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: 06-06 (41), 06-07 (35), 06-08 (28), 06-19 (23), 06-09 (22) — by astronomy; check the weather when the night is within four days.

2038-06-06astronomy score per night — click a bar for that night2038-07-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-06-06 Sun	41	—	unknown	23:05–00:45 (good, 1.67 h)	50.1° 20:50	4.63	15%	63.9°
2038-06-07 Mon	35	—	unknown	23:05–00:30 (good, 1.42 h)	50.1° 20:45	4.6	23%	50.7°
2038-06-08 Tue	28	—	unknown	23:05–00:20 (good, 1.25 h)	50.1° 20:45	4.58	33%	37.2°
2038-06-09 Wed	22	—	unknown	23:05–00:05 (good, 1.0 h)	50.1° 20:40	4.55	44%	23.5°
2038-06-10 Thu	17	—	unknown	23:05–00:55 (marginal, 1.83 h)	50.1° 20:35	4.53	55%	9.6°
2038-06-11 Fri	12	—	unknown	23:10–00:40 (marginal, 1.5 h)	50.1° 20:30	4.51	66%	4.6°
2038-06-12 Sat	9	—	unknown	23:10–00:25 (marginal, 1.25 h)	50.1° 20:30	4.49	77%	19.1°
2038-06-13 Sun	7	—	unknown	23:10–00:15 (marginal, 1.08 h)	50.1° 20:25	4.48	86%	33.7°
2038-06-14 Mon	8	—	unknown	23:10–00:15 (marginal, 1.08 h)	50.1° 20:20	4.46	93%	48.4°
2038-06-15 Tue	10	—	unknown	23:10–00:20 (marginal, 1.17 h)	50.1° 20:15	4.45	98%	63.0°
2038-06-16 Wed	13	—	unknown	23:10–00:25 (marginal, 1.25 h)	50.1° 20:10	4.44	100%	77.6°
2038-06-17 Thu	17	—	unknown	23:10–23:35 (good, 0.42 h)	50.1° 20:10	4.43	99%	91.9°
2038-06-18 Fri	20	—	unknown	23:10–23:40 (good, 0.5 h)	50.1° 20:05	4.43	96%	105.9°
2038-06-19 Sat	23	—	unknown	23:10–23:45 (good, 0.58 h)	50.1° 20:00	4.42	90%	119.5°
2038-06-20 Sun	22	—	unknown	23:15–23:50 (good, 0.58 h)	50.1° 19:55	4.42	83%	132.7°
2038-06-21 Mon	20	—	unknown	23:15–23:45 (good, 0.5 h)	50.1° 19:50	4.42	74%	145.5°
2038-06-22 Tue	19	—	unknown	23:15–23:40 (good, 0.42 h)	50.1° 19:50	4.43	65%	157.9°
2038-06-23 Wed	17	—	unknown	23:15–23:35 (good, 0.33 h)	50.1° 19:45	4.43	56%	170.1°
2038-06-24 Thu	16	—	unknown	23:15–23:30 (good, 0.25 h)	50.1° 19:40	4.44	46%	177.9°
2038-06-25 Fri	14	—	unknown	23:15–23:30 (good, 0.25 h)	50.1° 19:35	4.45	37%	166.0°
2038-06-26 Sat	13	—	unknown	23:15–23:25 (good, 0.17 h)	50.1° 19:30	4.46	28%	154.2°
2038-06-27 Sun	12	—	unknown	23:15–23:20 (good, 0.08 h)	50.1° 19:30	4.47	20%	142.3°
2038-06-28 Mon	10	—	unknown	22:20–23:45 (marginal, 1.42 h)	50.1° 19:25	4.48	13%	130.3°
2038-06-29 Tue	10	—	unknown	22:20–23:40 (marginal, 1.33 h)	50.1° 19:20	4.5	7%	118.2°
2038-06-30 Wed	9	—	unknown	22:20–23:35 (marginal, 1.25 h)	50.1° 19:15	4.52	3%	105.8°
2038-07-01 Thu	8	—	unknown	22:20–23:05 (marginal, 0.75 h)	50.1° 19:15	4.54	0%	93.2°
2038-07-02 Fri	7	—	unknown	22:20–23:00 (marginal, 0.67 h)	50.1° 19:10	4.56	0%	80.3°
2038-07-03 Sat	6	—	unknown	22:20–22:55 (marginal, 0.58 h)	50.1° 19:05	4.59	2%	67.2°
2038-07-04 Sun	5	—	unknown	22:20–22:55 (marginal, 0.58 h)	50.1° 19:00	4.61	6%	53.9°
2038-07-05 Mon	4	—	unknown	22:20–22:45 (marginal, 0.42 h)	50.1° 18:55	4.64	13%	40.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-06-06&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.