The Explore Scientific David H. Levy Comet Hunter is the result of a dream collaboration between long-time amateur astronomer & Explore Scientific founder, Scott Roberts, and one of his life-long heroes, David H. Levy. David is an author, lecturer, & discoverer of a plethora of comets and asteroids; most notably the co-discovery of Comet Shoemaker-Levy 9, the amazing "fuzzy snowball" that broke apart and whose fragments, streaming towards Jupiter like a celestial string of pearls, collided with the giant planet in 1994.
Scott and David wanted to create a durable, rich-field telescope that would produce high contrast, pinpoint star images whether the user was sweeping the heavens for comets, keeping an eye on Jupiter's Great Red Spot, or photographing the Sombrero galaxy or Orion nebula. The optics had to be fast, the tube assembly relatively lightweight but strong, and all components needed to be built to withstand the test of time, and hundreds of trips to a dark sky site!
Rich Field Optics
The 6-inch f/4.8 Maksutov-Newtonian primary mirror is crafted from BK-7 glass, and layered with Explore Scientific's Enhanced Multi-Layer Deposition (EMD)coatings for bright, high contrast images and the elimination of light scatter. The addition of a Maksutov corrector plate improves off-axis images over traditional Newtonian optics. The EMD-coated corrector eliminates spherical aberration and produces those pin-point star images across the field that are so desirable. Finally, the secondary mirror, held in place by the corrector plate, is provided with 99% dielectric coatings for high reflectivity and protection.
While our optics hold collimation very well, there will be times when you will need to make adjustments, especially after a bumpy ride to a dark sky site. The optics on the Explore Scientific Comet Hunter can easily be collimated by the end user, and we provide good instructions in the user's manual should you need to tweak the primary or secondary mirror. The primary mirror is center-marked to assist you in these efforts.
Carbon Fiber Tube Assembly & Dew Shield
Carbon fiber isn't the most economical choice when designing a telescope, but the high strength-to-weight ratio and low expansion characteristics of the material, which helps maintain focus despite fluctuations in temperature, made it the only choice for the Comet Hunter. Inside the tube assembly you will find we have taken extraordinary steps to keep stray light under control. The interior is painted flat black, and the primary is baffled to keep wayward photons from entering the optical path. On the exterior of the tube, we have taken care to make sure the focuser fits tightly and the primary mirror cell is sealed against light leaks.
A matching carbon fiber dew shield is included as standard equipment on the Explore Scientific Comet Hunter. A dew shield is an important accessory for telescopes with a corrector plate. Light from a porch light or passing car will lower the contrast of your images if they strike the corrector plate, and dew forming on the optics will slowly dim your celestial view until the stars disappear. A dew shield helps keeps moisture at bay, as well as putting up a wall of protection between possible stray light and the optics. You can keep this dew shield on all the time if you want, since the dust cover attaches to it nicely. However, when you travel with your telescope, there are times you may want to remove your dew shield, so we made it easy to take off and put on.
A Versatile Focuser
The Explore Scientific Comet Hunter includes a high quality precision 2" dual-speed Crayford-style focuser with 10:1 micro focus and tension adjustment. The ability to adjust and lock the tension on the draw tube is helpful when you change the weight of the load attached to the focuser.
You will appreciate the smooth movement, the large course and fine focusing knobs, and the graduated scale imprinted on the draw tube. Extension tubes are included to allow you to adjust the back focus when using different eyepieces or a camera, and a 2" and 1.25" compression ring eyepiece adapter is included.
Cradling Your Telescope
The cradle and mounting plate for a telescope is not to be trifled with. This is the component that secures your Comet Hunter to the mount, and keeps it from falling on your toes as you slew it around the sky. The cradle consists of two clamp rings, and bridging those rings, like the Golden Gate Bridge, is a sturdy handle that allows you to easily move the telescope in and out of its case or on and off its mount. The handle is slotted to accept 1/4-20 bolts so that you can piggyback a camera, guidescope or other accessory on the handle if you wish. It is a design element that, while simple, is much appreciated. The saddle plate (the part that attaches the tube to your choice of mount) is made of one piece of machined aluminum extrusion for security and rigidity, and fits any "Vixen-style" mount, such as any Explore mount, smaller Meade & Celestron mounts, Vixen mounts, and various other models.
May 21, 2013
Strong Construction,Easy to Use,Quality LensesCons:
Explore Scientific is fast becoming one of my favorite brands. The quality seems to be above average for today's market. The only caveat I have is that the "free" accessories once offered are no longer available. The EP, finder and especially the case are no longer included. For me the case was a strong selling point and I hope that it will be offered again. The optics are excellent. When I received the scope I collimated it and found that that was quite easy to do with a cheshire. First light from my yard near light polluted Chicago I was able to see M57, the ring nebula, which is no small feat for anything less than a 8" scope at this location. I can hardly wait to get this to the dark site! The field is truly flat and that being said though not all of my EP's performed well. Use better quality EP's. Cheap 100 degree knock offs showed quite a bit of field curvature but a 5mm BGO pointed at Saturn was quite crisp with excellent color. I barlowed a 9mm to 4.5mm and that was pushing the scopes ability.
A few cons I would mention are the weight and the felt tape that "secures" the dew shield and cap. The scope is to heavy for my Porta mount II and CG-4 eq mount. The Porta takes 20 seconds to calm down after the lightest touch. The CG-4 will not come to balance. I would caution that an EQ mount is a little difficult for this scope as the bolts on the clamp rings are not captive so rotating the scope frequently will require great care. If using for AP and only on one target for a while then it would be less of an issue.
The felt is not a good solution in my opinion. It tends to curl up and bind and over long exposure to heat the glue gets slimy. I cleaned it off the shield and replaced with black friction tape on the flange of the OTA and inside the cap. Nice solid grip and easy to attach and remove. Apogee's RA-88-SA bino's had the same issue with there caps. Lot of used ones will have that mentioned in the ad.
Overall this is a handsome scope with great performance. With the right mount it will be a regular at the star parties.
I would also like to thank Sarah and Manish at Agena for their help over the phone when I called. Once I had ordered the scope I received my tracking number within the hour. Really nice to do business with them.
This review was provided courtesy of AgenaAstro.comMar 10, 2013
Well corrected,Strong Construction,No Diffraction Spikes,High ContrastCons:
This scope checks all of the boxes.
Check...Amazing contrast that helps the detection of faint galaxies and nebula.
Check...Extremely well corrected FOV. Never again will you mistake coma aberrations for a small planetary nebula at the edge of the FOV.
Check...Wide field of view for amazing starfield views
Check...No diffraction spike and amazing optics that gives amazing views of Jupiter!
Check...Plenty of aperture to enjoy the deep sky wonders.
Check...Fast and well corrected field for astrophotography.
Check...Great build quality and durable case.
In the two months I have had this scope, I have not found ANYTHING this to complain about.
Overall I couldn't be happier with this telescope!
This review was provided courtesy of AgenaAstro.comSort by
|Telescope Aperture||5.98" (152mm)|
|Telescope Aperture||5in - 8in|
|Telescope Series||Exp Scientific Reflectors|