Thị kính kính thiên văn Reverse Kellner 52mm, đường kính 2"

This project was inspired by Jerry Oltion's article in the September 2020 issue of Sky & Telescope, p. 74.

This is an eyepiece for an astronomical telescope made from a lens set available from Surplus Shed (surplusshed.com): L3721 Reverse Kellner, 52mm fl

This set consists of two lenses (eye, field).

This is a remix of the 52mm 1.25" eyepiece in this set of four: https://www.thingiverse.com/thing:4597001

This eyepiece consists of the following parts:

1. 2" barrel with a 1.5mm pitch internal thread,
2. Retainer with a matching external thread,
3. Two lens spacers, one each for the eye lens and field lens.
4. Flexible eye guard.

I made this from ABS except for the flexible eye guard. ABS is more durable, lighter, and has a less glossy finish than PLA. The eye guard is printed from black TPU

The vertical resolution of the print is important to get acceptable quality on the threads. I printed mine at 0.12mm vertical resolution and a speed of 20mm/s. You can print all the parts without supports, but some files need to be flipped 180º when slicing.

I have compared this eyepieces with commercial eyepieces from Meade. The 3D printed eyepiece compares very favorably. There's a little distortion at the edges, and some chromatic aberration. A view of the moon shows color fringes, whereas the Meade eyepieces are color-free. Contrast is as good or better than the Meade lenses, and I notice no internal reflections.

Print Settings Printer brand: Anet

Printer: A8

Rafts: No Supports: No Resolution: 0.12mm

Infill: 20%

Filament brand: Inland

Filament color: Black

Filament material: ABS & TPU

Category: Physics & Astronomy