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: 01-24 (93), 01-25 (93), 01-26 (93), 01-27 (93), 01-28 (93) — by astronomy; check the weather when the night is within four days.

2044-01-17astronomy score per night — click a bar for that night2044-02-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-01-17 Sun	18	—	unknown	01:45–06:10 (marginal, 4.42 h)	50.1° 05:05	11.19	87%	26.5°
2044-01-18 Mon	25	—	unknown	01:10–06:10 (marginal, 5.0 h)	50.1° 05:00	11.17	79%	13.7°
2044-01-19 Tue	34	—	unknown	00:50–06:10 (marginal, 5.33 h)	50.1° 04:55	11.14	70%	6.1°
2044-01-20 Wed	47	—	unknown	00:40–06:10 (marginal, 5.5 h)	50.1° 04:50	11.12	60%	14.6°
2044-01-21 Thu	62	—	unknown	01:25–06:05 (good, 4.67 h)	50.1° 04:50	11.09	50%	26.3°
2044-01-22 Fri	85	—	unknown	00:55–06:05 (good, 5.17 h)	50.1° 04:45	11.07	41%	38.1°
2044-01-23 Sat	90	—	unknown	00:55–06:05 (good, 5.17 h)	50.1° 04:40	11.04	32%	49.9°
2044-01-24 Sun	93	—	unknown	00:50–06:05 (good, 5.25 h)	50.1° 04:35	11.01	24%	61.6°
2044-01-25 Mon	93	—	unknown	00:45–06:05 (good, 5.33 h)	50.1° 04:30	10.98	16%	73.3°
2044-01-26 Tue	93	—	unknown	00:40–06:05 (good, 5.42 h)	50.1° 04:30	10.95	10%	85.1°
2044-01-27 Wed	93	—	unknown	00:40–06:05 (good, 5.42 h)	50.1° 04:25	10.93	5%	97.0°
2044-01-28 Thu	93	—	unknown	00:35–06:05 (good, 5.5 h)	50.1° 04:20	10.9	2%	109.1°
2044-01-29 Fri	93	—	unknown	00:30–06:00 (good, 5.5 h)	50.1° 04:15	10.86	0%	121.3°
2044-01-30 Sat	93	—	unknown	00:25–06:00 (good, 5.58 h)	50.1° 04:15	10.83	1%	133.7°
2044-01-31 Sun	93	—	unknown	00:20–06:00 (good, 5.67 h)	50.1° 04:10	10.8	3%	146.2°
2044-02-01 Mon	93	—	unknown	00:20–06:00 (good, 5.67 h)	50.1° 04:05	10.77	8%	158.8°
2044-02-02 Tue	93	—	unknown	00:15–06:00 (good, 5.75 h)	50.1° 04:00	10.74	14%	170.5°
2044-02-03 Wed	93	—	unknown	00:10–06:00 (good, 5.83 h)	50.1° 03:55	10.7	22%	171.4°
2044-02-04 Thu	93	—	unknown	00:05–05:55 (good, 5.83 h)	50.1° 03:55	10.67	32%	159.5°
2044-02-05 Fri	93	—	unknown	00:05–05:55 (good, 5.83 h)	50.1° 03:50	10.63	43%	146.2°
2044-02-06 Sat	93	—	unknown	00:05–05:55 (good, 5.83 h)	50.1° 03:45	10.6	54%	132.4°
2044-02-07 Sun	93	—	unknown	00:05–05:55 (good, 5.83 h)	50.1° 03:40	10.56	65%	118.4°
2044-02-08 Mon	92	—	unknown	00:10–05:55 (good, 5.75 h)	50.1° 03:35	10.53	76%	104.1°
2044-02-09 Tue	88	—	unknown	00:45–05:50 (good, 5.08 h)	50.1° 03:35	10.49	85%	89.7°
2044-02-10 Wed	65	—	unknown	02:50–05:50 (good, 3.0 h)	50.1° 03:30	10.45	92%	75.2°
2044-02-11 Thu	45	—	unknown	23:50–05:50 (marginal, 6.0 h)	50.1° 03:25	10.42	98%	60.7°
2044-02-12 Fri	30	—	unknown	00:55–05:50 (marginal, 4.92 h)	50.1° 03:20	10.38	100%	46.4°
2044-02-13 Sat	20	—	unknown	03:25–05:50 (marginal, 2.42 h)	50.1° 03:15	10.34	99%	32.5°
2044-02-14 Sun	19	—	unknown	03:10–05:45 (marginal, 2.58 h)	50.1° 03:15	10.3	96%	19.1°
2044-02-15 Mon	24	—	unknown	23:30–05:45 (marginal, 6.25 h)	50.1° 03:10	10.26	92%	7.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-01-17&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.