Widefield experiment in Cassiopeia w an old prime lens

[vineyard]

Hello,

I got an old cheap 50mm f1.7 prime lens just before Christmas (about 40 yrs old I suspect - an old Pentax SMC).  And I thought I would experiment with it for some wide-field shots.  I stopped it down to f4.  60 lights of 60s last night, just pointed it up to Cassiopeia on an iOptron Skyguider Pro.  ASI294MCPro w CLSCCD filter between the lens and the sensor.  Darks, flats & dark flats applied.  Stacked in DSS w some minimal tinkering in PI.  JPG for size.

I guess that's vignetting in the corners - there is curvature as well, but since that's in the corners that would have to be cropped out, it's not a loss.  Is that the Pacman nebula, w the Heart Nebula at right hand edge & the double cluster?

What do folks think - is it worth persevering w this lens?  Had I framed it better, I could have positioned the Heart & Soul in the middle, and gone for much more data to see what emerged?

With an APS-C sensor, the 50mm effectively becomes about 75-80mm, so an alternative would be to look for a wider lens (Pentax used to do a great 28mm f3.5 K lens but that's pricey)?

Anyway, just some fun & quick experimentation!

Cheers & stay safe,

Vin

(PS - the weird shapes on the middle of the left hand side are the stacked silhouetted branches of a tree that came into the FOV as the mount rotated!)

[vineyard]

So what with all these clouds & tier 4 lockdowns, I tinkered a bit more.  Here are 3 images - cropped & downsampled, then star-reduced, and also an annotated one from Astrometry.net (lots of objects!).