Angling for a great shot
Phone meets eyepiece: straight and steady is the key
One of the trickiest aspects of afocal smartphone astrophotography with a telescope is getting the phone’s camera lined up to the eyepiece. If you don’t, the edge of the eyepiece field of view can encroach into the shot and spoil the image or, at the least, the view will show ‘vignetting’, where the picture exhibits dark gradients. The trick to overcoming this is to, firstly, use an eyepiece with a relatively large exit pupil, as these tend to be more forgiving. If you have several eyepieces, experiment to see which gives the best results. Secondly, while ensuring that your smartphone camera lens is centred above the eyepiece aperture itself, also check that the device is held parallel to the top of the eyepiece and isn’t at an angle.