RE: ATM Tube currents?

["Bertapelle, Ken" <Bertapelle.Ken@tci.com>]

Hello Peder,

My recollection from the discussion in Suiter's book is that tube currents
result in a distortion of the image that is asymmetrical in the vertical
direction.  This is due to the fact that the warmer air rises to the top 
of the tube, and the cooler air drops.  Atmospheric motion results in 
distortions that are randomly distributed all around the image. 

Regards,

- KenB

> -----Original Message-----
> From: Rovelstad, Peder [mailto:Peder.Rovelstad@standardregister.com]
> Sent: Monday, August 23, 1999 10:08 AM
> To: atm@shore.net
> Subject: ATM Tube currents?
> 
> 
> 
> Probably a simple answer to this question.  How does one 
> determine if they
> are seeing tube currents rather than atmospheric ones?  Do they look
> different?  I have a simple closed tube 6" Dob and it seems that stars
> appear rather fuzzy around the edges rather than points (120x), almost
> granular.  I'm using a Vixen LV 10mm at this power.  Hoping I 
> just don't
> have a crummy mirror,thanks...
>