Something like this is invaluable for checking to see if the arc tube in a lamp is still good. 

I believe I have a fluorescent lighted sign in my grandmothers basement.

They were still there as of August 2023!

Don’t forget the Wide-Lite 4000.

White SONs have a nice unique warm color that oversaturates yellows, greens and reds in a pleasing way and high CRI, amount of deep red is just ridiculous, but are downgrade from common SON in almost all other ways. They are expensive, life is short and light output drops to about 1/2 of SON of the same power. And of course they need a complex stabilized ballast with a special voltage-current curve.

Will do, RRK and Medved. I'll have a look this evening and let you know my findings. The lamp might be at fault? Not certain. It's a clear 70W 55V BT-25 lamp from 1985 (Philips-Westinghouse).

I wanted the 70w Deluxe versions for the ease of use (i already have a nice 70w Philips electronic driver), and because the amount of light is still somewhat doable indoors. Of course it's still a lot. But the 150w SON Deluxe i can find online, that would just be way too bright.
It's also because i like to see how good/bad the 'better' alternative to common SON lamps is. Why don't we see more of them? Were they that much more expensive, less efficient, or something else? The Deluxe mercury vapor lamps are really good in my opinion and even outdoors i feel that it would've made streets feel more friendy. I'm happily using my little 50w HPL-Deluxe, which has a very sufficient color rendering for domestic use. It's much nicer than a 640 fluorescent, for instance. Subjective of course, but still.

The SDW-T is neat because it marks the end of the line for sodium vapor lamps. I am really excited to see what kind of light it produces, and how it compares to warm white CDM-Ts or something.

Heya I'm willing to trade my industria Vectra that i was originally going to do a restoration project on but unfortunately I never had time to do it and plus I don't have motivation for it, So far I don't think most of the stuff most vectras have are in the lantern but wires and the bulb are inside with it's tray, However I don't think it had a gear when i found it. I'll be willing to trade it for another lantern in decent quality.

I think you have what would be called in Britain an MBTL lamp, where the L does not mean Luminescent (ie phosphor) but instead is a simple light diffusing coating of silica powder, as used on incandescent lamps to produce a more diffuse light.

In the British Philips catalogues they listed three types of 160W :  MBT with frosted bulb, MBTL with frosting+silica, and MBTF with frosting+phosphor.  It seems the Dutch nomenclature did not cater for all those variants, hence the confusion even within Philips’ own factories.  I also have one such Philips lamp with conflicting etch.

In the USA GE and Philips both made 70W Deluxe HPS lamps, but even those are quite rare.

If you only need the DX spectrum and not SDW, the easiest way might be to take eg an SDW-T 100W and run it on a lower power magnetic ballast or a dimmable metal halide electronic ballast.  That would cause the vapour pressure to decrease and rather closely replicate the DX spectrum.  Since you see to be rather good at spectroscopy, you could reduce power gradually until the sodium d-line drops to the same width as a DX lamp.

The opposite of taking a standard SON lamp and overdriving it is also possible, but the spectrum would appear slightly greener than a real DX since overloaded sodium lamps do not follow the blackbody locus when dimmed.  The DX lamps contain less mercury to brings their colour point back to the BBL.  SDW lamps have the necessarily high amalgam ratio to limit that effect.  It would still not be a perfect DX spectrum, but should be very close.