Alternatively, if you didnt mean fixed times (and want actual solar state from location coordinates) then you can simply poll the CRON node every minute & ask for solar state...
[{"id":"4a271714.8ef808","type":"cronplus","z":"a2d1264d.2189b8","name":"","outputField":"payload","timeZone":"","persistDynamic":false,"commandResponseMsgOutput":"output1","outputs":1,"options":[],"x":1700,"y":120,"wires":[["f741509.947aeb","3c05b2a6.a43e1e"]]},{"id":"560a940b.49825c","type":"cronplus","z":"a2d1264d.2189b8","name":"every-minute","outputField":"payload","timeZone":"","persistDynamic":false,"commandResponseMsgOutput":"output1","outputs":1,"options":[{"name":"min","topic":"describe","payloadType":"json","payload":"{\"command\":\"describe\",\"expressionType\":\"solar\",\"solarType\":\"all\",\"solarEvents\":\"sunrise,sunset\",\"location\":\"51.5024701136258 0.011844635009765625\"}","expressionType":"cron","expression":"0 * * * * *","location":"","offset":"0","solarType":"all","solarEvents":"sunrise,sunset"}],"x":1490,"y":120,"wires":[["4a271714.8ef808"]]},{"id":"8e87e155.6e8e5","type":"debug","z":"a2d1264d.2189b8","name":"","active":true,"tosidebar":true,"console":false,"tostatus":true,"complete":"payload","targetType":"msg","statusVal":"payload.state","statusType":"msg","x":1870,"y":200,"wires":[]},{"id":"f741509.947aeb","type":"function","z":"a2d1264d.2189b8","name":"morning? afternoon? night?","func":"var solarState = msg.payload.result.solarState;\nmsg.payload = { };\nif(solarState.day && solarState.direction == \"fall\") {\n msg.payload.state = \"afternoon\";\n} else if (solarState.eveningTwilight) {\n msg.payload.state = \"evening\";\n} else if (solarState.night) {\n msg.payload.state = \"night\";\n} else {\n msg.payload.state = \"morning\";\n}\nmsg.payload.details = solarState;\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","x":1540,"y":200,"wires":[["8e87e155.6e8e5"]]},{"id":"3c05b2a6.a43e1e","type":"debug","z":"a2d1264d.2189b8","name":"","active":false,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":1850,"y":120,"wires":[]}]