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: 12-04 (28), 12-05 (24), 12-15 (23), 12-16 (23), 12-17 (22) — by astronomy; check the weather when the night is within four days.

2027-12-04astronomy score per night — click a bar for that night2028-01-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2027-12-21 Tue	16	—	unknown	18:35–19:00 (good, 0.42 h)	87.1° 13:00	11.51	33%	92.5°
2027-12-22 Wed	15	—	unknown	18:35–18:55 (good, 0.33 h)	87.1° 12:55	11.51	24%	86.4°
2027-12-23 Thu	13	—	unknown	18:40–18:50 (good, 0.17 h)	87.1° 12:50	11.51	15%	80.5°
2027-12-24 Fri	12	—	unknown	18:40–18:45 (good, 0.08 h)	87.1° 12:50	11.5	8%	75.2°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-12-04&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.