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: 04-20 (100), 04-21 (100), 04-22 (100), 04-23 (100), 04-24 (100) — by astronomy; check the weather when the night is within four days.

2042-04-20astronomy score per night — click a bar for that night2042-05-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-04-20 Sun	100	—	unknown	00:10–04:50 (good, 4.67 h)	87.1° 06:00	7.0	1%	101.2°
2042-04-21 Mon	100	—	unknown	00:05–04:50 (good, 4.75 h)	87.1° 06:00	6.94	5%	106.0°
2042-04-22 Tue	100	—	unknown	00:00–04:50 (good, 4.83 h)	87.1° 05:55	6.88	11%	109.6°
2042-04-23 Wed	100	—	unknown	00:00–04:45 (good, 4.75 h)	87.1° 05:50	6.82	19%	112.0°
2042-04-24 Thu	100	—	unknown	23:55–04:45 (good, 4.83 h)	87.1° 05:45	6.76	28%	113.0°
2042-04-25 Fri	100	—	unknown	23:55–04:40 (good, 4.75 h)	87.1° 05:40	6.71	38%	112.8°
2042-04-26 Sat	100	—	unknown	23:55–04:40 (good, 4.75 h)	87.1° 05:40	6.65	48%	111.3°
2042-04-27 Sun	100	—	unknown	23:50–04:40 (good, 4.83 h)	87.1° 05:35	6.59	58%	108.9°
2042-04-28 Mon	100	—	unknown	23:55–04:35 (good, 4.67 h)	87.1° 05:30	6.53	68%	105.7°
2042-04-29 Tue	100	—	unknown	23:55–04:35 (good, 4.67 h)	87.1° 05:25	6.47	76%	101.9°
2042-04-30 Wed	86	—	unknown	23:55–04:35 (good, 4.67 h)	87.1° 05:25	6.41	84%	97.7°
2042-05-01 Thu	82	—	unknown	00:15–04:30 (good, 4.25 h)	87.1° 05:20	6.36	90%	93.2°
2042-05-02 Fri	78	—	unknown	00:40–04:30 (good, 3.83 h)	87.1° 05:15	6.3	95%	88.5°
2042-05-03 Sat	71	—	unknown	01:05–04:25 (good, 3.33 h)	87.1° 05:10	6.24	98%	83.9°
2042-05-04 Sun	67	—	unknown	01:15–04:25 (good, 3.17 h)	87.1° 05:05	6.18	100%	79.5°
2042-05-05 Mon	64	—	unknown	01:15–04:25 (good, 3.17 h)	87.1° 05:05	6.13	100%	75.4°
2042-05-06 Tue	63	—	unknown	00:50–04:20 (good, 3.5 h)	87.1° 05:00	6.07	97%	71.9°
2042-05-07 Wed	68	—	unknown	23:40–04:20 (good, 4.67 h)	87.1° 04:55	6.01	93%	69.2°
2042-05-08 Thu	85	—	unknown	22:55–04:20 (good, 5.42 h)	87.1° 04:50	5.96	87%	67.4°
2042-05-09 Fri	92	—	unknown	22:55–04:15 (good, 5.33 h)	87.1° 04:45	5.9	79%	66.9°
2042-05-10 Sat	99	—	unknown	22:50–04:15 (good, 5.42 h)	87.1° 04:45	5.84	70%	67.5°
2042-05-11 Sun	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.1° 04:40	5.79	60%	69.5°
2042-05-12 Mon	100	—	unknown	22:40–04:10 (good, 5.5 h)	87.1° 04:35	5.73	49%	72.7°
2042-05-13 Tue	100	—	unknown	22:35–04:10 (good, 5.58 h)	87.1° 04:30	5.68	37%	76.9°
2042-05-14 Wed	100	—	unknown	22:35–04:10 (good, 5.58 h)	87.1° 04:30	5.62	27%	82.0°
2042-05-15 Thu	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:25	5.57	17%	87.5°
2042-05-16 Fri	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:20	5.52	9%	93.3°
2042-05-17 Sat	100	—	unknown	22:35–04:05 (good, 5.5 h)	87.1° 04:15	5.47	3%	98.9°
2042-05-18 Sun	100	—	unknown	22:35–04:00 (good, 5.42 h)	87.1° 04:10	5.41	0%	104.0°
2042-05-19 Mon	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:10	5.36	0%	108.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-04-20&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.