Having tested the ZWO ASI178MM-cooled for UV imaging, and found that it is very capable for such invisible band imaging, I decided to take it to the next level of testing to see what are the limits to its capabilities. My subject is the more well known Dandelion flower which I had picked from my back garden. This flower has been imaged many times in UV, so it is sort of a reference flower for UV imaging.
First photo was taken with my Olympus E-M5, Coastal Optics 60mm F4 @ F11 using the Quantum X4D as light source, to show the dandelion in false UV colours.
I previously did not manage to get a good shot of the ZWO ASI178MM-cooled from the back. Because of the crop factor of the imager, I do have to move the camera fairly far from the flower (near the edge of the worktop furthest from the flower).
Below I have included the questions I was asking and show you the answer in the photos that I took as a result.
Q1. With the weak UV from the fluorescent tubes of my indoor studio, can I do UV-imaging with this camera?
Answer: Yes. With the gain of 100 and 5 seconds exposure it is possible to image in UV using the weak fluorescent lighting from my indoor studio.
Q2. What exposure will be required to image in UV using 365nm UV torch?
Answer: With 2 Nichia-chip 365nm UV torches (one on each side) and gain 0 & F5.6 aperture, I managed to capture the image below using 0.08s exposure. Using Gain 100 would result in a much faster exposure time.
Q3. Can this imager capture into deeper UV i.e. 320-330nm?
Answer: Yes it can.
I used 330AF20 and 325BP10 filters stacked together to get the images below; the reason to stack is that there are some areas where the dichroic coatings have come off from the 325BP10 filter. I used Gain 100 and the Quantum X4D as light source.