Sury, excellent details you have there.
I'm no expert in M42 lenses, but I'll gladly share my experience on this matter.
First of all you need an adapter from M42 --> Alpha mount. You can find many cheap ones online.
There are some which confirm the focus (look here:
http://eadpt.cn/eadpen.htm)
Mind you, you might be disappointed in some lenses you found rather great with film, yet others will force you to use much more often than your present beloved lens.
One more thing, you have neither AF nor Programmed mode, so you'll spend much time thinking on the picture.
Oh, one more thing, when viewing EXIF data, the aperture will usually show 1.0
May I add one more point? Buying M42 lenses is quite rewarding, they are very cheap and can/may give you excellent results as Sury posted here on this page.
Go for it, Mike