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Your Thoughts On The Celestron Binoviewer

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58 replies to this topic

#51 RLK1

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Posted 18 January 2024 - 10:16 PM

"you get what you pay for"

I suggest reading the following threads, especially those from dennis0007dl in the first link:

https://stargazerslo...orth-the-money/

and

https://www.cloudyni...-tv-bver-yikes/



#52 saemark30

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Posted 19 January 2024 - 12:58 PM

I read the threads, messaged dennis0007dll and he agrees the unit has problems. I messaged the seller.

The prisms are not replaced in supercharging so there is no fix.

Others should inspect their units to see if proper coatings are applied to all visible optical glass surfaces. The is a loss of 5% per uncoated glass surface and ghosting problems may result.



#53 Vansh

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Posted 19 January 2024 - 02:01 PM

Got mine today. Fast delivery.

I tested it on the mountains with a pair of RKE eypieces. Needs the 1.8x extension to focus in my refractor.

Here is the problem. The right side is not parfocal with the left, so the eyepiece needs to be moved out by about 2mm. There is a fine adjustment on the left side that makes things work it is already in the most.

Also the right prism is not coated, the other sides have a green coating and this one is not even purple.

Shoudl I return it, ask for a partial refund? Who do I email?

Both eyepieces can be individually moved inward/outward by around 10 mm. If the left side is already inward the most, then move the right side outward more. Unless there is some reason why the eyepieces need over 10 mm difference in light path, this shouldn't be an issue.

 

Regarding the coatings, I'm not sure why this is an issue. Even taking it at face value that this means uncoated (4% reflectance) versus anti-reflection coating (~1% reflectance), this is on the eyepiece-facing side of the binoviewer. So unless your eyes are radiating light, the stray light control is of the reflection coming from the eyepiece. And even assuming an uncoated eyepiece (and how many people use that?), it's a stray light of 0.04 * 0.04 = 0.0016 versus 0.04 * 0.01 = 0.0004, or stray light of 0.12%. Obviously any coating on the eyepiece will mean stray light of far less than 0.1%.

 

I haven't used it to observe bright stars yet due to the current weather, but using it on the moon briefly last night, I didn't see any ghosting effects out of either eyepiece.



#54 RLK1

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Posted 19 January 2024 - 02:48 PM

Both eyepieces can be individually moved inward/outward by around 10 mm. If the left side is already inward the most, then move the right side outward more. Unless there is some reason why the eyepieces need over 10 mm difference in light path, this shouldn't be an issue.

 

Regarding the coatings, I'm not sure why this is an issue. Even taking it at face value that this means uncoated (4% reflectance) versus anti-reflection coating (~1% reflectance), this is on the eyepiece-facing side of the binoviewer. So unless your eyes are radiating light, the stray light control is of the reflection coming from the eyepiece. And even assuming an uncoated eyepiece (and how many people use that?), it's a stray light of 0.04 * 0.04 = 0.0016 versus 0.04 * 0.01 = 0.0004, or stray light of 0.12%. Obviously any coating on the eyepiece will mean stray light of far less than 0.1%.

 

I haven't used it to observe bright stars yet due to the current weather, but using it on the moon briefly last night, I didn't see any ghosting effects out of either eyepiece.

I agree with the above. I might add that in the in case of the supposedly defective bino the use of 28mm RKEs would not be my first choice with any binoviewer. While I understand a lot of amateurs like the eyepiece, I and other observers have experienced blockout issues with it due to its long eye relief and, in the case of a binoviewer  coupled with a barlow, the eye relief would likely be exacerbated. That can affect perceived focus points when using two of these. I seem to recall the late eyepiece reviewer Tom Trusock having one purpose for this eyepiece: a paperweight!

Anyhow, I'd go with a couple of inexpensive Svbony 25mm plossls which would have about the same true field as a pair of 19mm panoptics and probably not have an issue. Those are the two that I use with my binoviewer without problems...



#55 RLK1

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Posted 19 January 2024 - 07:52 PM

I tried the binoviewer with my new ES 4" mak today on terrestrial targets and, unfortunately, had difficulty merging the image. I popped in my stellarvue unit with the same svbony 25mm plossls and had no issues.

So, I went on the Aliexpress website, followed their return procedure and immediately received a free-return shipping label and I'll drop the package off to the post office for my refund. That part was easier than trying to merge the image...



#56 Vansh

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Posted 19 January 2024 - 10:16 PM

I tried the binoviewer with my new ES 4" mak today on terrestrial targets and, unfortunately, had difficulty merging the image. I popped in my stellarvue unit with the same svbony 25mm plossls and had no issues.

So, I went on the Aliexpress website, followed their return procedure and immediately received a free-return shipping label and I'll drop the package off to the post office for my refund. That part was easier than trying to merge the image...

Yeah, that's a shame. I've been testing out my binoviewer today, put some 6 mm plossls into my Nexstar 8i and had no trouble with merging images. Even tried closing one eye, then quickly switching to the other, or close both eyes, wait 5 seconds, then open both at the same time, and it's still one image without any hint of brief double image before merging. In fact I'm not sure how else I'm supposed to check for collimation when I can't make a double image happen. Maybe it's luck of the draw with their quality control.

 

From my experience with binoculars, sometimes it's a matter of playing around with the IPD, or having one eyepiece a bit above your eye line and the other one below, etc., to make the images merge. Hopefully you already tried those things, along with rotating the eyepieces in their holders, etc.

 

I'll definitely be returning the Angeleyes solar filter though, it was still a blurry mess with clear skies today.



#57 RLK1

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Posted 28 January 2024 - 01:13 AM

I tried the binoviewer with my new ES 4" mak today on terrestrial targets and, unfortunately, had difficulty merging the image. I popped in my stellarvue unit with the same svbony 25mm plossls and had no issues.

So, I went on the Aliexpress website, followed their return procedure and immediately received a free-return shipping label and I'll drop the package off to the post office for my refund. That part was easier than trying to merge the image...

I got my refund notification today and that was pretty quick, too. The process just took a couple of clicks on the return and refund link next to the account page. Uploaded a picture of the bino, followed by a free return label which I printed out and affixed to a box with the bino, dropped it at the post office and got a receipt with a tracking number. So it didn't take long to get there given the fact that I got the refund alert via email tonight (1-27-24). 


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#58 Vansh

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Posted 29 January 2024 - 11:56 PM

I got my refund notification today and that was pretty quick, too. The process just took a couple of clicks on the return and refund link next to the account page. Uploaded a picture of the bino, followed by a free return label which I printed out and affixed to a box with the bino, dropped it at the post office and got a receipt with a tracking number. So it didn't take long to get there given the fact that I got the refund alert via email tonight (1-27-24). 

I'm having the opposite experience. The binoviewer works just fine, but they ignored my return/refund request on the solar filters, then AliExpress stepped in after the seller didn't respond past the deadline. I had uploaded a picture of the blurry sun saying this is as sharp as I can focus the sun using their solar filter with my Nexstar 8i, and AliExpress rejected it saying it doesn't show if it's from the seller, and that I need to upload a video showing my testing process and demonstrating the problem (and that the problem is with the seller's product) to verify the claim. I have 3 days to dispute their decision, meaning I have to hope that it'll be sunny sometime during the next 3 days and set up the telescope during the day to film the setup and show that the filter is the problem, or I lose out on the money.

 

So I suppose that's customer service from China. I mean obviously nowadays most of the stuff is manufactured overseas even if you buy from a U.S. company, but the customer service is better if you have issues. Fortunately for me my binoviewer works really well, but I don't know how I'd have proven that their binoviewer had issues with merging images if I had that problem if that's what it takes to get a return. (I don't know if it's because I selected "poor quality" instead of "does not work properly" for the solar filters.)

 

I did eventually find a way to have problems merging images with my binoviewer, by the way. It happens if I move the individual diopters to certain amounts. So the helical focusers of the diopters aren't really lined up. (I assume it's basically the same issue with zoom binoculars, which is why they don't work well at higher magnifications.) Having said that, it's easy to avoid those certain amounts, and how it comes "natively" works just fine for me, hence why I haven't had issues with it at all.



#59 RLK1

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Posted 30 January 2024 - 07:39 PM

I'm having the opposite experience. The binoviewer works just fine, but they ignored my return/refund request on the solar filters, then AliExpress stepped in after the seller didn't respond past the deadline. I had uploaded a picture of the blurry sun saying this is as sharp as I can focus the sun using their solar filter with my Nexstar 8i, and AliExpress rejected it saying it doesn't show if it's from the seller, and that I need to upload a video showing my testing process and demonstrating the problem (and that the problem is with the seller's product) to verify the claim. I have 3 days to dispute their decision, meaning I have to hope that it'll be sunny sometime during the next 3 days and set up the telescope during the day to film the setup and show that the filter is the problem, or I lose out on the money.

 

So I suppose that's customer service from China. I mean obviously nowadays most of the stuff is manufactured overseas even if you buy from a U.S. company, but the customer service is better if you have issues. Fortunately for me my binoviewer works really well, but I don't know how I'd have proven that their binoviewer had issues with merging images if I had that problem if that's what it takes to get a return. (I don't know if it's because I selected "poor quality" instead of "does not work properly" for the solar filters.)

 

I did eventually find a way to have problems merging images with my binoviewer, by the way. It happens if I move the individual diopters to certain amounts. So the helical focusers of the diopters aren't really lined up. (I assume it's basically the same issue with zoom binoculars, which is why they don't work well at higher magnifications.) Having said that, it's easy to avoid those certain amounts, and how it comes "natively" works just fine for me, hence why I haven't had issues with it at all.

"and AliExpress rejected it saying it doesn't show if it's from the seller, and that I need to upload a video showing my testing process and demonstrating the problem (and that the problem is with the seller's product) to verify the claim."

 

That's really odd since all they would need to do is look at your order number for the item to verify it was from the seller. Additionally, I had selected the "poor quality" option for my binoviewer return without issue. I uploaded an image of the binoviewer and noted the problem with merging the image and that's all it took and the refund was processed after I had sent essentially the same message to the seller.




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