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: 02-17 (93), 02-18 (93), 02-19 (93), 02-20 (93), 02-21 (93) — by astronomy; check the weather when the night is within four days.

2048-02-17astronomy score per night — click a bar for that night2048-03-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2048-02-17 Mon	93	—	unknown	23:15–05:45 (good, 6.5 h)	50.1° 03:00	10.18	16%	165.8°
2048-02-18 Tue	93	—	unknown	23:10–05:40 (good, 6.5 h)	50.1° 03:00	10.14	24%	155.4°
2048-02-19 Wed	93	—	unknown	23:10–05:40 (good, 6.5 h)	50.1° 02:55	10.1	33%	144.1°
2048-02-20 Thu	93	—	unknown	23:05–05:40 (good, 6.58 h)	50.1° 02:50	10.05	42%	132.6°
2048-02-21 Fri	93	—	unknown	23:05–05:35 (good, 6.5 h)	50.1° 02:45	10.01	51%	121.1°
2048-02-22 Sat	93	—	unknown	23:05–05:35 (good, 6.5 h)	50.1° 02:40	9.97	61%	109.4°
2048-02-23 Sun	92	—	unknown	23:10–05:35 (good, 6.42 h)	50.1° 02:40	9.93	70%	97.7°
2048-02-24 Mon	89	—	unknown	23:45–05:35 (good, 5.83 h)	50.1° 02:35	9.88	78%	85.7°
2048-02-25 Tue	86	—	unknown	01:20–05:30 (good, 4.17 h)	50.1° 02:30	9.84	86%	73.5°
2048-02-26 Wed	81	—	unknown	04:10–05:30 (good, 1.33 h)	50.1° 02:25	9.8	92%	61.1°
2048-02-27 Thu	42	—	unknown	23:00–05:30 (marginal, 6.5 h)	50.1° 02:25	9.75	97%	48.3°
2048-02-28 Fri	28	—	unknown	01:10–05:25 (marginal, 4.25 h)	50.1° 02:20	9.71	99%	35.4°
2048-02-29 Sat	24	—	unknown	02:10–05:25 (marginal, 3.25 h)	50.1° 02:15	9.66	100%	22.7°
2048-03-01 Sun	25	—	unknown	22:45–05:25 (marginal, 6.67 h)	50.1° 02:10	9.62	98%	11.8°
2048-03-02 Mon	29	—	unknown	22:15–05:20 (marginal, 7.08 h)	50.1° 02:05	9.57	93%	12.3°
2048-03-03 Tue	44	—	unknown	21:50–05:20 (marginal, 7.5 h)	50.1° 02:05	9.52	86%	23.7°
2048-03-04 Wed	83	—	unknown	22:10–23:15 (good, 1.08 h)	50.1° 02:00	9.48	77%	37.0°
2048-03-05 Thu	90	—	unknown	22:10–04:15 (good, 6.08 h)	50.1° 01:55	9.43	67%	50.9°
2048-03-06 Fri	93	—	unknown	22:05–05:15 (good, 7.17 h)	50.1° 01:50	9.38	56%	64.8°
2048-03-07 Sat	93	—	unknown	22:00–05:15 (good, 7.25 h)	50.1° 01:45	9.34	44%	78.6°
2048-03-08 Sun	93	—	unknown	21:55–05:10 (good, 7.25 h)	50.1° 01:45	9.29	34%	92.4°
2048-03-09 Mon	93	—	unknown	21:55–05:10 (good, 7.25 h)	50.1° 01:40	9.24	23%	106.1°
2048-03-10 Tue	93	—	unknown	21:50–05:10 (good, 7.33 h)	50.1° 01:35	9.19	15%	119.6°
2048-03-11 Wed	93	—	unknown	21:45–05:05 (good, 7.33 h)	50.1° 01:30	9.14	8%	132.8°
2048-03-12 Thu	93	—	unknown	21:40–05:05 (good, 7.42 h)	50.1° 01:25	9.09	3%	145.7°
2048-03-13 Fri	93	—	unknown	21:35–05:05 (good, 7.5 h)	50.1° 01:25	9.04	1%	158.0°
2048-03-14 Sat	93	—	unknown	21:35–05:00 (good, 7.42 h)	50.1° 01:20	8.99	0%	168.1°
2048-03-15 Sun	93	—	unknown	21:30–05:00 (good, 7.5 h)	50.1° 01:15	8.94	2%	168.7°
2048-03-16 Mon	93	—	unknown	21:25–05:00 (good, 7.58 h)	50.1° 01:10	8.89	6%	159.4°
2048-03-17 Tue	93	—	unknown	21:20–04:55 (good, 7.58 h)	50.1° 01:10	8.84	11%	148.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2048-02-17&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.