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: 11-12 (6), 11-13 (6), 11-14 (6), 11-11 (5), 11-15 (5) — by astronomy; check the weather when the night is within four days.

2038-10-17astronomy score per night — click a bar for that night2038-11-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-10-17 Sun	0	—	unknown	—	50.1° 12:10	9.91	81%	109.8°
2038-10-18 Mon	0	—	unknown	—	50.1° 12:00	9.95	73%	97.8°
2038-10-19 Tue	0	—	unknown	—	50.1° 12:00	10.0	64%	85.6°
2038-10-20 Wed	0	—	unknown	—	50.1° 11:50	10.04	54%	73.2°
2038-10-21 Thu	0	—	unknown	—	50.1° 11:50	10.08	44%	60.4°
2038-10-22 Fri	0	—	unknown	—	50.1° 11:45	10.12	34%	47.2°
2038-10-23 Sat	0	—	unknown	—	50.1° 11:40	10.16	24%	33.6°
2038-10-24 Sun	0	—	unknown	—	50.1° 11:35	10.2	15%	19.5°
2038-10-25 Mon	0	—	unknown	—	50.1° 11:35	10.24	8%	5.0°
2038-10-26 Tue	0	—	unknown	—	50.1° 11:30	10.28	3%	10.0°
2038-10-27 Wed	0	—	unknown	—	50.1° 11:25	10.32	0%	25.1°
2038-10-28 Thu	0	—	unknown	—	50.1° 11:20	10.36	1%	40.4°
2038-10-29 Fri	0	—	unknown	—	50.1° 11:15	10.39	5%	55.6°
2038-10-30 Sat	0	—	unknown	—	50.1° 10:15	10.43	11%	70.6°
2038-10-31 Sun	0	—	unknown	—	50.1° 10:10	10.47	20%	85.2°
2038-11-01 Mon	0	—	unknown	—	50.1° 10:05	10.5	29%	99.3°
2038-11-02 Tue	0	—	unknown	—	50.1° 10:00	10.54	40%	113.0°
2038-11-03 Wed	1	—	unknown	—	50.1° 09:55	10.58	50%	126.2°
2038-11-04 Thu	1	—	unknown	—	50.1° 09:55	10.61	60%	139.0°
2038-11-05 Fri	1	—	unknown	—	50.1° 09:50	10.65	70%	151.5°
2038-11-06 Sat	1	—	unknown	—	50.1° 09:45	10.68	79%	163.8°
2038-11-07 Sun	2	—	unknown	05:25–05:30 (marginal, 0.08 h)	50.1° 09:40	10.71	86%	175.9°
2038-11-08 Mon	3	—	unknown	05:50–06:05 (marginal, 0.25 h)	50.1° 09:40	10.75	92%	172.1°
2038-11-09 Tue	4	—	unknown	05:45–06:05 (marginal, 0.33 h)	50.1° 09:35	10.78	96%	160.2°
2038-11-10 Wed	4	—	unknown	05:15–05:30 (marginal, 0.25 h)	50.1° 09:30	10.81	99%	148.4°
2038-11-11 Thu	5	—	unknown	05:10–05:35 (marginal, 0.42 h)	50.1° 09:25	10.84	100%	136.5°
2038-11-12 Fri	6	—	unknown	05:05–05:35 (marginal, 0.5 h)	50.1° 09:20	10.87	99%	124.7°
2038-11-13 Sat	6	—	unknown	05:05–05:35 (marginal, 0.5 h)	50.1° 09:20	10.9	96%	112.8°
2038-11-14 Sun	6	—	unknown	05:00–05:35 (marginal, 0.58 h)	50.1° 09:15	10.93	92%	100.8°
2038-11-15 Mon	5	—	unknown	05:00–05:35 (marginal, 0.58 h)	50.1° 09:10	10.96	86%	88.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-10-17&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.