Criteria
Reflector
Refractor
CAT
Cost
Cost least per inch
Cost most per inch
In the middle, not
as inexpensive as a
reflector, not as
expensive as a
refractor.
Image Quality
Can produce very
good to excellent
images
APO Refractors tend
to have the best
image and contrast
Can produce very
good to excellent
image
False Color
No false color
An ACHRO
refractor will
produce false color
on bright objects,
APO which cost
$$$$ will eliminate
false color
No false color
Contrast
Will have some
contrast loss do
to
secondary mirror
Refractors provide
the best contrast.
As the secondary
mirror tends to be
larger, the loss of
contrast is more
than the other types
Coma (seagull
shaped stars at the
edge)
Fast scopes (F5 and
below) tend to have
more Coma. A coma
corr
ector is needed
for visual
For visual generally
not an issue, for AP
will need a focal
reducer to eliminate
coma
For visual generally
not an issue, for AP
will need a focal
reducer to eliminate
coma. Coma is
more pronounced
compared to a
refractor
Collima
tion
(aligning of
mirrors or lenses)
Must be done
regularly
Usually never done,
may also be
impossible for a user
to adjust
Rarely needed,
holds collimation
well.
Mounts available
Alt
-
az, dob or
equatorial for smaller
scopes (under 8”)
Alt az and
equatorial, rarely
included in the cost
except for
inexpensive Achro
scope.
Alt az (up to 16”)
equatorial (up to
20”)
Largest Size
commercially
available
50”
8” (Note: Several
companies make
larger scopes to
order, the largest I
have seen is
currently 10”
)
20”
Eyepieces
Fast scopes need
Fast scopes need
SCT’s (F10+) are
good quality
eyepieces
good quality
eyepieces
very forgiving of
eyepiece quality.
Ability to do AP
Smaller scopes
possible, large scopes
on Dob mount are
limited to webcams,
long term ex
posures
are not possible. RC’s
are excellent for AP
APO’s have the
highest quality
image for given
aperture. Usually
recommended for
beginners.
SCT’s are not
recommended for
beginners, fast
Schmidt Newtonian
and Mak
Newtonian are
excellent imaging
scopes.
Enter the password to open this PDF file:
File name:
-
File size:
-
Title:
-
Author:
-
Subject:
-
Keywords:
-
Creation Date:
-
Modification Date:
-
Creator:
-
PDF Producer:
-
PDF Version:
-
Page Count:
-
Preparing document for printing…
0%
Σχόλια 0
Συνδεθείτε για να κοινοποιήσετε σχόλιο