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: 06-10 (36), 06-09 (35), 06-11 (34), 06-12 (33), 06-13 (32) — by astronomy; check the weather when the night is within four days.

2028-06-06astronomy score per night — click a bar for that night2028-07-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-06-06 Tue	18	—	unknown	23:05–01:00 (marginal, 1.92 h)	50.2° 20:50	4.62	100%	67.3°
2028-06-07 Wed	22	—	unknown	23:05–23:40 (good, 0.58 h)	50.2° 20:45	4.59	99%	80.3°
2028-06-08 Thu	27	—	unknown	23:05–00:10 (good, 1.08 h)	50.2° 20:40	4.57	97%	93.0°
2028-06-09 Fri	35	—	unknown	23:05–00:15 (good, 1.17 h)	50.2° 20:35	4.54	92%	105.5°
2028-06-10 Sat	36	—	unknown	23:05–00:15 (good, 1.17 h)	50.2° 20:35	4.52	86%	117.7°
2028-06-11 Sun	34	—	unknown	23:10–00:15 (good, 1.08 h)	50.2° 20:30	4.5	79%	129.6°
2028-06-12 Mon	33	—	unknown	23:10–00:15 (good, 1.08 h)	50.2° 20:25	4.49	71%	141.2°
2028-06-13 Tue	32	—	unknown	23:10–00:15 (good, 1.08 h)	50.2° 20:20	4.47	62%	152.5°
2028-06-14 Wed	30	—	unknown	23:10–00:10 (good, 1.0 h)	50.2° 20:20	4.46	52%	163.0°
2028-06-15 Thu	29	—	unknown	23:10–00:05 (good, 0.92 h)	50.2° 20:15	4.45	43%	170.0°
2028-06-16 Fri	27	—	unknown	23:10–00:00 (good, 0.83 h)	50.2° 20:10	4.44	34%	166.1°
2028-06-17 Sat	26	—	unknown	23:10–00:00 (good, 0.83 h)	50.2° 20:05	4.43	25%	155.8°
2028-06-18 Sun	25	—	unknown	23:10–23:55 (good, 0.75 h)	50.2° 20:00	4.43	16%	144.1°
2028-06-19 Mon	24	—	unknown	23:10–23:50 (good, 0.67 h)	50.2° 20:00	4.42	10%	131.6°
2028-06-20 Tue	22	—	unknown	23:15–23:45 (good, 0.5 h)	50.2° 19:55	4.42	4%	118.7°
2028-06-21 Wed	20	—	unknown	23:15–23:40 (good, 0.42 h)	50.2° 19:50	4.42	1%	105.3°
2028-06-22 Thu	18	—	unknown	23:15–23:40 (good, 0.42 h)	50.2° 19:45	4.43	0%	91.6°
2028-06-23 Fri	16	—	unknown	23:15–23:35 (good, 0.33 h)	50.2° 19:40	4.43	2%	77.6°
2028-06-24 Sat	15	—	unknown	23:15–23:30 (good, 0.25 h)	50.2° 19:40	4.44	6%	63.5°
2028-06-25 Sun	13	—	unknown	23:15–23:25 (good, 0.17 h)	50.2° 19:35	4.45	13%	49.3°
2028-06-26 Mon	10	—	unknown	22:20–23:50 (marginal, 1.5 h)	50.2° 19:30	4.46	22%	35.3°
2028-06-27 Tue	8	—	unknown	22:20–23:05 (marginal, 0.75 h)	50.2° 19:25	4.47	32%	21.9°
2028-06-28 Wed	7	—	unknown	23:10–23:45 (marginal, 0.58 h)	50.2° 19:20	4.49	43%	11.2°
2028-06-29 Thu	5	—	unknown	23:10–23:40 (marginal, 0.5 h)	50.2° 19:20	4.51	55%	13.0°
2028-06-30 Fri	3	—	unknown	23:10–23:25 (marginal, 0.25 h)	50.2° 19:15	4.53	66%	24.5°
2028-07-01 Sat	3	—	unknown	23:10–23:20 (marginal, 0.17 h)	50.2° 19:10	4.55	76%	37.4°
2028-07-02 Sun	2	—	unknown	23:10–23:15 (marginal, 0.08 h)	50.2° 19:05	4.57	85%	50.5°
2028-07-03 Mon	2	—	unknown	23:10–23:15 (marginal, 0.08 h)	50.2° 19:05	4.6	92%	63.5°
2028-07-04 Tue	2	—	unknown	23:10–23:15 (marginal, 0.08 h)	50.2° 19:00	4.62	96%	76.4°
2028-07-05 Wed	2	—	unknown	23:10–23:15 (marginal, 0.08 h)	50.2° 18:55	4.65	99%	89.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-06-06&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.