Re: BK7 vrs. float glass in SCT correctors, UV pass abilities?

Hi,
I have measured some of the older SCTs correctors transmission. Some
of these were uncoated and had transmissions down about 84%. Uncoated
BK7 was about 92%.

Al M


"Richard F.L.R. Snashall" <[EMAIL PROTECTED]> wrote in message news:<[EMAIL 
PROTECTED]>...
> Gary Heath wrote:
> 
> >Assuming that is incorrect, or at least not directly applicable in the case
> >of correctors for SCTs, I have to wonder if the increased throughput of the
> >UHTC coatings (especially the advertised 21%+ increase that appears to
> >extend beyond 700nm) provides enough pass of UV to do studies in this region
> >(using CCD and other devices that can detect UV) as does the use of BK7 for
> >correctors.
> >So ... my 'refined' question becomes, does the older "classic" BK7 12"
> >provide use in the UV range, that the GPS and later "float glass" versions
> >will not?
> >  
> >
> Just the way this question is worded seems off to me.  "beyond 700nm"
> from a "normal" perspective would be IR, not UV.  Is "UV" really what
> you intended to ask?
> 
> >Gary
> >
> >
> >  
> >