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: 01-23 (32), 01-22 (29), 01-21 (27), 01-20 (25), 01-19 (22) — by astronomy; check the weather when the night is within four days.

2027-12-25astronomy score per night — click a bar for that night2028-01-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-12-25 Sat	12	—	unknown	18:40–18:45 (good, 0.08 h)	87.1° 12:45	11.5	4%	70.6°
2027-12-26 Sun	11	—	unknown	18:05–19:10 (marginal, 1.08 h)	87.1° 12:40	11.5	1%	66.9°
2027-12-27 Mon	10	—	unknown	18:40–19:05 (marginal, 0.42 h)	87.1° 12:35	11.49	0%	64.3°
2027-12-28 Tue	10	—	unknown	18:40–19:05 (marginal, 0.42 h)	87.1° 12:30	11.49	1%	63.0°
2027-12-29 Wed	9	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:30	11.48	4%	63.0°
2027-12-30 Thu	8	—	unknown	05:55–06:10 (marginal, 0.25 h)	87.1° 12:25	11.47	9%	64.3°
2027-12-31 Fri	8	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:20	11.46	15%	66.7°
2028-01-01 Sat	9	—	unknown	05:45–06:10 (marginal, 0.42 h)	87.1° 12:15	11.45	22%	70.0°
2028-01-02 Sun	9	—	unknown	05:45–06:10 (marginal, 0.42 h)	87.1° 12:15	11.44	30%	74.2°
2028-01-03 Mon	10	—	unknown	05:40–06:45 (marginal, 1.08 h)	87.1° 12:10	11.43	39%	79.0°
2028-01-04 Tue	11	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 12:05	11.42	49%	84.3°
2028-01-05 Wed	11	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 12:00	11.41	58%	89.9°
2028-01-06 Thu	13	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:55	11.4	68%	95.7°
2028-01-07 Fri	13	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:50	11.38	78%	101.4°
2028-01-08 Sat	15	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:45	11.37	86%	106.8°
2028-01-09 Sun	13	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:40	11.35	93%	111.5°
2028-01-10 Mon	14	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:35	11.33	98%	115.0°
2028-01-11 Tue	15	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:35	11.31	100%	116.9°
2028-01-12 Wed	15	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:30	11.3	99%	116.9°
2028-01-13 Thu	16	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:25	11.28	95%	114.8°
2028-01-14 Fri	16	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:20	11.26	89%	111.1°
2028-01-15 Sat	16	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:20	11.24	80%	106.1°
2028-01-16 Sun	17	—	unknown	05:40–06:10 (good, 0.5 h)	87.1° 11:15	11.21	70%	100.2°
2028-01-17 Mon	18	—	unknown	05:35–06:10 (good, 0.58 h)	87.1° 11:10	11.19	60%	94.0°
2028-01-18 Tue	20	—	unknown	05:25–06:10 (good, 0.75 h)	87.1° 11:05	11.17	49%	87.8°
2028-01-19 Wed	22	—	unknown	05:20–06:10 (good, 0.83 h)	87.1° 11:00	11.14	38%	81.9°
2028-01-20 Thu	25	—	unknown	05:10–06:10 (good, 1.0 h)	87.1° 11:00	11.12	28%	76.4°
2028-01-21 Fri	27	—	unknown	05:05–06:10 (good, 1.08 h)	87.1° 10:55	11.09	20%	71.6°
2028-01-22 Sat	29	—	unknown	04:55–06:05 (good, 1.17 h)	87.1° 10:50	11.07	12%	67.7°
2028-01-23 Sun	32	—	unknown	04:50–06:05 (good, 1.25 h)	87.1° 10:45	11.04	7%	64.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-12-25&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.