Light Meters

[DaveDragon]

UV rays cannot pass through glass.

Show us readings!!!!

 

[RehabRalphy]

UV rays cannot pass through glass.

Show us readings!!!!

Exactly :-D

 

[PuffDragon]

UV rays cannot pass through glass.

Show us readings!!!!

Exactly :-D

I know you both know this is a proven fact so there is really no reason for me to go take readings through glass.

But just to silence the critics, here you go.

Window closed

Window open w/screen

Window open w/o screen

 

[PinkPunisher]

Cool! I read somewhere that some UVB does pass through glass, not sure where but I didn't think it was true, glad to know the truth. You should be our researcher You know, test out some MVB's and see which one is the best. Who knows maybe it isn't the Megaray?

Spencer

 

[laurarfl]

I don't believe this info is on the UV UK website yet, but is from a member, posted to the pogona disease yahoo list. I gave credit to everyone so that it would be OK to post, I hope.

Good info, I think. By the way, anyone ever get a tan or burn through a rolled up car window in about an hour? I have with window down, not with window up (in short amount of time).

Laura

--- In <!-- e --><a href="mailto[email protected]">[email protected]</a><!-- e -->, "lilacdawndragon"
<lilacdragon@...> wrote:
>
> Hi, everyone.
>
> I'm concerned about some of the information being posted here
about
> UVB and UVB meters.
> I've been researching this subject for just over four years now
and
> I'm the author of the website <!-- m --><a class="postlink" href="http://www.uvguide.co.uk">http://www.uvguide.co.uk</a><!-- m --> where we
try
> to debunk the myths and test every UVB lamp currently on sale.
> We use a laboratory spectrometer and several broadband UVB meters
> including the Solarmeter 6.2 (readings in microwatts per cm2) and
> the Solarmeter 6.5 (readings in UV Index units). These meters are
> laboratory grade and are about $170 - $180 in the USA (I am in the
> UK and had mine sent over from America)
>
> We, too have cheap UVB meters and UV Index meters for around $25
for
> sale in the UK, and several were sent to me for assessment, by zoo
> keepers - since few people want to spend $200 when $20 will do.
> But unfortunately, these little toys are useless - I repeat,
> useless - for assessing reptile lamps.
> OK there's no way I can explain this simply so please excuse the
> technical terms.
>
> Expensive meters respond to the UVB wavelengths (280 - 320nm) and
> these are the wavelengths that produce vitamin D3 in the skin.
> Actually, the range is even narrower than that - the correct
> wavelengths for safe vitamin D3 production lie between 290nm and
> 315nm. Shorter wavelengths than 290nm are not found in sunlight.
> Such "non-terrestrial" rays are hazardous and have caused eye
damage
> when they are produced by certain reptile lamps. Wavelengths
longer
> than 315nm, although technically still UVB, don't produce much D3.
>
> The Solarmeters are extremely good because they use very expensive
> SiC sensors with interference filters fitted, so only the required
> wavelengths reach the sensor. Then each meter is calibrated by
hand
> to a NIST-traceable source... this calibration means that the
> reading is accurate to a certified 10% although it's probably
nearer
> 5%. The 6.2 meter records the entire UVB (280 - 320) and the 6.5
has
> a "weighted" response so the greatest response is exactly what we
> want; 280 - 315nm.
>
> The UV Index, measured accurately, is an extremely good indicator
of
> the D3 potential of a lamp - better than the full UVB spectrum. I
am
> changing over to UV Index as a unit of measurement for sun and
> lamps.... the Solarmeter 6.5 with a SiC sensor can be used for
both
> sun and lamps because it responds below 290nm. So dangerous lamps
> will give higher UV Index... See any weather website, or consult
> Wikipedia, for full information about the UV Index and its use as
a
> safety indicator, too.
> You can get the UV Index forecast for anywhere in the world, too,
> but REMEMBER, reptiles do NOT sit out in the mid-day sun. Some
> species bask in early morning sun, maybe till 9 or 10am only - a
UV
> Index of 3 or 4 is typical. Others live in shade all day. Oh yes,
> there is a GREAT deal of UVB in shade and even on overcast days,
far
> more than you get from most UVB tubes at recommended basking
> distances...about UV Index 1 or 2 is often seen.
> A UV Index of over 8 - 10 is "severe" and most reptiles have
> retreated. At mid-day in the tropics it can reach 15 - 17 but
> nothing is stupid enough to sit in that sort of sunlight (except
> maybe tourists.. or me, holding my meters.)
>
> But here's the BIG problem. The cheap meters don't use SiC
sensors.
> They use AlGaN sensors which are really cheap. These don't read
UVB
> below 290nm much anyway and are far more sensitive to UVA... and
> unless very carefully filtered, all they are really responding to
is
> the UVA. If carefully filtered to block the UVA response and
> properly calibrated they are fine for measuring UVB in sunlight,
but
> that type of meter is as expensive as a Solarmeter. Most of the
> cheap ones have no filters or proper calibration. I have tested 2
> brands here in the UK. They were hopeless.
>
> They were responding to the UVA in the sunlight... their readings
> roughly matched the Solarmeter 6.5 when the UV Index was 1 or 2,
but
> after that they soared up, so when the 6.5 gave the correct UV
Index
> as 3.7, one gave me a reading of 6 and the other, 11!! Now to get
11
> in Wales, UK is impossible....
>
> But when I tried them on reptile lamps they were not just bad,
they
> were totally useless. A particularly bad fluorescent compact lamp
> with dangerous short-wavelength UVB, giving horrific UV Index 20
at
> 6 inches with the high quality 6.5 meter - gave me only UV Index 1
> with both the cheap meters, because they couldn't see the UVB,
only
> the UVA - and there was hardly any UVA from these. This is
> dangerous - these meters would give a totally false sense of
> security.
>
> Then I tried them with mercury vapour lamps and halides, and these
> had far less UVB, all in the safe wavelengths, but a lot more UVA.
> Guess what? The cheap meters would give huge UV Indexes -even off
> the scale - where I was getting UV Index 1 or 2 on the Solarmeter.
>
> So please... don't buy a cheap meter. You aren't doing yourself
any
> favours. Your readings are likely to be totally misleading.
>
> I am hoping to publish my findings on the UV Guide website - and
> update it with UV Index information - over the winter.
>
> Best wishes,
> Frances
> UV Guide UK
>
>
> --- In <!-- e --><a href="mailto[email protected]">[email protected]</a><!-- e -->, "jon marsolais"
> <apsleymouse@> wrote:
> >
> > Good morning Jenea and Lily
> >
> > This one's very nice & cheap @ $24.95, it's in the US so
> > i hope that'll help you in the shipping part.
> > <!-- m --><a class="postlink" href="http://www.reliabilitydirectstore.com/Reliability-Direct-MS-98-">http://www.reliabilitydirectstore.com/R ... ect-MS-98-</a><!-- m -->
> Ultra-
> > Violet-Detector-p/rdi-ms98.htm?gclid=CMerldaAhJcCFSEfDQodr0WIXw
> >
> > And these are the ones just under and over $200
> > <!-- m --><a class="postlink" href="http://www.pro-measure.com/SearchResults.asp?Cat=31">http://www.pro-measure.com/SearchResults.asp?Cat=31</a><!-- m -->
> >
> > And this one is in Canada for a limited time. @$24.99 CAN
> > (the Source / circuit city is going bankrupt)
> > <!-- m --><a class="postlink" href="http://shopping.canoe.ca/shop/product--">http://shopping.canoe.ca/shop/product--</a><!-- m -->
> > catId_1002681__locale_en__productId_5793029.html
> >
> > Hope this is of help, the cheap ones work by a scale of 0<20
> > Use a pen & paper and start doing reading of light bulbs,
> > reptile bulbs, swirlies new and old, then start doing readings of
> > the sun.. 5.0rep bulb we get a new reading from 6 to 7.
> > I've never done a 10.0, but the sun on a 30C day is
> > off the scale of 20.
> >
> > The $200 ones read in wave lengths of NM
> >
> > Here's a useful table from Melissa Kaplan
> > on LIGHT SOURCES AND RADIATION (messurements in NanoMetre)
> > <!-- m --><a class="postlink" href="http://www.anapsid.org/uvtable.html">http://www.anapsid.org/uvtable.html</a><!-- m -->
> >
> > note: all bulb companies must give the wave length & intensity
> > (lumen)of they're bulbs.. rep., plant, normal.
> > should be posted on they're web site.
> > Here's one from GE for the plant bulb we use.
> > <!-- m --><a class="postlink" href="http://genet.gelighting.com/LightProducts/Dispatcher">http://genet.gelighting.com/LightProducts/Dispatcher</a><!-- m -->?
> > REQUEST=COMMERCIALSPECPAGE&PRODUCTCODE=49891
> >
> > Have a wonderful day,
> > - jon
> >
>