mercury-tungsten blended lamps ~ mercury vapour lamps ~ lampholders ~ ordering and p&p

Mercury-tungsten blended bulb for moth-trapping
...........Updated ~ 07 Jan 2008
2003 was my second year of moth trapping in my north London garden. I built a 'Skinner' trap and have used a 160w mercury-tungsten blended bulb from Apr/May to Sep/Oct, as has a friend in a Hertfordshire garden. Whereas I have trapped c.175 species of macro-moth, the more rural Hertfordshire location is undoubtedly richer with c.280 species of macro-moth recorded here. Click here to view the combined 2002-3 macro-moth list for these two gardens. We have been using 15W blacklight fluorescents over the same traps during winter ~ a page describing the results is under construction.
  • The 160w mercury-tungsten blended bulb fits a standard 27mm Edison Screw light fitting ~ see below for ES adpaters for standard 22mm Bayonet Cap lampholders and ES ceramic lampholders.
  • no expensive, heavy ballast unit is needed to run it, so it is simple to set up at home or away
  • it emits UV at similar levels (relative to other wavelengths) to traditional mercury vapour lamps. See spectral graphs below for more detail. Typical running cost would be less than 10p for an 8 hour night.
  • as with mercury vapour lamps, it runs hot and needs to be protected from breakage due to rain splash ~ although I use an umbrella, others use an upturned perspex coffee pot that lets through UV, unlike glass, and also gives some shatter-protection.
  • it attracts a wide variety of moths in good numbers and works very well as a moth-trap light source

160w Mercury-tungsten blended bulb....
....and mounted in a standard fitting above the trap
Internally coated with phosphor and containing a quartz mercury vapour discharge tube
(similar to a mercury vapour lamp), the bulb has a tungsten filament
which acts both as an incandescent light source and as a current-limiting device.
Some of the moths attracted to the mercury-tungsten bulbs in 2002/3

Green Arches
Old Lady (12 trapped in 2002)
Feathered Ranunculus

Sallow kitten
Eyed Hawk-moth
Merveille du Jour
Pale Eggar

Mullein Wave
 Toadflax Brocade


Spectral graphs ~ Ultra-violet (longer wavelength UV-A) around 365nm.

For comparison ~

Spectrum produced by a
250w mercury-tungsten blended lamp.

No need for a ballast, this type
of lamp will work direct from
standard light fittings.

  
Spectrum produced by a
250w mercury vapour lamp
which needs a ballast to run.		  

Mercury vapour lamps

Standard 125w mercury vapour bulb (needs ballast), ES27 fitting (Edison screw), Osram - £5.00 each

Lampholders

I can supply a simple Edison screw ES27 to bayonet cap BC22 (mm) adapter for £3.00 (left)
or an ES27 ceramic lampholder, to screw to a batten, also for £3.00 (right)

Ordering

In the first instance, please email acmiddleton@blueyonder.co.uk to confirm order details, total cost and ordering address.
Payment can be made by cheque, postal order or PayPal and order will be dispatched on receipt of cheque or funds.

160w mercury-tungsten blended bulb, E27, Philips Powertone ~ £10.00 each

125w mercury vapour bulb (needs ballast), E27, Osram ~ £7.00 each

Postage & package    
one bulb £1.50  
two bulbs £2.00  
three bulbs £2.50 email for p&p on larger orders

In general, ultra-violet lamp emissions decline quite quickly, and annual replacement is recommended to maintain UV output.
See Butterfly Conservation Herts & Middx Branch for more moth and butterfly information and links.


Andrew Middleton, London, UK ~ acmiddleton@blueyonder.co.uk