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: 03-29 (93), 03-30 (93), 03-31 (93), 04-01 (93), 04-02 (93) — by astronomy; check the weather when the night is within four days.

2035-03-19astronomy score per night — click a bar for that night2035-04-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-03-19 Mon	81	—	unknown	02:10–04:55 (good, 2.75 h)	50.2° 01:05	8.78	82%	57.0°
2035-03-20 Tue	45	—	unknown	21:30–04:55 (marginal, 7.42 h)	50.2° 01:00	8.73	90%	43.3°
2035-03-21 Wed	28	—	unknown	00:30–04:50 (marginal, 4.33 h)	50.2° 00:55	8.68	96%	29.8°
2035-03-22 Thu	23	—	unknown	01:30–04:45 (marginal, 3.25 h)	50.2° 00:50	8.63	99%	16.5°
2035-03-23 Fri	21	—	unknown	02:10–04:30 (marginal, 2.33 h)	50.2° 00:45	8.58	100%	4.2°
2035-03-24 Sat	24	—	unknown	21:00–05:15 (marginal, 7.25 h)	50.2° 00:45	8.52	99%	10.1°
2035-03-25 Sun	33	—	unknown	21:40–05:15 (marginal, 7.58 h)	50.2° 01:40	8.47	96%	22.5°
2035-03-26 Mon	78	—	unknown	21:50–22:25 (good, 0.58 h)	50.2° 01:35	8.42	91%	34.8°
2035-03-27 Tue	86	—	unknown	21:45–00:35 (good, 2.83 h)	50.2° 01:30	8.36	85%	47.0°
2035-03-28 Wed	91	—	unknown	21:40–03:15 (good, 5.58 h)	50.2° 01:25	8.31	77%	58.9°
2035-03-29 Thu	93	—	unknown	21:35–04:40 (good, 7.08 h)	50.2° 01:25	8.26	69%	70.8°
2035-03-30 Fri	93	—	unknown	21:35–04:55 (good, 7.33 h)	50.2° 01:20	8.2	60%	82.6°
2035-03-31 Sat	93	—	unknown	21:30–04:55 (good, 7.42 h)	50.2° 01:15	8.15	50%	94.4°
2035-04-01 Sun	93	—	unknown	21:25–04:55 (good, 7.5 h)	50.2° 01:10	8.09	41%	106.4°
2035-04-02 Mon	93	—	unknown	21:25–04:55 (good, 7.5 h)	50.2° 01:10	8.04	31%	118.6°
2035-04-03 Tue	93	—	unknown	21:25–04:55 (good, 7.5 h)	50.2° 01:05	7.98	22%	131.1°
2035-04-04 Wed	93	—	unknown	21:30–04:50 (good, 7.33 h)	50.2° 01:00	7.93	14%	143.9°
2035-04-05 Thu	93	—	unknown	21:30–04:50 (good, 7.33 h)	50.2° 00:55	7.87	8%	157.1°
2035-04-06 Fri	93	—	unknown	21:30–04:45 (good, 7.25 h)	50.2° 00:50	7.82	3%	170.4°
2035-04-07 Sat	93	—	unknown	21:35–04:40 (good, 7.08 h)	50.2° 00:50	7.76	0%	174.4°
2035-04-08 Sun	93	—	unknown	21:35–04:35 (good, 7.0 h)	50.2° 00:45	7.7	0%	160.6°
2035-04-09 Mon	93	—	unknown	21:35–04:30 (good, 6.92 h)	50.2° 00:40	7.65	3%	146.1°
2035-04-10 Tue	93	—	unknown	21:35–04:30 (good, 6.92 h)	50.2° 00:35	7.59	8%	131.5°
2035-04-11 Wed	93	—	unknown	21:40–04:25 (good, 6.75 h)	50.2° 00:30	7.53	16%	116.9°
2035-04-12 Thu	93	—	unknown	21:40–04:20 (good, 6.67 h)	50.2° 00:30	7.48	26%	102.4°
2035-04-13 Fri	91	—	unknown	21:40–04:15 (good, 6.58 h)	50.2° 00:25	7.42	37%	88.1°
2035-04-14 Sat	87	—	unknown	21:45–04:10 (good, 6.42 h)	50.2° 00:20	7.36	48%	74.0°
2035-04-15 Sun	82	—	unknown	22:10–04:10 (good, 6.0 h)	50.2° 00:15	7.3	59%	60.1°
2035-04-16 Mon	65	—	unknown	01:35–03:25 (good, 1.83 h)	50.2° 00:15	7.25	70%	46.5°
2035-04-17 Tue	39	—	unknown	21:45–04:25 (marginal, 6.67 h)	50.2° 00:10	7.19	79%	33.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-03-19&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.