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 3C 273: 01-02 (93), 01-03 (93), 01-04 (93), 01-05 (93), 01-06 (93) — by astronomy; check the weather when the night is within four days.

2027-12-25astronomy score per night — click a bar for that night2028-01-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-12-25 Sat	81	—	unknown	02:45–06:10 (good, 3.42 h)	50.2° 06:35	11.5	4%	66.6°
2027-12-26 Sun	82	—	unknown	02:45–06:10 (good, 3.42 h)	50.2° 06:30	11.5	1%	79.0°
2027-12-27 Mon	84	—	unknown	02:40–06:10 (good, 3.5 h)	50.2° 06:25	11.49	0%	91.2°
2027-12-28 Tue	86	—	unknown	02:35–06:10 (good, 3.58 h)	50.2° 06:20	11.49	1%	103.3°
2027-12-29 Wed	87	—	unknown	02:30–06:10 (good, 3.67 h)	50.2° 06:20	11.48	4%	115.2°
2027-12-30 Thu	88	—	unknown	02:25–06:10 (good, 3.75 h)	50.2° 06:15	11.47	9%	126.9°
2027-12-31 Fri	90	—	unknown	02:25–06:10 (good, 3.75 h)	50.2° 06:10	11.46	15%	138.4°
2028-01-01 Sat	91	—	unknown	02:20–06:10 (good, 3.83 h)	50.2° 06:05	11.45	22%	149.8°
2028-01-02 Sun	93	—	unknown	02:15–06:10 (good, 3.92 h)	50.2° 06:00	11.44	30%	160.6°
2028-01-03 Mon	93	—	unknown	02:10–06:10 (good, 4.0 h)	50.2° 06:00	11.43	39%	169.3°
2028-01-04 Tue	93	—	unknown	02:05–06:10 (good, 4.08 h)	50.2° 05:55	11.42	49%	168.2°
2028-01-05 Wed	93	—	unknown	02:05–06:10 (good, 4.08 h)	50.2° 05:50	11.41	58%	158.5°
2028-01-06 Thu	93	—	unknown	02:05–06:10 (good, 4.08 h)	50.2° 05:45	11.4	68%	146.6°
2028-01-07 Fri	93	—	unknown	02:05–06:10 (good, 4.08 h)	50.2° 05:45	11.38	78%	133.9°
2028-01-08 Sat	93	—	unknown	02:00–06:10 (good, 4.17 h)	50.2° 05:40	11.37	86%	120.6°
2028-01-09 Sun	77	—	unknown	02:10–06:10 (good, 4.0 h)	50.2° 05:35	11.35	93%	106.8°
2028-01-10 Mon	61	—	unknown	03:00–06:10 (good, 3.17 h)	50.2° 05:30	11.33	98%	92.5°
2028-01-11 Tue	46	—	unknown	04:50–06:10 (good, 1.33 h)	50.2° 05:25	11.31	100%	77.8°
2028-01-12 Wed	33	—	unknown	01:45–06:10 (marginal, 4.42 h)	50.2° 05:25	11.3	99%	63.0°
2028-01-13 Thu	24	—	unknown	01:55–06:10 (marginal, 4.25 h)	50.2° 05:20	11.28	95%	48.2°
2028-01-14 Fri	19	—	unknown	01:55–06:10 (marginal, 4.25 h)	50.2° 05:15	11.26	89%	33.7°
2028-01-15 Sat	24	—	unknown	01:25–06:10 (marginal, 4.75 h)	50.2° 05:10	11.24	80%	20.0°
2028-01-16 Sun	33	—	unknown	01:05–06:10 (marginal, 5.08 h)	50.2° 05:05	11.21	70%	10.1°
2028-01-17 Mon	46	—	unknown	00:50–06:10 (marginal, 5.33 h)	50.2° 05:05	11.19	60%	14.3°
2028-01-18 Tue	63	—	unknown	01:35–06:10 (good, 4.58 h)	50.2° 05:00	11.17	49%	26.1°
2028-01-19 Wed	86	—	unknown	01:10–06:10 (good, 5.0 h)	50.2° 04:55	11.14	38%	38.7°
2028-01-20 Thu	91	—	unknown	01:05–06:10 (good, 5.08 h)	50.2° 04:50	11.12	28%	51.3°
2028-01-21 Fri	93	—	unknown	01:00–06:10 (good, 5.17 h)	50.2° 04:50	11.09	20%	63.8°
2028-01-22 Sat	93	—	unknown	00:55–06:05 (good, 5.17 h)	50.2° 04:45	11.07	12%	76.0°
2028-01-23 Sun	93	—	unknown	00:55–06:05 (good, 5.17 h)	50.2° 04:40	11.04	7%	88.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-12-25&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.