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Product Review - Bresser Messier AR-127S/635


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Product Review
By Van Webster

***Bresser Messier AR-127S/635 127 mm f/5 Refractor Telescope***
Air Spaced Doublet Refracting Telescope Optical Tube Assembly
Street Price $519.99 From Agena Astro/Products
www.agenaastro.com



The Messier AR-127S/635 127 mm f/5 Refractor Telescope is an entry level, 5” aperture, wide field refractor telescope for visual and beginning astrophotography use.  While by no means competitive with the top refracting instruments, this telescope is an affordable way to get into refractor telescope operations.

About me and my astronomical interests.

I am based in Los Angeles and am a member of the Los Angeles Astronomical Society, The Local Group Astronomy Club of the Santa Clarita Valley and the Astronomical Unit Club of Santa Barbara.  I have a number of scopes in addition to the one being reviewed here with my primary visual scope being a custom packaged 13.1 Newtonian reflector on a Dobsonian mount.  Other scopes include 6” and  8” Newtonian reflectors, a 5” Maksutov-Cassegrain and a Vixen VMC-200 Cassegrain.  I have the iOptron ZEQ-25GT mount used for all but the 13”.  My general bias in purchasing astronomical equipment is towards getting the maximum value for the least expense.

My primary interest in astronomy is education and outreach.  I hold a Master Outreach designation from the Astronomical League and participate in 35-50 outreach events per year.  I attend dark sky events when I can and am getting started in astrophotography. I also teach Landscape Fine Art photography workshops and have introduced workshop attendees to wide field night time photography.

I had been looking for a moderately priced refractor telescope and had been attracted to the Explore Scientific doublet models, having seen reasonable specifications and a “just out of my budget” price.   I first saw the Bresser Messier AR-127S/635 127 mm f/5 Refractor Telescope on the Agena Astro/Products web page and was intrigued.  A “cosmetic blem” version was offered at a discounted price so I took the plunge and ordered.  As usual from Agena Astro/Products, the transaction was smooth and the scope arrived in a couple of days.

Product description

Opening the double layered shipping box, I found that the scope had shifted during handling and that some of the internal packaging inside the box was damaged.  The scope and its contents appeared to be fine.  The current specification of the scope includes a 1.25” diagonal and a 1.25”, 25mm eyepiece.  The version I was shipped included a 2” diagonal and a 2”, 25mm eyepieces that appeared to be virtually identical (except for the exterior finish) with the Explore Scientific 2”, 25 mm eyepiece I already had in stock.

Also included was a small planisphere that is very hard to read because of its small size and a CD, purportedly containing Stellarium software, that completely refused to load on my computer and so it is functionally useless.  Attached to the scope barrel were two logo stickers from F.A.O. Schwartz, the famous toy store in New York city.  These stickers were very difficult to remove.  The paperwork inside the box indicated that the scope was marketed by Meade Instruments Europe.  The warrantee card was from Explore Scientific.


The scope itself was substantial in appearance with a quality powder coat finish.  It looks very impressive when mounted on a tall tripod. Even experienced astronomers expected that the scope was priced hundreds if not a thousand dollars more than the actual cost.

 


The focuser is a 3” diameter rack and pinion device with plenty of travel but sloppy clearances.  Tightening the screws on the rack and the tension screws on the pinion improved the focuser’s performance but it is by no means precise or smooth.  The barrel of the focuser has a calibrated scale in centimeters that extends by 11.5 cm and is helpful for setting preliminary focus.  I found that focus could be achieved with the 2” diagonal and 2” eyepieces but that the optical path of the 2” diagonal was too long to use 1.25” eyepieces with a size reducing adaptor in the 2” diagonal.  Using a separate 1.25” diagonal with its shorter optical path, enabled 1.25 “eyepieces to come into focus and worked quite well.  If you purchase this scope, expect that you will need both sizes of diagonals.


The scope comes with a straight through 9X50 finder scope and the unexpected but appreciated illuminated reticule eyepiece.  The finder scope mount is fitted with metric thread, cast nylon adjustment screws.  As supplied, four of the screws were the correct size and one of the screws was undersized.  A trip to the hardware store produced a properly sized replacement screw, albeit in steel, not nylon.  (The sixth screw position is fitted with a spring loaded pressure device that makes centering the scope pretty simple.)  The finder scope mount uses the Meade style narrow grooved mounting fitting that is incompatible with the more common Vixen style dovetail.  Not an issue unless you want to use a different finder scope.


Attached to a mount rated at 30 pounds or more, you can expect reliable tracking within the mount’s specifications.  The Vixen style dovetail plate, with a steel reinforcing strip, is easily attached to most of the standard scope mounts.

Performance in the field

A 5” doublet optical design priced at about $500 should not produce high expectations of optical performance.  As tested, the image quality was really quite sharp with pinpoint stars at magnifications of up to 100x.  I found an observational sweet spot with an Orion 8mm Stratus eyepiece producing satisfying views at about 80x magnification.

Chromatic aberration, however, was substantial with even the most amateur of fifth graders at an astronomy outreach event commenting that the image looked like rainbows when viewing Jupiter.  Deep sky objects fared better with considerable detail in M-42.  Adding a Baader “Fringe Killer” with IR Cut filter (also available from Agena Astro/Products) to the optical path greatly reduced the chromatic artifacts but only with a truly dark sky.  Twilight viewing thorough the Fringe Killer filter produced a distracting yellow color in the background bluish sky.

My son and I are dipping our feet into the astrophotography pool and this instrument proved to be pretty successful for prime focus astrophotography when using a 2” camera adaptor coupled to a Nikon DSLR.  This scope is an affordable way to test the refractor scope waters before making a commitment to a pricier instrument.

A surprise to me was the quality of image when using this scope for white light solar viewing.  An Orion full aperture glass filter, intended for a 6” reflector telescope, fit the sunshade of the Messier perfectly.  Stacking the Fringe Killer and a Baader L-Booster UHC-S Filter on the eyepiece end of the scope produced a detailed image of the sun’s surface and sun spots.  Not the same image as a dedicated Ha solar scope but an excellent white light view.

Lunar views, with the Fringe Killer filter and an after-sunset darkish sky produced the “Oh! Wow!” moments from outreach participants that are the reward for sharing our scopes.  Not as dramatic an image as with my 13” reflector, but good enough to impress the public.

General summary.

So what is the Messier AR-127S/635 127 mm f/5 Refractor Telescope good for beyond solar viewing (with the appropriate filters)?  Someone once said that getting the first 95% of performance out of a telescope design is relatively inexpensive but getting the last 5% can be very costly.  So it is with this telescope.  You get a lot of bang for the buck.  It is ideal for school outreach events where you want to demonstrate a refractor design to students and don’t want to risk damage to a more expensive instrument.  The relatively short focal length gives satisfying wider field views of deep space objects and the scope can be easily attached to a DSLR for beginning astrophotographers.  It may be comparable with the Explore Scientific AR-127 127mm f/6.5 Achromatic Refractor telescope but selling for $200 less that the ES instrument.

For the price, this telescope is a good value but don’t expect the performance of a top imported scope, at thousands of dollars more out of pocket.  Set reasonable expectations and you won’t be disappointed.


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