TheSkySearchers

In June 2020 I started off the construction of my 16" f4 reflector, named after the star: Nunki in Sagittarius. The whole building took 10 months as I could only work at the weekend.

All the photos for this project can be found here: https://photos.app.goo.gl/DAZ8CqeRtJGe83jF8 .

In general, building this telescope has been an incredible experience. This was my first wood / metal project. I would highly recommend to make your own telescope if you can.

Here are some key features:

- mirror cell: based on Kriege's design using a Glatter sling cable for lateral support. This was designed using Plop software;
- mirrors: the primary is a Lightholder mirror with 1.5" thickness and coated by Spectrum Coatings in Florida. The secondary is a 3.5" Antares;
- UTA: the spider was installed with "+" orientation (as in John Pratte's design). The spider and secondary mirror holder are from Astrosystems. The secondary dew heater is also from Astrosystems. The focuser is Feathertouch FT2015BCR. I use two finders: an Antares VS60 RACI finder and a Rigel red dot quick finder;
- lower and upper truss attachments and connectors were made by me, based on the design of John Pratte and concepts in Highe's Portable Newtonian Telescope book;
- the mirror box is relatively shallow (11" deep). Joints are tongue and groove like in Teeter's design;
- the trunnions were designed after studying the beautiful 22" f4 dobsonian telescope designed by Friske on CN forum. There is some geometry regarding the upper curve and the cutoffs of my trunnions, but this is only due to my OCD, rather than added functionality;
- the rocker box is also quite shallow. I used doweling joints for this;
- light shroud was made by Heather Teeter

Other data:
- Metal was stainless steel 316 (also the MC apart from the triangles), aluminium 6082T;
- Wood is Baltic birch plywood: 15mm for UTA, MB; 3x12mm for trunnions, 2x15mm for RB side boards, 15mm for RB front/back boards, 2x12mm for RB bottom board and ground board;
- UTA struts are 1" diam, 1.6mm thick;
- Trusses are 1" 1/8" diam, 1.6mm thick;
- FRP + 1/4" virgin teflon was used for both altitude and azimuth movements;
- Lower / upper truss attachments and connectors, MC triangles use 1/4" thick aluminium.

Thanks for looking
Piero

Hi Piero, fantastic looking scope, congratulations for completing it in a reasonable time frame, and great workmanship, hope to see some observing reports with this scope.
Ivan

That's a lovely looking DOB Piero.

Regards

Graeme

Nice work Piero! That’s a beautiful scope! I’m looking forward to seeing your first light reports.

10538 wrote: ↑Thu Aug 26, 2021 12:16 pm Nice work Piero! That’s a beautiful scope! I’m looking forward to seeing your first light reports.

The telescope has already seen the sky in the past 4 months.
It allowed me to see the central star in M57 for the first time.
For the time being I've tested it on some galaxies in Hercules and Pegasus, and of course on a few globulars, including some of the less known in Ophiuchus.
It also works very well on planets. I've only tested it on Jupiter and Saturn, but the delivered views were breathtaking.

I hope to observe them again under decent seeing conditions and spend more time observing their moons at high power.

Great scope Piero. And a fantastic build.

Excellent! Great job Piero!