BS ISO 14490-4:2005 pdf download.Optics and optical instruments— Testmethods for telescopic systems— Part 4: Test methods for astronomical telescopes.
4.2 Focal lengths of objective and eyepiece
The test methods for the local lengths of objective and eyepiece shall be as given In 4.2.1 or 4.2.2.
4.2.1 Focal length of objective lens and eyepiece (nodal slide method)
Refer to Figure 1. Arrange the rotary table (item B wi Figure lj (nodal slide stand, so that the aiis ci rotahon perpendicular to the optical axis of the collimator lens (item 3) on an optical bench (Item 6). Place a reticle (item 2) at the focal plane of me collimator. On the rotary table, a slide stand (item 7) is moving in the direction of the optical axes of me microscope (item 5), which has its optical axis approximately coinciding with that of the collimator. Measure the focal length fin accordance with 4.2.1.1 to 4.2.1.3.
4.2.1.1 Install the alignment reticle (item 4 in Figure 1) on the slide stand (item 7) so that me alignment reticle (item 4) coincides with the axis l the rotation of the rotary table (item 6). as shown in Figure 1 a). While adjusting the microscope (item 5) so mat the relicle (item 4) can be seen clearly, read out the position of the microscope on the optical bench (item 6) and stop when the posItion of the reticle (item 4) is such that, when it is slightly rotated about its vertical axis, there is no lateral movement of the image.
The test methods for the local lengths of objective and eyepiece shall be as given In 4.2.1 or 4.2.2.
4.2.1 Focal length of objective lens and eyepiece (nodal slide method)
Refer to Figure 1. Arrange the rotary table (item B wi Figure lj (nodal slide stand, so that the aiis ci rotahon perpendicular to the optical axis of the collimator lens (item 3) on an optical bench (Item 6). Place a reticle (item 2) at the focal plane of me collimator. On the rotary table, a slide stand (item 7) is moving in the direction of the optical axes of me microscope (item 5), which has its optical axis approximately coinciding with that of the collimator. Measure the focal length fin accordance with 4.2.1.1 to 4.2.1.3.
4.2.1.1 Install the alignment reticle (item 4 in Figure 1) on the slide stand (item 7) so that me alignment reticle (item 4) coincides with the axis l the rotation of the rotary table (item 6). as shown in Figure 1 a). While adjusting the microscope (item 5) so mat the relicle (item 4) can be seen clearly, read out the position of the microscope on the optical bench (item 6) and stop when the posItion of the reticle (item 4) is such that, when it is slightly rotated about its vertical axis, there is no lateral movement of the image.
