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

2046-02-20astronomy score per night — click a bar for that night2046-03-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-02-20 Tue	24	—	unknown	02:15–05:40 (marginal, 3.42 h)	50.1° 02:50	10.03	100%	34.7°
2046-02-21 Wed	21	—	unknown	02:40–05:35 (marginal, 2.92 h)	50.1° 02:45	9.99	98%	20.3°
2046-02-22 Thu	25	—	unknown	23:00–05:35 (marginal, 6.58 h)	50.1° 02:40	9.95	94%	9.5°
2046-02-23 Fri	34	—	unknown	22:35–05:35 (marginal, 7.0 h)	50.1° 02:35	9.91	87%	14.7°
2046-02-24 Sat	62	—	unknown	22:45–22:55 (good, 0.17 h)	50.1° 02:30	9.86	78%	27.6°
2046-02-25 Sun	86	—	unknown	22:40–03:40 (good, 5.0 h)	50.1° 02:30	9.82	68%	41.1°
2046-02-26 Mon	92	—	unknown	22:40–05:30 (good, 6.83 h)	50.1° 02:25	9.77	58%	54.3°
2046-02-27 Tue	93	—	unknown	22:35–05:30 (good, 6.92 h)	50.1° 02:20	9.73	47%	67.3°
2046-02-28 Wed	93	—	unknown	22:30–05:25 (good, 6.92 h)	50.1° 02:15	9.69	37%	79.9°
2046-03-01 Thu	93	—	unknown	22:25–05:25 (good, 7.0 h)	50.1° 02:15	9.64	28%	92.2°
2046-03-02 Fri	93	—	unknown	22:20–05:25 (good, 7.08 h)	50.1° 02:10	9.59	20%	104.3°
2046-03-03 Sat	93	—	unknown	22:20–05:20 (good, 7.0 h)	50.1° 02:05	9.55	12%	116.2°
2046-03-04 Sun	93	—	unknown	22:15–05:20 (good, 7.08 h)	50.1° 02:00	9.5	7%	128.0°
2046-03-05 Mon	93	—	unknown	22:10–05:20 (good, 7.17 h)	50.1° 01:55	9.45	3%	139.6°
2046-03-06 Tue	93	—	unknown	22:05–05:15 (good, 7.17 h)	50.1° 01:55	9.41	1%	150.9°
2046-03-07 Wed	93	—	unknown	22:00–05:15 (good, 7.25 h)	50.1° 01:50	9.36	0%	161.8°
2046-03-08 Thu	93	—	unknown	22:00–05:15 (good, 7.25 h)	50.1° 01:45	9.31	1%	170.2°
2046-03-09 Fri	93	—	unknown	21:55–05:10 (good, 7.25 h)	50.1° 01:40	9.26	4%	168.2°
2046-03-10 Sat	93	—	unknown	21:50–05:10 (good, 7.33 h)	50.1° 01:35	9.22	9%	158.4°
2046-03-11 Sun	93	—	unknown	21:50–05:10 (good, 7.33 h)	50.1° 01:35	9.17	15%	147.0°
2046-03-12 Mon	93	—	unknown	21:45–05:05 (good, 7.33 h)	50.1° 01:30	9.12	23%	135.1°
2046-03-13 Tue	93	—	unknown	21:40–05:05 (good, 7.42 h)	50.1° 01:25	9.07	32%	122.9°
2046-03-14 Wed	93	—	unknown	21:40–05:05 (good, 7.42 h)	50.1° 01:20	9.02	42%	110.3°
2046-03-15 Thu	92	—	unknown	21:45–05:00 (good, 7.25 h)	50.1° 01:20	8.97	52%	97.4°
2046-03-16 Fri	88	—	unknown	21:55–05:00 (good, 7.08 h)	50.1° 01:15	8.92	63%	84.0°
2046-03-17 Sat	83	—	unknown	23:30–04:55 (good, 5.42 h)	50.1° 01:10	8.87	74%	70.2°
2046-03-18 Sun	74	—	unknown	04:35–04:55 (good, 0.33 h)	50.1° 01:05	8.82	83%	56.0°
2046-03-19 Mon	42	—	unknown	21:40–04:55 (marginal, 7.25 h)	50.1° 01:00	8.77	91%	41.5°
2046-03-20 Tue	27	—	unknown	00:35–04:50 (marginal, 4.25 h)	50.1° 01:00	8.71	97%	27.0°
2046-03-21 Wed	24	—	unknown	00:55–04:50 (marginal, 3.92 h)	50.1° 00:55	8.66	100%	13.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-02-20&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.