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: 07-05 (2), 07-06 (2), 07-07 (2), 07-08 (2), 07-09 (2) — by astronomy; check the weather when the night is within four days.

2028-07-05astronomy score per night — click a bar for that night2028-08-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-07-05 Wed	2	—	unknown	23:10–23:15 (marginal, 0.08 h)	50.2° 18:55	4.65	99%	89.1°
2028-07-06 Thu	2	—	unknown	22:15–22:25 (marginal, 0.17 h)	50.2° 18:50	4.68	100%	101.5°
2028-07-07 Fri	2	—	unknown	22:15–22:30 (marginal, 0.25 h)	50.2° 18:45	4.71	99%	113.8°
2028-07-08 Sat	2	—	unknown	22:15–22:30 (marginal, 0.25 h)	50.2° 18:45	4.75	95%	125.8°
2028-07-09 Sun	2	—	unknown	22:15–22:30 (marginal, 0.25 h)	50.2° 18:40	4.78	90%	137.5°
2028-07-10 Mon	2	—	unknown	22:15–22:25 (marginal, 0.17 h)	50.2° 18:35	4.82	84%	149.0°
2028-07-11 Tue	2	—	unknown	22:15–22:25 (marginal, 0.17 h)	50.2° 18:30	4.86	77%	159.8°
2028-07-12 Wed	2	—	unknown	22:15–22:20 (marginal, 0.08 h)	50.2° 18:25	4.9	68%	168.6°
2028-07-13 Thu	2	—	unknown	—	50.2° 18:25	4.94	59%	168.5°
2028-07-14 Fri	1	—	unknown	—	50.2° 18:20	4.98	49%	159.6°
2028-07-15 Sat	1	—	unknown	—	50.2° 18:15	5.02	40%	148.3°
2028-07-16 Sun	1	—	unknown	—	50.2° 18:10	5.06	30%	136.3°
2028-07-17 Mon	1	—	unknown	—	50.2° 18:10	5.11	21%	123.8°
2028-07-18 Tue	1	—	unknown	—	50.2° 18:05	5.15	13%	110.7°
2028-07-19 Wed	1	—	unknown	—	50.2° 18:00	5.2	6%	97.2°
2028-07-20 Thu	1	—	unknown	—	50.2° 17:55	5.25	2%	83.2°
2028-07-21 Fri	0	—	unknown	—	50.2° 17:50	5.3	0%	68.9°
2028-07-22 Sat	0	—	unknown	—	50.2° 17:50	5.35	1%	54.5°
2028-07-23 Sun	0	—	unknown	—	50.2° 17:45	5.4	5%	40.0°
2028-07-24 Mon	0	—	unknown	—	50.2° 17:40	5.45	11%	25.9°
2028-07-25 Tue	0	—	unknown	—	50.2° 17:35	5.5	20%	13.5°
2028-07-26 Wed	0	—	unknown	—	50.2° 17:30	5.55	30%	11.0°
2028-07-27 Thu	0	—	unknown	—	50.2° 17:30	5.6	41%	21.6°
2028-07-28 Fri	0	—	unknown	—	50.2° 17:25	5.66	52%	34.4°
2028-07-29 Sat	0	—	unknown	—	50.2° 17:20	5.71	63%	47.5°
2028-07-30 Sun	0	—	unknown	—	50.2° 17:15	5.77	73%	60.5°
2028-07-31 Mon	0	—	unknown	—	50.2° 17:15	5.82	82%	73.3°
2028-08-01 Tue	0	—	unknown	—	50.2° 17:10	5.88	89%	85.8°
2028-08-02 Wed	0	—	unknown	—	50.2° 17:05	5.93	94%	98.2°
2028-08-03 Thu	0	—	unknown	—	50.2° 17:00	5.99	98%	110.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-07-05&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.