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 North America Nebula: 01-09 (40), 01-08 (39), 01-10 (38), 01-11 (37), 01-12 (35) — by astronomy; check the weather when the night is within four days.

2042-01-02astronomy score per night — click a bar for that night2042-01-31

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-01-02 Thu	23	—	unknown	18:45–18:50 (good, 0.08 h)	87.2° 14:30	11.44	87%	83.4°
2042-01-03 Fri	25	—	unknown	18:45–19:10 (good, 0.42 h)	87.2° 14:30	11.43	94%	89.8°
2042-01-04 Sat	26	—	unknown	18:45–19:40 (good, 0.92 h)	87.2° 14:25	11.41	98%	96.1°
2042-01-05 Sun	29	—	unknown	18:45–20:10 (good, 1.42 h)	87.2° 14:20	11.4	100%	102.0°
2042-01-06 Mon	31	—	unknown	18:50–20:15 (good, 1.42 h)	87.2° 14:15	11.39	100%	107.4°
2042-01-07 Tue	34	—	unknown	18:50–20:15 (good, 1.42 h)	87.2° 14:15	11.37	97%	111.9°
2042-01-08 Wed	39	—	unknown	18:50–20:15 (good, 1.42 h)	87.2° 14:10	11.36	93%	115.4°
2042-01-09 Thu	40	—	unknown	18:50–20:20 (good, 1.5 h)	87.2° 14:05	11.34	88%	117.6°
2042-01-10 Fri	38	—	unknown	18:50–20:20 (good, 1.5 h)	87.2° 14:00	11.32	81%	118.6°
2042-01-11 Sat	37	—	unknown	18:50–20:15 (good, 1.42 h)	87.2° 13:55	11.3	73%	118.2°
2042-01-12 Sun	35	—	unknown	18:55–20:15 (good, 1.33 h)	87.2° 13:55	11.28	64%	116.5°
2042-01-13 Mon	34	—	unknown	18:55–20:10 (good, 1.25 h)	87.2° 13:50	11.26	55%	113.7°
2042-01-14 Tue	32	—	unknown	18:55–20:05 (good, 1.17 h)	87.2° 13:45	11.24	46%	109.8°
2042-01-15 Wed	30	—	unknown	18:55–20:00 (good, 1.08 h)	87.2° 13:40	11.22	36%	105.0°
2042-01-16 Thu	29	—	unknown	18:55–19:55 (good, 1.0 h)	87.2° 13:35	11.2	27%	99.6°
2042-01-17 Fri	27	—	unknown	19:00–19:55 (good, 0.92 h)	87.2° 13:35	11.18	18%	93.5°
2042-01-18 Sat	26	—	unknown	19:00–19:50 (good, 0.83 h)	87.2° 13:30	11.15	11%	87.2°
2042-01-19 Sun	25	—	unknown	19:00–19:45 (good, 0.75 h)	87.2° 13:25	11.13	5%	80.8°
2042-01-20 Mon	23	—	unknown	19:00–19:40 (good, 0.67 h)	87.2° 13:20	11.1	1%	74.6°
2042-01-21 Tue	23	—	unknown	19:00–19:40 (good, 0.67 h)	87.2° 13:15	11.08	0%	69.1°
2042-01-22 Wed	20	—	unknown	19:05–19:35 (good, 0.5 h)	87.2° 13:15	11.05	2%	64.7°
2042-01-23 Thu	18	—	unknown	19:05–19:30 (good, 0.42 h)	87.2° 13:10	11.03	6%	62.0°
2042-01-24 Fri	16	—	unknown	19:05–19:20 (good, 0.25 h)	87.2° 13:05	11.0	13%	61.3°
2042-01-25 Sat	13	—	unknown	19:05–19:10 (good, 0.08 h)	87.2° 13:00	10.97	22%	62.6°
2042-01-26 Sun	10	—	unknown	19:10–19:55 (marginal, 0.75 h)	87.2° 13:00	10.94	32%	65.8°
2042-01-27 Mon	9	—	unknown	19:10–19:50 (marginal, 0.67 h)	87.2° 12:55	10.91	43%	70.3°
2042-01-28 Tue	8	—	unknown	19:10–19:45 (marginal, 0.58 h)	87.2° 12:50	10.88	55%	75.8°
2042-01-29 Wed	7	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.2° 12:45	10.85	65%	81.8°
2042-01-30 Thu	7	—	unknown	19:10–19:35 (marginal, 0.42 h)	87.2° 12:40	10.82	75%	88.1°
2042-01-31 Fri	8	—	unknown	05:45–06:00 (marginal, 0.25 h)	87.2° 12:40	10.79	83%	94.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-01-02&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.