kosborn
02-07-2018, 11:56 AM
Hi all,
I have a Sky-Watcher Esprit 100ED (550mm focal length) that comes with a field flattener as standard. I understood that the flattener did not affect focal length but haven't been able to confirm that. When image solving in PixInsight, it reports among other things "Focal 630.93mm". I assume that's reporting calculated focal length based on pixel resolution and field of view but then that is increasing the native focal length rather than reducing as I'd expect from a flattener...? Or is that the effective focal length as the sensor doesn't cover the entire field of view of the telescope? Which leads me back to the first question: does anyone know if the standard Esprit field flattener is also a focal reducer?
Kevin
I have a Sky-Watcher Esprit 100ED (550mm focal length) that comes with a field flattener as standard. I understood that the flattener did not affect focal length but haven't been able to confirm that. When image solving in PixInsight, it reports among other things "Focal 630.93mm". I assume that's reporting calculated focal length based on pixel resolution and field of view but then that is increasing the native focal length rather than reducing as I'd expect from a flattener...? Or is that the effective focal length as the sensor doesn't cover the entire field of view of the telescope? Which leads me back to the first question: does anyone know if the standard Esprit field flattener is also a focal reducer?
Kevin