{"calculation_version":"2026-10-10.1","days":30,"nights":[{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.01,"date":"2025-04-02","moon_free_dark_hours":4.15,"moon_illumination":27,"moon_separation":109.6,"score":0,"score_astronomy":93,"score_weather":0,"transit_alt":50.2,"transit_local":"01:05","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.96,"date":"2025-04-03","moon_free_dark_hours":3.0,"moon_illumination":37,"moon_separation":95.6,"score":1,"score_astronomy":91,"score_weather":1,"transit_alt":50.2,"transit_local":"01:00","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":0.33,"best_label":"marginal","best_window":"21:40\u201322:00","dark_hours":7.9,"date":"2025-04-04","moon_free_dark_hours":2.05,"moon_illumination":48,"moon_separation":82.1,"score":3,"score_astronomy":86,"score_weather":4,"transit_alt":50.2,"transit_local":"01:00","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":2.0,"best_label":"good","best_window":"01:00\u201303:00","dark_hours":7.85,"date":"2025-04-05","moon_free_dark_hours":1.32,"moon_illumination":59,"moon_separation":69.0,"score":71,"score_astronomy":82,"score_weather":86,"transit_alt":50.2,"transit_local":"00:55","verdict":"good","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.79,"date":"2025-04-06","moon_free_dark_hours":0.73,"moon_illumination":69,"moon_separation":56.2,"score":0,"score_astronomy":64,"score_weather":0,"transit_alt":50.2,"transit_local":"00:50","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":2.42,"best_label":"marginal","best_window":"21:35\u201300:00","dark_hours":7.74,"date":"2025-04-07","moon_free_dark_hours":0.27,"moon_illumination":78,"moon_separation":43.7,"score":23,"score_astronomy":51,"score_weather":46,"transit_alt":50.2,"transit_local":"00:45","verdict":"poor","weather_source":"history","weekday":"Mon"},{"best_hours":2.5,"best_label":"marginal","best_window":"02:00\u201304:30","dark_hours":7.68,"date":"2025-04-08","moon_free_dark_hours":0.0,"moon_illumination":85,"moon_separation":31.5,"score":12,"score_astronomy":34,"score_weather":35,"transit_alt":50.2,"transit_local":"00:40","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":3.25,"best_label":"marginal","best_window":"01:20\u201304:35","dark_hours":7.62,"date":"2025-04-09","moon_free_dark_hours":0.0,"moon_illumination":92,"moon_separation":19.6,"score":24,"score_astronomy":27,"score_weather":88,"transit_alt":50.2,"transit_local":"00:40","verdict":"poor","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.57,"date":"2025-04-10","moon_free_dark_hours":0.0,"moon_illumination":96,"moon_separation":8.8,"score":1,"score_astronomy":23,"score_weather":6,"transit_alt":50.2,"transit_local":"00:35","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.51,"date":"2025-04-11","moon_free_dark_hours":0.0,"moon_illumination":99,"moon_separation":7.5,"score":0,"score_astronomy":21,"score_weather":0,"transit_alt":50.2,"transit_local":"00:30","verdict":"unusable","weather_source":"history","weekday":"Fri"},{"best_hours":1.0,"best_label":"marginal","best_window":"00:00\u201301:00","dark_hours":7.45,"date":"2025-04-12","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":17.9,"score":3,"score_astronomy":25,"score_weather":13,"transit_alt":50.2,"transit_local":"00:25","verdict":"poor","weather_source":"history","weekday":"Sat"},{"best_hours":2.33,"best_label":"marginal","best_window":"21:40\u201300:00","dark_hours":7.39,"date":"2025-04-13","moon_free_dark_hours":0.0,"moon_illumination":99,"moon_separation":29.4,"score":15,"score_astronomy":32,"score_weather":48,"transit_alt":50.2,"transit_local":"00:20","verdict":"poor","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.34,"date":"2025-04-14","moon_free_dark_hours":0.17,"moon_illumination":97,"moon_separation":41.0,"score":4,"score_astronomy":76,"score_weather":6,"transit_alt":50.2,"transit_local":"00:20","verdict":"poor","weather_source":"history","weekday":"Mon"},{"best_hours":1.0,"best_label":"good","best_window":"22:00\u201323:00","dark_hours":7.28,"date":"2025-04-15","moon_free_dark_hours":1.22,"moon_illumination":92,"moon_separation":52.8,"score":59,"score_astronomy":91,"score_weather":65,"transit_alt":50.2,"transit_local":"00:15","verdict":"marginal","weather_source":"history","weekday":"Tue"},{"best_hours":4.25,"best_label":"good","best_window":"21:45\u201302:00","dark_hours":7.22,"date":"2025-04-16","moon_free_dark_hours":2.27,"moon_illumination":87,"moon_separation":64.6,"score":87,"score_astronomy":93,"score_weather":94,"transit_alt":50.2,"transit_local":"00:10","verdict":"good","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.16,"date":"2025-04-17","moon_free_dark_hours":3.25,"moon_illumination":79,"moon_separation":76.6,"score":1,"score_astronomy":93,"score_weather":1,"transit_alt":50.2,"transit_local":"00:05","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":0.17,"best_label":"good","best_window":"21:50\u201322:00","dark_hours":7.11,"date":"2025-04-18","moon_free_dark_hours":4.13,"moon_illumination":71,"moon_separation":88.7,"score":17,"score_astronomy":93,"score_weather":18,"transit_alt":50.2,"transit_local":"00:05","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":5.17,"best_label":"good","best_window":"21:50\u201303:00","dark_hours":7.05,"date":"2025-04-19","moon_free_dark_hours":4.88,"moon_illumination":62,"moon_separation":101.1,"score":75,"score_astronomy":93,"score_weather":81,"transit_alt":50.2,"transit_local":"00:00","verdict":"good","weather_source":"history","weekday":"Sat"},{"best_hours":3.0,"best_label":"good","best_window":"23:00\u201302:00","dark_hours":6.99,"date":"2025-04-20","moon_free_dark_hours":5.5,"moon_illumination":52,"moon_separation":113.8,"score":69,"score_astronomy":93,"score_weather":74,"transit_alt":50.2,"transit_local":"23:55","verdict":"marginal","weather_source":"history","weekday":"Sun"},{"best_hours":0.67,"best_label":"good","best_window":"03:00\u201303:40","dark_hours":6.93,"date":"2025-04-21","moon_free_dark_hours":6.0,"moon_illumination":41,"moon_separation":126.8,"score":44,"score_astronomy":93,"score_weather":47,"transit_alt":50.2,"transit_local":"23:50","verdict":"marginal","weather_source":"history","weekday":"Mon"},{"best_hours":1.0,"best_label":"good","best_window":"00:00\u201301:00","dark_hours":6.87,"date":"2025-04-22","moon_free_dark_hours":6.43,"moon_illumination":30,"moon_separation":140.2,"score":28,"score_astronomy":93,"score_weather":30,"transit_alt":50.2,"transit_local":"23:45","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":0.42,"best_label":"good","best_window":"03:00\u201303:25","dark_hours":6.81,"date":"2025-04-23","moon_free_dark_hours":6.8,"moon_illumination":21,"moon_separation":154.0,"score":33,"score_astronomy":93,"score_weather":35,"transit_alt":50.2,"transit_local":"23:45","verdict":"poor","weather_source":"history","weekday":"Wed"},{"best_hours":4.33,"best_label":"good","best_window":"23:00\u201303:20","dark_hours":6.76,"date":"2025-04-24","moon_free_dark_hours":6.73,"moon_illumination":12,"moon_separation":167.7,"score":70,"score_astronomy":93,"score_weather":75,"transit_alt":50.2,"transit_local":"23:40","verdict":"good","weather_source":"history","weekday":"Thu"},{"best_hours":5.42,"best_label":"good","best_window":"22:00\u201303:25","dark_hours":6.7,"date":"2025-04-25","moon_free_dark_hours":6.68,"moon_illumination":5,"moon_separation":173.2,"score":92,"score_astronomy":93,"score_weather":99,"transit_alt":50.2,"transit_local":"23:35","verdict":"good","weather_source":"history","weekday":"Fri"},{"best_hours":1.58,"best_label":"marginal","best_window":"02:00\u201303:35","dark_hours":6.64,"date":"2025-04-26","moon_free_dark_hours":6.62,"moon_illumination":1,"moon_separation":160.2,"score":22,"score_astronomy":93,"score_weather":24,"transit_alt":50.2,"transit_local":"23:30","verdict":"poor","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.58,"date":"2025-04-27","moon_free_dark_hours":6.57,"moon_illumination":0,"moon_separation":145.3,"score":0,"score_astronomy":93,"score_weather":0,"transit_alt":50.2,"transit_local":"23:25","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":5.17,"best_label":"good","best_window":"22:05\u201303:15","dark_hours":6.52,"date":"2025-04-28","moon_free_dark_hours":6.5,"moon_illumination":2,"moon_separation":130.3,"score":93,"score_astronomy":93,"score_weather":100,"transit_alt":50.2,"transit_local":"23:25","verdict":"good","weather_source":"history","weekday":"Mon"},{"best_hours":5.08,"best_label":"good","best_window":"22:05\u201303:10","dark_hours":6.47,"date":"2025-04-29","moon_free_dark_hours":5.68,"moon_illumination":7,"moon_separation":115.4,"score":93,"score_astronomy":93,"score_weather":100,"transit_alt":50.2,"transit_local":"23:20","verdict":"good","weather_source":"history","weekday":"Tue"},{"best_hours":4.58,"best_label":"good","best_window":"22:10\u201302:45","dark_hours":6.41,"date":"2025-04-30","moon_free_dark_hours":4.42,"moon_illumination":14,"moon_separation":100.8,"score":88,"score_astronomy":92,"score_weather":95,"transit_alt":50.2,"transit_local":"23:15","verdict":"good","weather_source":"history","weekday":"Wed"},{"best_hours":0.83,"best_label":"marginal","best_window":"22:10\u201323:00","dark_hours":6.35,"date":"2025-05-01","moon_free_dark_hours":3.35,"moon_illumination":23,"moon_separation":86.7,"score":10,"score_astronomy":88,"score_weather":12,"transit_alt":50.2,"transit_local":"23:10","verdict":"poor","weather_source":"history","weekday":"Thu"}],"note":"score_astronomy for every night; score_weather/score only where a forecast (next 4 days) or ERA5 history exists \u2014 null otherwise","start":"2025-04-02","target":{"dec":2.05238823,"morphology":"E3","name":"3C 273","ra":187.27791594,"simbad_url":"https://simbad.cds.unistra.fr/simbad/sim-id?Ident=3C%20273","source":"sesame","type":"BLL","type_text":"BL Lac object \u2014 a blazar","vmag":14.83}}