Explore Scientific ED80 Essentials Triplet Review
The Explore Scientific ED80 Essentials Triplet is a poor choice for most astrophotography work compared to competing telescopes, and the scope’s triplet optical design has little correlation with high quality.
The Explore Scientific ED80 Essentials Triplet is a compact ED triplet refractor sold at a similar price tag to many 80mm ED doublets, and unsurprisingly concessions have been made to make this possible. The ED80 Essentials Triplet offers roughly equal quality views and images to most 80mm doublets at its price range but is heavier and less compact, with a variety of issues that make it less than ideal for the price. The more expensive FCD100 glass upgrade improves the optics but has a lot of competition and suffers from similar mechanical drawbacks to the Essentials version. Either is unsuitable for use with a reducer-flattener or large full-frame camera sensors, both of which are major disadvantages compared to most competing imaging telescopes. The Explore Scientific triplet refractors make great scopes for visual observation and were seemingly designed for such, with imaging capabilities as more of an afterthought.
80mm (3.2”) Aperture
480mm Focal Length
Triplet FCD-1 (FPL-51 equiv.) optics
The Explore Scientific ED80 Essentials Triplet is a 3.2″ apochromatic refractor telescope with a focal length of 480mm and an f/6 focal ratio. While triplet refractors are typically known for superior chromatic aberration control compared to doublets, the ED80 Essentials Triplet will produce blue halos around bright celestial objects visually and will show noticeable chromatic aberration comparable to a typical ED doublet refractor in images.
This is a consequence of the cheap FCD-1 glass used in the telescope, which is roughly equivalent to the cheaper FPL-51 glass used in the most inexpensive ED doublets and sure to be a disappointment if you expect the triplet design to mean improvement over a similarly priced doublet. The FCD-100 glass used in the more expensive ED80 offered by Explore Scientific does clean up the image, but not without significant expense.
At f/6, a field flattener is certainly necessary with the ED80 Essentials Triplet to eliminate field curvature in your images. Unfortunately, Explorer Scientific does not offer their own dedicated, optically optimized reducer-flattener anymore, and you will not be happy with the images produced by a 0.8x reducer flattener from another manufacturer; the only choice for an optimized flattener at all is Explore Scientific’s in-house unit. The size of the illuminated image circle of the ED80 is not specified by Explore Scientific but is around 21mm, which will vignette with full-frame sensors.
Another major issue with the ED80 Essentials Triplet is that the screws used to hold and adjust the objective lens in its cell poke into the light path. This introduces odd spikes and crosses on bright stars in your astrophotos. Backing off the screws can reduce the problem but will leave the lens loose in its cell and may introduce collimation issues. The only real fix is to stop down the telescope’s aperture by a few millimeters, which consequently reduces your speed for photography and your light gathering or resolving power for visual.
The ED80 Essentials Triplet is equipped with a 2″ dual-speed Crayford focuser with a brass compression ring, which can be rotated to adjust your framing for images. While this focuser is generally effective, it has been known to slip under heavy loads, while the single thumb screw that enables rotation can easily slip or cause the focuser assembly to become tilted. The FCD100 version has a 2.5” Crayford focuser with a hexagonal drawtube which is stiffer but suffers from the same issues with its rotation axis relying on a lone screw. You also get thread-on extension tubes to reach focus with certain cameras or eyepieces, which may require additional focus travel.
The ED80 Essentials Triplet features an unusually wide and stubby dew shield that retracts for transport. The dew shield does a poor job of preventing condensation or blocking stray light due to a narrower one and also would get in the way of mounting tube rings to the telescope, which is why the ED80 uses a simple ring and “foot” style dovetail like small, cheap 60-72mm ED doublets often come equipped with. This design can sag and also prevents the installation of a second dovetail atop the tube to attach a guide scope to.
In addition to the tube itself and a Vixen-style dovetail bar, you also get a finder/guide scope mounting shoe with the ED80 Essentials Triplet which is capable of fitting almost any style bracket, along with a 2” dielectric star diagonal and 1.25” adapter for visual use.
Weighing 7.5 lbs without the addition of any camera, guide scope or accessories such as a flattener or the provided star diagonal, the ED80 Essentials Triplet is heavy enough that it requires an EQ5-class mount like the Sky-Watcher HEQ5 Pro or Advanced VX for astrophotography use. For visual use, Explore Scientific’s own Twilight I or a similar heavy-duty alt-azimuth mount is ideal.
What can you see if you look through it?
While an 80mm refractor is hardly a capable instrument for visual astronomy – especially at the high price tag of the ED80 Essentials Triplet – this scope can still provide enjoyable views with the right eyepieces, and the provided 2” dielectric mirror star diagonal is included with that in mind. The short focal length of the ED80 means its ideal for wide-field, low-power viewing of nebulae or star clusters, and the 2” diagonal enables you to achieve the widest possible field of view with 2” oculars. You can also split double stars at high magnification even from the city, and view nebulae like the Veil or North America Nebula with a UHC filter and dark skies. Globular star clusters, planetary nebulae, and galaxies require a larger aperture telescope to see as much more than dim, detail-less smudges, even under dark skies.
Within the confines of the Solar System, the ED80 is sufficiently powerful to see the phases of Mercury and Venus, as well as the detailed features of the Moon, such as craters, ridges, and mountains. You can also see Mars’ ice caps and a few dark markings on its surface, which change in size and appearance over time, and the resolve the Great Red Spot, cloud belts, and moons of Jupiter. Saturn’s rings, the Cassini Division within them, and a few moons can be spotted, along with Saturn’s own cloud belts, though they are less prominent or vivid than those of Jupiter. A larger telescope is necessary to resolve Uranus and Neptune clearly from star-like points or observe their moons.
The small illuminated image circle, combined with the optical issues and even greater vignetting that would be induced by any attempt to use a third-party 0.8x reducer-flattener, confines the field of view of the ED80 Essentials Triplet severely for deep-sky imaging and limits you to smaller sensors like APS-C DSLRs, while the scope is prone to tons of mechanical flexure due to its higher weight than a doublet inducing more torque on a mount, along with the poorly designed focus rotator and dovetail foot design. For visual use, the ED80 is a sharp little scope, but those looking for an economical visual telescope are better off with a larger catadioptric or Dobsonian telescope for the money, which will also come with a mount and accessories included by default. Imagers should consider a better quality triplet or a well-made doublet or Petzval 80mm refractor in lieu of the ED80 Essentials Triplet.
The Explore Scientific ED80 Essentials Triplet is hardly the bargain that it may appear to be on the surface. Astrophotographers and visual observers alike would best be served by a different telescope with fewer flaws and design concessions.