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: 03-13 (93), 03-14 (93), 03-15 (93), 03-16 (93), 03-17 (93) — by astronomy; check the weather when the night is within four days.

2042-03-12astronomy score per night — click a bar for that night2042-04-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-03-12 Wed	91	—	unknown	21:45–03:45 (good, 6.0 h)	50.1° 01:30	9.12	70%	53.5°
2042-03-13 Thu	93	—	unknown	21:40–04:50 (good, 7.17 h)	50.1° 01:25	9.07	60%	65.9°
2042-03-14 Fri	93	—	unknown	21:35–05:00 (good, 7.42 h)	50.1° 01:20	9.02	50%	78.6°
2042-03-15 Sat	93	—	unknown	21:30–05:00 (good, 7.5 h)	50.1° 01:20	8.97	40%	91.6°
2042-03-16 Sun	93	—	unknown	21:25–05:00 (good, 7.58 h)	50.1° 01:15	8.92	30%	105.1°
2042-03-17 Mon	93	—	unknown	21:25–04:55 (good, 7.5 h)	50.1° 01:10	8.87	20%	119.1°
2042-03-18 Tue	93	—	unknown	21:20–04:55 (good, 7.58 h)	50.1° 01:05	8.82	11%	133.5°
2042-03-19 Wed	93	—	unknown	21:15–04:55 (good, 7.67 h)	50.1° 01:00	8.77	5%	148.3°
2042-03-20 Thu	93	—	unknown	21:10–04:50 (good, 7.67 h)	50.1° 01:00	8.72	1%	163.3°
2042-03-21 Fri	93	—	unknown	21:05–04:45 (good, 7.67 h)	50.1° 00:55	8.66	0%	176.9°
2042-03-22 Sat	93	—	unknown	21:05–04:40 (good, 7.58 h)	50.1° 00:50	8.61	2%	165.6°
2042-03-23 Sun	93	—	unknown	21:00–04:40 (good, 7.67 h)	50.1° 00:45	8.56	7%	150.8°
2042-03-24 Mon	93	—	unknown	20:55–04:35 (good, 7.67 h)	50.1° 00:40	8.51	15%	136.1°
2042-03-25 Tue	93	—	unknown	20:55–04:30 (good, 7.58 h)	50.1° 00:40	8.45	24%	121.9°
2042-03-26 Wed	93	—	unknown	20:55–04:25 (good, 7.5 h)	50.1° 00:35	8.4	34%	108.2°
2042-03-27 Thu	91	—	unknown	20:55–04:20 (good, 7.42 h)	50.1° 00:30	8.35	44%	94.9°
2042-03-28 Fri	86	—	unknown	21:05–04:20 (good, 7.25 h)	50.1° 00:25	8.29	55%	82.0°
2042-03-29 Sat	81	—	unknown	22:10–05:15 (good, 6.08 h)	50.1° 00:20	8.24	64%	69.4°
2042-03-30 Sun	62	—	unknown	01:35–04:45 (good, 3.17 h)	50.1° 01:20	8.18	74%	57.2°
2042-03-31 Mon	50	—	unknown	21:35–05:30 (marginal, 7.92 h)	50.1° 01:15	8.13	82%	45.1°
2042-04-01 Tue	33	—	unknown	22:45–05:20 (marginal, 6.58 h)	50.1° 01:10	8.08	88%	33.2°
2042-04-02 Wed	25	—	unknown	00:50–05:05 (marginal, 4.25 h)	50.1° 01:05	8.02	94%	21.4°
2042-04-03 Thu	22	—	unknown	01:50–04:50 (marginal, 3.0 h)	50.1° 01:05	7.97	98%	9.8°
2042-04-04 Fri	21	—	unknown	02:05–04:40 (marginal, 2.58 h)	50.1° 01:00	7.91	100%	3.8°
2042-04-05 Sat	25	—	unknown	21:30–04:30 (marginal, 7.0 h)	50.1° 00:55	7.85	100%	14.6°
2042-04-06 Sun	33	—	unknown	21:30–04:25 (marginal, 6.92 h)	50.1° 00:50	7.8	98%	26.4°
2042-04-07 Mon	79	—	unknown	21:35–22:05 (good, 0.5 h)	50.1° 00:45	7.74	95%	38.4°
2042-04-08 Tue	90	—	unknown	21:35–00:35 (good, 3.0 h)	50.1° 00:45	7.69	90%	50.5°
2042-04-09 Wed	93	—	unknown	21:35–02:55 (good, 5.33 h)	50.1° 00:40	7.63	83%	62.8°
2042-04-10 Thu	93	—	unknown	21:35–04:00 (good, 6.42 h)	50.1° 00:35	7.57	75%	75.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-03-12&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.