Interesting lamp - its lumen output is nearly halfway between the 400 and the 1000W model. I remember that in the late 80s Philips briefly made a 1500W HPS lamp with two 750W burners in series crammed in a ED37 bulb... interesting concept.
Yes if they were stuck against each other, but in the cram HPS lamps Philips sells there is a space of about 2-3 centimeters between the burners, so the extent of radiative heat transfer between the discharge tubes is very limited.
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Forget the nuclear glare bomb. Try a supernova glare bomb. 