16
S
S
P
P
E
E
C
C
I
I
F
F
I
I
C
C
A
A
T
T
I
I
O
O
N
N
S
S
#21076 #21085
Optical System:
Refractor
Refractor
Aperture:
70mm (2.8")
90mm (3.5")
Focal Length:
900mm
1000mm
F/ratio: f/13
f/11
Focuser
Rack and Pinion
Rack and Pinion
Standard Oculars (or
Eyepieces)
20mm 1¼" (45x)
10mm 1¼" (90x)
20mm 1¼" (50x)
10mm 1¼" (100x)
Resolution
1.7 arc seconds
1.3arc seconds
Light gathering Power
100x unaided eye
165x unaided eye
Limiting Magnitude
11.4
12.3
Highest useful Power
142x
213x
NOTE: Specifications are subject to change without notice.
OPTIONAL ACCESSORIES
You will find that additional accessories enhance your viewing pleasure and expand the usefulness of your telescope. For
ease of reference, all the accessories are listed in alphabetical order.
Barlow Lens
- A Barlow lens is a negative lens that increases the focal length of a telescope. Used with any eyepiece, it
doubles the magnification of that eyepiece. Celestron offers two Barlow lens in the 1-1/4" size. The 2x Ultima Barlow
(#93506) is a compact triplet design that is fully multicoated for maximum light transmission and parfocal when used with
the Ultima eyepieces. The OMNI Barlow (#93326) is a compact achromatic Barlow lens that is under three inches long and
weighs only 4 oz. It works very well with all Celestron eyepieces.
Exotherm
(#93504)- Perfect for chilly evenings outdoors camping, stargazing, or at sporting
events, the Exotherm hand warmer is convenient, reusable and made from nontoxic materials.
Heat lasts up to 1 hour.
Eyepieces
- Like telescopes, eyepieces come in a variety of designs. Each design has its own
advantages and disadvantages. For the 1-1/4" barrel diameter there are four different eyepiece
designs available.
•
OMNI Plössl
- Plössl eyepieces have a 4-element lens designed for low-to-high power observing. The Plössls offer
razor sharp views across the entire field, even at the edges! In the 1-1/4" barrel diameter, they are available in the
following focal lengths: 4mm, 6mm, 9mm, 12.5mm, 15mm, 20mm, 25mm, 32mm and 40mm.
•
X-Cel
- This 6 element design allows each X-Cel Eyepiece to have 20mm of eye relief,
55° field of view and more than 25mm of lens aperture (even with the 2.3mm). In order to
maintain razor sharp, color corrected images across its 55° field of view, extra-low
dispersion glass is used for the most highly curved optical elements. The excellent
refractive properties of these high grade optical elements, make the X-Cel line especially
well suited for high magnification planetary viewing where sharp, color-free views are
most appreciated. X-Cel eyepiece come in the following focal lengths: 2.3mm, 5mm,
8mm, 10mm, 12.5mm, 18mm, 21mm, 25mm.
