ATM re: herscellians #4

["Brien Stratton" <bstratton@sprint.ca>]

Hello,

First a few comments:

 I just threw this idea of mine for the herschellian out for discussion
since others were talking about their designs for  the  "modern"
herschellian (which involves off-axis parabolas, ect.). I thought it would
be interesting to talk and possibly make a "classical" design herschellian.
The reason you don't see many, is because the newtonian has been found to be
a better and more practical design.. This scope is not my first priority, I
have other newtonian-type scopes to make first.

Richard berry made a really long refractor once, I can't find the reference
right now. He found rediscovering an older design entertaining.( It's like
enjoying history. I read history books too..They are very instructive for
understanding where we have come from.) He also no doubt learned new skills
in lens making,mounts, ect. So if someone wants to make a herschellian, he
would gain skills in producing long focus mirrors , testing,  mounts,ect.

Those who say the images  of a 6" f/30 herschellian  are not good on the
planets , or the moon, can I kindly  ask you if you have made one, or have
looked through one?  I have heard from  people that the images were good,
not distorted.

About rouge making a better polish. I have heard many accounts of people
using it, and getting smoother results han other polishing agents. That is
how it is advertised from one supplier (Willman-Bell). If you are going to
make a really long focus mirror than the polish quality  becomes more
important since any defect on the mirror is magnified a lot. In fact that is
why you can make a longer focus mirror, because the mirrors imperfections
stand out at the coc null test. I don't have the time to have scientific
tests done to confirm that rouge is better. I would just use it based on the
advice I have received, and have it well polished.

The Berry tripod:

I have seen many pictures of the alt/azimuth type of mount for long focus
refractors.I have heard from two people that liked their Berry style tripod
. One guy told me that he can go past zenith when the tube is overhead, so
maybe the tube catches on the legs at only certain points? I would like
input from anyone else on how this tripod works at zenith. Also , is there
any other design that would work better than the Berry tripod for a long
focus herschellian telescope, which would be "quick" to setup, and not too
"heavy " to lug around?

Wind problem:

Just take it out when it is not windy! I will have a host of other scopes to
use when windy anyways.

This forum:

Remember the founding statements for this forum found at the ATM list FAQ
1:0: Introduction:

" The members of the ATM list are generally very helpful and very friendly.
In fact, we feel this is the friendliest gathering of individuals on the
net."

Love ya,

Brien Stratton