A somewhat lengthy description of all the equipment that I mainly use.
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Main Camera QHY8 One Shot Colour CCD
With the QHY-8 the world has finally got a large format camera at world beater prices. Costing less than many competitors medium format cameras. With full 16bit analog to digital conversion, cooled to -35C below ambient and in a small package (not much larger than a standard CD). CCD-labs has partnered with QHY Astronomy to bring this affordable imaging package to the US market. With very low read noise and outstanding sensitivity this camera is sure to be a winner.
This finderscope works with the SV standard 50mm ring systems except the clamshell. The 60mm finderscope comes in a neutral matte gray finish included with each finderscope is a SV standard 23mm, fully multicoated crosshair eyepiece with wide crosshairs, 1.25" helical focuser, rotating back (requires some finder re-alignment after rotation) and fully multi-coated correct image erecting prism. I have adapters for both configuration ie: RA or straight thru and use this finder as a guide scope on occassions Stellarvue ED 80 Refractor
As the name implies, this is the basic version of our 80ED
doublet refractor.
This telescope uses the same objective lens as all Stellarvue 80ED
telescopes.
The objective is a hand figured 80 mm clear aperture, 560 mm focal
length (f/7)
air-spaced doublet lens using Ohara extra low dispersion (ED) glass to
reduce
chromatic aberration or colour fringing. Color correction and contrast is
considerably better than an 80mm f-7 doublet achromat. While no f-7
doublet can
give you the reflector like colour correction of one of our apo triplets,
this
optic comes very close. Fully multicoated objective: The hand figured ED lens provides
high
contrast with several extreme broadband
coatings used on all four lens. This boosts contrast: the stars appear
vivid and the background, velvet black. These coatings
transmit light above and below the visual spectrum, which is important
to
minimize reflections seen on ccd images. Black anodized aluminum tube and dew shield: The tube, dew
shield, and
fittings are made of aluminum machined on an computer numeric controlled
milling
machine. All
aluminum parts are black anodized with a polished, high gloss finish.
The dew shield retracts
reducing the length of the telescope to only 17.5" when being stored and
extends to minimize dewing of the
objective at night. It can also serve as a glare shade during the day. Internal tube treatment: The inside of the
tube
assembly is painted "ultra flat black" and is fully baffled to
eliminate reflection. The
focuser has 11 baffle ridges to reduce draw tube reflections. These
ridges are painted,
reducing the most commonly found type of reflected glare. This treatment
provides better glare reduction than focuser's that only have the ridging
to
prevent glare. All of these methods add up to
provide the
outstanding contrast of the APO triplet lens. Dual speed Crayford focuser with precision bearings: The 2"
Crayford
focuser uses a compression ring and has three thumb screws to secure
accessories
and cameras firmly in place. A compression ring 1.25" adapter with 2"
filter
thread is also provided: The focuser has three focusing knobs, one on
the left
and two on the right. The single knob on the left and a larger knob on
the right
provide coarse focusing. On the right side is a second, slightly
smaller, brass
coloured fine focus knob. This fine focus knob has an 11-1 rotation
reducer,
allowing for extremely fine focusing. The reducer in the Stellarvue
focuser uses
a hardened stainless shaft and precision ball bearings. It has greater
longevity
than some competitive dual speed focuser's. A tension adjustment set
screw is
positioned under the focuser and a thumb screw allows for locking the
focuser
when engaged in astro photography. The draw tube is inscribed with a
millimetre
scale on top. Two 5 mm threaded holes on top of the focuser allow for
the
attachment of two separate finder scopes. There is also a third 5 mm
threaded
hole on the tube in front of the focuser for positioning a reflex finder
further
forward. The focuser is fully rotating. To rotate the focuser, simply
loosen the
rotation knob. Vixen shaped mounting base: The SVR80ED has an L-shaped
mounting base for
mounting the telescope to a heavy-duty camera tripod or to most
telescope mounts. The underside of the mounting base has two cork pads
and two
1/4-20 threaded holes. The shape of the L-shaped mounting base is
identical to a
Vixen rail, so it will work with most telescope mounts. Rings are available if you plan to
mount
this telescope on a larger mount that uses either the Losmandy rail or Vixen dovetail. The
L-shaped
mounting base will attach directly to our TP6 (Losmandy sized) plate
with two
screws. In addition, we include the TPBV rail to mount onto the bottom
of the
L-shaped mounting base, allowing for better balancing with a variety of
accessories. Supplied accessories: The 80ED comes with our C7 side
reinforced, foam
lined, airline carry on case. This case will hold the telescope, star
diagonal,
reflex finder and numerous eyepieces. Light gathering and magnification power: The 80ED gathers 131
times the amount of light the naked eye
can, revealing
faint objects in space. Magnification power is dependant upon the
eyepiece being used. Different
eyepieces provide different magnification powers. Since our 80ED uses a
highly
accurate, hand figured objective lens that has been tested three times
in the
USA, these telescopes are free of coma and astigmatism seen in many
import
telescopes. This
provides sharper details when viewing at higher powers. Dawes limit
states that
the maximum power for an 80 mm telescope under good conditions is about
186 power.
Losmandy Gemini 11 -G2 This mount now replaces the EQ6 which I've sold details at, http:\\www.losmandy.com/losmandygoto/gemini2-specs.html |
Main Scope GSO 200mm CF RC Having imaged with a Stellarvue 80ED for nearly 12 months and then in May 2009 a windfall provided the money to purchase a telescope with more aperture. I’d often been reminder on a number of forums that aperture was king. However this does not necessarily apply as far as imaging was concerned. I’d been following the progress of the GSO Carbon fibre RC since it was first announced over in 2008. I liked the black finish as it matched my mount and 80ED but I’d been tossing up between this and the Vixen V200CML as my interest these days is purely imaging. However with the recession causing a marked decline in the value of the $AUD against $US the Vixen came out to be more expensive. Suffice it too say after following a number of threads on Cloudynights and conflicting reports some for and against I took the plunge and purchased what is probably one out of the first batch sold in Australia. The Guan Sheng Optics RC-200 (8”) f/8 telescope (made in Taiwan) (astrograph) arrived from a supplier on the other side of the country within three days of the order being confirmed. GSO are distributing these scopes in varying configuration too Orion, Astronomics and under their own name to a number of retailers in Australia. The Orion version I believe is not being shipped with a carbon fibre tube and is selling cheaper than the CF version. Likewise the Astronomics version
ships with 2 dovetail bars a Vixen and Losmandy style whereas the GSO version
sold in Australia
only comes with the Vixen dovetail bar. I can only assume the dovetail
supplied differs because of the number of Synta EQ6 mounts that have been sold
here in comparison to the more expensive Losmandy mount. However it would have
been handy to have received an additional dovetail bar for mounting a guide
scope. The one thing we Australians have faired well in is that our version is shipping in an aluminium padded carrying case.
The telescope comes with a standard Synta finder dovetail shoe but is not supplied with a finder scope. First glance. On opening the case I was impressed with the shiny carbon fibre skin of this scope the built and finish appear to be top notch.
The scope was easily removed from the case but once removed the case does not stay upright needing the weight of the telescope to do this. The case was a bonus but there was no room to place anything else apart from the telescope inside it. Getting it on the mount was relatively easy as the telescope is fairly light but a handle would have made life easier and secure than trying to hold the scope by either the focuser or dovetail while mounting or dismounting it. Out of the case with nothing attached the telescope sit's well on the mount.
The telescope is decidedly back heavy which is indicative of the design and finding an equilibrium proved to be difficult once the guide scope and camera where attached and with 10” of back focus include a 3” extension tube balancing it satisfactorily took a little thinking. As to the finder shoe I cannot fathom the reason for supplying the shoe without a finder scope when finders come in a variety of fittings and I soon replaced it with a fitting for my red dot finder. Also there are only two screw holes of the left site looking forward to place a finder whereas people may prefer their finder on the right side or too have two finders a visual and red dot. The mirror finish and baffling look superb and the baffles appear to do what they are supposed too the only real issue with this telescope as is in my opinion is the focuser
The supplied focuser is a GSO Crayford 10:1 standard focuser however it is not sturdy or robust enough for a telescope being marketed for imaging and lacks sufficient draw tube length considering the back focus requirements.
As far as imaging is concerned a sturdy focuser without sag is of utmost importance to the serious astro photographer especially when tyring to collimate the mirror’s and during focussing. Already reports indicate that the focuser is the first item being replaced by those who have purchased this telescope. As can be seen from this photo the back focus is extreme and could probably have been catered for in the design more admirably considering the scope is not designed for visual work.
As mentioned the primary concern with this scope is the amount of back focus and the inadequate focuser, I can only assume that GSO didn’t want to increase the overall cost by increasing the tube length meaning more carbon fibre and more baffles or reduce the F ratio to fit the tube which in a way is disappointing as both would have eased the issue with back focus and balancing. First light GSO 8" RC
Collimation may be a bit out even
though it was checked on the bench at the retailers, it didn't appear to be
perfect when viewing a star out of focus but this also may have been
attributable in some way to sag in the focuser. I’ll probably need a fully adjustable side by side plate etc for this arrangement to work. Eventually I removed the saddle off
and just had scope on mount and nearly got it to balance although not perfect
in Dec.
As can be seen there is star elongation in the top right corner which is probably a result of focuser sag as doesn’t appear elsewhere in the image. Otherwise not a bad result and reports elsewhere indicate that the optics are quite respectable for the price. Conclusion On the downside the manufacturer
should probably have looked at some of the issues I’ve mentioned as a few
hundred dollars more for a near perfect RC at these prices would still have
been worth it. Did I make the right decision am I disappointed with my
purchase, I can say honestly not, as I resolved the focuser issue by replacing it with a Moonlite. |
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