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 (28), 06-17 (25), 06-18 (22), 06-19 (18) — by astronomy; check the weather when the night is within four days.

2045-06-15astronomy score per night — click a bar for that night2045-07-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-06-15 Thu	29	—	unknown	23:10–00:05 (good, 0.92 h)	50.1° 20:15	4.45	1%	89.3°
2045-06-16 Fri	28	—	unknown	23:10–00:05 (good, 0.92 h)	50.1° 20:10	4.44	5%	74.6°
2045-06-17 Sat	25	—	unknown	23:10–00:00 (good, 0.83 h)	50.1° 20:05	4.43	11%	60.0°
2045-06-18 Sun	22	—	unknown	23:10–23:50 (good, 0.67 h)	50.1° 20:05	4.43	20%	45.5°
2045-06-19 Mon	18	—	unknown	23:10–23:35 (good, 0.42 h)	50.1° 20:00	4.42	30%	31.4°
2045-06-20 Tue	14	—	unknown	23:15–23:25 (good, 0.17 h)	50.1° 19:55	4.42	41%	18.1°
2045-06-21 Wed	10	—	unknown	23:15–00:10 (marginal, 0.92 h)	50.1° 19:50	4.42	52%	8.5°
2045-06-22 Thu	8	—	unknown	23:15–00:00 (marginal, 0.75 h)	50.1° 19:45	4.43	63%	13.9°
2045-06-23 Fri	6	—	unknown	23:15–23:50 (marginal, 0.58 h)	50.1° 19:45	4.43	73%	25.9°
2045-06-24 Sat	5	—	unknown	23:15–23:45 (marginal, 0.5 h)	50.1° 19:40	4.44	82%	38.5°
2045-06-25 Sun	5	—	unknown	23:15–23:40 (marginal, 0.42 h)	50.1° 19:35	4.45	89%	51.1°
2045-06-26 Mon	5	—	unknown	23:15–23:40 (marginal, 0.42 h)	50.1° 19:30	4.46	94%	63.5°
2045-06-27 Tue	6	—	unknown	23:15–23:45 (marginal, 0.5 h)	50.1° 19:30	4.47	98%	75.8°
2045-06-28 Wed	6	—	unknown	23:10–23:45 (marginal, 0.58 h)	50.1° 19:25	4.49	100%	88.0°
2045-06-29 Thu	7	—	unknown	23:10–23:40 (marginal, 0.5 h)	50.1° 19:20	4.51	100%	100.0°
2045-06-30 Fri	7	—	unknown	22:20–22:55 (marginal, 0.58 h)	50.1° 19:15	4.53	98%	111.8°
2045-07-01 Sat	7	—	unknown	22:20–22:55 (marginal, 0.58 h)	50.1° 19:10	4.55	94%	123.6°
2045-07-02 Sun	6	—	unknown	22:20–23:00 (marginal, 0.67 h)	50.1° 19:10	4.57	88%	135.2°
2045-07-03 Mon	6	—	unknown	22:20–22:55 (marginal, 0.58 h)	50.1° 19:05	4.59	82%	146.7°
2045-07-04 Tue	5	—	unknown	22:20–22:50 (marginal, 0.5 h)	50.1° 19:00	4.62	74%	158.0°
2045-07-05 Wed	4	—	unknown	22:20–22:50 (marginal, 0.5 h)	50.1° 18:55	4.65	65%	168.2°
2045-07-06 Thu	4	—	unknown	22:15–22:45 (marginal, 0.5 h)	50.1° 18:50	4.68	55%	170.9°
2045-07-07 Fri	4	—	unknown	22:15–22:40 (marginal, 0.42 h)	50.1° 18:50	4.71	45%	161.9°
2045-07-08 Sat	3	—	unknown	22:15–22:35 (marginal, 0.33 h)	50.1° 18:45	4.74	35%	150.0°
2045-07-09 Sun	3	—	unknown	22:15–22:30 (marginal, 0.25 h)	50.1° 18:40	4.78	26%	137.2°
2045-07-10 Mon	2	—	unknown	22:15–22:30 (marginal, 0.25 h)	50.1° 18:35	4.81	17%	123.8°
2045-07-11 Tue	2	—	unknown	22:15–22:25 (marginal, 0.17 h)	50.1° 18:35	4.85	9%	109.9°
2045-07-12 Wed	2	—	unknown	22:15–22:20 (marginal, 0.08 h)	50.1° 18:30	4.89	3%	95.5°
2045-07-13 Thu	2	—	unknown	—	50.1° 18:25	4.93	0%	80.8°
2045-07-14 Fri	2	—	unknown	22:10–22:15 (marginal, 0.08 h)	50.1° 18:20	4.97	0%	65.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-06-15&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.