Finally – the Bresser Messier AR102S Comet Edition at the Salton Sea

February 26, 2017


Sometimes life is cruel.

(Did I say cruel? I meant ridiculously First World cushy, where a grown man can afford nice toys and has the time to play with them and blog about it. But within the context of this grown man’s play-time blog, sometimes life is cruel.)

To wit: my Bresser Messier AR102S Comet Edition (still sans snappy nickname) arrived on Sunday, January 29, just a few hours late for the new moon observing run at the Salton Sea that Terry Nakazono and I went on the night before. Since then it’s been mostly cloudy here, with poor transparency on the nights it hasn’t been totally socked in, so I’ve been misusing the scope on bright stuff like the moon and Jupiter. And waiting not-so-patiently for a chance to get out to dark skies and do some wide-field, low-power scanning.

I actually did get about 45 minutes of semi-dark time with the scope a week ago. I was on dawn patrol up in the foothills and I spent some time in the summer constellations before the sun came up. The views were bright and contrasty, but all it did was whet my appetite.

Friday night I finally got the scope out under decent skies, for a decent amount of time. I decided pretty late to go to the Salton Sea – originally we had other plans, but Vicki and London were wiped out from a long week, and the forecast said that Friday was the last clear night for a while, all over SoCal. I didn’t leave Claremont until almost 7:00 PM, and with set up time after I arrived at Mecca Beach, I didn’t start observing until 10:00.


I was rolling pretty light. I wanted to test the Bresser reflactor/bino set as a package, so I used the AR102S on the came-with mount and tripod. I essentially always have binos out while I’m observing, so I used the 7x50s that came with the scope. That was a novel experience – I usually roll with 10x50s or 15x70s. This was my first time using 7x binos for serious deep-sky observations.

The only way I broke with the Bresser package was with eyepieces. I did use the included 20mm 70-degree a few times early in the evening, and I briefly tested the 10mm 70-degree that just came in, but my most-used set for most of the evening consisted of the 28mm Edmund RKE, both natively (16.4x) and with a 2x Barlow (33x), and the 8.8mm ES82 (52x and 104x).


A word about the 28mm RKE. It is simply the most comfortable eyepiece I’ve ever used. There are several factors that play into that. One is the long eye relief. Another is the magical floating stars effect, which is real, and impressive. Finally, there’s the wide exit pupil it gives, which in the AR102S is 6.2mm. That’s probably wider than my pupils go these days (same is true of the 7mm exit pupil of the 7×50 binos). Using binos or eyepieces with exit pupils wider than your own will go is usually not recommended. The extra light falls on the muscles of your iris, not on your retina, so your pupil becomes an aperture mask, stopping down the system to a smaller working aperture. You could get just as much light delivered to your brain using a smaller instrument or eyepiece. But there is one positive effect of using a “too-wide” exit pupil: you can move your eye around a bit within the light beam, without any falloff in illumination. So “too-wide” exit pupils are very bright – maximally bright – and very comfortable. And if a bit of light is wasted, oh well, it’s not like the cops are going to come for you.

One nice effect of swapping the 28mm RKE for the 20mm 70-degree is that they have close to the same true field of view of 2.9-3.0 degrees, but the RKE gives a much sharper image with fewer aberrations. Unsurprisingly, since it’s bending light from the same true field into a much smaller apparent field. Normally, a 45-degree AFOV would feel downright claustrophobic to me these days, but for some reason the 28mm RKE doesn’t bother me. I think it’s the magical floating stars effect – most narrow-fields (okay, anything south of 50 degrees) feels tight, like looking through a soda straw, because so much my field of view is taken up by the inside of the eyepiece barrel. But with the 28mm RKE, there is no visible eyepiece barrel, so although the AFOV isn’t actually that big, it feels much more expansive.

I did have one minor gear screw-up: I forgot my laser. I haven’t installed a finder on the AR102S. Same with the C80ED, except for one or two nights early on. When I really need help I lay a laser finder along a straight edge and use it to point to things in the sky. On the C80ED, there are a couple of buckles on the tube clamp that together form a de facto trough like the one I built for the SkyScanner 100. On the AR102S, the finder bracket serves the same purpose. But I forgot my laser. So I did what I usually do, just dead-reckoned it. I’ve gotten to the point where I usually don’t even have to sight down the tube, I can just sort of look up and aim the scope and get the target within a 3-degree circle. The AR102S will go wider than 3 degrees – a 32mm Plossl or 24mm ES68 will give 3.6 degrees, and my 32mm Titan 2″ will go to 4.88 degrees. But none of those eyepieces do their thing with the same panache as the 28mm RKE – at least in this scope. I did get out the 32mm Plossl just in case I needed a wider ‘finder’ eyepiece, but it never made it into the focuser.


I had a program in mind. Long-time readers will know that I’m a big fan of Jay Reynolds Freeman’s astronomy essays, especially “Refractor Red Meets the Herschel 400”. More relevant to this post is “Messier Surveys”, in which Freeman relates his habit of running through all the Messier objects with every instrument he gets his hands on, from 7×50 binoculars to a 14-inch SCT. Despite my Messier Marathon attempts, I’ve never kept track of which Messiers I’ve seen with which instruments. I’m certain I’ve seen them all with the XT10, and I’ve seen almost all of them with my 15x70s, but beyond that, I have no idea. So I decided that the best way to properly test the Bresser would be to start a Messier survey with it.

To be clear, I had no intention of attempting an off-season or mini Messier Marathon. I decided to just go until I got tired. I also was not a purist – I looked at plenty of non-Messiers along the way, including some I had never seen and wasn’t planning to observe when I started.

And in fact, I started with some non-Messiers.


When I started observing at 10:00, plenty of good stuff was getting perilously low in the west. The western reaches of Cassiopeia were already down in the Palm Springs/Indio light dome. I started with the Double Cluster and Stock 2 – my first time looking at them with the AR102S. They were spectacular as always. Then I swept up through the Alpha Persei Association and followed the eastern ‘arm’ up to NGC 1528. The cluster was fully resolved at 33x, but I thought it was prettier at 16.4x, when the dimmer stars trembled just at the threshold of resolution. I also checked in on NGC 1545, which is a much less impressive cluster and a much tougher catch since it is dominated by a bright foreground star. But my favorite observation in this area was another OC, NGC 1513. I tried this one at a variety of magnifications and it always ‘popped’ a little more in averted vision, as previously unresolved stars swam into visibility. Not one of the sky’s stunning showpiece objects, but delicately beautiful if you have the time to tease out its secrets (and the skies – it’s not bright).

I hit M34 on my way out, and of course I stopped at the Pleiades, which were very nicely framed at 16.4x.

Orion and Vicinity

After all of that, I realized that I had to get a move on if I wanted to catch M79, the glob in Lepus, before it set. I hopped over to snag it, and visited Hind’s Crimson Star while I was in the neighborhood. It was a tiny red spark in the 28mm RKE.

The whole sword of Orion fits into the field of view of the RKE. The Trapezium was nicely broken out into four stars at 33x with the Barlow. I had a quick look at Sigma Orionis and scanned the Belt and the big OB association just off Orion’s western hip. M78 was delightful. Even at 16.4x, the two foreground stars were visible and distinct from each other and from the background glow, and the western edge of the nebula showed a more abrupt cut-off, which lent the whole object the feel of a comet.

Binocular Tours

Up to this point I had been using the 7x50s to trace my star hops in advance, but now I really started to run ahead. One thing about writing my deep-sky tour articles for Sky & Tel – I usually remember all the stops and I can run through them quickly anytime I’m out. In this case, I started at Sirius and followed the path of my December 2015 article down through Canis Major, across Puppis – with a side trip down to Vela that was not in the article – and into Hydra (for M48). Then I picked up where my tour from this March started, running northwest through Monoceros and northern Orion before ending in Gemini. Running through both tours took about 10 minutes, and I saw a lot and missed a lot more. Seriously, that stretch of the winter Milky Way is just ridiculous. You can swing your optics over it again and again and not pick out all there is to see.

Then I had a long break to rehydrate, eat a snack, and get into my cool-weather getup. I’ll have to write a whole post about that sometime.


After the break I went back through almost all of that with the telescope, in part just to see it all with more than 50mm of aperture. I noticed some Herschel 400 objects in Puppis that I had never observed, namely the open clusters NGC 2479 and 2509. Both were dim swarms of faint stars that were still not fully resolved at 52x, but very pretty. I had not noticed them in the binos, but after catching them in the scope I was able to see them when I went back with the 7x50s. I was comparing the two clusters in the binos when a meteor flashed through my field of view, which is always a cool sight. I spent about half an hour trying to catch the planetary nebula NGC 2440, and even hauled out Interstellarum to help me get on target, but I never got a definite sighting. I’m going to have to study that one and come back another time.  I did catch NGC 2438, the planetary nebula that is superimposed on M46 but only about half as far off as the cluster. It was obvious at 52x but I couldn’t separate it from the glow of the cluster at 16.4x. Needless to say, it didn’t show in the binos.


By the time I was finished retracing my winter Milky Way tours, the Auriga Messiers were getting low in the west, so I hopped over to check them out. After that I hit M44 and M67 in Cancer. M44 was just perfect at 16.4x – everything nicely resolved, but still compact enough to look like a coherent object. The stars in that cluster always seem to fall into geometric patterns to me, as if they were laid out using a grid system that got erased the morning after creation. I can’t think of anything else in the sky that gives me the same impression.

I also popped up north, past Iota Cancri and over the border into Lynx, to check on NGC 2683, a surprisingly bright and easy Herschel 400 galaxy that I had previously only observed with binoculars. (Want to know more about this galaxy and its neighbors? See the April 2017 Sky & Tel!) Since I’d seen it with smaller-aperture binos under worse skies, naturally it was an easy catch for the AR102S.

After that I turned south, to Omega Centauri. Although I haven’t written about it yet, when Terry and I were at the Salton Sea last month, I spent a long time looking at the monster ‘glob’ – actually the exposed core of a dwarf galaxy that was cannibalized long ago by the Milky Way. It’s a favorite spring target of mine when I have a good southern horizon. From Mecca Beach there is a definite light dome from El Centro and usually some near-horizon haze in the southwest – directly over the water. But Omega Centauri culminates between that particular Scylla and Charybdis. Last month I spent nearly an hour checking it out, using naked eyes, binoculars, and several levels of magnification with the C80ED. I could just get the outermost stars to resolve at 120x, albeit in imperfect seeing. This time was worse – about the same lousy seeing, and slightly worse transparency. I didn’t get any actual resolution, but I could make out pronounced differences in brightness across the face of the cluster. I also had a look at NGC 1528/Centaurus A, the famous radio galaxy. I think it should be naked-eye visible under optimum conditions, but my conditions were not optimum. It was obvious in the binos and showed some detail in the scope.

Then it was on to Corvus to check in on M104 and M68. I also observed the planetary nebula NGC 4361, I think for the first time. It’s bright but small, and it turned out that I could see it at 16.4x, I just didn’t recognize it – I had to go up to 52x to confirm that it was nonstellar. I also visited M83 while I was in that neck of the woods. What a wonderful galaxy, so big, bright, and obviously elongated even at low magnification.

By now it was almost 3:00 AM and I was getting pooped. I finished in Lyra, with Epsilon Lyrae and the Ring Nebula, M57. I couldn’t split the Double Double. That might have been the scope, but it might have been the skies – by this point there was a steady breeze blowing right in my face when I looked east. I have had other nights where the seeing was so bad that Epsilon Lyrae would not split. I did notice some CA around those stars at high power, which probably didn’t help.

I decided to finish with M57, which was fitting since it was a chance observation of that nebula with the TravelScope 70 a few years ago that got me hooked on refractors. I wanted to recreate the feel of that surprising low-power observation so I left in the 28mm RKE. The whole southern end of the parallelogram fit very nicely into the 3-degree field, with M57 showing as a pale little dot. Then I realized that I had stopped the scope down to 60mm while I was playing with the double star and had forgotten to take off the aperture mask. So I got to do one of my favorite tricks – reach up and pull of the mask while I’m observing, and watch the sky get brighter in a hurry, as if all the lights out there suddenly turned on. The nebula had been obvious at 60mm – at full aperture it was so bright it almost looked stellar.



I ended the night having observed several double stars and 46 unique DSOs with the telescope, of which only 22 were Messier objects. Three were Herschel 400s which I believe I observed for the first time – those were the open clusters NGC 2479 and 2509 in Puppis, and the planetary nebula NGC 4361 in Corvus.

I’ll have a more complete review along soon, but the Bresser Messier AR102S lived up to its middle name – it is a superb Messier-catcher. Every Messier I attempted was not just visible but easy at 16.4x. Will be interesting to try it on some of the smaller, tougher objects like M76. I think this will be my Marathon scope this year.

Don’t take this as a full-spectrum endorsement. When I do post a full review of the scope, I’ll have both good and bad to report. It’s not a good all-rounder, not a good first or only scope. But what it’s built to do, it does quite well.

The biggest surprise for me was how much I could see with the 7×50 bins. I didn’t catch everything, but of the 46 DSOs I observed telescopically, 34 were also visible in the binos, and some of the rest I simply forgot to check (the galaxy NGC 2683 comes to mind). There were more DSOs that I saw in the binos but didn’t take the time to log, including shedloads of clusters in Monoceros. I don’t know if I will be able to complete a Messier survey with the 7x50s – I reckon some of the smaller planetary nebulae will prove my undoing – but I’m at least going to make the attempt.



  1. Jeez, Matt. You have the endurance of a marathoner. Your haul in one night is a good month for me. Color me equal parts inspired and envious.

    I was buoyed by your continued success with the RKE 28; mine will be delivered on Tuesday, so all I need to do is wait for a clear night and go star surfing with it.

    Several of your constellations (Corvus, for one) I can’t see up here in Oregon, at least not from my observing sites. Ms 6 & 7 are about as low as I can go.

    I’m eager to read your complete review of the AR102S, but so far it seems that you are riding a low power/wide field winner. I like the idea of being able to put EVERYTHING in a single backpack. This is the kind of thing that might help me overcome my inertia and leave my back patio for a better observing site more than once or twice a year. Great. So now I am looking seriously at the Bresser package with bad intentions.

    I much liked your characterization of M44, how its chunks of geometrical precision suggest that the cluster was “laid out in a grid that was erased the next morning after creation.”

    How were the optics in the Bresser 7x50s? Comparable to those of your Celestron bins (10x50s, 15x70s)? Better? Worse? Just curious.

    Anyhow, thanks for yet another terrific observing report. Always enjoy these, always learn something, always feel motivated.


  2. I was buoyed by your continued success with the RKE 28; mine will be delivered on Tuesday, so all I need to do is wait for a clear night and go star surfing with it.

    I will look forward to hearing your impressions. I love mine, as you can surely tell. I’d say more about it but I think all of the technical stuff is in the blog posts already. It’s really sharp on-axis and surprisingly clean off-axis. At least, better than most of the rest of my stable. I need to do a serious head-to-head between the 28mm RKE and the 24mm ES68. That would be fun and informative, and I could do it from the driveway using Orion as a testing ground. Stay tuned.

    Several of your constellations (Corvus, for one) I can’t see up here in Oregon, at least not from my observing sites. Ms 6 & 7 are about as low as I can go.

    Are you thinking of Vela, maybe? Because Messiers 6 and 7 are further south than M104, M68, and M83.

    I’m eager to read your complete review of the AR102S, but so far it seems that you are riding a low power/wide field winner. I like the idea of being able to put EVERYTHING in a single backpack. This is the kind of thing that might help me overcome my inertia and leave my back patio for a better observing site more than once or twice a year. Great. So now I am looking seriously at the Bresser package with bad intentions.

    It’s great for low power/wide field, it’s compact and lightweight, and it will go in a backpack. So if that’s exactly what you want, it’s a good choice. But if you want it to anything else – moon, planets, double stars, whatever you might want north of 50x – you’ll be disappointed. It’s the most one-trick pony in my arsenal. Fortunately that one trick is something I like. But even the 60mm Mak is more versatile. So be certain before you pull the trigger.

    How were the optics in the Bresser 7x50s? Comparable to those of your Celestron bins (10x50s, 15x70s)? Better? Worse? Just curious.

    Mostly about the same, in that the images were good enough that I just never thought about it. Well, almost never – these binos give me a more pronounced illusion of three-dimensional depth than any others I’ve ever used. Beyond that, no problems. It may be that at 7x, any optical shortcomings are minimized below my threshold of perception.

    Anyhow, thanks for yet another terrific observing report. Always enjoy these, always learn something, always feel motivated.

    Many thanks for the kind words. After an evening as good as Friday night, I am compelled to share.

  3. Not Corvus; I was thinking of Crux. Typed in the wrong one.

  4. Or maybe Centaurus? Even I can’t see Crux. It’s close, though, so heartbreakingly close. I have the Southern Cross burned into my memory from my time in Uruguay back in 2010. Doesn’t seem like it can possibly have been seven years already.

  5. No, for some reason, at this point unknown to me, I had Crux of my mind. And still, I typed in Corvus. Attribute this to the aging brain.

  6. […] Stargazing for people who think they don't have time for stargazing. « Finally – the Bresser Messier AR102S Comet Edition at the Salton Sea […]

  7. Looking forward to reading the Bresser AR102s review Matt. But not being able to push it past 50x without compromising the images? Curious to know this is exactly all about. If it’s just a CA matter, then I understand.

  8. Interesting testing. I have 2 ES scopes , the ES AR 102 and the ED80. How is the tripod with that Badger?

  9. […] went to Mecca Beach again Saturday evening. Like my run at the end of February, it was a solo mission, decided on at the last minute. I made up my mind in the mid-afternoon and I […]

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