The following persons may be present at the execution: the executioner, and such persons as may be necessary to assist him in conducting the execution; the Board of Directors of the Department of Corrections, two physicians, including the prison physician, the spiritual advisor of the condemned, the chaplains of the Department of Corrections, the county judge and sheriff of the county in which the Department of Corrections is situated, and any of the relatives or friends of the condemned person that he may request, not exceeding five in number, shall be admitted. No convict shall be permitted by the prison authorities to witness the execution.