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: 07-14 (1), 07-15 (1), 07-16 (1), 07-17 (1), 07-18 (1) — by astronomy; check the weather when the night is within four days.

2027-07-14astronomy score per night — click a bar for that night2027-08-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-07-14 Wed	1	—	unknown	—	50.2° 18:20	4.95	88%	66.0°
2027-07-15 Thu	1	—	unknown	—	50.2° 18:20	4.99	93%	77.9°
2027-07-16 Fri	1	—	unknown	—	50.2° 18:15	5.03	97%	89.8°
2027-07-17 Sat	1	—	unknown	—	50.2° 18:10	5.07	100%	101.6°
2027-07-18 Sun	1	—	unknown	—	50.2° 18:05	5.12	100%	113.2°
2027-07-19 Mon	1	—	unknown	—	50.2° 18:05	5.17	98%	124.9°
2027-07-20 Tue	1	—	unknown	—	50.2° 18:00	5.21	95%	136.5°
2027-07-21 Wed	1	—	unknown	—	50.2° 17:55	5.26	91%	148.0°
2027-07-22 Thu	0	—	unknown	—	50.2° 17:50	5.31	84%	159.1°
2027-07-23 Fri	0	—	unknown	—	50.2° 17:45	5.36	77%	168.7°
2027-07-24 Sat	0	—	unknown	—	50.2° 17:45	5.41	68%	169.4°
2027-07-25 Sun	0	—	unknown	—	50.2° 17:40	5.46	58%	159.8°
2027-07-26 Mon	0	—	unknown	—	50.2° 17:35	5.51	48%	147.8°
2027-07-27 Tue	0	—	unknown	—	50.2° 17:30	5.56	37%	134.9°
2027-07-28 Wed	0	—	unknown	—	50.2° 17:25	5.62	27%	121.5°
2027-07-29 Thu	0	—	unknown	—	50.2° 17:25	5.67	17%	107.5°
2027-07-30 Fri	0	—	unknown	—	50.2° 17:20	5.72	9%	93.1°
2027-07-31 Sat	0	—	unknown	—	50.2° 17:15	5.78	3%	78.3°
2027-08-01 Sun	0	—	unknown	—	50.2° 17:10	5.83	0%	63.4°
2027-08-02 Mon	0	—	unknown	—	50.2° 17:10	5.89	0%	48.4°
2027-08-03 Tue	0	—	unknown	—	50.2° 17:05	5.94	4%	33.7°
2027-08-04 Wed	0	—	unknown	—	50.2° 17:00	6.0	9%	19.9°
2027-08-05 Thu	0	—	unknown	—	50.2° 16:55	6.06	17%	9.6°
2027-08-06 Fri	0	—	unknown	—	50.2° 16:50	6.11	26%	14.0°
2027-08-07 Sat	0	—	unknown	—	50.2° 16:50	6.17	37%	25.9°
2027-08-08 Sun	0	—	unknown	—	50.2° 16:45	6.23	47%	38.4°
2027-08-09 Mon	0	—	unknown	—	50.2° 16:40	6.28	57%	50.8°
2027-08-10 Tue	0	—	unknown	—	50.2° 16:35	6.34	67%	63.0°
2027-08-11 Wed	0	—	unknown	—	50.2° 16:30	6.4	76%	75.0°
2027-08-12 Thu	0	—	unknown	—	50.2° 16:30	6.46	84%	86.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-07-14&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.