Temperature of Grain of Wheat Bulbs

Technology Instrumentation & Equipment
1

Back in 2014 (I think) Arne did a series on variable star capture, data reduction, etc. One of the ways for doing flats was using Grain of Wheat Bulbs. I built an array of bulbs, put a couple of translucent panels between the bulbs and my scope, and it seems to be working well for variable stars and spectroscopy.

The one question I have is: what temperature should I assign to these bulbs? Through trial and error I’ve converged on 1880 C.

Thanks,
Bob

2

Hey Bob, virtual all the manufacturers of small incandescent bulbs are no longer making them. In the good old days, there was a data sheet that might give you a color temperature, eg 2700K for incandescents. Are you running them at the rated voltage? or lower (dimmer) because the color temperature will shift depending on voltage (and filament temperature).
These little bulbs aren’t really a good reference source these days.
Cheers,
Colin

3

Colin,

Thanks. I’m running the bulbs at the “normal” 12 volts.

What is considered to be a good reference source?

Bob

4

Sorry, I missed your question.
Some people use the Optec/Alnitak flat panels. Like this:
https://optecinc.us/collections/types?q=Alnitak
Others use a gas discharge tube or LED or halogen bulb source.