknown	23:25–05:45 (good, 6.33 h)	50.1° 03:15	10.3	1%	150.1°
2048-02-15 Sat	93	—	unknown	23:25–05:45 (good, 6.33 h)	50.1° 03:10	10.26	4%	162.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2048-01-17&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.