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: 04-23 (100), 04-24 (100), 04-25 (100), 04-26 (100), 04-27 (100) — by astronomy; check the weather when the night is within four days.

2028-04-23astronomy score per night — click a bar for that night2028-05-22

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2028-05-10 Wed	66	—	unknown	23:50–04:15 (good, 4.42 h)	87.1° 04:40	5.82	95%	68.2°
2028-05-11 Thu	84	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 04:40	5.77	89%	64.8°
2028-05-12 Fri	90	—	unknown	22:40–04:10 (good, 5.5 h)	87.1° 04:35	5.71	82%	62.8°
2028-05-13 Sat	94	—	unknown	22:35–04:10 (good, 5.58 h)	87.1° 04:30	5.66	73%	62.2°
2028-05-14 Sun	98	—	unknown	22:30–04:10 (good, 5.67 h)	87.1° 04:25	5.6	64%	63.0°
2028-05-15 Mon	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:20	5.55	55%	65.0°
2028-05-16 Tue	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:20	5.5	46%	68.1°
2028-05-17 Wed	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:15	5.45	36%	72.1°
2028-05-18 Thu	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:10	5.39	27%	76.8°
2028-05-19 Fri	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:05	5.34	19%	82.1°
2028-05-20 Sat	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:00	5.29	12%	87.7°
2028-05-21 Sun	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 04:00	5.24	6%	93.5°
2028-05-22 Mon	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:55	5.2	2%	99.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-04-23&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.