Thats really worth knowing. I have previously steered clear of trying to solve images with severely trailed stars assuming it would say “Sorry guv, no stars in here”.
Stop Press: seems to depend on the aspect ratio of the trails. The longer a trail is compared to its width the less likely it is to solve. Still worth knowing that Astrometry.net can be quite tolerant.
Following on from Paul. Defo Bennett. Print 6, morning of 11 Apr 1970; print 7, morning of 10 Apr 1970. I may be wrong, but the bright star to the right of the comet in print 6 may be omicron And, with 2 And even further to the right.