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: 02-26 (93), 02-27 (93), 02-28 (93), 03-01 (93), 03-02 (93) — by astronomy; check the weather when the night is within four days.

2038-02-22astronomy score per night — click a bar for that night2038-03-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-02-22 Mon	33	—	unknown	22:40–05:35 (marginal, 6.92 h)	50.1° 02:40	9.95	85%	13.9°
2038-02-23 Tue	58	—	unknown	22:50–22:55 (good, 0.08 h)	50.1° 02:35	9.91	76%	28.6°
2038-02-24 Wed	85	—	unknown	22:45–03:45 (good, 5.0 h)	50.1° 02:30	9.87	65%	42.9°
2038-02-25 Thu	91	—	unknown	22:40–05:30 (good, 6.83 h)	50.1° 02:30	9.82	54%	56.9°
2038-02-26 Fri	93	—	unknown	22:40–05:30 (good, 6.83 h)	50.1° 02:25	9.78	43%	70.6°
2038-02-27 Sat	93	—	unknown	22:35–05:30 (good, 6.92 h)	50.1° 02:20	9.73	32%	83.9°
2038-02-28 Sun	93	—	unknown	22:30–05:25 (good, 6.92 h)	50.1° 02:15	9.69	23%	97.0°
2038-03-01 Mon	93	—	unknown	22:25–05:25 (good, 7.0 h)	50.1° 02:15	9.64	15%	109.8°
2038-03-02 Tue	93	—	unknown	22:20–05:25 (good, 7.08 h)	50.1° 02:10	9.6	9%	122.5°
2038-03-03 Wed	93	—	unknown	22:20–05:20 (good, 7.0 h)	50.1° 02:05	9.55	4%	134.9°
2038-03-04 Thu	93	—	unknown	22:15–05:20 (good, 7.08 h)	50.1° 02:00	9.5	1%	147.2°
2038-03-05 Fri	93	—	unknown	22:10–05:20 (good, 7.17 h)	50.1° 01:55	9.46	0%	159.3°
2038-03-06 Sat	93	—	unknown	22:05–05:15 (good, 7.17 h)	50.1° 01:55	9.41	1%	171.3°
2038-03-07 Sun	93	—	unknown	22:00–05:15 (good, 7.25 h)	50.1° 01:50	9.36	4%	176.8°
2038-03-08 Mon	93	—	unknown	22:00–05:15 (good, 7.25 h)	50.1° 01:45	9.32	8%	165.0°
2038-03-09 Tue	93	—	unknown	21:55–05:10 (good, 7.25 h)	50.1° 01:40	9.27	14%	153.2°
2038-03-10 Wed	93	—	unknown	21:50–05:10 (good, 7.33 h)	50.1° 01:35	9.22	21%	141.3°
2038-03-11 Thu	93	—	unknown	21:50–05:10 (good, 7.33 h)	50.1° 01:35	9.17	29%	129.4°
2038-03-12 Fri	93	—	unknown	21:45–05:05 (good, 7.33 h)	50.1° 01:30	9.12	38%	117.4°
2038-03-13 Sat	93	—	unknown	21:50–05:05 (good, 7.25 h)	50.1° 01:25	9.07	48%	105.1°
2038-03-14 Sun	92	—	unknown	21:55–05:05 (good, 7.17 h)	50.1° 01:20	9.02	58%	92.4°
2038-03-15 Mon	87	—	unknown	22:25–05:00 (good, 6.58 h)	50.1° 01:15	8.97	68%	79.4°
2038-03-16 Tue	82	—	unknown	00:25–05:00 (good, 4.58 h)	50.1° 01:15	8.92	78%	65.9°
2038-03-17 Wed	55	—	unknown	21:30–05:00 (marginal, 7.5 h)	50.1° 01:10	8.87	86%	52.0°
2038-03-18 Thu	33	—	unknown	23:05–04:55 (marginal, 5.83 h)	50.1° 01:05	8.82	93%	37.5°
2038-03-19 Fri	22	—	unknown	01:55–04:55 (marginal, 3.0 h)	50.1° 01:00	8.77	98%	22.7°
2038-03-20 Sat	19	—	unknown	02:55–04:35 (marginal, 1.67 h)	50.1° 01:00	8.72	100%	7.6°
2038-03-21 Sun	22	—	unknown	21:15–00:45 (marginal, 3.5 h)	50.1° 00:55	8.67	99%	7.6°
2038-03-22 Mon	33	—	unknown	20:50–04:25 (marginal, 7.58 h)	50.1° 00:50	8.61	95%	22.8°
2038-03-23 Tue	82	—	unknown	21:00–21:50 (good, 0.83 h)	50.1° 00:45	8.56	88%	37.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-02-22&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.