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: 01-20 (27), 01-19 (23), 01-18 (20), 01-17 (17), 01-16 (16) — by astronomy; check the weather when the night is within four days.

2038-12-22astronomy score per night — click a bar for that night2039-01-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-12-22 Wed	15	—	unknown	18:35–18:55 (good, 0.33 h)	87.1° 12:55	11.51	14%	71.8°
2038-12-23 Thu	13	—	unknown	18:40–18:50 (good, 0.17 h)	87.1° 12:50	11.51	6%	67.2°
2038-12-24 Fri	12	—	unknown	18:40–18:45 (good, 0.08 h)	87.1° 12:45	11.5	2%	64.0°
2038-12-25 Sat	11	—	unknown	18:05–19:15 (marginal, 1.17 h)	87.1° 12:45	11.5	0%	62.6°
2038-12-26 Sun	11	—	unknown	18:05–19:10 (marginal, 1.08 h)	87.1° 12:40	11.5	1%	63.2°
2038-12-27 Mon	10	—	unknown	18:40–19:05 (marginal, 0.42 h)	87.1° 12:35	11.49	5%	65.6°
2038-12-28 Tue	9	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:30	11.48	11%	69.4°
2038-12-29 Wed	8	—	unknown	18:40–19:00 (marginal, 0.33 h)	87.1° 12:25	11.48	18%	74.2°
2038-12-30 Thu	8	—	unknown	05:55–06:10 (marginal, 0.25 h)	87.1° 12:25	11.47	27%	79.5°
2038-12-31 Fri	8	—	unknown	05:50–06:10 (marginal, 0.33 h)	87.1° 12:20	11.46	37%	85.1°
2039-01-01 Sat	9	—	unknown	05:45–06:10 (marginal, 0.42 h)	87.1° 12:15	11.45	46%	90.7°
2039-01-02 Sun	10	—	unknown	05:40–06:10 (marginal, 0.5 h)	87.1° 12:10	11.44	56%	96.2°
2039-01-03 Mon	10	—	unknown	05:40–06:45 (marginal, 1.08 h)	87.1° 12:10	11.43	65%	101.5°
2039-01-04 Tue	11	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 12:00	11.42	74%	106.2°
2039-01-05 Wed	12	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 12:00	11.4	82%	110.4°
2039-01-06 Thu	13	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:50	11.39	88%	113.8°
2039-01-07 Fri	14	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:50	11.38	94%	116.2°
2039-01-08 Sat	12	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:45	11.36	98%	117.3°
2039-01-09 Sun	13	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:40	11.34	100%	117.2°
2039-01-10 Mon	13	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:35	11.33	100%	115.6°
2039-01-11 Tue	14	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:30	11.31	98%	112.7°
2039-01-12 Wed	14	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:30	11.29	94%	108.6°
2039-01-13 Thu	14	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:25	11.27	88%	103.6°
2039-01-14 Fri	14	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:20	11.25	80%	97.8°
2039-01-15 Sat	14	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:15	11.23	70%	91.7°
2039-01-16 Sun	16	—	unknown	05:40–06:10 (good, 0.5 h)	87.1° 11:15	11.21	59%	85.4°
2039-01-17 Mon	17	—	unknown	05:35–06:10 (good, 0.58 h)	87.1° 11:10	11.18	48%	79.2°
2039-01-18 Tue	20	—	unknown	05:25–06:10 (good, 0.75 h)	87.1° 11:05	11.16	37%	73.4°
2039-01-19 Wed	23	—	unknown	05:15–06:10 (good, 0.92 h)	87.1° 11:00	11.14	26%	68.6°
2039-01-20 Thu	27	—	unknown	05:05–06:10 (good, 1.08 h)	87.1° 10:55	11.11	17%	65.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-12-22&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.