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: 05-01 (100), 05-02 (100), 05-03 (100), 05-04 (100), 05-05 (100) — by astronomy; check the weather when the night is within four days.

2043-04-26astronomy score per night — click a bar for that night2043-05-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-04-26 Sun	62	—	unknown	01:00–04:40 (good, 3.67 h)	87.1° 05:40	6.66	94%	72.9°
2043-04-27 Mon	68	—	unknown	00:10–04:40 (good, 4.5 h)	87.1° 05:35	6.6	88%	70.1°
2043-04-28 Tue	85	—	unknown	23:35–04:35 (good, 5.0 h)	87.1° 05:30	6.54	82%	68.1°
2043-04-29 Wed	91	—	unknown	23:35–04:35 (good, 5.0 h)	87.1° 05:30	6.49	74%	67.0°
2043-04-30 Thu	97	—	unknown	23:30–04:35 (good, 5.08 h)	87.1° 05:25	6.43	64%	67.1°
2043-05-01 Fri	100	—	unknown	23:25–04:30 (good, 5.08 h)	87.1° 05:20	6.37	55%	68.3°
2043-05-02 Sat	100	—	unknown	23:20–04:30 (good, 5.17 h)	87.1° 05:15	6.31	44%	70.6°
2043-05-03 Sun	100	—	unknown	23:20–04:30 (good, 5.17 h)	87.1° 05:10	6.25	34%	74.0°
2043-05-04 Mon	100	—	unknown	23:15–04:25 (good, 5.17 h)	87.1° 05:10	6.2	24%	78.4°
2043-05-05 Tue	100	—	unknown	23:10–04:25 (good, 5.25 h)	87.1° 05:05	6.14	15%	83.6°
2043-05-06 Wed	100	—	unknown	23:05–04:20 (good, 5.25 h)	87.1° 05:00	6.08	7%	89.3°
2043-05-07 Thu	100	—	unknown	23:00–04:20 (good, 5.33 h)	87.1° 04:55	6.03	2%	95.2°
2043-05-08 Fri	100	—	unknown	23:00–04:20 (good, 5.33 h)	87.1° 04:50	5.97	0%	100.8°
2043-05-09 Sat	100	—	unknown	22:55–04:15 (good, 5.33 h)	87.1° 04:50	5.91	1%	105.8°
2043-05-10 Sun	100	—	unknown	22:50–04:15 (good, 5.42 h)	87.1° 04:45	5.86	5%	109.7°
2043-05-11 Mon	100	—	unknown	22:50–04:15 (good, 5.42 h)	87.1° 04:40	5.8	12%	112.2°
2043-05-12 Tue	100	—	unknown	22:45–04:10 (good, 5.42 h)	87.1° 04:35	5.75	20%	113.1°
2043-05-13 Wed	100	—	unknown	22:45–04:10 (good, 5.42 h)	87.1° 04:35	5.69	30%	112.6°
2043-05-14 Thu	100	—	unknown	22:40–04:10 (good, 5.5 h)	87.1° 04:30	5.64	40%	110.8°
2043-05-15 Fri	100	—	unknown	22:40–04:05 (good, 5.42 h)	87.1° 04:25	5.58	50%	107.9°
2043-05-16 Sat	100	—	unknown	22:40–04:05 (good, 5.42 h)	87.1° 04:20	5.53	61%	104.3°
2043-05-17 Sun	100	—	unknown	22:45–04:05 (good, 5.33 h)	87.1° 04:15	5.48	70%	100.1°
2043-05-18 Mon	100	—	unknown	22:45–04:05 (good, 5.33 h)	87.1° 04:15	5.43	79%	95.5°
2043-05-19 Tue	84	—	unknown	22:55–04:00 (good, 5.08 h)	87.1° 04:10	5.38	86%	90.8°
2043-05-20 Wed	80	—	unknown	23:25–04:00 (good, 4.58 h)	87.1° 04:05	5.33	92%	86.2°
2043-05-21 Thu	77	—	unknown	23:45–04:00 (good, 4.25 h)	87.1° 04:00	5.28	96%	81.6°
2043-05-22 Fri	73	—	unknown	23:55–03:55 (good, 4.0 h)	87.1° 03:55	5.23	99%	77.5°
2043-05-23 Sat	68	—	unknown	23:50–03:55 (good, 4.08 h)	87.1° 03:55	5.18	100%	73.7°
2043-05-24 Sun	66	—	unknown	23:20–03:55 (good, 4.58 h)	87.1° 03:50	5.13	99%	70.6°
2043-05-25 Mon	68	—	unknown	22:50–03:55 (good, 5.08 h)	87.1° 03:45	5.09	96%	68.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-04-26&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.