First Impressions of the TMB130
Signature Series 5.1” F/7 Triplet APO Refractor
December 23rd, 2006, Larry Owens
Clevis
Jones first introduced me to TMB Optical with his TMB115 CNC APO several years
ago. The 115 presented amazingly detailed views of Jupiter, Saturn and of
course the Moon. Deep sky targets always yielded tack sharp stars and a
surprising amount of detail in galaxies and nebulae for a 4.5” refractor, all
without any noticeable color fringing.
The designer, Thomas M. Back (http://www.tmboptical.com/) recently introduced a new version of his TMB130 called the “Signature Series”. It sports a beautifully anodized and polished 4” focuser with a millimeter scale, 10:1 fine adjustment focusing knob and rotating camera adapter. Like all other TMB refractors, the Signature Series also has a retractable dew shield for compact storage.
The instrument is an F/7, 130mm (5.1”) triplet APO with a focal length of 910mm. Supporting the triplet is a temperature compensating cell with collimation screws and the entire OTA weighs 19 pounds.
TMB refractors have for years had a reputation for quality and as you might
expect the price reflected this high quality. The TMB130 Signature Series
however is offered at a surprisingly low price point through a more direct
approach to manufacturing and marketing. The mechanics are manufactured in Asia
and the Thomas Back designed APO triplet is manufactured in Japan by the same
manufacturer that produces
lenses
for Takhashi, one of the absolute best telescope manufacturers in the industry.
The process reduces the number of people involved in manufacturing and maintains
the highest standards in quality, but at a lower cost. The OTA’s are currently
sold and stocked only by Astronomics (http://www.astronomics.com).
After placing an order with Astronomics in early November 2006, I finally received the OTA on December 20th. The product appeared to be packed well with bubble wrap surrounding the very nice lockable aluminum padded case that comes standard with the OTA. However when I first lifted the box, I could feel the OTA shifting from side to side within the case. Upon closer inspection I noticed that one side of the case was pushed out a bit, and there was a sizable outward dent in the top (apparently caused by rings attached to the scope before shipment). Opening the case revealed the culprit; although the case was lined with foam padding, the padding was not form fitting, thus allowing the OTA to move from side to side. This didn’t seem to damage anything except the case, but I contacted Thomas Back and Astronomics to recommend additional padding or form fitting foam inside the case for future shipments.
The skies cleared by the 23rd and our “first light” experience with the scope occurred at 17:33 local time at the Charlie Elliott observing field. Clevis Jones was nice enough to bring his TMB115 along for the event, and we spent several hours comparing views through the two scopes. So our impressions would be OTA to OTA we used the same eyepiece and diagonal for each view. The conditions were not ideal, thin high altitude clouds were present and the atmospheric seeing conditions were poor to average.
Our first target was the waxing crescent moon. My first view through the TMB130
was exciting. The ring of mountains surrounding Mare Crisium appeared sharp and
distinct, however the view of the same region of the Moon through the TMB115
revealed a slightly crisper view. We continued to look for the finest details
through each scope to test and compare resolution and contrast. After
about 30 minutes, the 130 seemed to find its sea legs. Details appeared to
sharpen quite nicely, to equal or exceed the crispness of the view through the
115. This is almost certainly a cool down issue. Views of the moon at 228x and
303x were free of breakdown, but atmospheric stability was a problem on this
first night out with the scope.
For deep sky comparisons we observed numerous open clusters, several galaxies, a few planetaries, Uranus, Neptune, the Trapezium, and several double stars, though nothing very challenging to the two scopes. I also did some quick star tests with the 130.
In every type of deep sky object, the views through the 115 and the 130 were nearly identical, if not a tiny bit brighter in the 130. The stars were tack sharp and popped into focus, in fact it was fairly easy to find Neptune in a low power field of view by finding a star that didn't have that tack sharp appearance (because of the planetary disk). The disk of Neptune and Uranus were clearly visible and nicely presented at 228x.
I've looked through many telescopes in my 40+ years as an amateur astronomer and I am very impressed with the performance of the 130, especially since it compared so favorably to the hand picked optics of the TMB115 CNC, which incidentally is priced considerably more than the 130.
We're planning to do some additional detailed testing in the future, including some close doubles when the time and skies permit. But my initial assessment of the TMB130 Signature Series is that it’s an absolutely superb 5.1” APO, and very much under priced (and that’s a good thing).
Larry Owens.