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: 01-15 (24), 01-14 (23), 12-17 (22), 01-13 (21), 12-18 (20) — by astronomy; check the weather when the night is within four days.

2039-12-17astronomy score per night — click a bar for that night2040-01-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-12-17 Sat	22	—	unknown	18:35–19:15 (good, 0.67 h)	87.1° 13:15	11.5	8%	66.1°
2039-12-18 Sun	20	—	unknown	18:35–19:05 (good, 0.5 h)	87.1° 13:10	11.5	15%	69.4°
2039-12-19 Mon	17	—	unknown	18:35–19:00 (good, 0.42 h)	87.1° 13:10	11.51	24%	73.9°
2039-12-20 Tue	15	—	unknown	18:35–18:50 (good, 0.25 h)	87.1° 13:05	11.51	34%	79.2°
2039-12-21 Wed	12	—	unknown	18:35–18:45 (good, 0.17 h)	87.1° 13:00	11.51	45%	84.7°
2039-12-22 Thu	11	—	unknown	18:05–19:25 (marginal, 1.33 h)	87.1° 12:55	11.51	55%	90.3°
2039-12-23 Fri	9	—	unknown	18:40–19:25 (marginal, 0.75 h)	87.1° 12:50	11.51	65%	95.8°
2039-12-24 Sat	8	—	unknown	18:40–19:20 (marginal, 0.67 h)	87.1° 12:50	11.5	74%	100.9°
2039-12-25 Sun	8	—	unknown	18:40–19:15 (marginal, 0.58 h)	87.1° 12:45	11.5	82%	105.5°
2039-12-26 Mon	8	—	unknown	18:40–19:10 (marginal, 0.5 h)	87.1° 12:40	11.5	89%	109.5°
2039-12-27 Tue	8	—	unknown	18:40–19:05 (marginal, 0.42 h)	87.1° 12:35	11.49	94%	112.6°
2039-12-28 Wed	7	—	unknown	18:40–19:05 (marginal, 0.42 h)	87.1° 12:30	11.49	98%	114.7°
2039-12-29 Thu	7	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:30	11.48	100%	115.7°
2039-12-30 Fri	6	—	unknown	18:40–18:55 (marginal, 0.25 h)	87.1° 12:25	11.47	100%	115.6°
2039-12-31 Sat	6	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:20	11.46	98%	114.3°
2040-01-01 Sun	7	—	unknown	05:45–06:10 (marginal, 0.42 h)	87.1° 12:15	11.45	95%	111.9°
2040-01-02 Mon	7	—	unknown	05:45–06:10 (marginal, 0.42 h)	87.1° 12:15	11.44	90%	108.5°
2040-01-03 Tue	7	—	unknown	05:40–06:10 (marginal, 0.5 h)	87.1° 12:10	11.43	83%	104.3°
2040-01-04 Wed	8	—	unknown	05:35–06:10 (marginal, 0.58 h)	87.1° 12:05	11.42	75%	99.5°
2040-01-05 Thu	8	—	unknown	05:30–06:10 (marginal, 0.67 h)	87.1° 12:00	11.41	66%	94.1°
2040-01-06 Fri	9	—	unknown	05:25–06:10 (marginal, 0.75 h)	87.1° 11:55	11.39	56%	88.5°
2040-01-07 Sat	10	—	unknown	05:25–06:45 (marginal, 1.33 h)	87.1° 11:50	11.38	45%	82.8°
2040-01-08 Sun	12	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 11:45	11.36	34%	77.3°
2040-01-09 Mon	14	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:40	11.35	24%	72.3°
2040-01-10 Tue	16	—	unknown	05:45–06:10 (good, 0.42 h)	87.1° 11:35	11.33	15%	68.1°
2040-01-11 Wed	19	—	unknown	05:40–06:10 (good, 0.5 h)	87.1° 11:35	11.31	7%	65.3°
2040-01-12 Thu	20	—	unknown	05:35–06:10 (good, 0.58 h)	87.1° 11:30	11.29	2%	64.2°
2040-01-13 Fri	21	—	unknown	05:30–06:10 (good, 0.67 h)	87.1° 11:25	11.27	0%	65.1°
2040-01-14 Sat	23	—	unknown	05:25–06:10 (good, 0.75 h)	87.1° 11:20	11.25	1%	67.7°
2040-01-15 Sun	24	—	unknown	05:25–06:10 (good, 0.75 h)	87.1° 11:20	11.23	5%	71.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-12-17&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.