 Michael GambonJohn Harrison | John Harrison |
 Jeremy IronsRupert Gould | Rupert Gould |
 Ian HartWilliam Harrison (Adult) | William Harrison (Adult) |
 Andrew ScottJohn Campbell | John Campbell |
 Bill NighyLord Sandwich | Lord Sandwich |
 Gemma JonesElizabeth Harrison | Elizabeth Harrison |
 John WoodSir Edmund Halley | Sir Edmund Halley |
 Anna ChancellorMuriel Gould | Muriel Gould |
 Brian CoxLord Morton | Lord Morton |
 Samuel WestNevil Maskelyne | Nevil Maskelyne |
 Ian McNeiceDr. Bliss | Dr. Bliss |
 Jonathan CoyAdm. Sir Cloudsley Shovell | Adm. Sir Cloudsley Shovell |
| CChristopher HodsolCapt. Ainsley | Capt. Ainsley |
| LLiam JenningsWilliam Harrison (Young) | William Harrison (Young) |
 Peter VaughanGeorge Graham | George Graham |
 Nigel DavenportSir Charles Pelham | Sir Charles Pelham |
 Tim McInnernyChristopher Irwin | Christopher Irwin |
 John StandingCapt. Proctor | Capt. Proctor |
 Peter CartwrightArmy Doctor | Army Doctor |
 Stephen FrySir Kenelm Digby | Sir Kenelm Digby |
 Daragh O'MalleyCapt. Bourke | Capt. Bourke |
 Cliff ParisiLt. Draper | Lt. Draper |
 Michael CochraneWaddington, Gould's solicitor | Waddington, Gould's solicitor |
 Tobias MenziesHalley's Secretary | Halley's Secretary |
 Charles EdwardsLt. Seward | Lt. Seward |
 Pip TorrensCapt. Lindsay | Capt. Lindsay |
 T. P. McKennaEdmund Burke | Edmund Burke |
 Barbara Leigh-HuntDodo Gould | Dodo Gould |
 Peter-Hugo DalyJohn Jefferies | John Jefferies |
 John NormingtonMr. Greene | Mr. Greene |
