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: 01-18 (28), 01-17 (27), 01-16 (25), 01-15 (24), 01-14 (23) — by astronomy; check the weather when the night is within four days.

2036-12-20astronomy score per night — click a bar for that night2037-01-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-12-20 Sat	16	—	unknown	18:35–18:55 (good, 0.33 h)	87.1° 13:00	11.51	10%	63.6°
2036-12-21 Sun	14	—	unknown	18:35–18:50 (good, 0.25 h)	87.1° 12:55	11.51	16%	67.5°
2036-12-22 Mon	12	—	unknown	18:35–18:45 (good, 0.17 h)	87.1° 12:55	11.51	24%	72.2°
2036-12-23 Tue	10	—	unknown	18:40–19:20 (marginal, 0.67 h)	87.1° 12:50	11.5	32%	77.6°
2036-12-24 Wed	9	—	unknown	18:40–19:15 (marginal, 0.58 h)	87.1° 12:45	11.5	42%	83.4°
2036-12-25 Thu	8	—	unknown	18:40–19:10 (marginal, 0.5 h)	87.1° 12:40	11.5	51%	89.4°
2036-12-26 Fri	8	—	unknown	18:40–19:10 (marginal, 0.5 h)	87.1° 12:35	11.49	61%	95.6°
2036-12-27 Sat	7	—	unknown	18:40–19:05 (marginal, 0.42 h)	87.1° 12:35	11.49	70%	101.8°
2036-12-28 Sun	7	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:30	11.48	79%	107.7°
2036-12-29 Mon	8	—	unknown	05:55–06:10 (marginal, 0.25 h)	87.1° 12:25	11.47	87%	112.9°
2036-12-30 Tue	8	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:20	11.47	94%	117.2°
2036-12-31 Wed	7	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:20	11.46	98%	119.9°
2037-01-01 Thu	8	—	unknown	05:45–06:10 (marginal, 0.42 h)	87.1° 12:15	11.45	100%	120.6°
2037-01-02 Fri	8	—	unknown	05:40–06:10 (marginal, 0.5 h)	87.1° 12:10	11.44	99%	119.2°
2037-01-03 Sat	8	—	unknown	05:35–06:10 (marginal, 0.58 h)	87.1° 12:05	11.42	95%	115.6°
2037-01-04 Sun	8	—	unknown	05:30–06:10 (marginal, 0.67 h)	87.1° 12:00	11.41	89%	110.4°
2037-01-05 Mon	8	—	unknown	05:30–06:10 (marginal, 0.67 h)	87.1° 11:55	11.4	80%	104.0°
2037-01-06 Tue	9	—	unknown	05:25–06:10 (marginal, 0.75 h)	87.1° 11:50	11.38	70%	97.0°
2037-01-07 Wed	10	—	unknown	05:20–06:10 (marginal, 0.83 h)	87.1° 11:45	11.37	59%	89.8°
2037-01-08 Thu	11	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 11:40	11.35	48%	82.8°
2037-01-09 Fri	13	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:40	11.34	37%	76.3°
2037-01-10 Sat	15	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:35	11.32	27%	70.5°
2037-01-11 Sun	17	—	unknown	05:40–06:10 (good, 0.5 h)	87.1° 11:30	11.3	19%	65.6°
2037-01-12 Mon	20	—	unknown	05:35–06:10 (good, 0.58 h)	87.1° 11:25	11.28	11%	62.1°
2037-01-13 Tue	22	—	unknown	05:30–06:10 (good, 0.67 h)	87.1° 11:20	11.26	6%	59.9°
2037-01-14 Wed	23	—	unknown	05:25–06:10 (good, 0.75 h)	87.1° 11:20	11.24	2%	59.3°
2037-01-15 Thu	24	—	unknown	05:20–06:10 (good, 0.83 h)	87.1° 11:15	11.22	0%	60.3°
2037-01-16 Fri	25	—	unknown	05:15–06:10 (good, 0.92 h)	87.1° 11:10	11.2	0%	62.7°
2037-01-17 Sat	27	—	unknown	05:10–06:10 (good, 1.0 h)	87.1° 11:05	11.17	2%	66.3°
2037-01-18 Sun	28	—	unknown	05:10–06:10 (good, 1.0 h)	87.1° 11:05	11.15	6%	70.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-12-20&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.