iPad to Telescope Bracket for Generating Flats

thingiverse

This device securely holds an iPad against the lens of a 4-inch refractor telescope to capture flat field images in astrophotography. Astrophotographers combine three types of pictures: Lights (actual night sky images), Darks (noise created by long exposures with a lens cap), and Flats (uniformly lit source images used to remove lens vignetting). Multiple images are taken, with darks and flats subtracted from lights to create the final image. This device is designed to aid in creating Flat pictures using an iPad as the light source. Astrophotographers often use various methods to capture a uniformly lit flat field for Flats. Some use a t-shirt wrapped over the telescope's end while pointing at a light source, but this can be risky and may damage the expensive iPad. A more elegant solution is to display a uniform gray image on an iPad screen. This device prevents accidents by gripping the telescope lens and securely holding the iPad in place. This device was specifically designed for the Explore Scientific 102mm (4-inch) refractor telescope. It holds an iPad against this telescope to capture flat field images. A uniform gray image can be displayed on the iPad to create a flat field. Adding a sheet of paper helps diffuse the light even more. Four sliding brackets grip the iPad securely, and rubber bands bias the grippers. 3mm diameter by 6-10mm long metric screws hold the grippers in place. Note that the screws must not extend beyond the platform surface to avoid damaging the iPad screen. Check this before installing the bracket onto the iPad. This device is designed for a secure connection but does not provide a rigid attachment. The iPad may still fall off if the telescope is pointed sideways or downward. Use caution and only point the telescope vertically upward. This device was specifically designed for the Explore Scientific 102mm refractor. Other sizes may be created in the future as time allows. The actual outside diameter of the lens this bracket is designed for is 120mm, while the actual width of the iPad it is designed for is 175mm.