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: 05-18 (100), 05-19 (100), 05-20 (100), 05-21 (100), 05-22 (100) — by astronomy; check the weather when the night is within four days.

2034-05-18astronomy score per night — click a bar for that night2034-06-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-05-18 Thu	100	—	unknown	22:35–04:00 (good, 5.42 h)	87.1° 04:10	5.42	1%	117.0°
2034-05-19 Fri	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:10	5.37	5%	121.2°
2034-05-20 Sat	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:05	5.32	11%	123.1°
2034-05-21 Sun	100	—	unknown	22:40–04:00 (good, 5.33 h)	87.1° 04:00	5.27	20%	122.7°
2034-05-22 Mon	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:55	5.22	29%	120.2°
2034-05-23 Tue	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.17	39%	116.0°
2034-05-24 Wed	100	—	unknown	22:45–03:55 (good, 5.17 h)	87.1° 03:50	5.13	49%	110.8°
2034-05-25 Thu	100	—	unknown	22:50–03:55 (good, 5.08 h)	87.1° 03:45	5.08	59%	104.9°
2034-05-26 Fri	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:40	5.04	69%	98.6°
2034-05-27 Sat	100	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:35	4.99	77%	92.0°
2034-05-28 Sun	83	—	unknown	22:50–03:50 (good, 5.0 h)	87.1° 03:35	4.95	85%	85.5°
2034-05-29 Mon	77	—	unknown	23:25–03:50 (good, 4.42 h)	87.1° 03:30	4.91	91%	79.2°
2034-05-30 Tue	67	—	unknown	00:10–03:45 (good, 3.58 h)	87.1° 03:25	4.87	95%	73.2°
2034-05-31 Wed	58	—	unknown	00:50–03:45 (good, 2.92 h)	87.1° 03:20	4.83	98%	67.8°
2034-06-01 Thu	51	—	unknown	03:10–03:45 (good, 0.58 h)	87.1° 03:15	4.79	100%	63.1°
2034-06-02 Fri	48	—	unknown	23:00–03:45 (marginal, 4.75 h)	87.1° 03:15	4.76	99%	59.6°
2034-06-03 Sat	50	—	unknown	23:00–03:45 (marginal, 4.75 h)	87.1° 03:10	4.72	97%	57.4°
2034-06-04 Sun	58	—	unknown	23:00–01:50 (good, 2.83 h)	87.1° 03:05	4.69	93%	56.9°
2034-06-05 Mon	91	—	unknown	23:00–03:40 (good, 4.67 h)	87.1° 03:00	4.66	87%	58.1°
2034-06-06 Tue	98	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:55	4.63	79%	61.0°
2034-06-07 Wed	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:55	4.61	70%	65.4°
2034-06-08 Thu	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:50	4.58	60%	71.1°
2034-06-09 Fri	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:45	4.56	49%	77.8°
2034-06-10 Sat	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.1° 02:40	4.53	38%	85.2°
2034-06-11 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:40	4.51	27%	93.0°
2034-06-12 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:35	4.5	17%	100.8°
2034-06-13 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:30	4.48	9%	108.2°
2034-06-14 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:25	4.47	4%	114.7°
2034-06-15 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:20	4.45	1%	119.6°
2034-06-16 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.1° 02:20	4.44	0%	122.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-05-18&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.