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: 01-23 (93), 01-24 (93), 01-25 (93), 01-26 (93), 01-27 (93) — by astronomy; check the weather when the night is within four days.

2036-01-17astronomy score per night — click a bar for that night2036-02-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-01-17 Thu	27	—	unknown	01:05–06:10 (marginal, 5.08 h)	50.2° 05:05	11.19	74%	7.5°
2036-01-18 Fri	38	—	unknown	00:50–06:10 (marginal, 5.33 h)	50.2° 05:00	11.17	64%	6.4°
2036-01-19 Sat	53	—	unknown	01:55–05:40 (good, 3.75 h)	50.2° 04:55	11.14	54%	19.4°
2036-01-20 Sun	79	—	unknown	01:05–06:10 (good, 5.08 h)	50.2° 04:50	11.12	43%	32.1°
2036-01-21 Mon	86	—	unknown	01:00–06:05 (good, 5.08 h)	50.2° 04:50	11.09	34%	44.5°
2036-01-22 Tue	91	—	unknown	00:55–06:05 (good, 5.17 h)	50.2° 04:45	11.07	25%	56.7°
2036-01-23 Wed	93	—	unknown	00:55–06:05 (good, 5.17 h)	50.2° 04:40	11.04	17%	68.7°
2036-01-24 Thu	93	—	unknown	00:50–06:05 (good, 5.25 h)	50.2° 04:35	11.01	11%	80.6°
2036-01-25 Fri	93	—	unknown	00:45–06:05 (good, 5.33 h)	50.2° 04:30	10.98	6%	92.4°
2036-01-26 Sat	93	—	unknown	00:40–06:05 (good, 5.42 h)	50.2° 04:30	10.96	2%	104.2°
2036-01-27 Sun	93	—	unknown	00:35–06:05 (good, 5.5 h)	50.2° 04:25	10.93	0%	116.1°
2036-01-28 Mon	93	—	unknown	00:35–06:05 (good, 5.5 h)	50.2° 04:20	10.9	0%	128.0°
2036-01-29 Tue	93	—	unknown	00:30–06:00 (good, 5.5 h)	50.2° 04:15	10.87	2%	139.9°
2036-01-30 Wed	93	—	unknown	00:25–06:00 (good, 5.58 h)	50.2° 04:10	10.84	6%	152.0°
2036-01-31 Thu	93	—	unknown	00:20–06:00 (good, 5.67 h)	50.2° 04:10	10.8	11%	164.2°
2036-02-01 Fri	93	—	unknown	00:20–06:00 (good, 5.67 h)	50.2° 04:05	10.77	18%	176.4°
2036-02-02 Sat	93	—	unknown	00:15–06:00 (good, 5.75 h)	50.2° 04:00	10.74	26%	170.7°
2036-02-03 Sun	93	—	unknown	00:10–06:00 (good, 5.83 h)	50.2° 03:55	10.7	36%	157.9°
2036-02-04 Mon	93	—	unknown	00:10–05:55 (good, 5.75 h)	50.2° 03:55	10.67	46%	144.7°
2036-02-05 Tue	93	—	unknown	00:05–05:55 (good, 5.83 h)	50.2° 03:50	10.64	57%	131.2°
2036-02-06 Wed	93	—	unknown	00:05–05:55 (good, 5.83 h)	50.2° 03:45	10.6	68%	117.3°
2036-02-07 Thu	93	—	unknown	00:15–05:55 (good, 5.67 h)	50.2° 03:40	10.57	78%	103.0°
2036-02-08 Fri	91	—	unknown	00:55–05:55 (good, 5.0 h)	50.2° 03:35	10.53	87%	88.3°
2036-02-09 Sat	64	—	unknown	03:00–05:50 (good, 2.83 h)	50.2° 03:35	10.49	94%	73.3°
2036-02-10 Sun	44	—	unknown	23:55–05:50 (marginal, 5.92 h)	50.2° 03:30	10.46	98%	58.2°
2036-02-11 Mon	27	—	unknown	01:25–05:50 (marginal, 4.42 h)	50.2° 03:25	10.42	100%	43.1°
2036-02-12 Tue	18	—	unknown	03:50–05:50 (marginal, 2.0 h)	50.2° 03:20	10.38	98%	28.1°
2036-02-13 Wed	20	—	unknown	02:35–05:50 (marginal, 3.25 h)	50.2° 03:15	10.34	94%	13.5°
2036-02-14 Thu	25	—	unknown	23:25–05:45 (marginal, 6.33 h)	50.2° 03:15	10.3	88%	1.6°
2036-02-15 Fri	37	—	unknown	23:05–05:45 (marginal, 6.67 h)	50.2° 03:10	10.26	80%	14.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-01-17&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.