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: 07-12 (2), 07-13 (2), 07-14 (2), 07-15 (1), 07-16 (1) — by astronomy; check the weather when the night is within four days.

2026-07-12astronomy score per night — click a bar for that night2026-08-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2026-07-12 Sun	2	78	2	—	50.2° 18:30	4.87	3%	95.7°
2026-07-13 Mon	2	87	2	—	50.2° 18:25	4.91	0%	80.7°
2026-07-14 Tue	2	90	2	—	50.2° 18:20	4.96	0%	65.8°
2026-07-15 Wed	1	20	0	—	50.2° 18:20	5.0	3%	51.3°
2026-07-16 Thu	1	42	0	—	50.2° 18:15	5.04	9%	37.1°
2026-07-17 Fri	1	94	1	—	50.2° 18:10	5.08	16%	23.7°
2026-07-18 Sat	1	87	1	—	50.2° 18:05	5.13	25%	11.8°
2026-07-19 Sun	0	91	0	—	50.2° 18:00	5.18	35%	8.9°
2026-07-20 Mon	0	97	0	—	50.2° 18:00	5.22	45%	18.5°
2026-07-21 Tue	0	17	0	—	50.2° 17:55	5.27	55%	30.1°
2026-07-22 Wed	0	78	0	—	50.2° 17:50	5.32	64%	41.9°
2026-07-23 Thu	0	0	0	—	50.2° 17:45	5.37	73%	53.7°
2026-07-24 Fri	0	0	0	—	50.2° 17:40	5.42	81%	65.4°
2026-07-25 Sat	0	92	0	—	50.2° 17:40	5.47	88%	77.1°
2026-07-26 Sun	0	94	0	—	50.2° 17:35	5.52	93%	88.8°
2026-07-27 Mon	0	97	0	—	50.2° 17:30	5.58	97%	100.6°
2026-07-28 Tue	0	90	0	—	50.2° 17:25	5.63	100%	112.6°
2026-07-29 Wed	0	91	0	—	50.2° 17:25	5.68	100%	124.6°
2026-07-30 Thu	0	100	0	—	50.2° 17:20	5.74	98%	136.8°
2026-07-31 Fri	0	98	0	—	50.2° 17:15	5.79	95%	149.0°
2026-08-01 Sat	0	100	0	—	50.2° 17:10	5.85	89%	161.1°
2026-08-02 Sun	0	94	0	—	50.2° 17:05	5.9	82%	171.0°
2026-08-03 Mon	0	98	0	—	50.2° 17:05	5.96	73%	168.2°
2026-08-04 Tue	0	92	0	—	50.2° 17:00	6.01	63%	156.4°
2026-08-05 Wed	0	62	0	—	50.2° 16:55	6.07	52%	143.2°
2026-08-06 Thu	0	90	0	—	50.2° 16:50	6.13	40%	129.5°
2026-08-07 Fri	0	0	0	—	50.2° 16:45	6.18	30%	115.4°
2026-08-08 Sat	0	0	0	—	50.2° 16:45	6.24	19%	101.1°
2026-08-09 Sun	0	0	0	—	50.2° 16:40	6.3	11%	86.5°
2026-08-10 Mon	0	0	0	—	50.2° 16:35	6.35	5%	71.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-07-12&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.