TOA & SBIG 11k

http://astrosurf.com/legault/rosette_large.html

TOA & SBIG 11k
Posted by: "Thierry Legault" legault@club-internet.fr   th_legault
Thu Jun 8, 2006 11:51 am (PST)
hello

I have used the 130F during 2 years and now the 150 since november,
with a STL11k.
I would say that, considering the price of 130/150 plus STL, you do not
have to hesitate and take the F model with large flattener (it is not
compatible
with the 130S). You'll be sure to have sharp image from corner to corner
and very low vigneting. I used the reducer-flattener on the 130F with
a ST10 and it worked very well but I do not believe that it would give results
as good as the large flattener with the STL.
Anyway, even with a ST10 you'll see field curvature if you don't use one
of the flatteners, field curvature depends only of the focal length of a
refractor, not its design (doublet or triplet, apo or achro), if we except
special designs like FSQ.
You have also to consider the weight of the STL plus flattener (plus eventually
AO-L), the 4" focuser is much better for that reason too.

Here are full size images taken with 130F, flattener and STL:
- rosette in Halpha: http://astrosurf.com/legault/rosette_large.html
- bubble nebula LRGB: http://astrosurf.com/legault/bubble_large.html

and the 150, flattener and STL:
- M101 LRGB: http://astrosurf.com/legault/m101.jpg
- horse head LRGB: http://astrosurf.com/legault/b33_large.html

regards