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: 12-25 (82), 12-26 (82), 12-27 (81), 12-24 (80), 12-28 (80) — by astronomy; check the weather when the night is within four days.

2028-12-09astronomy score per night — click a bar for that night2029-01-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-12-09 Sat	28	—	unknown	04:20–06:00 (good, 1.67 h)	50.2° 07:35	11.45	42%	12.9°
2028-12-10 Sun	37	—	unknown	04:00–06:00 (good, 2.0 h)	50.2° 07:30	11.46	31%	11.6°
2028-12-11 Mon	46	—	unknown	03:45–06:00 (good, 2.25 h)	50.2° 07:25	11.47	21%	22.4°
2028-12-12 Tue	54	—	unknown	03:35–06:00 (good, 2.42 h)	50.2° 07:20	11.48	12%	35.7°
2028-12-13 Wed	60	—	unknown	03:30–06:05 (good, 2.58 h)	50.2° 07:20	11.48	6%	49.4°
2028-12-14 Thu	62	—	unknown	03:25–06:05 (good, 2.67 h)	50.2° 07:15	11.49	2%	63.2°
2028-12-15 Fri	65	—	unknown	03:25–06:05 (good, 2.67 h)	50.2° 07:10	11.49	0%	76.8°
2028-12-16 Sat	67	—	unknown	03:20–06:05 (good, 2.75 h)	50.2° 07:05	11.5	1%	90.2°
2028-12-17 Sun	68	—	unknown	03:15–06:05 (good, 2.83 h)	50.2° 07:00	11.5	4%	103.2°
2028-12-18 Mon	69	—	unknown	03:10–06:05 (good, 2.92 h)	50.2° 07:00	11.51	9%	115.9°
2028-12-19 Tue	71	—	unknown	03:05–06:05 (good, 3.0 h)	50.2° 06:55	11.51	15%	128.3°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-12-09&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.