Hi Tony, Don’t know how far your net investigations have gone but there are some good ADSABS links from the Wikipedia entry for Skalnate Pleso Atlas of the Heavens. Follow those through and see where it takes you. Apparently Sky Publishing Corp (Sky & Tel) took on publishing it in the mid fifties of last century.
A search for Antonin Becvar will get you to some more info with a piece by Lubor Kresak. If you go on to the Cloudy Nights Forum and do a search for Skalnate Pleso Atlas using the forum’s search facility there is more information. Do the broad full forum search rather than narrow yourself down to the specialist forum group.
My second (1957) observed N/E comet Mrkos was discovered at Skalnate Pleso so is a special place for me. Missed out on a market stall purchase of the atlas in Accrington back in the 1990s ( going for a song too).Managed a great astro holiday in the region with visits to Lomniki Stit , Skalnate Pleso and an occultation symposium at Stara Lesna Observatory back in the late nineties. Rafted down the Dunajek river on the same trip.