In answer to Mariner 2's question, I did this for several reasons:
For years I've been wondering if a pinhole camera could be used for nighttime astrophotography (imagining using pinholes, zone plates, pinhole sieves etc.) Then a new breakthrough came out last year (that I found out about relatively recently) regarding flat metalenses that could be used in Astronomy (not directly related to this, that has to do with paper thin optics without lenses, and I started thinking again about pinholes). All references I could find on google, including image searches, seemed to imply that it hasn't been done yet for nighttime astroimaging, and that it was not likely to have been done before (at least that's not detectable on the internet.) I've always wanted to make an image of the night sky with a pinhole, without glass in the imaging train.
I wanted to see if nighttime astrophotography is now possible without a telescope or glass optics (without using refraction or reflection, glass lenses or mirrors). I wanted to see if diffraction optics are useful for Astronomy (because ISO sensitivity is now so high that I imagined that it would now be possible to do; this is a proof of concept for me.)
I want to see what the colors of the stars and nebula look like without glass optics (it will not be natural looking, the nature of pinhole images, but I still want to see it, even if it looks artsy.)
I want to eventually see what the sky looks like with zero field curvature, with the ground in view (a Milky Way shot.)
I wanted to see if such a tiny aperture (<0.3 millimeters) could actually work for this purpose.) I wanted to have the smallest telescope in the world! :^) Now I do.
I had other images, but I chose the one with a basketball hoop in the frame to give a frame of reference relative to the focusing (because there is no manual focusing using this method, yet.)
I will now be able to improve the images understanding what will be needed to move forward.
Why did you do this though? Fun? Curiosity?