58 ASTRONOMY • DECEMBER 2018
D
o you like to take images of
large star fields or pictures of
extended nebulous objects using
an astronomical CCD, cooled
CMOS, or DSLR camera? If the
answer is yes, you’ll want to take a hard
look at Meade’s new 70mm Astrograph
Quadruplet APO Refractor. Sporting well-
corrected optics, a smooth 2.5" focuser, and
a 42-millimeter corrected image circle, this
scope can handle cameras with full-frame
chips. It’s also lightweight, so it rides easily
on just about any mount.
When I take wide-field shots, I enjoy
the simplicity of unguided imaging that
short-focal-length instruments allow. So,
I jumped at the opportunity to put this
scope through its paces in my backyard
observatory.
Unpacking
The scope arrived in a nice aluminum
carrying case packed in cutout foam. It
included attached rings with a short, blue-
anodized Vixen-style dovetail plate bolted
to them. Also mounted to the tube was
an adapter for a red-dot finder or other
pointing device.
The scope is quite light, weighing in at
just 4.5 pounds (2 kilograms). It has a
white finish and comes with a sliding dew
shield with a light-blue-anodized push-on
lens cover. The 2.5" focuser features a
standard coarse-focus knob on one side
and a 10-to-1 blue-anodized fine-focus
knob on the other. The range of the focuser
is 30 mm with an engraved scale on top.
Racking it in and out felt buttery smooth.
The back end of the drawtube includes
a screw-on cover and terminates with a
48-mm rotatable threaded opening, which
is also smooth. Meade doesn’t include a
star diagonal because the scope is an astro-
graph and not a visual instrument.
Optically, the 70mm Astrograph is
a Petzval design with a doublet lens up
front and two more corrective elements
farther back within the tube assembly.
Each of the four elements is made from
extra-low-dispersion glass, and all are
fully multicoated.
Mounting
When I tried to mount the scope on my
Paramount MyT, I noticed a problem. I
wanted to use a Losmandy-style dovetail
plate and slide it onto my mount’s plate.
However, that wasn’t possible because of
the low-profile rings. There was barely any
room between the bottom of the scope
and dovetail plate, so it was impossible to
attach a camera. The camera would hit
the dovetail plate, and there was no way to
move the scope forward to balance.
The only solution would be to attach a
set of risers to the rings. These would raise
the scope enough to allow me to attach a
camera. I didn’t have any risers that would
fit the rings, so I mounted a different scope
on the MyT and bolted the Meade to a
short dovetail plate that rode on top of the
other scope’s rings. This provided me with
enough room to attach the camera to the
scope and still slide it forward or backward
to balance the setup.
The critical focus zone of an f/5 tele-
scope like this one is tiny, on the order of
22 micrometers through a green filter, so
I also wanted to hook up a motorized
focuser to achieve best focus using automa-
tion. Luckily I had one designed for 2.5"
and 3" focusers. I easily adapted it to the
Meade focuser, mounting it on the fine-
focuser knob’s side. I used a few shims to
allow the unit to tighten around the plan-
etary gear housing, and it fit nicely.
Under the stars
With the scope mounted, the first camera
I decided to use was the SBIG STL-11000.
I wanted to see how the scope handled a
full-frame chip and to see if the focuser
would handle the weight of this large
Meade’s 70mm Astrograph Quadruplet APO
Refractor is for astroimaging only. The optics
sport a four-element Petzval design with a focal
ratio of f/5. IMAGE COURTESY OF MEADE
