Great Red Spot
Jupiter Series
40-inch
Dobsonian Telescope

Seriously large aperture
for the seriously avid astronomer
 

The Great Red Spot Astronomy Jupiter Series of large aperture telescopes is a truly large telescope with a primary mirror of 40 inches in diameter.

We had the opportunity of starting with a completely blank sheet of paper for our design.  Most telescope companies have to make any new telescope match the “look and feel” of other telescopes in their line, or worse, have to choose from whatever features their Asian suppliers offer.  Sometimes the only difference between brands is the color of the paint.

JUPITER DESIGN GOALS

PROTECT THE PRIMARY MIRROR:  A disturbing trend we have seen lately with some telescopes is to have the Primary Mirror totally exposed.  Owners of these telescopes quickly find to their horror that people walking nearby kick up small stones out of the grass – you hear them pinging off the face of the mirror all night long. 

We ran the numbers, and adding protection around the mirror added a mere 28 pounds to the design- a small price to pay for the security of a $40,000 mirror. The mirror enclosure also blocks stray light, giving higher contrast images at the eyepiece.

PROTECT THE SECONDARY MIRROR: We completely enclosed the back and sides of the Secondary mirror securely protecting it from dew and damage.  This design allows you to set it on the ground without damaging the secondary mirror.  Our mirror holder is entirely made of aluminum, no plastic disk to crack as other designs. We fully offset secondary mirror, allowing for proper optical collimation and preventing vignetting in the eyepiece.

PROTECT THE COMPUTER WIRING AND CONNECTIONS:  Another disturbing trend we see is that some manufacturers have been installing the ServoCat brain on the outside of their telescopes, leaving the wiring open to damage.  Even worse, some have the face of the ServoCat sticking out of the telescope body at ground level.  One can too easily step on the connectors and break them off flush with the face of the control box!   In addition, placing the computer ports at ground level where they can collect dew and dirt is an alarming design flaw. We designed the wiring for minimal exposure.  Tucked out of harm’s way, the ServoCat has no connectors exposed or placed anywhere they may be stepped on.

PORTABILITY:  Although some customers live under dark skies and use their telescopes only at home, many others enjoy taking their telescopes out using them with astronomy clubs or public outreach. Those who choose to travel with their telescopes will be pleased to know that we designed the 40-inch Jupiter so that it may be easily hauled and set up.

SENSIBLE DESIGN:  We designed the Jupiter series telescopes for peak performance rather than design them to a certain price point. Our telescopes are true performers, not just eye candy.

Carbon Fiber has reached a “boutique” status in America lately, including ballpoint pens, briefcases, golf tees; anything you can imagine. Do any of these items require carbon fiber? Not at all, but it sure looks pretty. Carbon Fiber is not very durable (ask anyone with a bicycle frame made from it), and you have to be careful not to leave it for prolonged periods in sunlight.

To manufacture the UTA light shroud in Carbon Fiber would have cost just over $900, and the two-inch truss poles would have run $3600.  Would either of these choices have improved the performance of the telescope?  Not one bit.  We just saved you $4500.

All of the aluminum is anodized flat black. We could have buffed all of the aluminum to a mirror finish before anodizing, but every smudge and fingerprint on the glossy surface would be clearly visible.

A giant telescope like our Jupiter Series is at its best working in the field, not sitting around looking pretty.

GRS JUPITER FEATURES

PRIMARY MIRROR:  Our 40” parabolic mirror is a cast monolithic piece of SupraMax from the Schott Glass Company in Germany. Great Red Spot uses no fused “honeycomb sandwich” construction. History has shown that many fused mirrors can de-laminate over time, ruining their figure. SupraMax is a low expansion borosilicate. We would never use Soda Lime or Plate Glass for a telescope of this quality. Made by master optician Mike Lockwood, the mirror is crafted to the  highest standards of quality.

MIRROR CELL:  The most important structural part of any telescope is the mirror cell.  We made the Jupiter cell from USA made steel. Steel is three times stiffer than aluminum and is the obvious choice in this most critical area.

The mirror edge support is provided by a 49 strands of stainless steel cable. Extensive computer modeling has shown that a cable sling is the most accurate edge support available. The cable prevents astigmatism and keeps the mirror from pulling away from the support triangles at low altitudes.

Our mirror cell provides 27 points of support. The support triangle's movements are completely guided by spherical bearings, giving you a slop free system.

TRUSS POLES:  We make our massive truss poles from high strength 6061 alloy aluminum.  They are 2" in diameter, and anodized in flat black.  Seamless 6061 aluminum truss is strong and lightweight; you can step on them without damage (Do not try that with brittle carbon fiber).

ALTITUDE BEARINGS:  Our Altitude Bearings are lightweight cast aluminum. Cast aluminum is much stronger than plywood laminate used in lesser designs. At 52 inches in diameter, our bearings have massive staying power. This allow you to change from small planetary eyepieces to heavy binoviewers without needing to add counterweights.

FOCUSER:  No one can argue that the best focuser available is the FeatherTouch by Starlight Instruments. The FeatherTouch focuser is simply the smoothest, highest gear ratio, highest precision focuser made. We never considered any other focuser for a telescope of this caliber.

UPPER TUBE ASSEMBLY:  Our UTA features a 360° light shield that keeps stray light out of the focuser and from reaching the secondary mirror, assuring you of the highest contrast images.  Other lesser designs skimp on the light shielding in order to save money and weight.  Saving a few pounds but loosing precious contrast at the eyepiece is a tradeoff you should never settle for.

The controls for the Argo Navis and ServoCat are both up on the UTA where they belong.   It makes the most sense to have your computer and controls at your fingertips while observing.  Who wants to climb up and down a ladder just to read object descriptions or GOTO the next nearby object in the Virgo Cluster?  We placed the controls with the serious observer in mind.

FINDER SCOPE:  We chose the most durable finder scope in the galaxy, the Telrad.  Unlike other reflex finders, the Telrad works from several feet away without introducing a parallax error.  What does this mean to you?  You can stand on the ground and sight through the Telrad while it is many feet above your head.  We have found that you cannot do that with any other finder.

 

PRICING AND SPECIFICATIONS:

Price includes ServoCat and Argo Navis for $59,000 USD
Available with the Pyxis 2-inc Field Derotator for use use SBIG CCD Cameras. http://www.optecinc.com/astronomy/catalog/pyxis/pyxis.htm
Please inquire about availability and shipping dates: info@greatredspot.com