Hey guys,
I'm quite new to this hobby so I'm still trying to sort a few things out.
I currently have the SW 72ED with the OVL field flattener mounted on the Star Adventurer and I'm imaging with a Canon EOS 800D.
I'm struggling a bit with the distortion at the edges of my images where the stars are elongated away from the centre. This distortion can be seen most easily in my horse head and Orion Nebula image (both of which were cropped pretty aggressively). I've seen that graphic showing what differently distorted stars at the edge of an image means regarding back focus and, based off this, I should try increasing the back focus distance to get rounder stars across the entirety of the image, would this be correct? And if it is, does anyone know by how much I should increase this distance (I'm guessing only a few mm)?
I know with my current beginner setup I'm putting a bit of strain on the poor Star Adventurer but the distorted stars don't seem to be from bad guiding or bad polar alignment on my part, at least I don't think so, perhaps I'm wrong here too?
If anyone has any suggestions or has experienced a similar problem I would be extremely grateful for any help.
-Evan
I'm quite new to this hobby so I'm still trying to sort a few things out.
I currently have the SW 72ED with the OVL field flattener mounted on the Star Adventurer and I'm imaging with a Canon EOS 800D.
I'm struggling a bit with the distortion at the edges of my images where the stars are elongated away from the centre. This distortion can be seen most easily in my horse head and Orion Nebula image (both of which were cropped pretty aggressively). I've seen that graphic showing what differently distorted stars at the edge of an image means regarding back focus and, based off this, I should try increasing the back focus distance to get rounder stars across the entirety of the image, would this be correct? And if it is, does anyone know by how much I should increase this distance (I'm guessing only a few mm)?
I know with my current beginner setup I'm putting a bit of strain on the poor Star Adventurer but the distorted stars don't seem to be from bad guiding or bad polar alignment on my part, at least I don't think so, perhaps I'm wrong here too?
If anyone has any suggestions or has experienced a similar problem I would be extremely grateful for any help.
-Evan
