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: 07-07 (3), 07-08 (3), 07-09 (2), 07-10 (2), 07-11 (1) — by astronomy; check the weather when the night is within four days.

2035-07-07astronomy score per night — click a bar for that night2035-08-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-07-07 Sat	3	—	unknown	22:15–22:40 (marginal, 0.42 h)	50.2° 18:50	4.69	9%	45.5°
2035-07-08 Sun	3	—	unknown	22:15–22:30 (marginal, 0.25 h)	50.2° 18:45	4.73	17%	31.2°
2035-07-09 Mon	2	—	unknown	22:15–22:20 (marginal, 0.08 h)	50.2° 18:40	4.76	26%	17.4°
2035-07-10 Tue	2	—	unknown	—	50.2° 18:40	4.79	36%	4.5°
2035-07-11 Wed	1	—	unknown	—	50.2° 18:35	4.83	46%	9.2°
2035-07-12 Thu	1	—	unknown	—	50.2° 18:30	4.87	56%	21.6°
2035-07-13 Fri	1	—	unknown	—	50.2° 18:25	4.91	66%	33.9°
2035-07-14 Sat	1	—	unknown	—	50.2° 18:25	4.95	75%	45.9°
2035-07-15 Sun	1	—	unknown	—	50.2° 18:20	4.99	82%	57.8°
2035-07-16 Mon	1	—	unknown	—	50.2° 18:15	5.03	89%	69.7°
2035-07-17 Tue	0	—	unknown	—	50.2° 18:10	5.08	94%	81.5°
2035-07-18 Wed	0	—	unknown	—	50.2° 18:05	5.12	98%	93.3°
2035-07-19 Thu	1	—	unknown	—	50.2° 18:05	5.17	100%	105.2°
2035-07-20 Fri	1	—	unknown	—	50.2° 18:00	5.22	100%	117.2°
2035-07-21 Sat	0	—	unknown	—	50.2° 17:55	5.26	98%	129.3°
2035-07-22 Sun	0	—	unknown	—	50.2° 17:50	5.31	94%	141.6°
2035-07-23 Mon	0	—	unknown	—	50.2° 17:45	5.36	89%	154.0°
2035-07-24 Tue	0	—	unknown	—	50.2° 17:45	5.41	82%	166.6°
2035-07-25 Wed	0	—	unknown	—	50.2° 17:40	5.46	73%	177.8°
2035-07-26 Thu	0	—	unknown	—	50.2° 17:35	5.52	63%	167.0°
2035-07-27 Fri	0	—	unknown	—	50.2° 17:30	5.57	52%	153.6°
2035-07-28 Sat	0	—	unknown	—	50.2° 17:30	5.62	41%	139.8°
2035-07-29 Sun	0	—	unknown	—	50.2° 17:25	5.67	30%	125.7°
2035-07-30 Mon	0	—	unknown	—	50.2° 17:20	5.73	20%	111.2°
2035-07-31 Tue	0	—	unknown	—	50.2° 17:15	5.78	11%	96.5°
2035-08-01 Wed	0	—	unknown	—	50.2° 17:10	5.84	5%	81.6°
2035-08-02 Thu	0	—	unknown	—	50.2° 17:10	5.89	1%	66.7°
2035-08-03 Fri	0	—	unknown	—	50.2° 17:05	5.95	0%	51.8°
2035-08-04 Sat	0	—	unknown	—	50.2° 17:00	6.0	2%	37.2°
2035-08-05 Sun	0	—	unknown	—	50.2° 16:55	6.06	7%	23.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-07-07&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.