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Orion SkyView Deluxe 8 |
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REVIEW ARCHIVES Refractors Barlow
Lenses LINKS FAVORITE LINKS NASA
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History
& Observing Location
I
have been using the SVD 8 Newtonian reflector for more than one year,
enough time to evaluate the quality of the instrument, optics and ease of
use, albeit subjectively biased.
I am located in Northeastern Ohio (41o Latitude)
approximately 15 miles south of Cleveland. Sky glow is moderate although
increasing as urban sprawl continues into the countryside.
The majority of my observing is conducted from my backyard with the
SVD EQ in the down position, a pneumatic secretarial chair, small side
table and classical music playing softly in the background. Naked eye
visibility of the firmament is approximately 4th magnitude on
clear nights. Equipment
Choice
I
spent two months researching telescopes - refractors through catadioptics.
Each class has its merits and demerits; i.e., the refractor gives
the best image quality but in larger apertures is very costly, while the
cassegrains offer larger aperture optics, the image intensity suffers due
to the additional lens
“folding” the light path to the eyepiece and the first lens
collects dew.
The first rule of telescopic viewing is aperture
– “Bigger is Better”.
The larger the lens the more light it will capture, the more light
it captures, the better the image quality. Following
this simple axiom “Bigger is Better” the Newtonian reflector became my
preferred format - you obtain the most aperture for the dollar and you do
not have an intervening lens to reduce light transmission. Within the
reflector class of instruments you are faced with two choices: Newtonian
reflectors on an equatorial tripod or the Dobsonian format mounted on an
alt-azimuth base.
The Dobsonian has the advantage that is very easy to set-up and
use; it’s a “point and look”. The only disadvantages are:
to track an object you have to constantly move the telescope to
keep the object centered in your field of view, and should you ever decide
to enter into astrophotography the Dobsonian does not facilitate
conversion. Thus,
I chose the Newtonian reflector with an equatorial mount as my preferred
format. After
reviewing the available manufacturers, numerous articles and equipment
reviews within Sky & Telescope and on the web, I chose the Orion
Telescope Company due to availability, pricing, and the quality of their
product line.
The equipment is imported from Taiwan. Features
The
Orion SVD 8 comes standard with two 1.25 “ Plossl eyepieces (25mm &
9 mm), a 6 X 30mm finder scope, moon filter, and the SVD equatorial tripod
with polar-alignment scope. Shipping
takes 4 – 5 days via either UPS or Fedex ground and my equipment arrived
in good condition in 2 separate boxes.
I assembled the telescope and tripod in about one hour taking my
time to read the included instruction manual, which by the way is easy to
understand.
Once assembled the telescope looked great, high gloss black with
gray accessories and a gold and gray EQ tripod. Performance
I
first took the telescope outside to align the finder scope and main
telescope during the day as recommended within the instruction manual.
This is not a good idea with a large aperture telescope of short
focal length – you cannot get the telescope focused on an object only a
½ mile away, plus the image is inverted and backwards.
So I recommend that you do only gross alignment during the day and
complete the final alignment and focus of the finder scope during the
night. A
word of advice, take your time to learn how your telescope and EQ tripod
work together and do not expect to take it out the first night and view
deep-sky objects (galaxies, nebulae).
It took about two months of twice-weekly viewing (eight sessions)
before I became comfortable with the operation of the SVD 8 EQ. Collimation
- aligning the primary and secondary mirrors. The instruction manual states that the telescope was collimated at the factory prior to shipment. But after the shipping and handling you can count on the telescope being out of alignment. What this means are the images you see are not as well defined as possible and you probably won’t notice this if this is your first telescope. But you will notice that the deep-sky denizens your searching for will not come into focus and you will note aberrations in the star field caused by the vanes holding the secondary mirror. The manual collimation explained within the owner manual does not properly align the mirrors. I recommend that you include in your purchase of the SVD 8 EQ or any reflector telescope a laser collimator (from $70.00 - $200.00). My 8” was improperly collimated during the first three months and once I received Orion’s laser collimator I was amazed at how grossly misaligned the mirrors were. The image quality doubled upon proper alignment – those deep sky denizens I was searching for finally came into view. Observing
Performance In
a word – wonderful, after three months of practice with the equipment
and reading everything I could find about the art of astronomical
observation, I began to understand how to use this telescope. Planetary
Observations – Though a Newtonian reflector of short focal
length is not the instrument of choice for planetary observation, I found
the SVD 8 EQ to perform adequately when observing Jupiter, Mars, Saturn,
and the Moon. I
did not purchase this telescope to view the planets and the SVD 8 EQ
excels at deep-sky observations.
The light capturing ability of this telescope is excellent. The
local nighttime sky resolves to only 4th magnitude to the naked
eye due to moderate sky glow, but this telescope will resolve 8th
magnitude on an average night and on nights of truly dark sky viewing it
can be pushed to 10th and fainter magnitudes.
On nights of good seeing the Milky Way at low power is a truly
wonderful sight, the Great Andromeda Galaxy at 2.2 million light years
distance is easy for the SVD 8 EQ and the views of the Orion Nebula are
breath taking. (Note to the first time observers – nothing you will see
will be in color except the planets, moon and bright stars). Stellar
Observations – The SVD 8 EQ can resolve doubles with ease;
the disadvantage of a short focal length reflector is that they introduce
coma effects (distortion) at the edge of the field of view on fainter
stars. The
support vanes introduce distortion on distant stars due to their thickness
and these should be reduced to at least 0.5 mm instead of their 1 mm size.
It should be mentioned that this distortion does not detract from
the overall performance of this telescope.
It is a side effect of the classic reflector design and appears
only on distance stellar bodies (7 – 8th magnitudes).
To an equipment purist with unlimited funds this distortion would
be unacceptable and they would recommend refractors within the $2,500 -
$6,000.00 range.
The SVD 8 EQ exceeds my current observational abilities and I plan
to use this instrument for many years to come. Accessory
Equipment – The SVD 8 comes standard with a 6 X 30mm straight
finder scope, which I found to be insufficient for a telescope of this
size. The
quality of the finder scope is excellent yet the straight design forces
you to contort your neck and body into unnatural positions at times.
I recommend that you upgrade the finder scope to at least a 9 X
50mm and consider the right angle correct image finder scope currently
available from Orion telescopes.
I have upgraded to this finder scope and its ease of use is
superior to the standard 6 X 30mm. Eyepieces
– The SVD 8 comes with two 1.25” Plossl eyepieces: a 25mm and a 9mm.
I use the 25mm most of the time and have found the lens to be of
good quality and suffer little inherent distortion.
The included lenses are good performers and I recommend adding a 2X
Barlow lens to your collection to double your viewing capabilities. Equatorial
Tripod – the best $229.00 telescope mount available. The only
problems I have experienced are the RA and Dec settings scales are not as
accurate as I would like.
When I use the setting scales they point the telescope in the
general area and I still have to hunt for the object I want to view.
The other problem is the weight of the telescope tube with
eyepiece, Barlow, and 9 X 50mm finder scope appears to be the upper weight
limit for this tripod causing the telescope and tripod to vibrate when
bumped in the full upright position.
I have found that by keeping the legs in the “down” position
(not extended) increases the rigidity of the tripod base giving you a
solid viewing platform.
I highly recommend viewing from a seated position with the tripod
in the down position. I use an old pneumatic secretarial chair during my
sessions. Conclusion
In
conclusion the Orion SVD 8” performance is excellent, I have not
experienced noticeable aberrations from the primary mirror related to
temperature variations even though it is not made from Pyrex glass.
The mirror cell is heavy duty and collimates easily.
I have added additional mirror support pads beneath the primary
mirror to reduce any distortion of the mirror surface due to the edge
mounted support brackets that theoretically could warp the mirrors surface
(Sky & Telescope, 2000).
This “tweak” has reduced the coma effect (astigmatism) I
mentioned earlier.
Ease
of operation is the hallmark of the SVD 8 EQ; the image quality is
excellent when properly colliminated and the focusing tube operates
smoothly with good fingertip control. The SVD 8 EQ has provided hours of
enjoyable use.
The SVD 8 EQ weights approximately 50 pounds with the added
accessories and tripod. Submitted by Charles Haase - C.R.Haase@Worldnet.Att.Net - Cleveland, OH
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