A solar collector comprising: • a trough-formed reflector , • at least one holder for securing a fluid tube for receiving reflected solar radiation from the reflector to the solar collector , the fluid tube being connected to the solar collector by the at least one holder , wherein the holder is configured to, in an operation mode of the solar collector , partly encircle a circumference of a cross-section of the fluid tube and leave a portion of the circumference un-encircled by the holder , and direct the un-encircled portion to face a reflective surface of the reflector , such that the un-encircled portion is accessible for concentrated solar radiation reflected by the reflective surface, the holder comprising: • a base member adapted to abut the fluid tube , the base member comprising at least one securing means adapted to secure the base member to the solar collector , and • an immobilising member adapted to together with the base member immobilise a centre-line of the fluid tube in the solar collector when the fluid tube abuts the holder , the base member being connected with the immobilising member , such that the base member together with the immobilising member can partly encircle the circumference of the cross-section of the fluid tube and, in the operation mode of the solar collector , form an opening smaller than a diameter of the cross-section of the fluid tube , characterised in that the opening is located asymmetrically in relation to the solar collector's optical plane of symmetry. • a trough-formed reflector , • at least one holder for securing a fluid tube for receiving reflected solar radiation from the reflector to the solar collector , the fluid tube being connected to the solar collector by the at least one holder , wherein the holder is configured to, in an operation mode of the solar collector , partly encircle a circumference of a cross-section of the fluid tube and leave a portion of the circumference un-encircled by the holder , and direct the un-encircled portion to face a reflective surface of the reflector , such that the un-encircled portion is accessible for concentrated solar radiation reflected by the reflective surface, the holder comprising: • a base member adapted to abut the fluid tube , the base member comprising at least one securing means adapted to secure the base member to the solar collector , and • an immobilising member adapted to together with the base member immobilise a centre-line of the fluid tube in the solar collector when the fluid tube abuts the holder , the base member being connected with the immobilising member , such that the base member together with the immobilising member can partly encircle the circumference of the cross-section of the fluid tube and, in the operation mode of the solar collector , form an opening smaller than a diameter of the cross-section of the fluid tube , characterised in that the opening is located asymmetrically in relation to the solar collector's optical plane of symmetry. • a base member adapted to abut the fluid tube , the base member comprising at least one securing means adapted to secure the base member to the solar collector , and • an immobilising member adapted to together with the base member immobilise a centre-line of the fluid tube in the solar collector when the fluid tube abuts the holder , <EOS>