Whats the difference between Spider & Parabolic reflectors for MH's?

jay-cee123 · 01/19/2006, 12:54 PM

Which is better? they look similar.

Parabolic
http://www.hellolights.com/methalparref.html

Spider
http://www.marinedepot.com/md_viewIt...product=CP5753

Planning on using with Single end / mogul type bulbs.

TIA

physicslord · 01/19/2006, 01:22 PM

My guess would be there is no difference between those two designs - just the name.

The word "parabolic" just refers to the overall curved shape. Obviously a real parabola wouldn't have those kinks in it like that though.

If it weren't for the bulb blocking the middle, I think a parabola would be an almost ideal design for dispersing light in a uniform manner.

zangler · 01/19/2006, 01:45 PM

the parabola works even with the bulb in the middle

physicslord · 01/19/2006, 02:25 PM

Well, to clarify, a parabola with a tiny bulb at the focus would work even better.

Unfortunately, a real life bulb actually blocks many of the light rays being reflected off the back.

01/19/2006, 12:54 PM	#1
jay-cee123 Registered Member Join Date: Dec 2005 Location: West Coast Posts: 188	Whats the difference between Spider & Parabolic reflectors for MH's? Which is better? they look similar. Parabolic http://www.hellolights.com/methalparref.html Spider http://www.marinedepot.com/md_viewIt...product=CP5753 Planning on using with Single end / mogul type bulbs. TIA

01/19/2006, 01:22 PM	#2
physicslord Registered Member Join Date: Feb 2005 Location: Santa Cruz Posts: 469	My guess would be there is no difference between those two designs - just the name. The word "parabolic" just refers to the overall curved shape. Obviously a real parabola wouldn't have those kinks in it like that though. If it weren't for the bulb blocking the middle, I think a parabola would be an almost ideal design for dispersing light in a uniform manner. __________________ a border collie is my pilot animal Current Tank Info: 12 gal. JBJ nanoDX, BB, 2x24W PC lighting, JBJ ballast, Maxijet 400 powerhead, Hagen Tronic 100W heater, Red Sea 60 skimmer with Hagen Elite 802 pump.

01/19/2006, 02:25 PM	#4
physicslord Registered Member Join Date: Feb 2005 Location: Santa Cruz Posts: 469	Well, to clarify, a parabola with a tiny bulb at the focus would work even better. Unfortunately, a real life bulb actually blocks many of the light rays being reflected off the back. __________________ a border collie is my pilot animal Current Tank Info: 12 gal. JBJ nanoDX, BB, 2x24W PC lighting, JBJ ballast, Maxijet 400 powerhead, Hagen Tronic 100W heater, Red Sea 60 skimmer with Hagen Elite 802 pump.

01/19/2006, 01:45 PM	#3
zangler Registered Member Join Date: Feb 2003 Location: Houston Posts: 62	the parabola works even with the bulb in the middle