Astronomical Telescope Accessories D114F900mm with Short-axis Secondary Mirror 25mm, Newton Reflector Spherical Mirror

Great value and worked great for my DIY 114 mm "Hadley" Newtonian reflector. Could see craters and features on the moon, as well as Jupiter amd Saturn and their moons. Clarity was good and didn't notice any image defects.

I was very happy with the quality of the main mirror. For my daughter's middle school science fair project, I made a Schlieren imaging setup using this mirror on a kinematic adjustable mount I made with plywood and some hardware. Paired with a Canon 5D4 and a 100-400 lens, the results were great for seeing heat waves coming off hands, candle flame gases, butane, carbon dioxide, nail polish remover, etc. Yeah, I know it was my daughter's science fair project, but come on, that's just what dads do. Anyways, thumbs up to the quality of the mirror in this type of usage; didn't get to try the secondary lens.

The first set I got were damaged but the supplier replaced them quickly. They are working great and fit right in as needed. Could have used a slightly bigger secondary mirror, but I got it to fit no problem since it was smaller.

I received a part with a chipped secondary. I contacted the vendor for a replacement secondary with no reply (edit: As it turns out, they did reply, but I never saw the email), so I sourced another secondary. After getting the new secondary in, primary installed, and collimated, I have struggled for multiple weeks to get a good image. I could not get a good sharp image with higher power lenses (150x, well under the theoretical capability of this primary). Defocused star performance is *abysmal* in spite of the airy disk having nearly perfect concentric rings (indicating good collimation). I repeated collimation quite a few times wondering if I had done anything poorly with that. I guess the old, dirty mirror is going back into the telescope. Maybe I'll give this primary to someone as a vanity mirror.

Used this mirror to make a homemade Dobsonian just in time for the 2024 solar eclipse. The top of my images were a little out of focus due to my 3d printed focuser not supporting the camera's weight properly - but this wasn't the mirror's fault. I only paid around $20 for this mirror set, it came well packaged, dust free, and visually flawless - and the images I've seen through mine seemed great for the price.

The large mirror is excellent; however, the small mirror did not fit. It was too large. I might try grinding it down later.

My old mirror was extremely dirty and when I attempted to clean it I scratched it I was not aware that when I ordered it I got both mirrors it was a great value and the mirrors fit perfectly as well as fitting perfectly and were perfect as far as shine. If you need mirrors for a Meade 4500 series or compatible telescope those will exceed your expectations.

I bought this not expecting a lot, I tried to replace my dobsonian parabola mirror with this non-parabola mirror and it did not work out, the larger mirror was the correct size but the smaller one was too small to fit my Celestron scope, the mirrors were clean and would most likely work pretty good in a non-parabola scope.