Stellarvue 80mm Nighthawk

Stellarvue 80mm f/6 "Original" Nighthawk Achromatic Refractor with 2-inch focuser

Introduction

I purchased a Nighthawk 80mm f/6 achromatic refractor as clearance new stock from Stellarvue; it is called the "original Nighthawk" on the Stellarvue website. Compared to the current "Classic" Nighthawk model and the new Nighthawk model, the version reviewed has a 2-inch rack and pinion focuser instead of the Crayford focuser of the newer models, and does not have push-pull bolts around the objective lens cell for collimation adjustment.
My goal was to purchase a portable, high quality telescope for "quick-look" use at home compared my older 8-inch SCT with heavy fork mount. I wanted a telescope suitable for air travel, and squeezing in as the car fills up for family camping trips. This meant finding a "two cubic foot telescope' to complement my 12-cubic foot SCT.
My interest in such a telescope started with pre-purchase ads for a 4" f/5.6 "semi-apo" refractor, at the extremes of my budget, that caught my eye before a summer trip. That scope was still "pre-purchase' in November, so I looked at small Maksutov-Cassegrains and small refractors. Based on past use of an f/5.6 Dobsonian, I wanted a shorter-focus telescope to complement my f/10 C8, so the f/12 or f/15 Maks were less appealing. There were a few OTA choices for 80mm longer focus refractors, and shorter focus 80mm to 100mm or 120 mm scopes. For me, portability, quality and budget met at the Nighthawk on the Stellarvue clearance list. Stellarvue staff answered my pre-order questions attentively by voice and e-mail. A few days later the scope arrived securely packed, and I was pleased with the on-time arrival, before our air travel to join extended family on vacation over Thanksgiving.

Description and Initial Impressions

The overall impression presented by the Nighthawk is sturdy workmanship and good materials. The tube comes with a white or black finish, I chose white for easier visibility in low light. A sliding dew cap extends out about four inches from the multi-coated objective, and accepts a screw-in aluminum lens cover. The objective appears very dark, with good multi-coatings. The tube interior is blackened, but not up to the standards of the objective coatings, the flat black paint throughout the tube seems to have good coverage, but it's not dead black. There are sharp-edged metal baffles in the main tube and the focuser drawtube.


My 50-yr old photo tripod has more "mystery grease" than any focuser!...
Note lack of objective reflections.

The tube is held in a felt-lined black cradle with three 1/4-20 threaded holes at top and bottom. The cradle allows the tube to slide a few inches for balance on an equatorial mount or a photo tripod. The cradle works well with the photo tripod I've used as an alt-az mount. The base of the cradle is over 2-1/4 by 2-1/2 inches, making a steady tripod connection. The supplied red-dot finder attaches to a dovetail on the cradle.


Overall view of OTA with diagonal, focuser, cradle, finder, with dewshield extended.
The 2-inch focuser has a diagonal-cut rack and pinion, and a locking screw. The knobs have a grippable texture and the focuser moves smoothly. There is also a female dovetail with locking screw on the focuser body, for use with a Vixen or Orion style finder. A 2-inch eyepiece holder threads onto the drawtube. The included 2-inch to 1-1/4-inch adapter also features a male T-thread that could be used to adapt a camera.

Observing

I mount the Nighthawk on a 1950-vintage aluminum photo tripod with a pan-tilt head and observe with the 1-1/4 eyepiece set that I also use with my SCT. These travel easily and give a range of magnification from 30mm 16x, 20mm 24x, 12.5mm at about 38x; adding a 2x Orion Shorty-Plus Barlow gets the 12.5mm up to 77x.
The nearly parfocal Celestron Ultima and Parks Gold eyepieces have about 50 degree apparent field of view, good sharpness to near the field edge, and give actual FOV from just over 3 degrees at 16x, to 0.6 degree at 77x. Based on the view at 77x, I added an inexpensive 3x Barlow for about 115x and about 0.4 degree FOV. The 3x also gives about 72x with the 20mm eyepiece, which I used for comparison with the 2x and the 12.5mm at 77x.


Starting Lineup: Stellarvue enhanced diagonal, 12.5 mm Celestron Ultima, 20mm Parks Gold, 30mm Ultima, Apogee 3x Barlow and Orion Shorty Plus 2x (3-element) Barlow. T-threads are visible on 1.25-inch adapter on OTA. Focuser knob shows grip texture. Apogee Barlow is not edge-blackened.
The low power eyepieces gave the full diameter, evenly lit exit pupil size expected for an 80mm objective, indicating a lack of vignetting by tube or focuser.

Deep Sky

First light was on Florida's Gulf Coast under a nice view of the Milky Way. Star hopping with the red dot finder was really a pleasure; I found it easy to use with both eyes open. The finder is still holding the first night's alignment after having the scope on and off the tripod a handful of times and traveling cross-country.
M15 was easy to find and showed a few stars resolved at 38x.

M31 showed its elongated oval shape over 2 degrees, with companions visible with averted vision. M33 filled about a degree with a faint diffuse glow, and was noticeably less elongated than M31, and also showed less of a gradient of brightness from center to edges.

Later in the evening, M42 showed up well, with nice wings of nebulosity at all magnifications, and the trapezium resolved distinctly at 24x. Orion's sword was a pretty sight in the 3 degree field at 16x. Double stars in Orion's head and belt area were split, these were Lambda and Zeta Orionis, at 2.3 to 4.4 arc-seconds when looked up back home.
Viewing some familiar planetary nebulae brought home the difference in image scale between the 480mm focal length of the Nighthawk and 2,000 mm focal length telescopes like an 8-inch SCT. The little smoke ring of M57 was pretty small at 16x or 24x compared to the "low power' views I was used to at 38x or more in longer-focus scopes. I began to think of the small refractor as a bridge between binoculars and larger, less portable scopes. Looking at more planetary nebulae, M1 showed up easily, with elongated form and a hint of irregular edges, and M27 showed up well as an apple shape with a few bites out.

The Pleiades, the Double Cluster, and open clusters along the Milky Way in Auriga and Gemini gave wonderful views at 16x to 38x, all resolved to bright or faint pinpoints. Stars were sharp across the wide field. Earlier sweeps across Cygnus also were also rewarding views filled with sharply resolved stars. Overall, the deep sky views were appealing, and on several nights I looked at Messier objects or swept the Milky Way for 2 hours, until it was time to tiptoe back to our room to be ready for the next day's family activities. Nephews and nieces were excited by views of Venus and star clusters, and my brother-in-law gamely went on an hour-plus sky tour. Unfortunately I worked from memory and neglected some opportunities in the southern sky, forgetting to try for NGC 253 or NGC 55!

The main differences for deep sky objects viewed with the Nighthawk, compared with my past use of 8-inch or 10-inch scopes, are:

1. For globular clusters, seeing grainy partial resolution (at best) in the 80mm scope differs noticeably from 8-inch and 10-inch scopes.
2. For galaxies, overall shape can be observed pretty well in the small scope, much better than I'd expected with 80mm, but without much detail or texture visible, again noticeably different from larger scopes but not quite as pronounced as for globular clusters .
3. The small image scale of 480 mm focal length (or the wide field of view, to look at it another way) required a switch to higher power eyepieces for smaller planetaries or efforts to resolve globular clusters. What I thought of as "high power" for the Nighthawk, at 38x or above, gave the image scale seen at low power with an 8-inch SCT or a larger-aperture Dobsonian.

However, the Nighthawk's wide view gives a frame and context that makes for really enjoyable views of open star clusters and the larger/brighter nebulae and galaxies.

Planets

Venus was nearly setting over its dazzling trail reflected in the Gulf of Mexico our first evening. The image shimmered, and the upper and lower limbs of the crescent flashed yellow, green and blue. When Venus was higher in the sky viewed a week later, a little false color could be seen at the limb at 38x and 77x. The color was sensitive to eye position, changing in color and intensity as the eye was moved laterally.

Viewed almost a month after opposition, Mars looked like a reddish BB at 77x, or about the size of a small peppercorn held at arms length. The broadest shadings of surface features were glimpsed at 77x or 115x as the air steadied momentarily.

Saturn was well shown in the early morning, appearing crisp as the seeing steadied, with the Cassini division clearly visible at 77x and 115x, and glimpsed at 38x. The largest belts were just visible on the planet's disk.

Jupiter's equatorial belts and moons showed up at all magnifications. When the seeing steadied, several smaller belts were visible. The view was nicely framed by the Galilean moons.

Moon

The waxing gibbous moon also provided several chances to check resolution and false color. On the first two nights when the moon was convenient, the Las Vegas Valley had a temperature inversion. On the first night, the lunar image boiled in a way that reminded of a daytime solar image, and the disc of Mars bounced 10 arc seconds at a time. The next night was better but still not optimal seeing, with a very slight high haze present both nights. The lunar terminator showed no false color at all, but a yellow-orange to green or purple tint just rimmed the bright limb opposite the terminator. The color varied from either end of the spectrum based on eye placement. With optimum eye placement at 77x, the color was a thin violet fringe at the bright limb.

As the lunar image settled in moments of better seeing, the terminator was stunning as always, and free from false color at 38x and 77x. Copernicus was filled with shadow on the first night and fully illuminated the second. Terraces stood out on Copernicus' rim. The many craters in north-south chains between Copernicus and Eratosthones could be glimpsed at instants of steady air the first night and were held in view better at 77x the second night. They were not as easy with the small refractor as when viewed with 8-inch or 10-inch scopes, but were visible. Wandering up and down near the terminator and switching back to Saturn several times occupied all the time available on these two weeknights. While some false color was seen as described earlier, there was no ghosting or flare with the moon or any planet in the field of view.

In late December the early morning waning crescent moon was rewarding, with steadier skies and 115x using the newly arrived Apogee 3x Barlow. Both 77x and 115x invited slow perusal of the terminator, with rewarding detail at steady moments. There was still a hint of false color that varied with eye placement.

Comparing the moon and planets again made me appreciate how friendly the moon is to new observers. The details are at a scale we can see , with one or two kilometer craters, scarps, or mountains at the limit of resolution. And details are vivid in the high contrast oblique sunlight near the terminator. On Mars we struggle to see albedo features the size of Texas, on other planets we are trying to see clouds.

The moon-watching also confirmed an impression from other viewing. Focusing has real "snap' at 38x and lower magnifications, and becomes more sensitive at 77x and 115x. This is a threshold that I also notice in my 8-inch SCT, and the 10-inch and 8-inch reflectors that preceded the SCT over a few decades. The bigger scopes went from snappy focus at 50x or 100x and exit pupils greater than 2 mm, to more sensitive focusing at 170x or 200x and exit pupils approaching 1mm, so this seems to be a function of image brightness and my own eyes more than the mechanics of any single scope. I liked the view at 77x enough to add the inexpensive 3x Apogee Barlow for the moon, planets and double stars. I've never been a fan of magnifications above 20x to 25x per inch on any scope I've used before, so trying 35-38x per inch is a nod to the versatility of the Nighthawk.

Conclusions

I like this telescope. Keep in mind that I bought a discontinued version of the Nighthawk from clearance stock. I didn't save much over the price of a new lightweight Nighthawk II, but saved about 1/3 off a new Nighthawk Classic. Both of those current models have Crayford focusers and bolts to adjust collimation of the objective lens cell. But I got the overall sturdy construction of the Classic, and rationalized getting the Stellarvue 1.25-inch enhanced diagonal to keep with this scope.

Mechanically there is no room for complaint. Everything is well finished, well machined and works smoothly and properly with an overall feeling of sturdiness. A few places have some fit that is less than a millimeter off, just enough to notice (the meeting of the 2 halves of the tube ring cradle, for example) but with no effect on function. The interior flat black finish could be more flat or "dead'. The tube baffles may offset minor concern about the finish.

Above this very competent or workmanlike standard, many nice touches are overlaid, such as the excellent red dot finder and its sturdy dovetail, the smooth long-travel focuser, the overall finish, the massive dew shield and cap, the solid tube cradle, and the well-made star diagonal.

The objective is well multicoated and the tube sufficiently baffled that there is no flare at all with bright objects in the field of view, and just a hint of sky brightness with the moon or a bright planet outside the field, just enough to help aim at 77x or 115x when lining up on the moon or a planet without using a lower power eyepiece first.

What's Great

- Objective multicoatings
- Red-dot finder is a pleasure to use ? I would it pick over many 5x to 8x finders I've used
- Solid build, big mounting base
- Smooth focuser
- Effective dew cap/shade
- Overall quality from the "low-end' model speaks well for Stellarvue product line.

What's OK

- Inner tube blackening looks a bit less than flat (but seems to be adequate)

What's Disappointing

- Really, nothing I can put my finger on. This is an 80mm scope and the smaller aperture compared to 8 and 10-inch scope use is more apparent for some objects than others. Newer Nighthawks offer collimation adjustment and Crayford focusers, and a lighter-weight Nighthawk II is available.

Portable refractors like this can provide "grab and go" observing, and wide field deep-sky views not possible with larger or longer-focus scopes. Compared to larger scopes this holds up pretty well on Jupiter, Saturn and Venus, not so well on Mars, and gives up very little for moon observing. With a copy of Berry's Discover the Stars, or the Celestron Seasonal Star Charts, this would make a beginning scope that could provide years of learning the sky. I met my goal of finding a portable second scope that provides rewarding views for me and the family.

Bonus mini-review of Apogee 3x Barlow

I didn't want to get a high-power eyepiece that I wouldn't use on the C8, so I settled on this 3X Barlow from Apogee in Illinois for about $20. It is more lightly made than the Orion Shorty Plus 2x, with thinner walls that feel like they actually flex if squeezed. It arrived with the front black lens cell barely loose, and the fraction of a turn to snug it back up made me aware of the thin-walled metal and slightly rough threads.

But it costs under 1/3 of the 2x Shorty Plus. I was hard pressed to tell apart the view at 72x (20mm and 3x Apogee) from 77x (12.5mm and 2x Orion). If anything, I was left with the impression of a tiny bit less false color on the moon's limb with the 3x in use. I'd say the Orion is much more likely to last a lifetime, and less likely to ghost or flare under challenging conditions. For the price I'm very pleasantly surprised with this high-power experiment for Nighthawk use.


Apogee 3x at left, Orion Shorty Plus 2x (3-element) at middle, Celestron Ultima 12.5mm at right. Both Barlows have lens elements right at the end of their tubes, facing up here (watch those fingers!) and grip texture on anodized part of tube. The Orion is better coated and blackened, but differences were hard to see in use at the scope.

Here is a summary of my impressions compared to the excellent 2x Orion Barlow:

- Apogee 3x has no edge blackening and less effective multi-coatings (more reflections visible on lens surfaces of the Apogee, but didn't see ghosts in first use, Orion Barlow lens elements are blackened, with no reflections visible)
- Both have thumbscrew (not compression ring)
- Apogee has thinner walls, rough thread at lens cell, feels more fragile/lightweight
- Apogee has excellent supplied caps for top and bottom, nicer than Ultima or Orion supplied with the other eyepieces shown
- Dramatic differences were not evident in use.

About me

Here's my astronomical autobiography:
- My father was a navigator trained when celestial navigation was an essential backup to new radar or radio systems. He knew over 200 stars by name, and could confidently identify them through holes in the clouds. Once I stopped snickering at Betelgeuse I was hooked, learning from Altair to Zubenelgenubi by the early 1970s.
- I used a pair of family spotting scopes, one 10x30, one 10-30x30 zoom, and binoculars, to start viewing planets, the moon, and begin finding objects from Seasonal Star Charts and What Star is That?. My dad encouraged me to teach him more sky facts. First views of Saturn, lunar eclipses, or the North America Nebula under dark skies are still memorable. The same old tripod from those days is under the Nighthawk.
- Persistent study was encouraged first with a 3-inch reflector that had a terrible mount and plastic rack and pinion focuser with a glued in Ramsden eyepiece, but which gave many hours of moon and bright planet views. I still have the mirror to someday make into a plank and pipe mount scope a la old Edmund Scientific ATM brochures. Then a used 60mm f/15 equatorial refractor with slow-motion cables invited more planetary study.
- Most of that was sold to a school teacher, to help fund a used 8-inch reflector with a clock drive as I entered high school. Set-up sometimes involved 4-5 trips up 2 ladders to the flat part of our roof, last trip with the OTA on my shoulder. Mars had features! Jupiter's shadow transits and the red spot were vivid. The moon was stunning. M 11 was always a favorite. I didn't add to the mixed bag of eyepieces and in hindsight, the views were pretty narrow. After about 6-7 years, moving during college, I sold this and became an occasional binocular observer for 10 years.
- Then I moved to Nevada and got a 10-inch f/5.6 Dobsonian on clearance from Orion. Our backyard had a dark eastern sky and a terribly bright western sky. I saw more deep sky objects in three years of viewing the eastern sky than with all previous efforts, using the Skalnate Pleso Atlas of the Heavens to fill in gaps I hadn't noticed before in the simper charts. I seldom went over 125x with a pair of Plossls, and a 2" Rini that I pulled the field stop from to give 1.5 degrees of nearly-sharp spectacle. Star party trips were few, and I preferred the local public outreach events to members-only dark sky trips. The big Dob was always popular with views of earthlight on the crescent moon, the Orion nebula or the double cluster.
- I went back to binocular observing for a few years in the Midwest
- Now I have a 20 year old C8 that gets a couple nights a month of backyard use, and kids who think planets, the deep sky, the moon and sunspots are cool, but telescope set-ups are too infrequent. I hope to bring the Nighthawk on most of our family camping trips. It seems to recapture the wide field I enjoyed with the Dob (although not the stunning brightness), and by virtue of being easy to set up and share, also recaptures the first views I recall from learning the sky.