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: 12-13 (23), 12-14 (20), 01-11 (20), 12-15 (18), 01-10 (18) — by astronomy; check the weather when the night is within four days.

2026-12-13astronomy score per night — click a bar for that night2027-01-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2026-12-13 Sun	23	—	unknown	18:35–19:25 (good, 0.83 h)	87.1° 13:30	11.48	20%	66.3°
2026-12-14 Mon	20	—	unknown	18:35–19:15 (good, 0.67 h)	87.1° 13:25	11.49	28%	68.8°
2026-12-15 Tue	18	—	unknown	18:35–19:05 (good, 0.5 h)	87.1° 13:20	11.49	37%	72.3°
2026-12-16 Wed	15	—	unknown	18:35–18:55 (good, 0.33 h)	87.1° 13:20	11.5	47%	76.7°
2026-12-17 Thu	13	—	unknown	18:35–18:50 (good, 0.25 h)	87.1° 13:15	11.5	57%	81.7°
2026-12-18 Fri	12	—	unknown	18:35–18:40 (good, 0.08 h)	87.1° 13:10	11.5	67%	87.2°
2026-12-19 Sat	12	—	unknown	18:00–19:35 (marginal, 1.58 h)	87.1° 13:05	11.51	77%	93.1°
2026-12-20 Sun	11	—	unknown	18:00–19:35 (marginal, 1.58 h)	87.1° 13:05	11.51	86%	99.0°
2026-12-21 Mon	10	—	unknown	18:05–19:30 (marginal, 1.42 h)	87.1° 13:00	11.51	93%	104.7°
2026-12-22 Tue	10	—	unknown	18:05–19:25 (marginal, 1.33 h)	87.1° 12:55	11.51	98%	109.6°
2026-12-23 Wed	9	—	unknown	18:40–19:20 (marginal, 0.67 h)	87.1° 12:50	11.51	100%	113.2°
2026-12-24 Thu	10	—	unknown	18:40–19:20 (marginal, 0.67 h)	87.1° 12:45	11.5	99%	115.2°
2026-12-25 Fri	11	—	unknown	18:05–19:15 (marginal, 1.17 h)	87.1° 12:45	11.5	95%	115.3°
2026-12-26 Sat	10	—	unknown	18:05–19:10 (marginal, 1.08 h)	87.1° 12:40	11.5	88%	113.6°
2026-12-27 Sun	9	—	unknown	18:40–19:05 (marginal, 0.42 h)	87.1° 12:35	11.49	79%	110.4°
2026-12-28 Mon	9	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:30	11.49	70%	106.0°
2026-12-29 Tue	8	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:25	11.48	59%	100.9°
2026-12-30 Wed	8	—	unknown	18:40–18:55 (marginal, 0.25 h)	87.1° 12:25	11.47	48%	95.5°
2026-12-31 Thu	7	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:20	11.46	38%	90.1°
2027-01-01 Fri	8	—	unknown	05:45–06:10 (marginal, 0.42 h)	87.1° 12:15	11.45	29%	84.7°
2027-01-02 Sat	9	—	unknown	05:40–06:10 (marginal, 0.5 h)	87.1° 12:10	11.44	20%	79.6°
2027-01-03 Sun	10	—	unknown	05:40–06:10 (marginal, 0.5 h)	87.1° 12:10	11.43	13%	75.1°
2027-01-04 Mon	11	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 12:00	11.42	8%	71.1°
2027-01-05 Tue	12	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 12:00	11.41	3%	67.9°
2027-01-06 Wed	13	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:50	11.39	1%	65.7°
2027-01-07 Thu	15	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:50	11.38	0%	64.6°
2027-01-08 Fri	15	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:45	11.36	1%	64.6°
2027-01-09 Sat	16	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:40	11.35	4%	65.7°
2027-01-10 Sun	18	—	unknown	05:40–06:10 (good, 0.5 h)	87.1° 11:35	11.33	8%	68.0°
2027-01-11 Mon	20	—	unknown	05:40–06:10 (good, 0.5 h)	87.1° 11:30	11.31	14%	71.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-12-13&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.