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BB Reviews the Bresser Messier AR-102L

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#1 Bomber Bob

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Posted 27 March 2019 - 12:23 PM

Way back in DEC 2016, I reviewed the new ultra-economical Explore Scientific FirstLight AR-102 F10 kit / https://www.cloudyni...hinese-imports/.  That was my first hands-on experience with China-made refractors -- my APM 152ED is my latest.

 

Thanks to the folks at Teleskop-Express, I'll review the Bresser Messier AR-102L/1350 OTA in this thread, from shipping time, to packaging, to fit / finish / functionality, to everything I can think of -- and that y'all have questions about.

 

The Big First Question:  Will this scope renew interest in (& buying!) high F-ratio achromatic refractors?  We will see...

 

I have some new tools for this review that I didn't have before:  a DPAC rig to objectively assess the optical quality; and, a deep-sky digital imager to (hopefully!) make pictures of the star test results.

 

I placed the order today.  It was marked IN STOCK.  How long will it take to get from Germany to The Swamp?

 

While we wait, here are the specs from the T-S site / https://www.teleskop...e-Assembly.html

 

Optical design: Achromatic refractor
Magnification from: 30x
Magnification up to: 200x
Objective diameter: 102 mm
Focal length: 1350 mm
Aperture ratio: f/13.2
Angular resolution: 1.35 arc seconds
Type of coating: Multi coated
Finderscope: 6 x 30 mm
Material OTA: Aluminium
Focusing system: 2.5" Hexafoc
Total length: 139 cm
Total width: 18 cm
Total height: 18 cm
Tube diameter: 104 mm
Net weight optical tube (incl. accessories): 5.3 kg


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#2 Steve Allison

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Posted 27 March 2019 - 02:50 PM

Looking forward to your review, JW!



#3 Gabby76

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Posted 27 March 2019 - 07:34 PM

I am also interested in your review, I just sold my 102 f/13 that was from the first shipment of these. 

Once I had the issues straightened out it was a really nice observing refractor. 


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#4 Bomber Bob

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Posted 28 March 2019 - 08:20 AM

My AR-102L shipped today, 28 MAR, via UPS Express.  No ETA yet (IIRC, I didn't get accurate tracking on my APM 152ED until it cleared US Customs.)  T-S processed the order quickly, and I've received several email messages from them, including a Thank You! for the purchase.



#5 KerryR

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Posted 28 March 2019 - 09:56 AM

Very cool. Looking forward to the review. Sounds like you have some excellent tools to help with objectivity!



#6 precaud

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Posted 28 March 2019 - 10:04 AM

Thanks to the folks at Teleskop-Express, I'll review the Bresser Messier AR-102L/1350 OTA in this thread, from shipping time, to packaging, to fit / finish / functionality, to everything I can think of -- and that y'all have questions about.

I have some new tools for this review that I didn't have before:  a DPAC rig to objectively assess the optical quality; and, a deep-sky digital imager to (hopefully!) make pictures of the star test results.

 

Good man. Maybe this will finally put an end to the itch I've felt for one of these.


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#7 memento

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Posted 29 March 2019 - 03:28 PM

I was actually following your review on that 102mm f/10 throughly, as I was looking for achromats myself last year, but eventually I went for the Vixen 90M instead. So I'm curious about your new review. Do you still have that f/10 for a direct comparison? Thomas



#8 Bomber Bob

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Posted 29 March 2019 - 03:34 PM

Do you still have that f/10 for a direct comparison?

 

I don't.  I parted it out:  Gave the mount to a new CN member who needed one, and gave the OTA to a young CN member who didn't have a "big" refractor.  I do have my vintage Dakin 4" F10, and my 1950s Edmund 4" F15 for comparisons.


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#9 mikerepp

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Posted 29 March 2019 - 03:35 PM

Look forward to your review.  I've been itching for a longer FL refractor.



#10 Bomber Bob

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Posted 03 April 2019 - 07:07 PM

The AR-102L arrived yesterday - 6 days after my order - all the way from Germany to The Swamp with no damage to the 5' long exterior box.  I'll get unpacking pix up tomorrow.  No shifting sounds or rattling glass, and that's a good sign!


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#11 Bomber Bob

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Posted 04 April 2019 - 07:52 PM

Unpacking the Bresser AR-102L:  Boxes w/in Boxes + Layers & Layers

 

Bresser AR-102L S01 (Shipping Box).jpg Bresser AR-102L S02 (Shipping Box).jpg Bresser AR-102L S04 (Outer Box).jpg Bresser AR-102L S06 (Inner Box).jpg Bresser AR-102L S07 (Inner Box).jpg Bresser AR-102L S09 (OTA Bag).jpg Bresser AR-102L S10 (OTA).jpg Bresser AR-102L S11 (OTA).jpg Bresser AR-102L S12 (OTA).jpg Bresser AR-102L S13 (OTA).jpg Bresser AR-102L S14 (Lens).jpg

 

Excellent packing!

 

BIF:  The shipping box is 67" x 17" x 17" & 32 lbs.

 

BIF2:  The 6x30 Finder, mirror diagonal, 2" extension tubes, & eyepiece are packed well in a small box at the lens end of the inner box.  No red-dot finder, but a traditional optical with - looks to be - a coated glass objective.


Edited by Bomber Bob, 05 April 2019 - 07:20 AM.

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#12 Bomber Bob

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Posted 04 April 2019 - 08:23 PM

First Impressions

 

- Attractive!  Simple, traditional, understated - single red stripe is a nice touch.

- Light!  It feels much lighter than my Dakin F10.  I like the way the weight is distributed in the long tube.

- Focuser:  the action is smooth, though I do hear a rubbing noise from about halfway to fully extended.  The focuser rotation is also smooth, but is it as accurate as my APM 152 (which doesn't require re-tweaking the focus)?

- Lens:  Under bright light, I don't see any dust / debris between the elements.  The coatings are a darker green than expected.

 

So, nice-looking long refractor.  There are plastics, but they don't look/feel cheap, especially considering the price.  The mechanics have a good feel, but I reserve judgment until field testing.  We're probably gonna be socked-in through the weekend - as usual!  On the bright side, it'll give me time to put the lens on my DPAC rig.

 

Mounts:  It's so light, I'm gonna try it first on my vintage Vixen Polaris mount, with the Bresser rings attached to an 18" custom dovetail bar.  I know my Goto & Takahashi mounts will have no problem carrying it.


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#13 Bomber Bob

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Posted 05 April 2019 - 10:20 PM

First Light

 

Temperature 69°F (21°C)

Humidity 90%
Wind Speed Calm
Dewpoint 66°F (19°C) 

Seeing 5 -  8 / 10 (in cloud gaps)

 

Thanks to my wife, I got in 90+ minutes in the first solo session with the AR-102L.  Based on the NWS forecast, I thought it would be mid-week before the weather would cooperate.  But after supper she went to get something from her car, and told me the stars were out... Talk about scrambling!

 

Star Test:  Lens is slightly under-corrected.  I tested straight-through with 5 eyepieces -- UO HD 12.5 & 9mm Orthos; and, spectros 15, 10, & 7.5mm Plossls.  I observed Capella, Betelgeuse, Procyon, and Pollux.  Inside focus was near perfect, outside focus was as symmetrical, but fuzzy.  I think it'll look worse in DPAC, which is more sensitive than my old eyes.

 

In sky testing, it wasn't noticeable.  BUT, tonight I was limited to just double stars & open clusters, and I had to find gaps to see those.  As usual, I used my gear -- Baader 1.25" prism diagonal, and I ran most of my 1.25" & .965" eyepieces through the rotation.

 

What I did see looked very good.  I started with the RKE 28mm at 48x, and even in this long frac, I got that Space Walk view with big eye relief.  Castor was in the clear & cleanly split.  Very pretty, but the color of both stars was strong yellow-orange.  M35 was glorious -- filled the field.  Couldn't get the whole Beehive, but M67 did, and that string of yellow stars really stood out.

 

Besides Castor, I observed my favorite Cancer Doubles.  The prettiest in this frac was Struve 1187 (7&8 @ 3") with - of all eyepieces - a vintage Meade Research Grade 20mm Erfle at 68x.  Both stars looked tangerine to me, separated by a fine black line.

 

Functionally, no complaints.  The r&p focuser has a short range, but I didn't need either of the two 2" extension rings tonight, and was sufficient for 5mm to 28mm eyepieces.  I had already tightened it up using the 3 main thumbscrews, and the resistance was perfect -- no slipping at any orientation.  The rotation is smooth, and I didn't have to refocus.  With the diagonal & eyepiece, the OTA's balance point on the Goto EQ favored the lens end, which put the eyepiece at a comfortable height for seated observing.  The finder & bracket have the most plastic, but it's easier to just sight along the tube for the bright stuff.


Edited by Bomber Bob, 05 April 2019 - 10:51 PM.

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#14 barbie

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Posted 05 April 2019 - 11:16 PM

Your startest confirms the same as I've observed with my AR90L. Slightly uncorrected but a nice!y performing lens nonetheless.


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#15 memento

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Posted 06 April 2019 - 02:56 AM

Great first report, many thanks for sharing and also for the pics! Looking forward to more observations. This scope took quite a beating when it first appeared on the market, with the plastic lens cell and what not.

 

Did you try the supplied diagonal and eyepiece once? (Or did the scope even come with one?) I have the impression that Bresser tend to supply sub-par accessories with several of their lower priced scopes. But then the 102L is one step up from their baseline offerings already.

 

Also curious if your Polaris mount can handle the scope. I have a Super Polaris myself, and the long vintage 102mm refractors (Vixen f/13 etc.) are definitely too long and heavy for it.



#16 Bomber Bob

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Posted 06 April 2019 - 07:24 AM

Slightly uncorrected but a nice!y performing lens nonetheless.

 

That's what I saw last night.  I won't be convinced until I've seen Jupiter at high power -- hopefully tomorrow morning -- about its "long frac" performance.

 

Did you try the supplied diagonal and eyepiece once?

 

Thomas, not yet.  I always start with my gear -- known good -- when testing an unknown lens.  Honestly, the bundled diagonal & eyepiece look just like those with the ES FL AR-102, and that diagonal was worthless above ~ 70x.  Your Super Polaris shouldn't have trouble carrying this scope; but, I would use a long dovetail / mount plate.  I will test it on my Polaris with wood tripod.  Last night, it was smooth on that old Goto + Unitron wood tripod -- the kind of combo I would've loved 40 years ago when I had a Tasco/Towa 80mm F15.


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#17 barbie

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Posted 06 April 2019 - 08:22 AM

I did not use the supplied eyepiece or diagonal that came with my AR90L. I upgraded the diagonal to a Celestron prism diagonal #94115-A.



#18 precaud

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Posted 06 April 2019 - 08:44 AM

Thanks Bob. Looking forward to the DPAC results.

Given the present hooplah about LED light color bandwidth, filtering, etc., perhaps you could mention what you're using, so that we know just how much to discount the results...   (just kidding!! of course!!)


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#19 droid

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Posted 06 April 2019 - 08:47 AM

And how much does this scope cost?

 

The reason I ask is because , at the low end of refractors, where I live,  Pretty much every scope I've ever gotten came with accessories that needed to be replaced, diagonal ,eye pieces, finders , focusers etc.

 

So if this thing needed a replacement diagonal outa the hole, wow....hope its not to expensive.



#20 memento

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Posted 06 April 2019 - 08:49 AM

Yes most of us long refractor guys will have good (prism) diagonals already at home. I also use a Celestron prism diagonal from Japan which seems very decent with my refracs, and sometimes even some really old .965" diagonals.

 

Still I am wondering why Bresser even includes such a bad one with the 102L. Not a big point of complaint though as the scope is not targeted towards first time buyers anyway.


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#21 Bomber Bob

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Posted 06 April 2019 - 09:05 AM

AR-102L on Goto 106 (3" EQ) + Unitron 142 Tripod

 

Bresser AR-102L S15 (Goto Unitron).jpg Bresser AR-102L S16 (Goto Unitron).jpg

 

This is as used last night.  As I posted, eyepiece height is comfortable for me in either of my lawn chairs.

 

 


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#22 precaud

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Posted 06 April 2019 - 09:07 AM

And how much does this scope cost?

 

The reason I ask is because , at the low end of refractors, where I live,  Pretty much every scope I've ever gotten came with accessories that needed to be replaced, diagonal ,eye pieces, finders , focusers etc.

 

So if this thing needed a replacement diagonal outa the hole, wow....hope its not to expensive.

 

To the US, about $300 delivered.

 

Your situation and mine are similar. I also have a C102GT, a very good one. Just how much "long-focus magic" this 102L provides over what I have is what I'm wondering. If they're all coming through undercorrected, it's questionable...


Edited by precaud, 06 April 2019 - 09:09 AM.


#23 Bomber Bob

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Posted 06 April 2019 - 09:12 AM

And how much does this scope cost?

 

$320 from Germany to The Swamp.


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#24 Gabby76

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Posted 07 April 2019 - 02:53 PM

Good observations and nice to hear that there were not any obvious issues with the refractor!

Looking forward to the rest of your evaluation. 



#25 Bomber Bob

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Posted 07 April 2019 - 03:59 PM

1st DPAC Test  

 

I put the lens on my DPAC rig after lunch.  I haven't seen this exact pattern before, so I'll run the test again when I have more time.  (Finished & filed my taxes today.)

 

I use 4-5 bars to check for edge curvature, and 3 bars to check for central bowing / curving of the bars.  Like this one from my Takahashi FC-50:

 

Takahashi FC-50 IF S01.jpg

 

(My !@##$#@!! Nikon camera thickens the bars & otherwise distorts the pattern, which is why I don't post photos.)

 

With the AR-102L lens, the DPAC bars are railroad straight, but the two central bars thicken a bit towards the middle of each.  At 3 bars, only the center-line bar thickens -- yet there's no bowing in or out... Very strange.  I switched from the green to red LED, and the effect was more obvious -- but that could be the way my eyes respond to the color.  I already had the lens from a vintage Tasco (Towa) 4VTE in line to test, so I swapped the lenses out.  The Towa 40mm F13 showed nice straight narrow bars, very similar to a 1960s Astro Optical 40mm F12.5 lens.  After removing the Towa lens, I re-verified rig collimation, put the Bresser lens back in, and saw the same pattern in both green & red light.

 

Since I've run all of my scope lenses through DPAC, I went back through the archives, and I found 2 lenses with similar "bubble middle" bars:  the vintage unknown maker 5" F5 triplet, and the 1956 Space Scope 151 60mm F15 (made by the predecessor to Astro Optical):

 

DPAC - SS151 (OF) D01.jpg

 

The SS 151 gave great views for its aperture, so if today's test is valid, I doubt I'll see any defects with high-power planetary, but I really want to put the Bresser F13 up against my excellent Edmund F15 for sure!


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