Problems with CCD-world

[Tim Abbott]

The recent problems with CCD world have probably resulted from the
Hawaii<->Mainland upgrades that UH has been working on.  We have seen
badly reduced bandwidth from time to time.  Once this upgrade is
complete, I hope that the problems will go away (if they have not
already).  In the meantime, if your messages do bounce, or fail to
appear, please send them on to me, and I will remail them.  Otherwise,
please use CCD-world as normal.  I know it is tempting, but I would
appreciate it if subscribers would not send test messages to
CCD-world themselves -- the remailer is really quite dumb (deliberately
so) and such test messages do not acheive much.  Alternatively,
the challenge is to say something erudite about CCDs in such a 
message!  

Speaking of which: Keck observatory were recently kind enough to
arrange a two-day seminar on vacuum technology and were kind enough
to invite CFHT personel.  One recommendation which I thought I would
pass on to those who are interested is that we do not grease O-rings,
or at least, use the smallest amount on those surfaces which are 
under mechanical pressure.

Another interesting tidbit: the manufacturer's definition of Viton,
a common O-ring material, requires that it contain only 25% actual
Viton.  The rest can be anything - old tires, shoe soles, whatever.
The recommendation, therefore, for reliable O-rings is that the buyer
explicitly ask what fraction of Viton is in his O-rings.

And another: turbopumps should be allowed to slow to half speed after
use and then vented with dry nitrogen to avoid contamination with
lubricants from a roughing pump.

Cheers,

	Tim

-- 
Timothy M. C. Abbott                http://www.cfht.hawaii.edu/~tmca/tmca.html