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: 01-16 (25), 01-15 (24), 01-14 (23), 01-13 (21), 12-18 (20) — by astronomy; check the weather when the night is within four days.

2044-12-18astronomy score per night — click a bar for that night2045-01-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-12-18 Sun	20	—	unknown	18:35–19:10 (good, 0.58 h)	87.1° 13:10	11.51	0%	68.7°
2044-12-19 Mon	19	—	unknown	18:35–19:05 (good, 0.5 h)	87.1° 13:05	11.51	0%	66.6°
2044-12-20 Tue	17	—	unknown	18:35–19:00 (good, 0.42 h)	87.1° 13:00	11.51	2%	65.5°
2044-12-21 Wed	16	—	unknown	18:35–18:55 (good, 0.33 h)	87.1° 12:55	11.51	6%	65.4°
2044-12-22 Thu	14	—	unknown	18:35–18:50 (good, 0.25 h)	87.1° 12:55	11.51	11%	66.5°
2044-12-23 Fri	11	—	unknown	18:05–19:20 (marginal, 1.25 h)	87.1° 12:50	11.5	17%	68.7°
2044-12-24 Sat	10	—	unknown	18:40–19:15 (marginal, 0.58 h)	87.1° 12:45	11.5	25%	71.7°
2044-12-25 Sun	9	—	unknown	18:40–19:10 (marginal, 0.5 h)	87.1° 12:40	11.5	34%	75.6°
2044-12-26 Mon	8	—	unknown	18:40–19:10 (marginal, 0.5 h)	87.1° 12:35	11.49	44%	80.1°
2044-12-27 Tue	7	—	unknown	18:40–19:05 (marginal, 0.42 h)	87.1° 12:35	11.49	54%	85.1°
2044-12-28 Wed	7	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:30	11.48	64%	90.5°
2044-12-29 Thu	7	—	unknown	05:55–06:10 (marginal, 0.25 h)	87.1° 12:25	11.47	74%	96.1°
2044-12-30 Fri	8	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:20	11.47	83%	101.6°
2044-12-31 Sat	8	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:20	11.46	91%	106.6°
2045-01-01 Sun	7	—	unknown	05:45–06:10 (marginal, 0.42 h)	87.1° 12:15	11.45	96%	110.7°
2045-01-02 Mon	8	—	unknown	05:40–06:10 (marginal, 0.5 h)	87.1° 12:10	11.43	100%	113.6°
2045-01-03 Tue	8	—	unknown	05:35–06:10 (marginal, 0.58 h)	87.1° 12:05	11.42	100%	114.7°
2045-01-04 Wed	9	—	unknown	05:30–06:10 (marginal, 0.67 h)	87.1° 12:00	11.41	96%	114.0°
2045-01-05 Thu	9	—	unknown	05:30–06:10 (marginal, 0.67 h)	87.1° 11:55	11.4	91%	111.5°
2045-01-06 Fri	9	—	unknown	05:25–06:10 (marginal, 0.75 h)	87.1° 11:50	11.38	83%	107.7°
2045-01-07 Sat	10	—	unknown	05:20–06:45 (marginal, 1.42 h)	87.1° 11:45	11.37	73%	102.9°
2045-01-08 Sun	11	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 11:40	11.35	63%	97.6°
2045-01-09 Mon	13	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:40	11.33	52%	92.2°
2045-01-10 Tue	14	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:35	11.32	42%	86.8°
2045-01-11 Wed	16	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:30	11.3	32%	81.6°
2045-01-12 Thu	19	—	unknown	05:40–06:10 (good, 0.5 h)	87.1° 11:25	11.28	23%	76.9°
2045-01-13 Fri	21	—	unknown	05:30–06:10 (good, 0.67 h)	87.1° 11:20	11.26	16%	72.8°
2045-01-14 Sat	23	—	unknown	05:25–06:10 (good, 0.75 h)	87.1° 11:20	11.24	9%	69.5°
2045-01-15 Sun	24	—	unknown	05:20–06:10 (good, 0.83 h)	87.1° 11:15	11.22	5%	67.0°
2045-01-16 Mon	25	—	unknown	05:15–06:10 (good, 0.92 h)	87.1° 11:10	11.19	2%	65.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-12-18&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.