According to the product's specs, it has an eyepiece size body (1.25" diameter). However, I have tried to insert it into a number of 1.25" accessories and it is just too tight. Did I just happen to get one out of spec? William Shaheen Gold Canyon, AZ
Hi, Tim. The body appears normal except that the black end ring is slightly smaller and does fit into 1-1/2 inch openings. But, that stops at the beginning of the red barrel. I have since found that the camera will fit into a Celestron OAG - but nothing else. Have there been other reports of this difficulty? Thanks for your reply, William
There have been no other reports of this. What other accessories have you tried it with? Who is the manufacturer?
I have tried it in a Celestron 2x Barlow, a Celestron 3x Barlow, an Explore Scientific 1-1/4 to 2" adapter, a Williams Optic 1-1/4 to 2" adapter and an Orion 1.25" extension tube. William
Do you have a caliper to measure the red cylinder body? Would the difference be visible in a photo? Can you send me an image showing the black ring and the red body?
The difference is much too small to show up in a photo. I need to go to a repair shop this week and will get them to measure with their calipers. William
Hi, Tim - I just returned from the repair shop I mentioned earlier. The STi's red barrel measured 31.85mm (1.2539 inches). Measurements were taken 90 deg apart to check for eccentricity and both measurements were the same. Hope this helps, William
It is within spec. The unit that I have here that I just meausred is also almost exactly the same as yours... 1.253-1.254 and it fits perfectly all of the accessories that I tried. My only guess would be that your accessories may not be within spec.
Thank you, Tim. In addition to the accessories I listed earlier, "Celestron 2x Barlow, a Celestron 3x Barlow, an Explore Scientific 1-1/4 to 2" adapter, a Williams Optic 1-1/4 to 2" adapter and an Orion 1.25" extension tube.", it also does not fit a parfocal ring I recently bought. That seems awfully strange, that we would have such a dichotomy. But, I guess it is what it is and I will move on since it does fit my Celestron OAG nice and snuggly, fortunately. Thanks, again. William
Hi William, has the ST-i still got the C adapter on it by any chance? https://www.sbig.com/products/accessories/c-mount-adapter-for-st-i/
Unfortunately the 1.25" barrel "standard" isn't really a standard. There is no document you can point to that recommends tolerances etc. Occasionally this results in problems with eyepieces not fitting, etc.
