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 HD 189733: 07-20 (100), 07-21 (100), 07-31 (100), 08-01 (100), 08-02 (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)	71.1° 01:25	5.24	76%	76.9°
2029-07-21 Sat	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:25	5.29	85%	66.5°
2029-07-22 Sun	97	—	unknown	23:15–04:10 (good, 4.92 h)	71.1° 01:20	5.34	92%	56.8°
2029-07-23 Mon	55	—	unknown	03:00–04:10 (good, 1.17 h)	71.1° 01:15	5.39	97%	48.5°
2029-07-24 Tue	41	—	unknown	22:45–04:15 (marginal, 5.5 h)	71.1° 01:10	5.44	100%	42.4°
2029-07-25 Wed	37	—	unknown	22:45–04:15 (marginal, 5.5 h)	71.1° 01:05	5.49	100%	39.3°
2029-07-26 Thu	39	—	unknown	22:45–04:15 (marginal, 5.5 h)	71.1° 01:05	5.54	98%	39.9°
2029-07-27 Fri	47	—	unknown	22:45–04:20 (marginal, 5.58 h)	71.1° 01:00	5.59	94%	43.7°
2029-07-28 Sat	60	—	unknown	22:40–00:05 (good, 1.42 h)	71.1° 00:55	5.65	88%	49.8°
2029-07-29 Sun	72	—	unknown	22:40–02:05 (good, 3.42 h)	71.1° 00:50	5.7	81%	57.3°
2029-07-30 Mon	99	—	unknown	22:40–03:45 (good, 5.08 h)	71.1° 00:50	5.75	73%	65.7°
2029-07-31 Tue	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:45	5.81	64%	74.5°
2029-08-01 Wed	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:40	5.86	55%	83.6°
2029-08-02 Thu	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:35	5.92	46%	92.8°
2029-08-03 Fri	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:30	5.97	36%	102.0°
2029-08-04 Sat	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:30	6.03	27%	111.2°
2029-08-05 Sun	100	—	unknown	22:25–04:30 (good, 6.08 h)	71.1° 00:25	6.09	19%	120.1°
2029-08-06 Mon	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:20	6.14	11%	128.3°
2029-08-07 Tue	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:15	6.2	6%	135.2°
2029-08-08 Wed	100	—	unknown	22:20–04:35 (good, 6.25 h)	71.1° 00:10	6.26	2%	139.7°
2029-08-09 Thu	100	—	unknown	22:20–04:40 (good, 6.33 h)	71.1° 00:10	6.31	0%	140.7°
2029-08-10 Fri	100	—	unknown	22:20–04:40 (good, 6.33 h)	71.1° 00:05	6.37	1%	137.7°
2029-08-11 Sat	100	—	unknown	22:15–04:40 (good, 6.42 h)	71.1° 00:00	6.43	5%	131.1°
2029-08-12 Sun	100	—	unknown	22:15–04:45 (good, 6.5 h)	71.1° 23:55	6.49	11%	122.3°
2029-08-13 Mon	100	—	unknown	22:10–04:45 (good, 6.58 h)	71.1° 23:55	6.54	19%	112.1°
2029-08-14 Tue	100	—	unknown	22:10–04:45 (good, 6.58 h)	71.1° 23:50	6.6	29%	101.3°
2029-08-15 Wed	100	—	unknown	22:10–04:50 (good, 6.67 h)	71.1° 23:45	6.66	40%	90.2°
2029-08-16 Thu	100	—	unknown	22:05–04:45 (good, 6.67 h)	71.1° 23:40	6.72	52%	79.3°
2029-08-17 Fri	100	—	unknown	22:05–04:45 (good, 6.67 h)	71.1° 23:35	6.77	63%	68.8°
2029-08-18 Sat	100	—	unknown	22:05–04:40 (good, 6.58 h)	71.1° 23:35	6.83	73%	59.0°

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.