Thu, 12/17/2020 - 05:57
Hi ,
I was wondering if any progress has been made on this project.
Personally i am in need of a flat fielding system and the idea of illuminating from the OTA is very appealing. I the past i have built flat field "boxes" using LEDs and diffusing the light thru white Acrylic. Fine for portable systems but not so good for implementing an automated system in an observatory.
I will be persuing these ideas and install a system in my own observatory in the near future.
I will be using White expanded polystyrene as the "screen".
Does anyone have any recomendations for the type of LEDs to use?
Regards,
Bruce
I would love to see a recommendation for a specific ratio and makes* of LEDs to use to cover BVRI plus a detailed wiring diagram and power requirements that could be controlled remotely (on-off might be fine).
The alternative is to talk with light panel suppliers to include LEDs that would cover the entire BVRI spectrum and could provide panels similar to Spike-a-Flat. The problem is whether a company would be willing to make such panels for such a specialized and tiny market at a reasonable cost.
Ed
*from my own reading, the kinds of LEDs to include requires someone who understands LEDs and their spectral coverage to provide a recommendation.
Hi Ed
Light-Emitting Diodes: A Primer | light sources | Photonics Handbook | Photonics Buyers' Guide
White LEDs use UV on phosphers and are fairly uneven.
Light-emitting diode - Wikipedia
As for power, I would series them to your power supply voltage, then add parallel branches until you get enough light. That saves dumping power into current-limiting resistors. All diodes have current specs, so just design around that current. Once you pick a diode and have a power supply in hand, I can help.
Ray
I would also suspect if the leds are used to project onto a "white" panel, the material used for the panel will have a significant effect on the wavelength of light reflecting from that surface?
Hello! For my LED light box, I had to add incandescent bulbs (Christmas tree rice bulb string worked great) in order to cover I filter range. I could not find any I-band LEDs that cover the appropriate range.
Would incandescent be needed as well for projection? Best regards.
Mike