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GSO 1.25" 90-deg 99% Dielectric Mirror Diagonal with Compression Ring
| Brand | GSO |
| Part Number | ODIA-GS-125D-COMP |
| Availability | available |
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Product Info
Manufacturer Description
New, improved model - Now with compression ring in eyepiece barrel
GSO's new 1.25" dielectric diagonal continues their tradition of offering superb products at excellent prices. This beautiful1.25" mirror diagonal features a BK7 mirror that is precision ground to a flatness of 1/10th wave (minimum) and features dielectric 6-layer enhanced silver coatings with an over-coat protective layer for a light efficiency of over 99% reflectivity across the entire visual spectrum. The clear aperture is 27.9mm.
The mechanics of this diagonal are also top-notch. The robust aluminum body and attachment barrels are precision CNC machined to strict tolerances from solid stock throughout. The 1.25" nosepiece is threaded to accept standard 1.25" astronomy filters. The 1.25" eyepiece holder features a brass compression ring to protect your eyepieces and accessories. It also includes an internal safety stop to prevent long barrels on some eyepieces and barlows from hitting the diagonal mirror. The diagonal sports a handsome anodized finish.
The combined result is a superb diagonal offering excellent mechanical and optical quality at a great price. Dielectric coatings are more durable than regular or enhanced aluminum coatings, so you will enjoy years of excellent performance from this product.
The diagonal comes in a nice foam-fitted storage box and includes 2 end caps. Weight = 5.9oz.. Made in Taiwan.
Reviews
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Feb 9, 2019
Nice GSO Diagonal
Pros: Cons: Comments:Needed another good 1 1/4" diagonal. I purchased a GSO 1 1/4" diagonal with a compression ring. This is a nice good quality diagonal and I use it all of the time.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Dec 22, 2018Well made diagonal
Pros: Cons: Comments:In getting an old Jaegers refractor back into service I needed a diagonal that would do justice to the optics, but that I wouldn't mind having the barrel scuffed by the friction-fit focuser, and this hit a perfect price point for that goal. This barrel on this diagonal has a milled finish that engages well with the focuser and keeps the diagonal from rotating, even with fairly heavy eyepieces. The inside of the barrel is fully ribbed and blackened, and the mirror is very bright and clear. Its body is nicely machined from a single block, with the back held on by four screws. The compression band on the ocular end prevents scratching of eyepieces. So, in addition to being a very good diagonal for the price, it can also be considered as an adapter between a scratch-inducing vintage focuser and a scratch-free modern eyepiece holder.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jun 27, 2018Not bad at all :)
Pros: Cons: Comments:I am quite satisfied with this diagonal, which is clearly one class over the standard "kit" ones (i'm talking about the metal case diagonals, not plastic ones, of course), in terms of build quality and optical performance.
Bottom Line: Would you recommend this item? Yes
I'm yet to test it against other models, but so far the improvement is hard not to notice.
The compression ring does a great job at holding the eyepiece or binoviewer straight centered without marking the barrel.
At this price (except shipping and duty) it was quite affordable, so no big hole in the budget for such welcome upgrade.This review was provided courtesy of AgenaAstro.com
Dec 20, 20171.25" GSO Dielectric 90° Diagonal
Pros:Low price an added attraction.
Cons:None.
Comments:I have 4 - 2" dielectric William Optics diagonals, but needed a good 1.25" diagonal. So I 'rolled the dice' and got a GSO model. The low price was an added incentive. It arrived quickly, as always with Agena, and I plugged it into my 150mm Maksutov. I was amazed! This excellent diagonal worked every bit as well as the higher-cost 2" WO cousins. I resolved that if I needed another 2" model - it would be a GSO. Everything just says 'Quality' - from the aesthetic appeal and up to the excellent optics manifest at high-power viewing through the powerful Maksutov telescope.
Bottom Line: Would you recommend this item? YesDec 20, 2017GSO 1.25" Dielectric diagonal
Pros: Cons: Comments:I got this to update an old Celestron C5. This diagonal is well made, nicely finished and packaged and a bargain at its selling price. I was able to compare it to others I have that are similar, but more expensive. My Tele Vue is clearly better optically--less scatter and a bit brighter, but it costs twice as much as the GSO. My problem with the GSO is not that eyepieces 'bottom out' when inserted, as I have read in some reviews; but that the compression ring hangs up several of my eyepieces, making them hard to place in the diagonal. Maybe this will wear in over time, but I don't know. Maybe mine is unusual, but don't know that either. In any event, it beats most of the stock diagonals that come with scopes today.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Dec 20, 2017Nice diagonal
Pros: Cons: Comments:Arrived quickly from Agena, this diagonal looks as good as any I have ever had. Appears to be well made, much better than the stock diagonals that are shipped with scopes. Always a great experience buying from Agena Astro, I always look to them first for my astronomy gear.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Dec 10, 2017Buy it
Pros: Cons: Comments:It is a good diagonal mirror for that price. It is good for short tubes in which chromatic aberration with diagonal prisms is seen.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jul 6, 2017Excellent Optical Upgrade With Great Build Quality
Pros: Cons: Comments:This was an excellent upgrade for the prism diagonal which came with my telescope, a Celestron Omni XLT 102AZ. Images are brighter and sharper, with higher contrast. More detail can clearly be seen on the moon and Jupiter. Build quality is excellent - this is very well made, solidly built, and nicely finished. This is a very good value!
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jun 28, 2017Superb upgrade for my refractors
Pros: Cons: Comments:A huge improvement over the stock Prisms of my two Meade refractors; 80mm and 102mm. Better sharpness, contrast and darker fields, this diagonal is an exceptional performer and an excellent value.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
May 2, 2017Good Value. Great Views.
Pros: Cons: Comments:As has been my experience with GSO products in the past, this diagonal exceeded my expectations. Workmanship, the diagonal body and the mirror were top notch. It even has the "heft" of a high-end diagonal. I have had numerous high-end diagonals over the past few years. This GSO diagonal is the equal of each of them. Would I recommend it to a friend? My best friend is me and this is my third diagonal from the GSO lineup.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Apr 5, 2017Very good replacement
Pros: Cons: Comments:Nicely made diagonal with brass compression fitting instead of thumbscrews. I really like that it has a smooth nosepiece intead of being tapered or having a safety groove. Minus one star for its eyepiece safety stop being a bit shallow - all but one of my eyepieces "bottoms out" before registering at their shoulder.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Mar 24, 2017GSO 1.25" 90-deg 99% Dielectric Mirror Diagonal with Compression
Pros: Cons: Comments:Great product. You can pay more but I think this diagonal offers a big bang for the buck.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jan 9, 2017Really Good Diagonal
Pros: Cons: Comments:Not having much to compare against except the stock diagonals that came with my telescopes, this diagonal just blew them away. What imaging problems I had attributed to shoddy telescope manufacturing are now corrected for the most part and now I can tell what is at the limits of my equipment versus everything looking, well..., like crap. I would rather not have a bad or cheap eyepiece or diagonal than be severely disappointed by them.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jul 20, 2016Good choice
Pros:Accurate
Cons: Comments:I bought this diagonal because I was not sure how good the prism diagonal I had purchased years ago was. I am impressed. The image quality is very good and does not need refocusing to view other portions of the image. This tells me that the image in this mirror diagonal is 90 degrees from point of entry to the exit point. I live 4 miles from the center of a major light pollution source and it allows to see very deep in the sky. Would I recommend it? Yes. Would I buy another one if I needed it? Another yes. If you don't have big bucks to spend, this is worth the money you will spend.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jun 10, 2016Very good
Pros:Strong Construction,Quality Lenses
Cons:Mechanical
Comments:This diagonal puts up very good images and feels nice and solid. My only issue is the set screw/ retainer isn't all that smooth. It catches some but still operates as intended. At this price that is probably what you can expect.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Mar 6, 2016Well collimated & well built
Pros:Lightweight,Strong Construction,Accurate
Cons: Comments:I asked for this for Christmas after doing some research. I bought it to replace stock diagonal that came out of collimation with my ST80. I plugged it in on Jupiter and finally, spot-on collimation. I also use it with C102 and noticed the same difference was noticed. Don't spend 100$ on fancy dielectrics when this one does the same job, albeit with less flare.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jan 24, 2016Works as advertised.
Pros:Accurate,Lightweight,Easy to Use,Compact,Quality Lenses,Strong Construction
Cons: Comments:Works great! Mirror is well centered, good construction.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Aug 19, 2015My favorite!
Pros:Quality Lenses,Compact,Strong Construction,Lightweight,Easy to Use,Accurate
Cons: Comments:I have other preminum diagonals that cost much more, yet this is still my favorite due to its low profile construction which gives me a little more back focus with my refractors.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jun 6, 2015Sharp images
Pros:Compact,Strong Construction,Easy to Use,Accurate,Quality Lenses
Cons: Comments:I used this to replace the stock diagonal that came with my SWE ED80. Wow! What a difference. Much brighter images. I highly recommend this product to anyone who wants high quality optics. If you are going to spend the money on a high quality telescope and eyepieces, don't forget to get a great diagonal. This is the one I recommend. You can spend more money than the price for this diagonal, but you will not get any better performance in my opinion!
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jan 30, 2015Top notch diagonal at a good price
Pros:Easy to Use,Strong Construction
Cons: Comments:I replaced the diagonal that came with my 6" SCT with this diagonal. The images are much brighter. The diagonal is of good quality and is well constructed. This is a must in my opinion if your new scope takes 1.25" eyepieces and doesn't have a quality diagonal. You won't be sorry, I highly recommend.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jan 30, 2015A must for small telescopes
Pros:Compact,Strong Construction,Accurate,Quality Lenses,Easy to Use
Cons: Comments:I use this on a small 80mm telescope. It brightens the image a lot better than the diagonal that came with scope.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Oct 20, 2014Great!
Pros: Cons: Comments:This diagonal is great. It's a definite improvement over the stock diagonal that came with my Celestron 102SLT. While the differences between the two mirrors are subtle I feel that I can actually tell a difference. Fainter objects are just a little easier to see with the dielectric mirror. I have read some complaints about the compression ring (vs a set screw) but as long as one uses common sense it's not a problem. I am glad I bought it.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Aug 15, 2014Great Diagonal
Pros:Strong Construction,Lightweight,Easy to Use,Quality Lenses
Cons: Comments:SOOO much better than the stock diagonals. Should be one of your first upgrades.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Nov 29, 2013No need to pay more elsewhere
Pros:Strong Construction,Lightweight,QUALITY MIRROR,Easy to Use,Compact
Cons:Gso Labeling Will Fade
Comments:Big improvement over Diagonal supplied new as standard equipment on my Celestron Nexstar 5SE SCT
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
May 30, 2013A winner from GSO
Pros:Lightweight,Compact,Strong Construction
Cons: Comments:This is a well made component. It was bought to replace a flimsy diagonal that came with an SCT. The GSO product is far superior to the stock part. The compression ring and 99% coatings are well executed. Fit and finish are excellent and the price is reasonable.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Mar 22, 2013Fine quality.
Pros:Compact,Lightweight
Cons: Comments:Rather than the conventional thing, since the fixed method has been improved, accuracy is maintained at attachment of an eyepiece. It is wonderful quality.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Feb 8, 2013Excellent diagonal
Pros:Accurate,Lightweight,Easy to Use,Compact
Cons: Comments:Excellent lightweight diagonal. Best feature is it is square with the optical path so collimation is not negated. This applies to the 2" model as well.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
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