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: 07-17 (1), 07-18 (1), 07-19 (1), 07-20 (1), 07-21 (1) — by astronomy; check the weather when the night is within four days.

2030-07-17astronomy score per night — click a bar for that night2030-08-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-07-17 Wed	1	—	unknown	—	50.2° 18:10	5.09	89%	145.9°
2030-07-18 Thu	1	—	unknown	—	50.2° 18:05	5.13	82%	158.4°
2030-07-19 Fri	1	—	unknown	—	50.2° 18:00	5.18	73%	168.4°
2030-07-20 Sat	1	—	unknown	—	50.2° 18:00	5.23	64%	168.6°
2030-07-21 Sun	1	—	unknown	—	50.2° 17:55	5.27	54%	159.3°
2030-07-22 Mon	0	—	unknown	—	50.2° 17:50	5.32	44%	148.1°
2030-07-23 Tue	0	—	unknown	—	50.2° 17:45	5.37	35%	136.7°
2030-07-24 Wed	0	—	unknown	—	50.2° 17:40	5.42	26%	125.1°
2030-07-25 Thu	0	—	unknown	—	50.2° 17:40	5.48	18%	113.5°
2030-07-26 Fri	0	—	unknown	—	50.2° 17:35	5.53	12%	101.8°
2030-07-27 Sat	0	—	unknown	—	50.2° 17:30	5.58	6%	89.9°
2030-07-28 Sun	0	—	unknown	—	50.2° 17:25	5.63	2%	77.9°
2030-07-29 Mon	0	—	unknown	—	50.2° 17:25	5.69	0%	65.7°
2030-07-30 Tue	0	—	unknown	—	50.2° 17:20	5.74	0%	53.3°
2030-07-31 Wed	0	—	unknown	—	50.2° 17:15	5.79	2%	40.8°
2030-08-01 Thu	0	—	unknown	—	50.2° 17:10	5.85	7%	28.3°
2030-08-02 Fri	0	—	unknown	—	50.2° 17:05	5.9	13%	16.5°
2030-08-03 Sat	0	—	unknown	—	50.2° 17:05	5.96	21%	9.5°
2030-08-04 Sun	0	—	unknown	—	50.2° 17:00	6.02	31%	16.5°
2030-08-05 Mon	0	—	unknown	—	50.2° 16:55	6.07	41%	28.9°
2030-08-06 Tue	0	—	unknown	—	50.2° 16:50	6.13	53%	42.3°
2030-08-07 Wed	0	—	unknown	—	50.2° 16:45	6.19	64%	56.2°
2030-08-08 Thu	0	—	unknown	—	50.2° 16:45	6.24	75%	70.3°
2030-08-09 Fri	0	—	unknown	—	50.2° 16:40	6.3	84%	84.5°
2030-08-10 Sat	0	—	unknown	—	50.2° 16:35	6.36	92%	98.8°
2030-08-11 Sun	0	—	unknown	—	50.2° 16:30	6.41	97%	112.9°
2030-08-12 Mon	0	—	unknown	—	50.2° 16:30	6.47	100%	126.9°
2030-08-13 Tue	0	—	unknown	—	50.2° 16:25	6.53	100%	140.5°
2030-08-14 Wed	0	—	unknown	—	50.2° 16:20	6.59	97%	153.6°
2030-08-15 Thu	0	—	unknown	—	50.2° 16:15	6.64	92%	165.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-07-17&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.