A very short review of the Apertura AD8 Dobsonian Telescope
Introduction
First things first, a Dobsonian telescope is a reflecting telescope (that uses 2 mirrors, a primary and a secondary) on a mount popularized by San Franciso astronomer John Dobson (hence the name). The main benefit of a Dobsonian mount is cost (a refractor on an equatorial or altazimuth mount of the same size would be much more expensive, as would a reflector on the same mounts)
Purchasing decision
I love amateur Astronomy and I’ve owned various telescopes over the years. The last large telescope I had was a 12 Inch Dobsonian telescope (Skywatcher 300P Collapsible Flextube). I sold this telescope over a decade ago when we moved cross country (from the East Coast to the West Coast). I used that telescope for many years in New England, and while I loved it for its incredible views, moving it was a chore (it was about 100 lbs and pretty unwieldy even when broken into its two components and fitting it into a small sedan was doable but a challenge). It also took about 10–15 minutes to set up (place the tube on the base, expand it out, collimate it etc). Also a 12 inch mirror takes some time to cool down (on the order of 45 minutes to an hour, though I got a cooling fan that sped up the process).
I got to see some amazing things in that telescope (I tend to like looking at the faint fuzzies, nebulae, globular clusters etc). The highlight of my viewing was seeing the supernova in M51 (Whirlpool galaxy) from a dark site in Western Massachusetts.
After I sold it, I kept my Orion Short-tube 80 mm wide field refractor (and got an Altazimuth mount for it). It is a fine telescope especially considering how inexpensive it was, but it just doesn’t cut it for the types of things I love to view (nebula, globular clusters etc) which require a lot of light gathering capability.
A few months ago, I decided to get another large dobsonian, and knew I did not want a truss tube 12 inch dobsonian. I also knew I did not want a 12 inch solid tube dobsonian (think about moving a tube the size of a water heater that weights ~70 lbs). Thus the choice became between an 8 inch and a 10 inch dobsonian. I did some research and the consensus seemed to be that while the views through a 10 inch dobsonian were slightly better/brighter than those through an 8 inch, the added weight of the 10 inch made it less likely to be used as often. This video by Ed Ting goes into why for most people an 8 inch Dobsonian is preferable to 10 inch Dobsonian (also, all of Ed Ting’s videos are amazing and full of great information). And I can second his sentiment, there were times with the 12 inch where even though I could go observing, sometimes it did not feel worth the hassle to get it set up. I wanted a scope that would be relatively easy to move while still gathering enough light to allow me to see the objects I was interested in.
After deciding on an 8 inch dobsonian I began looking at 3 popular 8 inch dobsonian telescopes; Orion Skyquest XT8 (Orion sadly just went out of business), Zhumell and Apertura AD8. The Apertura AD8 was the more expensive of the 3 but it came with 3 things I considered essential, a 2 speed Crayford focuser, a cooling fan and a really nifty system for balancing the optical tube with heavier eyepieces.
I also ordered the Apertura Dobsonian Performance Upgrade Kit which adds collimation knobs for the secondary, flocking material for some of the tube and better collimation springs for the primary. The telescope itself cost about $700 and the upgrade kit around $70.
Setup
Once it arrived (in 2 boxes), putting it together was very easy and done in about 20 minutes, including initial collimation and aligning the finder. I also attached a Telrad Reflex Sight Finder because I’ve found that using a finder (the AD8 comes with a nice 8x50 Finder) only does not work that well for me. And then it was time to wait for night. For the first time in my life, I did not suffer the dreaded new telescope jinx (every time I have bought a new telescope clouds have rolled in for a few days preventing me from using said telescope).
First Light
I moved the telescope out to my backyard (in a relatively light polluted area), plugged in the batteries for the cooling fan and let the scope acclimatize for about an hour. And then I began viewing. The eyepieces I was using were a 27mm Televue Panoptic, a 13 mm Baader Hyperion eyepiece, a 9 mm Televue Delite and a 5 mm Baader Hyperion. The telescope has a focal length of 1200 mm so below are the magnifications yielded by those eyepieces.
- Televue Panoptic 27mm 2 Inch Eyepiece (44.4 x Magnification)
- Baader Hyperion 13mm 1.5/2 Inch Eyepiece (92.3 x Magnification)
- Televue DeLite 9mm 1.25 Inch Eyepiece (133.3 x Magnification)
- Baader Hyperion 5mm Inch 1.5/2 Inch Eyepiece (240 x Magnification)
I also had my trusty pair of 7x50 Astronomy binoculars. My rough process was locating the object in the Telrad (which projects concentric red circles that you can use to position the scope) and then use the 8x50 finder to fine tune. The scope also came with an adapter to allow wide angle eyepieces to come into focus, as well as 1.25 inch adapter to allow usage of 1.25 inch eyepieces in the 2 inch focuser. I was using the famous book “Turn Left at Orion” to locate objects of interest and using Stellarium on my iPad Pro (rather than a traditional sky chart) to aid me.
Below are my rough viewing notes.
M13
M13 is a globular cluster in the Hercules constellation. It is the best globular cluster viewable from the Northern Hemisphere (Omega Centauri in the Southern Hemisphere is much more spectacular). Very easy to find in the 27 Panoptic which has a very wide angle of view. Viewing through the 13 mm Baader Hyperion and 9 mm Televue DeLite allows resolving of some of the stars. The view has the classic ‘salt spilled on black velvet’ look.
M57
M57, the Ring Nebula in Lyra shows like a very small, dim out of focus circle in the 27mm Panoptic. In the 9mm DeLite starts to show some structure, minor irregularity with averted vision.
Albireo
Albireo is a double star in Cygnus, famous for the different colors of the stars. Very easy to find. In the 9mm DeLite, the contrast in color between the 2 stars (blue and yellow/orange) is readily apparent. Using the 5 mm Hyperion does not yield much of a difference.
Double Double (Epsilon Lyrae)
The Double Double (Epsilon Lyrae) is a double star in Lyra that holds a surprise. In the finderscope and 27 Panoptic it is clearly a double star but at high magnification (in the 13 and 9 mm eyepieces) I could make out that each component of the double star was a double star itself (in the 5mm eyepiece I could separate each double into its components). This is considered a good test of a telescope though it is also dependent on the seeing, how stable the atmosphere is).
M17 (Omega Nebula/Swan Nebula)
M17 is a nebula in Sagittarius with a very distinctive shape. Viewable in the 27 mm eyepiece but looks better once I used an Orion Ultrablock 2 inch filter. Was able to make out the brighter part of the nebula and see the classic swan shape.
Final Thoughts
I’m really happy with the AD8. I still find myself wondering whether I should have gotten the AD10 but whenever I have to move the AD8 I think it is the perfect compromise. I can move it short distances in 1 piece (and it comes apart easily to move it in 2 parts). The telescope seems high quality, as do the included eyepieces (the 30mm 68-deg. 2 Inch Super View Eyepiece and the 9mm 52-deg. 1.25 inch Plossl Eyepiece). The upgrade kit definitely adds to the utility/quality of the scope (I wish there was an option to purchase the scope with it already installed, as it was, it took about an hour to replace the secondary knobs, primary collimation knobs and flock the telescope). The only thing I can fault is the included laser collimator, which was out of true (a common problem according to other owners). There is a process to fix this but it is somewhat involved. I already had an Orion LaserMate collimation tool so that is what I used but I can see the issue with the included collimator frustrating new owners who don’t have their own collimation tool. I did a star test of the primary mirror and it seems pretty decent.
I will do a more detailed review in the future to go into the ingenious system for balancing the tube with heavier eyepieces, as well as go into detail on the 2 speed Crayford focuser (which is butter smooth and excellent). I can’t wait to get this telescope to a true dark site!
