I will soon be in the possession of a 20w itty-bitty LPS lamp. It is a spectral source, and has a tubular envelope and an octal vacuum tube base, which I do have a socket for.

The arc tube has 2 tungsten-wire-bundle electrodes (like an HID lamp) instead of emissive beehive filaments like in commercial LPS lamps. This lamp also contains a starting probe electrode connected with an internal resistor, just like any other probe-start lamp. The arc tube proportions are very similar to an MV or MH lamp, but it is not made of quartz, probably (hopefully) just 2 ply typical LPS glass.

The running arc voltage is  very low, 15V, and the lamp is supposed to be used with a specialized (probably electronic) ballast that costs over $100. This is a limiting factor for me, so I want to find a way to run it with what I have handy.

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I have the following questions:

Considering the low running voltage in conjunction with the starting probe, do you think this lamp would strike reliably on 120V OCV? I would think so but I just wanna make sure.

I know that a 120V choke ballast with a 15V lamp would have astronomical ballast losses compared to the lamp power itself, but I was wondering if I could just use my spare variac as an adjustable choke so I can dial in the right current. Do you think this would work? This would be around 1.3A line current for a 20w lamp lol, but it wont be running all day.

Is there a better way of running these other than the proper ballast?

Thanks!