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 (22), 01-12 (21) — by astronomy; check the weather when the night is within four days.

2042-12-18astronomy score per night — click a bar for that night2043-01-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-12-18 Thu	15	—	unknown	18:35–18:55 (good, 0.33 h)	87.1° 13:10	11.5	38%	77.8°
2042-12-19 Fri	14	—	unknown	18:35–18:45 (good, 0.17 h)	87.1° 13:05	11.51	49%	82.8°
2042-12-20 Sat	12	—	unknown	18:35–18:40 (good, 0.08 h)	87.1° 13:05	11.51	60%	88.2°
2042-12-21 Sun	10	—	unknown	18:35–19:30 (marginal, 0.92 h)	87.1° 13:00	11.51	71%	93.8°
2042-12-22 Mon	9	—	unknown	18:35–19:25 (marginal, 0.83 h)	87.1° 12:55	11.51	81%	99.3°
2042-12-23 Tue	8	—	unknown	18:40–19:20 (marginal, 0.67 h)	87.1° 12:50	11.51	89%	104.3°
2042-12-24 Wed	8	—	unknown	18:40–19:20 (marginal, 0.67 h)	87.1° 12:45	11.5	95%	108.5°
2042-12-25 Thu	8	—	unknown	18:40–19:15 (marginal, 0.58 h)	87.1° 12:45	11.5	99%	111.5°
2042-12-26 Fri	8	—	unknown	18:40–19:10 (marginal, 0.5 h)	87.1° 12:40	11.5	100%	113.0°
2042-12-27 Sat	8	—	unknown	18:40–19:05 (marginal, 0.42 h)	87.1° 12:35	11.49	98%	113.1°
2042-12-28 Sun	9	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:30	11.48	94%	111.8°
2042-12-29 Mon	8	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:25	11.48	88%	109.2°
2042-12-30 Tue	7	—	unknown	18:40–18:55 (marginal, 0.25 h)	87.1° 12:25	11.47	80%	105.8°
2042-12-31 Wed	6	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:20	11.46	72%	101.8°
2043-01-01 Thu	7	—	unknown	05:45–06:10 (marginal, 0.42 h)	87.1° 12:15	11.45	62%	97.3°
2043-01-02 Fri	8	—	unknown	05:40–06:10 (marginal, 0.5 h)	87.1° 12:10	11.44	53%	92.7°
2043-01-03 Sat	8	—	unknown	05:40–06:10 (marginal, 0.5 h)	87.1° 12:10	11.43	44%	88.0°
2043-01-04 Sun	9	—	unknown	05:35–06:10 (marginal, 0.58 h)	87.1° 12:00	11.42	34%	83.4°
2043-01-05 Mon	10	—	unknown	05:30–06:45 (marginal, 1.25 h)	87.1° 12:00	11.4	26%	79.1°
2043-01-06 Tue	12	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 11:50	11.39	18%	75.1°
2043-01-07 Wed	14	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:50	11.38	11%	71.7°
2043-01-08 Thu	15	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:45	11.36	6%	69.0°
2043-01-09 Fri	16	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:40	11.34	2%	67.3°
2043-01-10 Sat	18	—	unknown	05:40–06:10 (good, 0.5 h)	87.1° 11:35	11.33	0%	66.7°
2043-01-11 Sun	20	—	unknown	05:40–06:10 (good, 0.5 h)	87.1° 11:30	11.31	1%	67.4°
2043-01-12 Mon	21	—	unknown	05:35–06:10 (good, 0.58 h)	87.1° 11:30	11.29	3%	69.4°
2043-01-13 Tue	22	—	unknown	05:30–06:10 (good, 0.67 h)	87.1° 11:25	11.27	8%	72.5°
2043-01-14 Wed	23	—	unknown	05:25–06:10 (good, 0.75 h)	87.1° 11:20	11.25	15%	76.6°
2043-01-15 Thu	24	—	unknown	05:20–06:10 (good, 0.83 h)	87.1° 11:15	11.23	24%	81.5°
2043-01-16 Fri	25	—	unknown	05:20–06:10 (good, 0.83 h)	87.1° 11:15	11.21	34%	86.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-12-18&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.