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: 05-17 (83), 05-16 (82), 05-18 (81), 05-15 (80), 05-19 (79) — by astronomy; check the weather when the night is within four days.

2044-05-14astronomy score per night — click a bar for that night2044-06-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-05-14 Sat	77	—	unknown	22:30–01:40 (good, 3.17 h)	50.1° 22:20	5.6	92%	81.6°
2044-05-15 Sun	80	—	unknown	22:35–01:50 (good, 3.25 h)	50.1° 22:15	5.54	86%	93.4°
2044-05-16 Mon	82	—	unknown	22:35–01:50 (good, 3.25 h)	50.1° 22:10	5.49	79%	105.1°
2044-05-17 Tue	83	—	unknown	22:35–01:55 (good, 3.33 h)	50.1° 22:10	5.44	71%	116.9°
2044-05-18 Wed	81	—	unknown	22:40–01:55 (good, 3.25 h)	50.1° 22:05	5.39	62%	128.8°
2044-05-19 Thu	79	—	unknown	22:40–01:50 (good, 3.17 h)	50.1° 22:00	5.34	52%	140.9°
2044-05-20 Fri	77	—	unknown	22:40–01:50 (good, 3.17 h)	50.1° 21:55	5.29	42%	153.2°
2044-05-21 Sat	74	—	unknown	22:45–01:45 (good, 3.0 h)	50.1° 21:50	5.24	32%	165.3°
2044-05-22 Sun	73	—	unknown	22:45–01:40 (good, 2.92 h)	50.1° 21:50	5.19	23%	173.6°
2044-05-23 Mon	71	—	unknown	22:45–01:35 (good, 2.83 h)	50.1° 21:45	5.14	14%	164.7°
2044-05-24 Tue	69	—	unknown	22:45–01:30 (good, 2.75 h)	50.1° 21:40	5.1	7%	151.2°
2044-05-25 Wed	66	—	unknown	22:50–01:30 (good, 2.67 h)	50.1° 21:35	5.05	2%	136.8°
2044-05-26 Thu	64	—	unknown	22:50–01:25 (good, 2.58 h)	50.1° 21:35	5.01	0%	122.0°
2044-05-27 Fri	63	—	unknown	22:50–01:20 (good, 2.5 h)	50.1° 21:30	4.97	1%	107.0°
2044-05-28 Sat	60	—	unknown	22:55–01:15 (good, 2.33 h)	50.1° 21:25	4.92	5%	92.0°
2044-05-29 Sun	56	—	unknown	22:55–01:10 (good, 2.25 h)	50.1° 21:20	4.88	11%	77.1°
2044-05-30 Mon	50	—	unknown	22:55–01:10 (good, 2.25 h)	50.1° 21:15	4.85	20%	62.5°
2044-05-31 Tue	42	—	unknown	22:55–00:55 (good, 2.0 h)	50.1° 21:15	4.81	30%	48.3°
2044-06-01 Wed	32	—	unknown	23:00–00:40 (good, 1.67 h)	50.1° 21:10	4.77	41%	34.5°
2044-06-02 Thu	25	—	unknown	23:00–23:35 (good, 0.58 h)	50.1° 21:05	4.74	52%	21.4°
2044-06-03 Fri	19	—	unknown	23:00–01:15 (marginal, 2.25 h)	50.1° 21:00	4.7	62%	9.8°
2044-06-04 Sat	15	—	unknown	23:00–01:05 (marginal, 2.08 h)	50.1° 20:55	4.67	72%	8.5°
2044-06-05 Sun	12	—	unknown	23:05–00:55 (marginal, 1.83 h)	50.1° 20:55	4.64	80%	19.2°
2044-06-06 Mon	10	—	unknown	23:05–00:45 (marginal, 1.67 h)	50.1° 20:50	4.62	88%	31.0°
2044-06-07 Tue	11	—	unknown	23:05–00:45 (marginal, 1.67 h)	50.1° 20:45	4.59	93%	43.0°
2044-06-08 Wed	14	—	unknown	23:05–00:45 (marginal, 1.67 h)	50.1° 20:40	4.56	97%	54.9°
2044-06-09 Thu	16	—	unknown	23:05–00:50 (marginal, 1.75 h)	50.1° 20:35	4.54	99%	66.7°
2044-06-10 Fri	19	—	unknown	23:10–23:25 (good, 0.25 h)	50.1° 20:35	4.52	100%	78.5°
2044-06-11 Sat	22	—	unknown	23:10–23:55 (good, 0.75 h)	50.1° 20:30	4.5	98%	90.3°
2044-06-12 Sun	25	—	unknown	23:10–00:00 (good, 0.83 h)	50.1° 20:25	4.48	95%	102.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-05-14&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.