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: 11-21 (59), 11-22 (57), 11-23 (56), 11-24 (54), 11-25 (53) — by astronomy; check the weather when the night is within four days.

2027-11-21astronomy score per night — click a bar for that night2027-12-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-11-21 Sun	59	—	unknown	18:35–20:55 (good, 2.33 h)	87.1° 15:00	11.11	40%	108.3°
2027-11-22 Mon	57	—	unknown	18:35–20:55 (good, 2.33 h)	87.1° 14:55	11.14	29%	103.0°
2027-11-23 Tue	56	—	unknown	18:35–20:50 (good, 2.25 h)	87.1° 14:50	11.16	20%	97.1°
2027-11-24 Wed	54	—	unknown	18:35–20:45 (good, 2.17 h)	87.1° 14:45	11.19	12%	90.9°
2027-11-25 Thu	53	—	unknown	18:35–20:40 (good, 2.08 h)	87.1° 14:40	11.21	6%	84.8°
2027-11-26 Fri	52	—	unknown	18:35–20:35 (good, 2.0 h)	87.1° 14:40	11.23	2%	79.0°
2027-11-27 Sat	50	—	unknown	18:35–20:35 (good, 2.0 h)	87.1° 14:35	11.25	0%	73.8°
2027-11-28 Sun	48	—	unknown	18:35–20:30 (good, 1.92 h)	87.1° 14:30	11.27	1%	69.4°
2027-11-29 Mon	46	—	unknown	18:35–20:25 (good, 1.83 h)	87.1° 14:25	11.29	3%	66.0°
2027-11-30 Tue	45	—	unknown	18:35–20:20 (good, 1.75 h)	87.1° 14:20	11.31	8%	63.8°
2027-12-01 Wed	41	—	unknown	18:35–20:20 (good, 1.75 h)	87.1° 14:20	11.33	14%	63.0°
2027-12-02 Thu	36	—	unknown	18:35–20:05 (good, 1.5 h)	87.1° 14:15	11.34	21%	63.4°
2027-12-03 Fri	32	—	unknown	18:35–20:00 (good, 1.42 h)	87.1° 14:10	11.36	29%	65.0°
2027-12-04 Sat	28	—	unknown	18:35–19:50 (good, 1.25 h)	87.1° 14:05	11.38	38%	67.7°
2027-12-05 Sun	24	—	unknown	18:35–19:40 (good, 1.08 h)	87.1° 14:05	11.39	47%	71.4°
2027-12-06 Mon	21	—	unknown	18:35–19:30 (good, 0.92 h)	87.1° 14:00	11.4	57%	75.8°
2027-12-07 Tue	19	—	unknown	18:35–19:15 (good, 0.67 h)	87.1° 13:55	11.42	66%	80.9°
2027-12-08 Wed	18	—	unknown	18:35–19:00 (good, 0.42 h)	87.1° 13:50	11.43	75%	86.4°
2027-12-09 Thu	17	—	unknown	18:35–18:55 (good, 0.33 h)	87.1° 13:45	11.44	83%	92.2°
2027-12-10 Fri	17	—	unknown	18:35–19:05 (good, 0.5 h)	87.1° 13:45	11.45	90%	98.1°
2027-12-11 Sat	18	—	unknown	18:35–19:10 (good, 0.58 h)	87.1° 13:40	11.46	96%	103.8°
2027-12-12 Sun	19	—	unknown	18:35–19:15 (good, 0.67 h)	87.1° 13:35	11.47	99%	109.0°
2027-12-13 Mon	19	—	unknown	18:35–19:15 (good, 0.67 h)	87.1° 13:30	11.48	100%	113.2°
2027-12-14 Tue	21	—	unknown	18:35–19:15 (good, 0.67 h)	87.1° 13:25	11.48	98%	116.0°
2027-12-15 Wed	23	—	unknown	18:35–19:15 (good, 0.67 h)	87.1° 13:25	11.49	93%	117.1°
2027-12-16 Thu	23	—	unknown	18:35–19:20 (good, 0.75 h)	87.1° 13:20	11.5	86%	116.2°
2027-12-17 Fri	22	—	unknown	18:35–19:15 (good, 0.67 h)	87.1° 13:15	11.5	77%	113.6°
2027-12-18 Sat	21	—	unknown	18:35–19:10 (good, 0.58 h)	87.1° 13:10	11.5	66%	109.5°
2027-12-19 Sun	20	—	unknown	18:35–19:05 (good, 0.5 h)	87.1° 13:10	11.51	55%	104.4°
2027-12-20 Mon	18	—	unknown	18:35–19:05 (good, 0.5 h)	87.1° 13:05	11.51	44%	98.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-11-21&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.