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Light Meters

PuffDragon

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RehabRalphy said:
DaveDragon said:
PuffDragon said:
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
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Window open w/screen
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Window open w/o screen
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PinkPunisher

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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 :p You know, test out some MVB's and see which one is the best. Who knows maybe it isn't the Megaray?

Spencer
 

laurarfl

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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:p[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:p[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
> >
>
 

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