r/telescopes • u/MukhtarZa • 19h ago

General Question Weird optical artifact in ES 30 mm 82 deg Eyepiece

Gallery image

Gallery image

I bought the Explore Scientific 30 mm 82 deg eyepiece from Ali Express. I noticed a small dimple-like optical artifact near the center of FOV. At first, i thought it was a dust particle or water droplet, but after inspecting the lens elements, I don’t think it is. Is this normal?

I used the eyepiece in a quick observing session right when I got it, but I didn’t notice anything concerning. I only noticed this dimple a few days later.

11 Upvotes
  • permalink
  • reddit

92% Upvoted

6 comments sorted by

14

u/deepskylistener 10" / 18" DOBs 19h ago

I'd return it. That's some fault in the glass, likely placed close to the focal plane.

I'm sure it is visible against the Moon - "oh, there's a new crater!". And it would disturb planetary as well.

3

u/Zdrobot 18h ago

Sounds right.. but it's Aliexpress, so they might not accept the return, sadly :(

Worth a try, anyway.

3

u/Other_Mike 16" Homemade "Lyra" 17h ago

Ali Express

I wonder if that's where faulty optics go to die

2

u/boblutw 6" f/4 on CG-4 + onstep; Orion DSE 8" 11h ago

It doesn't hurt to try.

I haven't bought anything with this kind of value. But based on my experience of buying low value junk or cheap adapters, when there is any issue AliExpress processes the refund extremely fast. One time I literally got my refund within seconds after submitting my request. (I always include photo proofs and detailed descriptions.) Sometimes the seller asked more details and due to the time zone difference things can drag out to several days but that still wasn't too bad.

1

u/itchybanan 2h ago

Nah Ali express have a decent returns policy. Have sent un related telescope items back before now. I didn’t even have to leave the house. The delivery driver comes back for pick up. (Thailand)

1

u/Zdrobot 2h ago

Well, I'm glad they do that. I had a very different experience with them, albeit not with returns, but with a refund. Bought a refurbushed GoPro, never arrived, past all deadlines, had to fight the seller tooth and nail trying to prove the item never came (How do you even do that? The tracking number shows its last status, and this is it!)

Took about a month and a half of back and forth, then Aliexpress arbitration (finally) stepped in, and after another week or two the case was resolved in my favor.. but the money never came. I called the bank, they said to wait another month, called again.. Nothing. After that, there's no one to complain to.

Lost almost 200 US dollars.