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: 01-28 (93), 01-29 (93), 01-30 (93), 01-31 (93), 02-01 (93) — by astronomy; check the weather when the night is within four days.

2030-01-25astronomy score per night — click a bar for that night2030-02-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-01-25 Fri	54	—	unknown	02:20–04:30 (good, 2.17 h)	50.2° 04:30	10.97	59%	21.5°
2030-01-26 Sat	83	—	unknown	00:40–06:05 (good, 5.42 h)	50.2° 04:25	10.94	48%	34.5°
2030-01-27 Sun	90	—	unknown	00:35–06:05 (good, 5.5 h)	50.2° 04:20	10.91	37%	48.2°
2030-01-28 Mon	93	—	unknown	00:30–06:05 (good, 5.58 h)	50.2° 04:20	10.88	26%	62.1°
2030-01-29 Tue	93	—	unknown	00:25–06:00 (good, 5.58 h)	50.2° 04:15	10.85	17%	76.0°
2030-01-30 Wed	93	—	unknown	00:25–06:00 (good, 5.58 h)	50.2° 04:10	10.82	9%	90.0°
2030-01-31 Thu	93	—	unknown	00:20–06:00 (good, 5.67 h)	50.2° 04:05	10.79	4%	103.8°
2030-02-01 Fri	93	—	unknown	00:15–06:00 (good, 5.75 h)	50.2° 04:00	10.76	1%	117.5°
2030-02-02 Sat	93	—	unknown	00:10–06:00 (good, 5.83 h)	50.2° 04:00	10.72	0%	130.8°
2030-02-03 Sun	93	—	unknown	00:10–06:00 (good, 5.83 h)	50.2° 03:55	10.69	2%	143.8°
2030-02-04 Mon	93	—	unknown	00:05–05:55 (good, 5.83 h)	50.2° 03:50	10.65	6%	156.0°
2030-02-05 Tue	93	—	unknown	00:00–05:55 (good, 5.92 h)	50.2° 03:45	10.62	12%	166.5°
2030-02-06 Wed	93	—	unknown	23:55–05:55 (good, 6.0 h)	50.2° 03:45	10.58	19%	169.7°
2030-02-07 Thu	93	—	unknown	23:50–05:55 (good, 6.08 h)	50.2° 03:40	10.55	27%	161.9°
2030-02-08 Fri	93	—	unknown	23:50–05:55 (good, 6.08 h)	50.2° 03:35	10.51	36%	151.2°
2030-02-09 Sat	93	—	unknown	23:50–05:50 (good, 6.0 h)	50.2° 03:30	10.48	45%	139.9°
2030-02-10 Sun	93	—	unknown	23:45–05:50 (good, 6.08 h)	50.2° 03:25	10.44	54%	128.4°
2030-02-11 Mon	93	—	unknown	23:45–05:50 (good, 6.08 h)	50.2° 03:25	10.4	64%	116.7°
2030-02-12 Tue	93	—	unknown	23:50–05:50 (good, 6.0 h)	50.2° 03:20	10.36	72%	104.9°
2030-02-13 Wed	91	—	unknown	23:55–05:45 (good, 5.83 h)	50.2° 03:15	10.32	81%	92.8°
2030-02-14 Thu	88	—	unknown	01:20–05:45 (good, 4.42 h)	50.2° 03:10	10.28	88%	80.5°
2030-02-15 Fri	62	—	unknown	03:20–05:45 (good, 2.42 h)	50.2° 03:05	10.24	94%	67.8°
2030-02-16 Sat	45	—	unknown	23:30–05:45 (marginal, 6.25 h)	50.2° 03:05	10.2	98%	54.9°
2030-02-17 Sun	31	—	unknown	00:45–05:40 (marginal, 4.92 h)	50.2° 03:00	10.16	100%	41.7°
2030-02-18 Mon	22	—	unknown	02:45–05:40 (marginal, 2.92 h)	50.2° 02:55	10.12	99%	28.5°
2030-02-19 Tue	24	—	unknown	23:30–05:40 (marginal, 6.17 h)	50.2° 02:50	10.08	96%	16.0°
2030-02-20 Wed	28	—	unknown	23:00–05:40 (marginal, 6.67 h)	50.2° 02:50	10.04	91%	9.8°
2030-02-21 Thu	40	—	unknown	22:40–05:35 (marginal, 6.92 h)	50.2° 02:45	10.0	83%	18.4°
2030-02-22 Fri	81	—	unknown	22:55–23:30 (good, 0.58 h)	50.2° 02:40	9.95	74%	31.4°
2030-02-23 Sat	88	—	unknown	22:50–04:45 (good, 5.92 h)	50.2° 02:35	9.91	63%	45.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-01-25&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.