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: 06-12 (23), 06-13 (18), 06-14 (15), 06-25 (14), 06-23 (13) — by astronomy; check the weather when the night is within four days.

2043-06-12astronomy score per night — click a bar for that night2043-07-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-06-12 Fri	23	—	unknown	23:10–00:05 (good, 0.92 h)	50.1° 20:30	4.5	35%	31.5°
2043-06-13 Sat	18	—	unknown	23:10–23:50 (good, 0.67 h)	50.1° 20:25	4.48	45%	19.0°
2043-06-14 Sun	15	—	unknown	23:10–00:40 (marginal, 1.5 h)	50.1° 20:20	4.47	55%	7.7°
2043-06-15 Mon	11	—	unknown	23:10–00:30 (marginal, 1.33 h)	50.1° 20:15	4.45	64%	7.8°
2043-06-16 Tue	9	—	unknown	23:10–00:20 (marginal, 1.17 h)	50.1° 20:15	4.44	73%	18.7°
2043-06-17 Wed	7	—	unknown	23:10–00:10 (marginal, 1.0 h)	50.1° 20:10	4.43	81%	30.3°
2043-06-18 Thu	8	—	unknown	23:10–00:05 (marginal, 0.92 h)	50.1° 20:05	4.43	88%	42.0°
2043-06-19 Fri	8	—	unknown	23:10–00:05 (marginal, 0.92 h)	50.1° 20:00	4.42	93%	53.8°
2043-06-20 Sat	9	—	unknown	23:15–00:05 (marginal, 0.83 h)	50.1° 19:55	4.42	97%	65.6°
2043-06-21 Sun	11	—	unknown	23:15–00:10 (marginal, 0.92 h)	50.1° 19:55	4.42	99%	77.6°
2043-06-22 Mon	12	—	unknown	22:20–00:10 (marginal, 1.83 h)	50.1° 19:50	4.42	100%	89.7°
2043-06-23 Tue	13	—	unknown	23:15–23:20 (good, 0.08 h)	50.1° 19:45	4.43	98%	102.0°
2043-06-24 Wed	13	—	unknown	23:15–23:25 (good, 0.17 h)	50.1° 19:40	4.43	94%	114.4°
2043-06-25 Thu	14	—	unknown	23:15–23:30 (good, 0.25 h)	50.1° 19:40	4.44	89%	127.0°
2043-06-26 Fri	13	—	unknown	23:15–23:25 (good, 0.17 h)	50.1° 19:35	4.45	82%	139.8°
2043-06-27 Sat	12	—	unknown	23:15–23:20 (good, 0.08 h)	50.1° 19:30	4.47	73%	152.8°
2043-06-28 Sun	11	—	unknown	22:20–23:45 (marginal, 1.42 h)	50.1° 19:25	4.48	63%	165.7°
2043-06-29 Mon	10	—	unknown	23:10–23:15 (good, 0.08 h)	50.1° 19:20	4.5	52%	175.0°
2043-06-30 Tue	9	—	unknown	22:20–23:40 (marginal, 1.33 h)	50.1° 19:20	4.51	41%	165.0°
2043-07-01 Wed	8	—	unknown	22:20–23:05 (marginal, 0.75 h)	50.1° 19:15	4.53	30%	151.2°
2043-07-02 Thu	7	—	unknown	22:20–23:00 (marginal, 0.67 h)	50.1° 19:10	4.56	20%	136.8°
2043-07-03 Fri	6	—	unknown	22:20–23:00 (marginal, 0.67 h)	50.1° 19:05	4.58	11%	122.2°
2043-07-04 Sat	5	—	unknown	22:20–22:55 (marginal, 0.58 h)	50.1° 19:00	4.61	5%	107.5°
2043-07-05 Sun	5	—	unknown	22:20–22:50 (marginal, 0.5 h)	50.1° 19:00	4.63	1%	92.8°
2043-07-06 Mon	4	—	unknown	22:20–22:45 (marginal, 0.42 h)	50.1° 18:55	4.66	0%	78.2°
2043-07-07 Tue	3	—	unknown	22:15–22:40 (marginal, 0.42 h)	50.1° 18:50	4.69	2%	63.9°
2043-07-08 Wed	3	—	unknown	22:15–22:35 (marginal, 0.33 h)	50.1° 18:45	4.73	6%	49.9°
2043-07-09 Thu	2	—	unknown	22:15–22:30 (marginal, 0.25 h)	50.1° 18:40	4.76	13%	36.4°
2043-07-10 Fri	2	—	unknown	22:15–22:20 (marginal, 0.08 h)	50.1° 18:40	4.8	21%	23.4°
2043-07-11 Sat	2	—	unknown	—	50.1° 18:35	4.83	30%	11.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-06-12&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.