Re: ATM Eye piece suggestions for f/5 10" Dob please

["Albert Highe" <ahighe@ix.netcom.com>]

Chris,

My main scope is a 12.5" f/5. Shorter focal ratios show too much coma for my
taste. IMHO, f/5 is the minimum for a pleasing visual field without using
coma correctors. At very low powers, you'll detect some coma at the edges.
At higher magnifications, you'll never notice it.

Rather than thinking about spending the same amount on each eyepiece, think
about spreading your dollars proportionally over what you will use the most.
I think that magnification will be somewhere around 100X. I use a
wide-field 14mm eyepiece, producing 113X, 90% of the time. Spend the most on
this eyepiece. Then take your time to pick the others.
On a budget, I would buy eyepieces in this order:

100X
150X
2X Barlow (the Barlow will then give you 200X and 300X with your other two
eyepieces).
50X

There isn't too much in the $30-$50 range that I would recommend. (Of
course, we all have different thresholds for acceptable quality). Shop
Astromart for used name brand Plossls and orthos and you will find some in
this range. Everything else of quality will be in the $100-$200 range and
up. However, after you have used your scope for a while, I suspect you'll
want a good $200+ eyepiece in the 100X range.

Albert

----- Original Message -----
From: "ChrisR" <chrisr@es.co.nz>
To: <atm@shore.net>
Sent: Monday, April 02, 2001 12:46 AM
Subject: ATM Eye piece suggestions for f/5 10" Dob please


>
> Hi, I'm new to this list and telescope building in general.  I have a 10
> " f/5 mirror on the way along with a lot of other components. The mirror
> is actually being made by a guy with 40 years experience.  I was going
> to buy some blanks from him and have a go, but he had a nearly finished
> blank and offered to finish it for $50....great deal.  The question is
> what are good eyepieces to get for this scope considering a good  price
> and quality are both high on my list?  How many eyepieces would be a
> good idea at what magnifications considering the scope?  I'm not after
> one of these super pieces that cost like $200 US ...but quality around
> the $30-50 point would be nice if possible....  I know the mirror is
> perhaps a tad fast.....should I be looking at any particular eyepieces
> because of this?
>
> thanks for any and all help,
> Chris.
>
>