A Time of Flight mass analyser comprising: one or more devices arranged and adapted to correct for tilt in one or more isochronous planes of ions that results from misalignment of ion-optical components of the mass analyser, wherein said one or more devices comprise one or more electrostatic devices for electrostatically correcting for said tilt; and an ion detector; wherein said one or more devices comprise a first acceleration stage and/or a first deceleration stage, wherein said first acceleration stage and/or said first deceleration stage comprises a third grid electrode and a fourth grid electrode, wherein said third grid electrode is inclined at an angle to said fourth grid electrode, and wherein said first acceleration stage and/or said first deceleration stage is arranged and adapted to act upon said ion beam passing through said first acceleration stage and/or said first deceleration stage in a manner such that the time of flight or time of flight characteristics of ions in said ion beam are varied non-uniformly in a first transverse direction (X-direction) across said ion beam; wherein said one or more devices comprise a second acceleration stage and/or a second deceleration stage, wherein said second acceleration stage and/or said second deceleration stage comprises a fifth grid electrode and a sixth grid electrode, wherein said fifth grid electrode is inclined at an angle to said sixth grid other electrode, and wherein said second acceleration stage and/or said second deceleration stage is arranged and adapted to act upon said ion beam passing therethrough in a manner such that the time of flight or time of flight characteristics of ions in said ion beam are varied non-uniformly in a second transverse direction (Y-direction) across said ion beam, wherein said second transverse direction is substantially orthogonal to said first transverse direction (X-direction); and wherein said first acceleration stage and/or said first deceleration stage is arranged and adapted to correct for tilt in a first direction, wherein said second acceleration stage and/or said second deceleration stage is arranged and adapted to correct for tilt in a second direction, and wherein said second direction is substantially orthogonal to said first direction, such that the isochronous plane of ions is brought into alignment with said detector plane of said ion detector. one or more devices arranged and adapted to correct for tilt in one or more isochronous planes of ions that results from misalignment of ion-optical components of the mass analyser, wherein said one or more devices comprise one or more electrostatic devices for electrostatically correcting for said tilt; and an ion detector; wherein said one or more devices comprise a first acceleration stage and/or a first deceleration stage, wherein said first acceleration stage and/or said first deceleration stage comprises a third grid electrode and a fourth grid electrode, wherein said third grid electrode is inclined at an angle to said fourth grid electrode, and wherein said first acceleration stage and/or said first deceleration stage is arranged and adapted to act upon said ion beam passing through said first acceleration stage and/or said first deceleration stage in a manner such that the time of flight or time of flight characteristics of ions in said ion beam are varied non-uniformly in a first transverse direction (X-direction) across said ion beam; wherein said one or more devices comprise a second acceleration stage and/or a second deceleration stage, wherein said second acceleration stage and/or said second deceleration stage comprises a fifth grid electrode and a sixth grid electrode, wherein said fifth grid electrode is inclined at an angle to said sixth grid other electrode, and wherein said second acceleration stage and/or said second deceleration stage is arranged and adapted to act upon said ion beam passing therethrough in a manner such that the time of flight or time of flight characteristics of ions in said ion beam are varied non-uniformly in a second transverse direction (Y-direction) across said ion beam, wherein said second transverse direction is substantially orthogonal to said first transverse direction (X-direction); and wherein said first acceleration stage and/or said first deceleration stage is arranged and adapted to correct for tilt in a first direction, wherein said second acceleration stage and/or said second deceleration stage is arranged and adapted to correct for tilt in a second direction, and wherein said second direction is substantially orthogonal to said first direction, such that the isochronous plane of ions is brought into alignment with said detector plane of said ion detector.