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: 06-15 (29), 06-16 (29), 06-17 (27), 06-18 (26), 06-19 (24) — by astronomy; check the weather when the night is within four days.

2039-06-15astronomy score per night — click a bar for that night2039-07-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-06-15 Wed	29	—	unknown	23:10–00:10 (good, 1.0 h)	50.1° 20:15	4.45	28%	164.4°
2039-06-16 Thu	29	—	unknown	23:10–00:05 (good, 0.92 h)	50.1° 20:15	4.44	19%	152.4°
2039-06-17 Fri	27	—	unknown	23:10–00:00 (good, 0.83 h)	50.1° 20:10	4.44	12%	140.5°
2039-06-18 Sat	26	—	unknown	23:10–23:55 (good, 0.75 h)	50.1° 20:05	4.43	7%	128.7°
2039-06-19 Sun	24	—	unknown	23:10–23:55 (good, 0.75 h)	50.1° 20:00	4.42	3%	116.8°
2039-06-20 Mon	22	—	unknown	23:15–23:50 (good, 0.58 h)	50.1° 19:55	4.42	1%	105.0°
2039-06-21 Tue	21	—	unknown	23:15–23:45 (good, 0.5 h)	50.1° 19:55	4.42	0%	93.1°
2039-06-22 Wed	19	—	unknown	23:15–23:40 (good, 0.42 h)	50.1° 19:50	4.42	1%	81.1°
2039-06-23 Thu	17	—	unknown	23:15–23:35 (good, 0.33 h)	50.1° 19:45	4.43	4%	69.0°
2039-06-24 Fri	16	—	unknown	23:15–23:35 (good, 0.33 h)	50.1° 19:40	4.43	10%	56.7°
2039-06-25 Sat	13	—	unknown	23:15–23:25 (good, 0.17 h)	50.1° 19:35	4.44	16%	44.3°
2039-06-26 Sun	10	—	unknown	22:20–23:55 (marginal, 1.58 h)	50.1° 19:35	4.45	24%	31.6°
2039-06-27 Mon	8	—	unknown	23:15–23:50 (marginal, 0.58 h)	50.1° 19:30	4.47	34%	18.7°
2039-06-28 Tue	6	—	unknown	23:15–23:45 (marginal, 0.5 h)	50.1° 19:25	4.48	44%	5.5°
2039-06-29 Wed	5	—	unknown	23:10–23:35 (marginal, 0.42 h)	50.1° 19:20	4.5	55%	8.1°
2039-06-30 Thu	3	—	unknown	23:10–23:25 (marginal, 0.25 h)	50.1° 19:20	4.51	66%	22.0°
2039-07-01 Fri	3	—	unknown	23:10–23:15 (marginal, 0.08 h)	50.1° 19:15	4.53	77%	36.3°
2039-07-02 Sat	2	—	unknown	23:10–23:15 (marginal, 0.08 h)	50.1° 19:10	4.56	86%	50.9°
2039-07-03 Sun	2	—	unknown	23:10–23:15 (marginal, 0.08 h)	50.1° 19:05	4.58	93%	65.8°
2039-07-04 Mon	3	—	unknown	23:10–23:20 (marginal, 0.17 h)	50.1° 19:00	4.61	98%	80.9°
2039-07-05 Tue	3	—	unknown	23:10–23:20 (marginal, 0.17 h)	50.1° 19:00	4.63	100%	95.9°
2039-07-06 Wed	3	—	unknown	22:20–22:35 (marginal, 0.25 h)	50.1° 18:55	4.66	99%	110.8°
2039-07-07 Thu	3	—	unknown	22:15–22:40 (marginal, 0.42 h)	50.1° 18:50	4.69	95%	125.4°
2039-07-08 Fri	3	—	unknown	22:15–22:40 (marginal, 0.42 h)	50.1° 18:45	4.73	89%	139.6°
2039-07-09 Sat	3	—	unknown	22:15–22:35 (marginal, 0.33 h)	50.1° 18:40	4.76	81%	153.4°
2039-07-10 Sun	2	—	unknown	22:15–22:30 (marginal, 0.25 h)	50.1° 18:40	4.79	72%	166.6°
2039-07-11 Mon	2	—	unknown	22:15–22:25 (marginal, 0.17 h)	50.1° 18:35	4.83	62%	179.4°
2039-07-12 Tue	2	—	unknown	22:15–22:20 (marginal, 0.08 h)	50.1° 18:30	4.87	52%	168.0°
2039-07-13 Wed	2	—	unknown	22:15–22:20 (marginal, 0.08 h)	50.1° 18:25	4.91	42%	155.7°
2039-07-14 Thu	2	—	unknown	22:10–22:15 (marginal, 0.08 h)	50.1° 18:25	4.95	33%	143.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-06-15&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.