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: 12-18 (69), 12-17 (68), 12-16 (67), 12-15 (65), 12-14 (62) — by astronomy; check the weather when the night is within four days.

2028-11-19astronomy score per night — click a bar for that night2028-12-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-11-19 Sun	20	—	unknown	05:05–05:40 (good, 0.58 h)	50.2° 08:50	11.08	14%	95.5°
2028-11-20 Mon	21	—	unknown	05:00–05:45 (good, 0.75 h)	50.2° 08:50	11.11	21%	108.3°
2028-11-21 Tue	23	—	unknown	05:00–05:45 (good, 0.75 h)	50.2° 08:45	11.13	30%	120.7°
2028-11-22 Wed	24	—	unknown	04:55–05:45 (good, 0.83 h)	50.2° 08:40	11.16	40%	132.7°
2028-11-23 Thu	26	—	unknown	04:50–05:45 (good, 0.92 h)	50.2° 08:35	11.18	49%	144.3°
2028-11-24 Fri	28	—	unknown	04:45–05:45 (good, 1.0 h)	50.2° 08:35	11.2	59%	155.5°
2028-11-25 Sat	29	—	unknown	04:40–05:50 (good, 1.17 h)	50.2° 08:30	11.22	68%	165.4°
2028-11-26 Sun	31	—	unknown	04:40–05:50 (good, 1.17 h)	50.2° 08:25	11.25	76%	170.1°
2028-11-27 Mon	33	—	unknown	04:35–05:50 (good, 1.25 h)	50.2° 08:20	11.27	84%	163.7°
2028-11-28 Tue	34	—	unknown	04:35–05:50 (good, 1.25 h)	50.2° 08:15	11.29	90%	153.2°
2028-11-29 Wed	30	—	unknown	04:35–05:50 (good, 1.25 h)	50.2° 08:15	11.3	95%	141.5°
2028-11-30 Thu	30	—	unknown	04:35–05:50 (good, 1.25 h)	50.2° 08:10	11.32	98%	129.4°
2028-12-01 Fri	30	—	unknown	04:35–05:55 (good, 1.33 h)	50.2° 08:05	11.34	100%	116.9°
2028-12-02 Sat	26	—	unknown	04:40–05:55 (good, 1.25 h)	50.2° 08:00	11.36	99%	104.1°
2028-12-03 Sun	22	—	unknown	05:30–05:55 (good, 0.42 h)	50.2° 07:55	11.37	96%	91.1°
2028-12-04 Mon	18	—	unknown	03:50–05:55 (marginal, 2.08 h)	50.2° 07:55	11.39	91%	77.9°
2028-12-05 Tue	15	—	unknown	03:55–05:55 (marginal, 2.0 h)	50.2° 07:50	11.4	84%	64.5°
2028-12-06 Wed	14	—	unknown	03:50–05:55 (marginal, 2.08 h)	50.2° 07:45	11.41	75%	51.0°
2028-12-07 Thu	16	—	unknown	03:45–06:00 (marginal, 2.25 h)	50.2° 07:40	11.43	65%	37.5°
2028-12-08 Fri	21	—	unknown	03:30–06:00 (marginal, 2.5 h)	50.2° 07:40	11.44	54%	24.4°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-11-19&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.