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 Vega: 04-17 (100), 04-18 (100), 04-19 (100), 04-20 (100), 04-21 (100) — by astronomy; check the weather when the night is within four days.

2028-04-10astronomy score per night — click a bar for that night2028-05-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-04-10 Mon	59	—	unknown	02:05–05:10 (good, 3.08 h)	87.1° 06:40	7.55	97%	82.2°
2028-04-11 Tue	59	—	unknown	01:50–05:10 (good, 3.33 h)	87.1° 06:35	7.49	92%	76.1°
2028-04-12 Wed	61	—	unknown	01:05–05:05 (good, 4.0 h)	87.1° 06:30	7.44	85%	71.0°
2028-04-13 Thu	75	—	unknown	00:35–05:05 (good, 4.5 h)	87.1° 06:30	7.38	76%	66.9°
2028-04-14 Fri	87	—	unknown	00:30–05:05 (good, 4.58 h)	87.1° 06:25	7.32	67%	64.1°
2028-04-15 Sat	92	—	unknown	00:25–05:00 (good, 4.58 h)	87.1° 06:20	7.26	57%	62.6°
2028-04-16 Sun	97	—	unknown	00:20–05:00 (good, 4.67 h)	87.1° 06:15	7.21	48%	62.6°
2028-04-17 Mon	100	—	unknown	00:20–04:55 (good, 4.58 h)	87.1° 06:10	7.15	38%	63.8°
2028-04-18 Tue	100	—	unknown	00:15–04:55 (good, 4.67 h)	87.1° 06:10	7.09	29%	66.2°
2028-04-19 Wed	100	—	unknown	00:10–04:55 (good, 4.75 h)	87.1° 06:05	7.03	21%	69.5°
2028-04-20 Thu	100	—	unknown	00:05–04:50 (good, 4.75 h)	87.1° 06:00	6.97	14%	73.8°
2028-04-21 Fri	100	—	unknown	00:00–04:50 (good, 4.83 h)	87.1° 05:55	6.92	8%	78.6°
2028-04-22 Sat	100	—	unknown	00:00–04:45 (good, 4.75 h)	87.1° 05:50	6.86	4%	84.0°
2028-04-23 Sun	100	—	unknown	23:55–04:45 (good, 4.83 h)	87.1° 05:50	6.8	1%	89.6°
2028-04-24 Mon	100	—	unknown	23:50–04:45 (good, 4.92 h)	87.1° 05:45	6.74	0%	95.4°
2028-04-25 Tue	100	—	unknown	23:45–04:40 (good, 4.92 h)	87.1° 05:40	6.68	1%	101.1°
2028-04-26 Wed	100	—	unknown	23:40–04:40 (good, 5.0 h)	87.1° 05:35	6.62	5%	106.4°
2028-04-27 Thu	100	—	unknown	23:40–04:40 (good, 5.0 h)	87.1° 05:35	6.57	10%	111.0°
2028-04-28 Fri	100	—	unknown	23:35–04:35 (good, 5.0 h)	87.1° 05:30	6.51	18%	114.7°
2028-04-29 Sat	100	—	unknown	23:35–04:35 (good, 5.0 h)	87.1° 05:25	6.45	27%	117.0°
2028-04-30 Sun	100	—	unknown	23:30–04:30 (good, 5.0 h)	87.1° 05:20	6.39	37%	117.7°
2028-05-01 Mon	100	—	unknown	23:30–04:30 (good, 5.0 h)	87.1° 05:15	6.33	48%	116.7°
2028-05-02 Tue	100	—	unknown	23:30–04:30 (good, 5.0 h)	87.1° 05:15	6.28	59%	114.0°
2028-05-03 Wed	100	—	unknown	23:30–04:25 (good, 4.92 h)	87.1° 05:10	6.22	70%	109.7°
2028-05-04 Thu	100	—	unknown	23:30–04:25 (good, 4.92 h)	87.1° 05:05	6.16	80%	104.3°
2028-05-05 Fri	100	—	unknown	23:35–04:25 (good, 4.83 h)	87.1° 05:00	6.1	89%	98.1°
2028-05-06 Sat	81	—	unknown	23:55–04:20 (good, 4.42 h)	87.1° 04:55	6.05	95%	91.4°
2028-05-07 Sun	76	—	unknown	00:20–04:20 (good, 4.0 h)	87.1° 04:55	5.99	99%	84.8°
2028-05-08 Mon	71	—	unknown	00:40–04:20 (good, 3.67 h)	87.1° 04:50	5.93	100%	78.5°
2028-05-09 Tue	66	—	unknown	00:35–04:15 (good, 3.67 h)	87.1° 04:45	5.88	98%	72.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-04-10&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.