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 (27), 01-19 (26), 01-16 (25), 01-17 (25), 01-15 (24) — by astronomy; check the weather when the night is within four days.

2026-12-28astronomy score per night — click a bar for that night2027-01-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2027-01-12 Tue	21	—	unknown	05:35–06:10 (good, 0.58 h)	87.1° 11:30	11.29	22%	75.3°
2027-01-13 Wed	22	—	unknown	05:30–06:10 (good, 0.67 h)	87.1° 11:25	11.27	31%	80.1°
2027-01-14 Thu	23	—	unknown	05:25–06:10 (good, 0.75 h)	87.1° 11:20	11.25	40%	85.4°
2027-01-15 Fri	24	—	unknown	05:20–06:10 (good, 0.83 h)	87.1° 11:15	11.23	51%	91.0°
2027-01-16 Sat	25	—	unknown	05:20–06:10 (good, 0.83 h)	87.1° 11:15	11.21	62%	96.8°
2027-01-17 Sun	25	—	unknown	05:15–06:10 (good, 0.92 h)	87.1° 11:10	11.19	72%	102.4°
2027-01-18 Mon	27	—	unknown	05:10–06:10 (good, 1.0 h)	87.1° 11:05	11.16	82%	107.5°
2027-01-19 Tue	26	—	unknown	05:20–06:10 (good, 0.83 h)	87.1° 11:00	11.14	90%	111.7°
2027-01-20 Wed	24	—	unknown	05:15–06:10 (good, 0.92 h)	87.1° 10:55	11.11	96%	114.5°
2027-01-21 Thu	23	—	unknown	05:15–06:05 (good, 0.83 h)	87.1° 10:55	11.09	100%	115.6°
2027-01-22 Fri	23	—	unknown	05:10–06:05 (good, 0.92 h)	87.1° 10:50	11.06	100%	114.7°
2027-01-23 Sat	23	—	unknown	05:10–06:05 (good, 0.92 h)	87.1° 10:45	11.04	97%	112.1°
2027-01-24 Sun	23	—	unknown	05:10–06:05 (good, 0.92 h)	87.1° 10:40	11.01	92%	108.0°
2027-01-25 Mon	23	—	unknown	05:05–06:05 (good, 1.0 h)	87.1° 10:35	10.98	84%	103.0°
2027-01-26 Tue	24	—	unknown	05:00–06:05 (good, 1.08 h)	87.1° 10:35	10.95	75%	97.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-12-28&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.