Explore Scientific AR127 Review
By: Vlad Fedosov
At one point or another, I think the refractor bug bites all of us. It has certainly bit me hard on several occasions. Once bit we are faced with a decision of whether we pick up an amazingly priced achromat like the Explore Scientific AR127 that we are looking at today of an ED/APO scope costing 2-∞ times more. The AR127 is a 5” doublet achromatic refractor that has a fast f/6.5 design. It has a focal length of 826mm and weighs in at 15.6lb.
Having concluded 2017, I wanted to start off the new year right and took the first relatively clear night to get my new AR127 under the night sky! As a bit of background: I have already owned the AR127’s little brother the AR102 a few years back. I decided to upgrade it to a Lunt 102ED refractor as I wanted better color correction and the ability to do planetary observing better. After about a year even the Lunt 102ED was not doing it for me and I decided to upgrade to a William Optics 102GT triplet APO. I guess what I have found over the years is that chromatic aberration does bother me enough to end up with a true APO. So why did I end up with an AR127? Well, I got it to see if the jump to the true APO was really worth it I guess, or if I could have gotten by with the excellent value of an achromat(and also to compare a 5” refractor to a 4”).
The scope was tested in my mag 4 backyard with a full moon. Transparency was a bit below average as was seeing. I used a Meade 5000 Plossl 40mm(20.65x) and a Meade 5000 HD-60 6.5mm(127x) eyepieces for the test. Orion was well positioned and I could not resist taking a look at the Great Orion Nebula as my first look with the 40mm. Magnificent view at 20x! All the stars where pinpoint and I did not notice any chromatic aberration to speak of! Was I wrong to jump ship from the achromat? I proceeded to take a look at Sirius to see how it looked. A tiny bit of blue around this gem, but nothing I would consider objective and I really had to look for it to really notice it. The moon was next in line. I did notice a small amount of color around the moon but again this was not something that I found objective at all. So far I was impressed!
I now decided to switch over to the 6.5mm which produces a relatively moderate 127x. 120-130x is my favorite magnification for most DSO viewing. I was very interested to see how the scope would do here. This is unfortunately where it got ugly, and fast, as far as secondary color. The view of the moon was sharp in the AR127 but the chromatic aberration was just out of control. The craters that were visible on the edge of the moon had washed out contrast due to the secondary color. The entire view was just not pleasing to me. I thought; ok, well I know that this is not a moon/planet scope. On to m42. The view of the Orion Nebula was pretty but even here I was surprised to find that I could see secondary color around the relatively dim stars. I took a quick look at Sirius again, and again I was greeted with what is to me, an unacceptable amount of color. I now remember why I longed for an APO.
The overall build quality of the scope is very nice, and it is a beautiful instrument to look at. It’s not quit on par with a TeleVue scope or the premium William Optics scopes. But for the money, I’m very impressed with the quality that the Explore Scientific scopes are. The focuser is a nice 2” unit that works well. It does have a bit of slop in the drawtube and I found the coarse focus knob on my unit a bit choppy. The fine focus knob was smooth, and a pleasure to use. It’s defiantly not up to par with the 3” Feather Touch that is on my William Optics but considering this entire scope is less expensive than that focuser that is to be expected. I did want to mention that I had the scope mounted on my LXD-75 mount and the settle time for vibrations was about 2 seconds. That is very acceptable, so any Vixen clone mount similar to my LXD-75 will be able to handle this scope nicely for visual use but I think would be a challenge for astrophotography.
The quality Explore Scientific provides in these achromats is quite impressive considering their very reasonable price. As I re-discovered though if you are hoping that this scope can provide similar views to its more expensive ED counterparts then you would be a mistaking. I think that the sweet spot for this scope is in the absolutely wonderful low power views of the milky way or observing very large objects such as the North American nebula or M31.