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: 07-16 (1), 07-17 (1), 07-18 (1), 07-19 (1), 07-20 (1) — by astronomy; check the weather when the night is within four days.

2038-07-16astronomy score per night — click a bar for that night2038-08-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-07-16 Fri	1	—	unknown	—	50.1° 18:15	5.05	100%	114.3°
2038-07-17 Sat	1	—	unknown	—	50.1° 18:10	5.09	98%	127.7°
2038-07-18 Sun	1	—	unknown	—	50.1° 18:05	5.14	93%	140.7°
2038-07-19 Mon	1	—	unknown	—	50.1° 18:00	5.18	87%	153.5°
2038-07-20 Tue	1	—	unknown	—	50.1° 18:00	5.23	80%	165.9°
2038-07-21 Wed	1	—	unknown	—	50.1° 17:55	5.28	71%	178.0°
2038-07-22 Thu	0	—	unknown	—	50.1° 17:50	5.33	62%	169.9°
2038-07-23 Fri	0	—	unknown	—	50.1° 17:45	5.38	53%	158.1°
2038-07-24 Sat	0	—	unknown	—	50.1° 17:40	5.43	43%	146.2°
2038-07-25 Sun	0	—	unknown	—	50.1° 17:40	5.48	34%	134.3°
2038-07-26 Mon	0	—	unknown	—	50.1° 17:35	5.53	25%	122.3°
2038-07-27 Tue	0	—	unknown	—	50.1° 17:30	5.58	17%	110.0°
2038-07-28 Wed	0	—	unknown	—	50.1° 17:25	5.64	10%	97.5°
2038-07-29 Thu	0	—	unknown	—	50.1° 17:25	5.69	5%	84.7°
2038-07-30 Fri	0	—	unknown	—	50.1° 17:20	5.74	1%	71.6°
2038-07-31 Sat	0	—	unknown	—	50.1° 17:15	5.8	0%	58.1°
2038-08-01 Sun	0	—	unknown	—	50.1° 17:10	5.85	1%	44.4°
2038-08-02 Mon	0	—	unknown	—	50.1° 17:05	5.91	5%	30.4°
2038-08-03 Tue	0	—	unknown	—	50.1° 17:05	5.96	11%	16.3°
2038-08-04 Wed	0	—	unknown	—	50.1° 17:00	6.02	19%	2.1°
2038-08-05 Thu	0	—	unknown	—	50.1° 16:55	6.08	29%	12.2°
2038-08-06 Fri	0	—	unknown	—	50.1° 16:50	6.13	40%	26.5°
2038-08-07 Sat	0	—	unknown	—	50.1° 16:45	6.19	51%	40.7°
2038-08-08 Sun	0	—	unknown	—	50.1° 16:45	6.25	62%	54.8°
2038-08-09 Mon	0	—	unknown	—	50.1° 16:40	6.3	73%	68.8°
2038-08-10 Tue	0	—	unknown	—	50.1° 16:35	6.36	82%	82.6°
2038-08-11 Wed	0	—	unknown	—	50.1° 16:30	6.42	90%	96.3°
2038-08-12 Thu	0	—	unknown	—	50.1° 16:30	6.47	95%	109.8°
2038-08-13 Fri	0	—	unknown	—	50.1° 16:25	6.53	99%	123.1°
2038-08-14 Sat	0	—	unknown	—	50.1° 16:20	6.59	100%	136.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-07-16&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.