These prints are a high quality print reproducing “The Asia Astra Robot”  cover painting from ASTRA album (1985) they  printed on museum quality paper with archival ink.
This is an open edition but with 250  signed by the artist Roger Dean.
The dimensions and paper are, 
Paper 155 lb’s (330 gsm) Somerset Velvet
Paper Size 23.4” x 16.5” (A2)
Approximate Image Size 21.5” x 15” (510mm x 330mm)