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 North America Nebula: 07-20 (100), 07-21 (100), 07-22 (100), 07-31 (100), 08-01 (100) — by astronomy; check the weather when the night is within four days.

2029-07-20astronomy score per night — click a bar for that night2029-08-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-07-20 Fri	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.2° 02:25	5.24	76%	97.9°
2029-07-21 Sat	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.2° 02:20	5.29	85%	89.5°
2029-07-22 Sun	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.2° 02:15	5.34	92%	81.1°
2029-07-23 Mon	74	—	unknown	22:50–04:10 (good, 5.33 h)	87.2° 02:15	5.39	97%	73.2°
2029-07-24 Tue	66	—	unknown	22:45–04:15 (good, 5.5 h)	87.2° 02:10	5.44	100%	66.0°
2029-07-25 Wed	55	—	unknown	22:45–04:15 (marginal, 5.5 h)	87.2° 02:05	5.49	100%	60.1°
2029-07-26 Thu	52	—	unknown	22:45–04:15 (marginal, 5.5 h)	87.2° 02:00	5.54	98%	55.7°
2029-07-27 Fri	55	—	unknown	22:45–23:35 (good, 0.83 h)	87.2° 01:55	5.59	94%	53.2°
2029-07-28 Sat	63	—	unknown	22:40–00:25 (good, 1.75 h)	87.2° 01:55	5.65	88%	52.8°
2029-07-29 Sun	71	—	unknown	22:40–01:40 (good, 3.0 h)	87.2° 01:50	5.7	81%	54.4°
2029-07-30 Mon	98	—	unknown	22:40–04:20 (good, 5.67 h)	87.2° 01:45	5.75	73%	57.6°
2029-07-31 Tue	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.2° 01:40	5.81	64%	62.3°
2029-08-01 Wed	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.2° 01:40	5.86	55%	67.9°
2029-08-02 Thu	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:35	5.92	46%	74.3°
2029-08-03 Fri	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:30	5.97	36%	81.3°
2029-08-04 Sat	100	—	unknown	22:30–04:30 (good, 6.0 h)	87.2° 01:25	6.03	27%	88.6°
2029-08-05 Sun	100	—	unknown	22:25–04:30 (good, 6.08 h)	87.2° 01:20	6.09	19%	96.1°
2029-08-06 Mon	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.2° 01:20	6.14	11%	103.6°
2029-08-07 Tue	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.2° 01:15	6.2	6%	110.9°
2029-08-08 Wed	100	—	unknown	22:20–04:35 (good, 6.25 h)	87.2° 01:10	6.26	2%	117.4°
2029-08-09 Thu	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.2° 01:05	6.31	0%	122.8°
2029-08-10 Fri	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.2° 01:00	6.37	1%	126.2°
2029-08-11 Sat	100	—	unknown	22:15–04:40 (good, 6.42 h)	87.2° 01:00	6.43	5%	127.2°
2029-08-12 Sun	100	—	unknown	22:15–04:45 (good, 6.5 h)	87.2° 00:55	6.49	11%	125.4°
2029-08-13 Mon	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.2° 00:50	6.54	19%	121.2°
2029-08-14 Tue	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.2° 00:45	6.6	29%	115.1°
2029-08-15 Wed	100	—	unknown	22:10–04:50 (good, 6.67 h)	87.2° 00:45	6.66	40%	107.8°
2029-08-16 Thu	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:40	6.72	52%	99.7°
2029-08-17 Fri	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:35	6.77	63%	91.3°
2029-08-18 Sat	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:30	6.83	73%	83.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-07-20&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.