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: 04-02 (93), 04-03 (93), 04-04 (93), 04-05 (93), 04-06 (93) — by astronomy; check the weather when the night is within four days.

2038-04-02astronomy score per night — click a bar for that night2038-05-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-04-02 Fri	93	—	unknown	21:25–05:00 (good, 7.58 h)	50.1° 01:05	8.02	3%	168.2°
2038-04-03 Sat	93	—	unknown	21:25–04:55 (good, 7.5 h)	50.1° 01:05	7.97	1%	179.8°
2038-04-04 Sun	93	—	unknown	21:30–04:50 (good, 7.33 h)	50.1° 01:00	7.91	0%	168.1°
2038-04-05 Mon	93	—	unknown	21:30–04:45 (good, 7.25 h)	50.1° 00:55	7.86	2%	156.3°
2038-04-06 Tue	93	—	unknown	21:30–04:45 (good, 7.25 h)	50.1° 00:50	7.8	5%	144.5°
2038-04-07 Wed	93	—	unknown	21:35–04:40 (good, 7.08 h)	50.1° 00:45	7.74	9%	132.6°
2038-04-08 Thu	93	—	unknown	21:35–04:35 (good, 7.0 h)	50.1° 00:45	7.69	16%	120.6°
2038-04-09 Fri	93	—	unknown	21:35–04:30 (good, 6.92 h)	50.1° 00:40	7.63	23%	108.5°
2038-04-10 Sat	92	—	unknown	21:35–04:25 (good, 6.83 h)	50.1° 00:35	7.57	32%	96.1°
2038-04-11 Sun	89	—	unknown	21:40–04:25 (good, 6.75 h)	50.1° 00:30	7.52	42%	83.5°
2038-04-12 Mon	84	—	unknown	21:40–04:20 (good, 6.67 h)	50.1° 00:25	7.46	52%	70.6°
2038-04-13 Tue	72	—	unknown	23:05–04:15 (good, 5.17 h)	50.1° 00:25	7.4	62%	57.3°
2038-04-14 Wed	52	—	unknown	21:45–04:40 (marginal, 6.92 h)	50.1° 00:20	7.35	73%	43.5°
2038-04-15 Thu	32	—	unknown	21:45–04:25 (marginal, 6.67 h)	50.1° 00:15	7.29	82%	29.2°
2038-04-16 Fri	23	—	unknown	21:45–04:10 (marginal, 6.42 h)	50.1° 00:10	7.23	90%	14.5°
2038-04-17 Sat	18	—	unknown	00:35–03:50 (marginal, 3.25 h)	50.1° 00:10	7.17	96%	0.5°
2038-04-18 Sun	19	—	unknown	21:50–01:10 (marginal, 3.33 h)	50.1° 00:05	7.11	99%	15.7°
2038-04-19 Mon	26	—	unknown	21:50–03:25 (marginal, 5.58 h)	50.1° 00:00	7.06	100%	31.0°
2038-04-20 Tue	47	—	unknown	21:50–03:45 (marginal, 5.92 h)	50.1° 23:55	7.0	96%	46.1°
2038-04-21 Wed	92	—	unknown	21:55–01:00 (good, 3.08 h)	50.1° 23:50	6.94	91%	61.0°
2038-04-22 Thu	93	—	unknown	21:55–02:50 (good, 4.92 h)	50.1° 23:50	6.88	83%	75.5°
2038-04-23 Fri	93	—	unknown	21:55–03:15 (good, 5.33 h)	50.1° 23:45	6.82	74%	89.5°
2038-04-24 Sat	93	—	unknown	22:00–03:20 (good, 5.33 h)	50.1° 23:40	6.77	64%	103.0°
2038-04-25 Sun	93	—	unknown	22:00–03:25 (good, 5.42 h)	50.1° 23:35	6.71	53%	116.1°
2038-04-26 Mon	93	—	unknown	22:00–03:25 (good, 5.42 h)	50.1° 23:30	6.65	43%	128.7°
2038-04-27 Tue	93	—	unknown	22:05–03:20 (good, 5.25 h)	50.1° 23:30	6.59	34%	141.1°
2038-04-28 Wed	93	—	unknown	22:05–03:15 (good, 5.17 h)	50.1° 23:25	6.53	25%	153.2°
2038-04-29 Thu	93	—	unknown	22:05–03:10 (good, 5.08 h)	50.1° 23:20	6.47	17%	165.2°
2038-04-30 Fri	93	—	unknown	22:10–03:10 (good, 5.0 h)	50.1° 23:15	6.42	11%	177.1°
2038-05-01 Sat	93	—	unknown	22:10–03:05 (good, 4.92 h)	50.1° 23:15	6.36	6%	171.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-04-02&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.