S & T Test Report

Megawedge and Auriga TriPlus

by Dennis di Cicco

     The first company many amateurs turn to for telescope accessories is JMI — Jim's Mobile, Inc.  And, at present, it's the only company they can turn to for an equatorial wedge for the Celestron NexStar telescopes.
     "We developed the Megawedge," notes JMI founder, Jim Burr, "because of customer demand.  We have the Megapod for the NexStar 5 and the Meade ETX scopes, but the additional weight of the 8-inch called for something heavier."  Made of steel 1/8" (3.2 millimeters) thick, and finished in black wrinkle paint, the Megawedge is adjustable for any latitude on Earth from the equator to the poles.  It attaches to all Meade and Celestron field tripods, including those custom made for the NexStar base.  Like the lighter-duty Megapod, the Megawedge accepts NexStar scopes as well as all of the Meade ETX models.  It also comes with a detachable plate that holds four 1¼-inch and two 2-inch eyepieces.   There's a foldaway peep sight to aid in polar aligning the Megewedge.  The only thing lacking is a fine azimuth adjustment.  To position the Megawedge in azimuth requires the user to turn the whole tripod, which makes small adjustments difficult.
     The heavy-duty tripods for Celestron and Meade telescopes make a fine support for the Megawedge.  But when you attach the wedge to the standard NexStar or ETX tripods you end up with a rather wobbly system due mainly to flexing in the tripod heads, especially when the NexStar 8 is on the wedge.  Surprisingly, this flexure was more of a problem when I was trying to align the wedge than when observing, since the vibration damping time was only about three seconds, even with the heavier scope.
     Auriga's TriPlus is a much more solid support for the Megawedge.   Manufactured in Italy and based on an extremely heavy-duty Manfrotto camera tripod, the TriPlus has a custom top plate that accepts the NexStar base.  The TriPlus is made of aluminum and chrome-plated steel and has reversible feet with spiked tips on one end and rubber caps on the other.  Its height adjusts from 31 to 62 inches (79 to 157 centimeters).  Designed for loads up to 66 pounds (30 kilograms), the TriPlus is rock solid.  But this rigidity comes with a price.  At 18 pounds (8 kilograms) the TriPlus is twice as heavy as the standard NexStar tripod.  There is another tradeoff as well.  Although the amplitude of vibration is smaller with the TriPlus, damping time is longer even when the rubber-capped feet are in place.  Fitted with a NexStar 8, the TriPlus damped in about 2½ seconds (alt-azimuth configuration) and 5 seconds (with the Megawedge) as opposed to the standard Celestron tripod's 1 and 3 seconds, respectively.
     For visual work I found little advantage in having the NexStar telescopes polar aligned on the Megawedge.  Because these instruments lack setting circles, there is no quick and easy way to achieve accurate polar alignment.   Furthermore, in equatorial mode you must use the two-star method to initialize the scopes with the sky for computer-pointing (but this is not needed if you are just doing equatorial tracking).  Be forewarned that the alignment instructions scrolling across NexStar's LCD are misleading for a two-star alignment in equatorial mode.   They tell you to level the telescope tube, when in fact you must point it toward the celestial equator.  Even so, I had more trouble getting the scope initialized in equatorial mode, and this resulted in less accurate computer pointing.
     The advantages of polar alignment, however, include slightly more accurate tracking since only one motor has to operate to keep objects centered in the field of view.  The equatorial drive rate was precise and remarkably smooth for a spur-gear based system.  It would certainly be good enough for piggyback photography with moderate-length exposures using wide-angle and normal lenses.  And someone up for a challenge could even try guiding exposures made with telephoto lens.  I would not, however, suggest that anyone who can't tolerate frustration try guiding the NexStar for any type of long-exposure imaging through the telescope.  It just wasn't intended for this kind of work.

The Italian-made TriPlus and JMI's Megawedge offer an ideal solution for people interested in using the NexStar telescope, as well as the Meade ETX series, in polar-aligned equatorial mode.