Unidentified HPS Holophane Style High Mast Offset Light « on: June 14, 2026, 10:46:29 PM » Author: Omnilight37
Hello everyone, this particular 400W High Pressure Sodium offset lamp was a staple of the American Southwest in the 1990s and early 2000s. I'm pretty sure it was made by Holophane but I'm having trouble identifying the precise model and optics. Do any of you recognize the model and manufacturer?
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I'm an avid lighting enthusiast who works with and studies ballasts, ignitors and lighting optics while identifying various models and manufacturers of electric lighting. I am actively studying particle physics and seek to understand the mechanics of a photon.

	Re: Unidentified HPS Holophane Style High Mast Offset Light « Reply #1 on: June 15, 2026, 03:14:05 AM » Author: LightsoftheWest
Those are the GE Turnpike, model RPFT. Holophane made the Mongoose, which ADOT also used quite a bit. The AEL InterState Series 185 was also a popular offset roadway luminaire. Most in the Phoenix area have been replaced by Holophane Mongoose MGLEDs and MGLEDMs.
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	Re: Unidentified HPS Holophane Style High Mast Offset Light « Reply #2 on: June 15, 2026, 11:00:20 AM » Author: Omnilight37
@LightsoftheWest Do you happen to know what might be causing these RPFTs to turn around and twist so frequently? I've seen multiple over the years whose luminaires have twisted in the wrong direction, such as an RPFT supposed to be illuminating a shoulder lane illuminating an exit lane, and the right RPFT in this image has been alternating angles for years. Are the bolts just poor or are people out there changing the angles of light?
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*Getting Brighter by the Day!*

I'm an avid lighting enthusiast who works with and studies ballasts, ignitors and lighting optics while identifying various models and manufacturers of electric lighting. I am actively studying particle physics and seek to understand the mechanics of a photon.

	Re: Unidentified HPS Holophane Style High Mast Offset Light « Reply #3 on: June 15, 2026, 03:19:27 PM » Author: LightsoftheWest
I would say poor bolts. Arizona gets pretty strong winds.
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LG's North American luminaire identification specialist

**If anyone wants to learn more about any company or product you've never heard of before, do please leave a comment saying so on one of my gallery pictures or by PM, and I'd be happy to give a thorough explanation.**