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: 01-30 (93), 01-31 (93), 02-01 (93), 02-02 (93), 02-03 (93) — by astronomy; check the weather when the night is within four days.

2046-01-23astronomy score per night — click a bar for that night2046-02-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-01-23 Tue	23	—	unknown	02:05–06:05 (marginal, 4.0 h)	50.1° 04:40	11.02	97%	42.5°
2046-01-24 Wed	19	—	unknown	02:45–06:05 (marginal, 3.33 h)	50.1° 04:35	11.0	92%	28.1°
2046-01-25 Thu	25	—	unknown	00:45–06:05 (marginal, 5.33 h)	50.1° 04:30	10.97	84%	14.8°
2046-01-26 Fri	35	—	unknown	00:25–06:05 (marginal, 5.67 h)	50.1° 04:25	10.94	74%	9.3°
2046-01-27 Sat	49	—	unknown	00:10–06:05 (marginal, 5.92 h)	50.1° 04:20	10.91	64%	19.1°
2046-01-28 Sun	81	—	unknown	00:30–06:05 (good, 5.58 h)	50.1° 04:20	10.88	53%	31.9°
2046-01-29 Mon	89	—	unknown	00:30–06:00 (good, 5.5 h)	50.1° 04:15	10.85	42%	44.9°
2046-01-30 Tue	93	—	unknown	00:25–06:00 (good, 5.58 h)	50.1° 04:10	10.82	32%	57.8°
2046-01-31 Wed	93	—	unknown	00:20–06:00 (good, 5.67 h)	50.1° 04:05	10.79	22%	70.4°
2046-02-01 Thu	93	—	unknown	00:15–06:00 (good, 5.75 h)	50.1° 04:05	10.75	15%	82.9°
2046-02-02 Fri	93	—	unknown	00:10–06:00 (good, 5.83 h)	50.1° 04:00	10.72	8%	95.1°
2046-02-03 Sat	93	—	unknown	00:10–06:00 (good, 5.83 h)	50.1° 03:55	10.69	4%	107.2°
2046-02-04 Sun	93	—	unknown	00:05–05:55 (good, 5.83 h)	50.1° 03:50	10.65	1%	119.2°
2046-02-05 Mon	93	—	unknown	00:00–05:55 (good, 5.92 h)	50.1° 03:45	10.62	0%	130.9°
2046-02-06 Tue	93	—	unknown	23:55–05:55 (good, 6.0 h)	50.1° 03:45	10.58	1%	142.5°
2046-02-07 Wed	93	—	unknown	23:55–05:55 (good, 6.0 h)	50.1° 03:40	10.54	4%	153.8°
2046-02-08 Thu	93	—	unknown	23:50–05:55 (good, 6.08 h)	50.1° 03:35	10.51	8%	164.3°
2046-02-09 Fri	93	—	unknown	23:45–05:50 (good, 6.08 h)	50.1° 03:30	10.47	14%	171.0°
2046-02-10 Sat	93	—	unknown	23:40–05:50 (good, 6.17 h)	50.1° 03:25	10.43	21%	166.0°
2046-02-11 Sun	93	—	unknown	23:35–05:50 (good, 6.25 h)	50.1° 03:25	10.4	29%	155.6°
2046-02-12 Mon	93	—	unknown	23:35–05:50 (good, 6.25 h)	50.1° 03:20	10.36	38%	144.0°
2046-02-13 Tue	93	—	unknown	23:35–05:45 (good, 6.17 h)	50.1° 03:15	10.32	48%	131.9°
2046-02-14 Wed	93	—	unknown	23:30–05:45 (good, 6.25 h)	50.1° 03:10	10.28	58%	119.3°
2046-02-15 Thu	93	—	unknown	23:35–05:45 (good, 6.17 h)	50.1° 03:10	10.24	68%	106.2°
2046-02-16 Fri	90	—	unknown	23:45–05:45 (good, 6.0 h)	50.1° 03:05	10.2	78%	92.7°
2046-02-17 Sat	86	—	unknown	01:25–05:40 (good, 4.25 h)	50.1° 03:00	10.16	87%	78.7°
2046-02-18 Sun	56	—	unknown	04:35–05:40 (good, 1.08 h)	50.1° 02:55	10.12	94%	64.2°
2046-02-19 Mon	38	—	unknown	23:30–05:40 (marginal, 6.17 h)	50.1° 02:50	10.08	98%	49.5°
2046-02-20 Tue	24	—	unknown	02:15–05:40 (marginal, 3.42 h)	50.1° 02:50	10.03	100%	34.7°
2046-02-21 Wed	21	—	unknown	02:40–05:35 (marginal, 2.92 h)	50.1° 02:45	9.99	98%	20.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-01-23&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.