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: 06-03 (49), 06-04 (47), 06-05 (45), 06-06 (43), 06-07 (41) — by astronomy; check the weather when the night is within four days.

2040-06-03astronomy score per night — click a bar for that night2040-07-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-06-03 Sun	49	—	unknown	23:00–00:55 (good, 1.92 h)	50.1° 21:00	4.71	31%	179.0°
2040-06-04 Mon	47	—	unknown	23:00–00:50 (good, 1.83 h)	50.1° 20:55	4.67	21%	166.0°
2040-06-05 Tue	45	—	unknown	23:05–00:45 (good, 1.67 h)	50.1° 20:55	4.64	14%	153.2°
2040-06-06 Wed	43	—	unknown	23:05–00:40 (good, 1.58 h)	50.1° 20:50	4.62	8%	140.7°
2040-06-07 Thu	41	—	unknown	23:05–00:35 (good, 1.5 h)	50.1° 20:45	4.59	3%	128.3°
2040-06-08 Fri	40	—	unknown	23:05–00:35 (good, 1.5 h)	50.1° 20:40	4.57	1%	116.1°
2040-06-09 Sat	38	—	unknown	23:05–00:30 (good, 1.42 h)	50.1° 20:35	4.54	0%	104.0°
2040-06-10 Sun	36	—	unknown	23:10–00:25 (good, 1.25 h)	50.1° 20:35	4.52	1%	92.1°
2040-06-11 Mon	35	—	unknown	23:10–00:20 (good, 1.17 h)	50.1° 20:30	4.5	4%	80.2°
2040-06-12 Tue	32	—	unknown	23:10–00:15 (good, 1.08 h)	50.1° 20:25	4.49	9%	68.4°
2040-06-13 Wed	29	—	unknown	23:10–00:15 (good, 1.08 h)	50.1° 20:20	4.47	15%	56.6°
2040-06-14 Thu	25	—	unknown	23:10–00:00 (good, 0.83 h)	50.1° 20:20	4.46	22%	44.7°
2040-06-15 Fri	20	—	unknown	23:10–23:50 (good, 0.67 h)	50.1° 20:15	4.45	31%	32.7°
2040-06-16 Sat	16	—	unknown	23:10–23:35 (good, 0.42 h)	50.1° 20:10	4.44	40%	20.5°
2040-06-17 Sun	13	—	unknown	23:10–00:25 (marginal, 1.25 h)	50.1° 20:05	4.43	50%	8.1°
2040-06-18 Mon	10	—	unknown	23:10–00:15 (marginal, 1.08 h)	50.1° 20:00	4.43	61%	4.7°
2040-06-19 Tue	8	—	unknown	23:10–00:05 (marginal, 0.92 h)	50.1° 20:00	4.42	71%	17.8°
2040-06-20 Wed	6	—	unknown	23:15–23:50 (marginal, 0.58 h)	50.1° 19:55	4.42	80%	31.5°
2040-06-21 Thu	6	—	unknown	23:15–23:50 (marginal, 0.58 h)	50.1° 19:50	4.42	88%	45.6°
2040-06-22 Fri	6	—	unknown	23:15–23:50 (marginal, 0.58 h)	50.1° 19:45	4.43	95%	60.1°
2040-06-23 Sat	7	—	unknown	23:15–23:55 (marginal, 0.67 h)	50.1° 19:40	4.43	99%	75.0°
2040-06-24 Sun	9	—	unknown	23:15–00:00 (marginal, 0.75 h)	50.1° 19:40	4.44	100%	90.2°
2040-06-25 Mon	10	—	unknown	23:15–23:55 (marginal, 0.67 h)	50.1° 19:35	4.45	98%	105.4°
2040-06-26 Tue	11	—	unknown	22:20–23:50 (marginal, 1.5 h)	50.1° 19:30	4.46	93%	120.5°
2040-06-27 Wed	11	—	unknown	23:15–23:20 (good, 0.08 h)	50.1° 19:25	4.48	86%	135.4°
2040-06-28 Thu	11	—	unknown	23:10–23:15 (good, 0.08 h)	50.1° 19:25	4.49	76%	149.9°
2040-06-29 Fri	10	—	unknown	22:20–23:40 (marginal, 1.33 h)	50.1° 19:20	4.51	66%	164.0°
2040-06-30 Sat	8	—	unknown	22:20–23:05 (marginal, 0.75 h)	50.1° 19:15	4.53	55%	177.7°
2040-07-01 Sun	7	—	unknown	22:20–23:05 (marginal, 0.75 h)	50.1° 19:10	4.55	45%	169.0°
2040-07-02 Mon	6	—	unknown	22:20–23:00 (marginal, 0.67 h)	50.1° 19:05	4.57	34%	156.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-06-03&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.