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: 01-10 (93), 01-11 (93), 01-12 (93), 01-13 (93), 01-14 (93) — by astronomy; check the weather when the night is within four days.

2028-12-20astronomy score per night — click a bar for that night2029-01-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-12-20 Wed	73	—	unknown	03:05–06:05 (good, 3.0 h)	50.2° 06:50	11.51	23%	140.2°
2028-12-21 Thu	74	—	unknown	03:00–06:05 (good, 3.08 h)	50.2° 06:45	11.51	32%	151.7°
2028-12-22 Fri	77	—	unknown	02:55–06:10 (good, 3.25 h)	50.2° 06:45	11.51	41%	162.3°
2028-12-23 Sat	78	—	unknown	02:50–06:10 (good, 3.33 h)	50.2° 06:40	11.5	50%	169.6°
2028-12-24 Sun	80	—	unknown	02:50–06:10 (good, 3.33 h)	50.2° 06:35	11.5	60%	166.6°
2028-12-25 Mon	82	—	unknown	02:45–06:10 (good, 3.42 h)	50.2° 06:30	11.5	69%	156.9°
2028-12-26 Tue	82	—	unknown	02:45–06:10 (good, 3.42 h)	50.2° 06:25	11.49	77%	145.7°
2028-12-27 Wed	81	—	unknown	02:45–06:10 (good, 3.42 h)	50.2° 06:25	11.49	85%	133.8°
2028-12-28 Thu	80	—	unknown	02:45–06:10 (good, 3.42 h)	50.2° 06:20	11.48	92%	121.4°
2028-12-29 Fri	65	—	unknown	02:50–06:10 (good, 3.33 h)	50.2° 06:15	11.47	96%	108.7°
2028-12-30 Sat	54	—	unknown	03:20–06:10 (good, 2.83 h)	50.2° 06:10	11.47	99%	95.6°
2028-12-31 Sun	42	—	unknown	04:50–06:10 (good, 1.33 h)	50.2° 06:05	11.46	100%	82.2°
2029-01-01 Mon	31	—	unknown	02:15–06:10 (marginal, 3.92 h)	50.2° 06:05	11.45	98%	68.5°
2029-01-02 Tue	24	—	unknown	02:25–06:10 (marginal, 3.75 h)	50.2° 06:00	11.44	94%	54.7°
2029-01-03 Wed	20	—	unknown	02:25–06:10 (marginal, 3.75 h)	50.2° 05:55	11.42	87%	40.9°
2029-01-04 Thu	21	—	unknown	02:10–06:10 (marginal, 4.0 h)	50.2° 05:50	11.41	78%	27.3°
2029-01-05 Fri	30	—	unknown	01:45–06:10 (marginal, 4.42 h)	50.2° 05:50	11.4	68%	15.0°
2029-01-06 Sat	41	—	unknown	01:30–06:10 (marginal, 4.67 h)	50.2° 05:45	11.38	57%	10.4°
2029-01-07 Sun	55	—	unknown	02:15–06:10 (good, 3.92 h)	50.2° 05:40	11.37	46%	19.7°
2029-01-08 Mon	78	—	unknown	01:50–06:10 (good, 4.33 h)	50.2° 05:35	11.35	35%	32.5°
2029-01-09 Tue	89	—	unknown	01:45–06:10 (good, 4.42 h)	50.2° 05:30	11.34	24%	45.8°
2029-01-10 Wed	93	—	unknown	01:40–06:10 (good, 4.5 h)	50.2° 05:30	11.32	16%	59.2°
2029-01-11 Thu	93	—	unknown	01:35–06:10 (good, 4.58 h)	50.2° 05:25	11.3	8%	72.5°
2029-01-12 Fri	93	—	unknown	01:35–06:10 (good, 4.58 h)	50.2° 05:20	11.28	4%	85.7°
2029-01-13 Sat	93	—	unknown	01:30–06:10 (good, 4.67 h)	50.2° 05:15	11.26	1%	98.7°
2029-01-14 Sun	93	—	unknown	01:25–06:10 (good, 4.75 h)	50.2° 05:10	11.24	0%	111.5°
2029-01-15 Mon	93	—	unknown	01:20–06:10 (good, 4.83 h)	50.2° 05:10	11.22	2%	123.9°
2029-01-16 Tue	93	—	unknown	01:15–06:10 (good, 4.92 h)	50.2° 05:05	11.2	5%	136.1°
2029-01-17 Wed	93	—	unknown	01:15–06:10 (good, 4.92 h)	50.2° 05:00	11.17	10%	147.8°
2029-01-18 Thu	93	—	unknown	01:10–06:10 (good, 5.0 h)	50.2° 04:55	11.15	17%	158.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-12-20&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.