Custom-made film test target resolution chart (resolution up to 250cy/mm) Description: New. This is a test target resolution chart printed on 24x35mm high resolution film (which reaches specifically up to 250cy/mm of optical resolution) for testing resolving power of high magnification optical devices. Great for telescopes (any magnification) and low magnification microscopes/lopues (I would say up to a max. of 150-200x in microscopes would be good). It is custom-made with tiles and siemens stars arranged, compatible with testing software like IMATEST and similar. It was ordered custom-made to test telescopes. Several copies were sent to me and I keep one for myself (the one pictured on my LED testing device in first picture) and sell the rest to fund other projects. The dust spots you see in FIRST picture are from a covering glass that I placed over the film test. These are new and no dust on them. TWO AVAILABLE. MOUNTING: These charts are made to be illuminated from the back. How to mount it? I just put a 100x100mm white "scattering" glass at the back and a clear window glass at the front of this chart, and then placed it on a square LED ceiling light to which I added a variable driver with remote control. The ceiling LED cost was around 13, the variable driver for led was around 7. The glasses around 10. So, total cost was around 30 to mount these resolution charts. If you are using IMATEST and similar, I recommend to prevent overclipping and therefore to have variable driver added to the equation. I am testing right now at 20% of LED's total power to prevent "overclipping" (which makes slanted edge results more unreliable). More detailed information on how to use this chart for testing telescopes here: https://www.marronyazul.es/azul/how.htm (Click on PDF documents under "tests").