The Optical Tube
The FirstLight AR80 sold with the Twilight I is an achromatic refractor with an aperture of 80mm, a focal ratio of f/8, and a focal length of 640mm. Fast f/ratio refractors tend to have lots of chromatic aberration, especially as they increase in size. At f/8 with only 80mm of aperture, the FirstLight AR80 shows moderate chromatic aberration on bright targets such as the Moon, planets, and bright stars. However, there is not enough chromatic aberration to severely impede sharpness. The optics of the FirstLight 80 are good quality and perform as expected for a telescope of this size.
The FirstLight AR80 has a 1.25” plastic rack-and-pinion focuser. This is pretty standard for cheaper and smaller entry-level telescopes. The rack-and-pinion design has some slop and can’t hold expensive, heavy wide-angle eyepieces. But since such eyepieces cost more than the FirstLight AR80 itself, this is unlikely to be of much concern. The plastic teeth of the focuser drawtube are fragile, however, and a replacement is not easy to come by, so you should be careful not to accidentally damage the focuser when setting up or transporting the AR80.
The FirstLight AR80 attaches to the Twilight Nano mount with a clamshell that wraps around the tube and is bolted to a Vixen-style dovetail rail. The dovetail rail gives you the option to put the AR80 on a different mount if you desire, and you can adjust the tube cradle to rotate the eyepiece/finder to your preferred position as well as slide the tube backwards and forwards for proper balance.
Accessories
I’ve noticed that the accessories included with the Explore Scientific FirstLight telescopes are a far cry from high quality, though there are worse options out there. The provided 1.25”, 25mm Super Plossl (26x) eyepiece is okay, but it uses a lot of plastic and has an oddly recessed eye lens, making it a lot less comfortable to look through than it should be. The apparent field of view of 50 degrees translates to a true field of 1.9 degrees at 26x, a fairly wide field just under 4 times the angular diameter of the full Moon. However, 26x is not enough for planetary observing or high-resolution views of the Moon, and the 25mm Plossl has a lot of glare and internal reflection issues.
The star diagonal included with the FirstLight AR80 and other scopes from the FirstLight line is a 1.25” mirror diagonal with a plastic housing. The mirror is pretty low quality, and some mild astigmatism can be induced by the out-of-flat mirrors often installed in these diagonals. There is also a lot of scattering from the cheap mirror coatings, which is worsened by the internal reflections inside the plastic body and the 25mm Plossl eyepiece.
The red dot finder provided with the FirstLight telescopes slides into a non-standard shoe design that only Explore Scientific uses, making using anything else difficult. It has a slightly tinted window, probably as a consequence of being originally manufactured for non-astronomical purposes. The bracket can have trouble being aligned with the telescope, but this finder otherwise suffices for aiming the FirstLight AR80.
The Twilight Nano Mount
The Explore Scientific Twilight Nano mount that comes with the FirstLight AR80 is a single-arm, alt-azimuth fork with a steel tripod that can be extended. The optical tube is attached to the side of the Twilight Nano’s altitude (up-down) axis instead of above it, like a typical photo tripod. This helps keep the telescope from falling over when it is pointed at the sky. Most cheap alt-azimuth mounts are built like photo tripods or are extremely spindly fork mounts, which are unsteady and hard to aim; the sleek, rock-solid Twilight Nano is exceptionally high-quality for such an inexpensive product.
The Twilight Nano mount uses a standard Vixen-style dovetail saddle to hold the optical tube in place. You aim the Twilight Nano just by pushing it around; a handle is attached for finer adjustment, but there are no clutches or slow-motion cables. It is nearly as smooth as a Dobsonian, however, so making fine adjustments isn’t a huge challenge.
Should I buy a Used FirstLight AR80?
I’ve observed that the FirstLight AR80 has a lot of plastic components, which are easily damaged, but a used one in good shape makes for a fine scope as long as it either comes with additional accessories or you don’t mind spending the money to upgrade one. Make sure that the objective lens is free of damage and that the teeth on the focuser aren’t stripped.
Alternative Recommendations
The FirstLight AR80 isn’t our top pick in its price range – there are a few other scopes we might recommend you consider instead, though most of them are reflectors.
Under $200
- The Zhumell Z100/Orion SkyScanner 100 offers an even wider field of view, along slightly more light-gathering and resolving ability than the FirstLight AR80, free of chromatic aberration. Two quality eyepieces are provided along with an easy-to-use and compact tabletop Dobsonian mount.
- The SarBlue Mak60 w/Tabletop Dobsonian Mount offers similar capabilities to the FirstLight AR80 when it comes to planetary viewing, albeit in a considerably smaller and more portable package and with next to zero usefulness for deep-sky observation.
- The Orion SpaceProbe II 76EQ is similar in capabilities to the FirstLight AR80 but uses a more complex – albeit more easily adjusted – equatorial mount, and includes slightly better accessories.
$200-$350
- The Sky-Watcher Heritage 150P has nearly double the resolving power and just under 4 times the light gathering ability of the FirstLight AR80, along with a pair of high-quality eyepieces and a steady, easy-to-aim tabletop Dobsonian mount. The tube collapses for portability, too.
- The Sky-Watcher Heritage 130P offers many of the same features as the Heritage 130P but with a slightly smaller aperture and significantly lower price tag. It is an equally excellent telescope to its larger sibling, and boasts a nearly as large performance advantage over the FirstLight AR80.
- The Zhumell Z114/Orion StarBlast 4.5 Astro offers slightly more light gathering and resolving power than their 100mm counterparts and a sizeable gain in both qualities over the FirstLight AR80 as well, with a simple solid tubed tabletop Dobsonian design and decent included accessories to match.
Aftermarket Accessory Recommendations
If you replace the cheap, low-quality diagonal that came with the FirstLight AR80, sharpness and contrast at the eyepiece get much better. Either a dielectric mirror diagonal or prism is fine for the job. The Celestron 94115, a prism diagonal, is one of the cheaper options and our favorite for equipping low-cost telescopes with 1.25” focusers.
With the FirstLight AR80, a 32mm Plossl eyepiece will be sharper and have a wider true field than the stock 25mm Plossl. It will provide a magnification of 20x and a true field of 2.6 degrees, or over 5 times the angular diameter of the full Moon. At the other end of the spectrum, a 6mm “goldline” eyepiece will produce 107x with the FirstLight AR80, about as high as you should probably use but ideal for lunar, planetary, and double star viewing. At least one or two additional eyepieces—perhaps something around 15mm focal length (43x), like a 15mm SWA—will bridge the gap between low and high magnifications for lunar and deep-sky viewing.
While expensive, a UHC nebula filter such as the Orion UltraBlock 1.25” will enhance contrast on nebulae like Orion within city skies and allow you to go after fainter large nebulae like the North America Nebula under sufficiently dark skies with the FirstLight AR80.
What can you see with FirstLight AR80?
The FirstLight AR80 is decent for both planetary and deep-sky viewing, offering a wide field of view but without too much in the way of open clusters. You can view dozens of bright open star clusters, like the Double Cluster, the Pleiades (M45), or the Wild Duck cluster (M11), throughout the night sky, even from fairly light-polluted locales. However, with only an aperture of 80mm, globular star clusters remain unresolved fuzzy balls. While a larger aperture is required for viewing planetary nebulae, the Dumbbell (M27) is sufficiently bright and large to be recognized with the FirstLight AR80, along with the dimmer Helix Nebula, under dark skies. You can also observe the Ring (M57) and the Blinking Planetary at higher magnifications.
With the FirstLight AR80, you can enjoy the Orion Nebula (M42), the Lagoon (M8), and the Swan (M17) even from a suburban area. However, dark skies and/or a UHC filter give the best views and let you see more nebulae like the Trifid (M20) or Eagle (M16). The fainter but gigantic Rosette Nebula and North America Nebula can be seen with dark skies and are brought out best by a UHC filter. The massive Veil Nebula supernova remnant requires a good UHC filter to be seen but delights at low power with the AR80, stretching well past a singular low-power field of view.
An 80mm telescope is insufficient to show you much in the way of galaxies. Under dark skies, you might be just barely able to see the dust lanes and orbiting companions of Andromeda (M31), along with the eponymous cigar shape of M82 and its dust lanes. Most other galaxies will remain dim fuzzy streaks, orbs, and ovals, often hard to see at all, though you can still just barely glimpse a couple dozen galaxies within the Virgo Cluster at low magnification.
The FirstLight AR80 does a good job on planets with a suitable high-power eyepiece. You can see the phases of Mercury and Venus, as well as the polar ice caps and a few dark markings on Mars when the latter is at its closest to Earth. The Moon shows plenty of detail, such as ridges, mountain ranges, and countless craters. Jupiter’s cloud belts and four large moons can be seen; steady seeing will allow you to resolve smaller cloud details, including the Great Red Spot as well as the disks and shadows of the moons when they transit in front of Jupiter.
Saturn’s rings and the Cassini Division within them are a delight, and the FirstLight 80 should also have no trouble resolving some of Saturn’s dull cloud bands along with at least a handful of its many moons, with the most obvious being Titan and Rhea. Uranus and Neptune are little more than unresolved fuzzy dots, though Uranus is noticeably not a star at higher magnifications. The moons of Uranus and Neptune, as well as even dimmer Pluto, are beyond the reach of a telescope with only an 80-mm aperture.
