Talk:Heliometer

Error in illustration
The image described as 'Double image of the solar disk' is misleading. A vertical cut of the lens and the vertical shift of one half would produce a figure of two disks shifted vertically (overlapping like here, or touching). The illustration should look like a digit 8. A horizontal displacement is an error. --CiaPan (talk) 08:13, 5 June 2017 (UTC)
 * The split objective lens is rotatable and does not have to align vertically. This is not so important for the sun, but if you want to measure the separation of two stars you need to be able to align the lens cut with those stars. --Wrongfilter (talk) 16:28, 10 January 2018 (UTC)