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 V1057 Cyg: 12-29 (60), 12-30 (59), 12-31 (56), 01-01 (54), 01-02 (53) — by astronomy; check the weather when the night is within four days.

2040-12-29astronomy score per night — click a bar for that night2041-01-27

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-12-29 Sat	60	—	unknown	18:40–21:05 (good, 2.42 h)	87.2° 14:45	11.47	19%	101.3°
2040-12-30 Sun	59	—	unknown	18:40–21:05 (good, 2.42 h)	87.3° 14:45	11.47	11%	95.1°
2040-12-31 Mon	56	—	unknown	18:45–21:00 (good, 2.25 h)	87.3° 14:40	11.46	5%	88.5°
2041-01-01 Tue	54	—	unknown	18:45–20:55 (good, 2.17 h)	87.3° 14:35	11.45	1%	81.8°
2041-01-02 Wed	53	—	unknown	18:45–20:50 (good, 2.08 h)	87.3° 14:30	11.44	0%	75.4°
2041-01-03 Thu	51	—	unknown	18:45–20:45 (good, 2.0 h)	87.2° 14:25	11.42	2%	69.8°
2041-01-04 Fri	48	—	unknown	18:45–20:45 (good, 2.0 h)	87.3° 14:25	11.41	7%	65.5°
2041-01-05 Sat	43	—	unknown	18:45–20:40 (good, 1.92 h)	87.3° 14:20	11.4	14%	62.9°
2041-01-06 Sun	37	—	unknown	18:50–20:25 (good, 1.58 h)	87.3° 14:15	11.38	24%	62.3°
2041-01-07 Mon	31	—	unknown	18:50–20:15 (good, 1.42 h)	87.3° 14:10	11.37	34%	63.6°
2041-01-08 Tue	27	—	unknown	18:50–20:05 (good, 1.25 h)	87.2° 14:10	11.35	45%	66.5°
2041-01-09 Wed	22	—	unknown	18:50–19:50 (good, 1.0 h)	87.3° 14:05	11.34	56%	70.5°
2041-01-10 Thu	19	—	unknown	18:50–19:00 (good, 0.17 h)	87.3° 14:00	11.32	66%	75.5°
2041-01-11 Fri	17	—	unknown	18:55–20:45 (marginal, 1.83 h)	87.3° 13:55	11.3	75%	80.9°
2041-01-12 Sat	16	—	unknown	18:55–20:40 (marginal, 1.75 h)	87.2° 13:50	11.28	83%	86.6°
2041-01-13 Sun	17	—	unknown	18:20–20:35 (marginal, 2.25 h)	87.3° 13:50	11.26	90%	92.3°
2041-01-14 Mon	18	—	unknown	18:55–19:20 (good, 0.42 h)	87.3° 13:45	11.24	95%	97.9°
2041-01-15 Tue	18	—	unknown	18:55–19:30 (good, 0.58 h)	87.3° 13:40	11.22	98%	103.2°
2041-01-16 Wed	19	—	unknown	18:55–19:35 (good, 0.67 h)	87.3° 13:35	11.2	100%	107.9°
2041-01-17 Thu	19	—	unknown	19:00–19:35 (good, 0.58 h)	87.2° 13:30	11.17	100%	111.9°
2041-01-18 Fri	21	—	unknown	19:00–19:35 (good, 0.58 h)	87.3° 13:30	11.15	97%	115.0°
2041-01-19 Sat	24	—	unknown	19:00–19:35 (good, 0.58 h)	87.3° 13:25	11.12	94%	117.0°
2041-01-20 Sun	23	—	unknown	19:00–19:40 (good, 0.67 h)	87.3° 13:20	11.1	88%	117.8°
2041-01-21 Mon	20	—	unknown	19:05–19:35 (good, 0.5 h)	87.3° 13:15	11.07	82%	117.3°
2041-01-22 Tue	20	—	unknown	19:05–19:35 (good, 0.5 h)	87.2° 13:15	11.05	74%	115.6°
2041-01-23 Wed	18	—	unknown	19:05–19:30 (good, 0.42 h)	87.3° 13:10	11.02	65%	112.6°
2041-01-24 Thu	16	—	unknown	19:05–19:25 (good, 0.33 h)	87.3° 13:05	10.99	55%	108.5°
2041-01-25 Fri	15	—	unknown	19:05–19:20 (good, 0.25 h)	87.3° 13:00	10.96	45%	103.5°
2041-01-26 Sat	13	—	unknown	19:10–19:15 (good, 0.08 h)	87.3° 12:55	10.93	34%	97.8°
2041-01-27 Sun	12	—	unknown	19:10–19:15 (good, 0.08 h)	87.2° 12:55	10.9	24%	91.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-12-29&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.