m38-300_POSTING
Single five minute shot of M38 in Auriga with the 80mm ED doublet. The night was getting on and I was getting tired. This image is not cropped, so if you zoom in you can see the (to my eye minor) effect of field curvature. Field curvature grows like the square of the distance from the center of the image, so even cropping out the outermost 30% (15% on either side) of the image reduces the small amount shown here by 1/2, making it almost impossible to see.
m38-300_POSTING
Single five minute shot of M38 in Auriga with the 80mm ED doublet. The night was getting on and I was getting tired. This image is not cropped, so if you zoom in you can see the (to my eye minor) effect of field curvature. Field curvature grows like the square of the distance from the center of the image, so even cropping out the outermost 30% (15% on either side) of the image reduces the small amount shown here by 1/2, making it almost impossible to see.