The ZWO AM5 telescope mount is a great piece of kit… It integrates very well with software allowing easy computer control, just click and go. The mount tracks wonderfully allowing excellent astrophotos. It is small, does not require a counterweight for smaller ‘scopes, and precise polar alignment is a breeze.
A 3D printed battery caddy on the side of a ZWO AM5 telescope mount
The mount is not without issues… Without a camera integrated into the system the GOTO accuracy is awful, using the mount as a visual mount is frustrating. You really need to have at least a guide camera and the ASI Air computer connected to allow to plate solving and automatic correction of the position at the end of each slew to a new target.
Another issue is that the mount has no concept of cord wrap. It will happily spin around and around as you wander across the sky. In equatorial mode this is not an issue, in alt-azimuth mode this runs the risk of damaging your equipment if you do not notice the power cord getting wrapped up on the mount in the dark.
One of the things I brought back from Oregon Star Party was a set of solar filters for binoculars.
A simple set of solar filters for my Nikon binoculars
The filters were from DayStar Filters who had a booth at the star party. I spent a while chatting with the gal running the booth and enjoying the hydrogen alpha views through the ‘scope they had set-up. The Daystar SS60 Hydrogen alpha ‘scope they had on sale was rather tempting.
Leaking alkaline batteries, the bane of our portable, battery powered existence. All too many times I have found myself repairing electronic devices damage by leaking batteries, or just junking the gear when the damage is too severe.
Corrosion damage in the base section of a Celestron 8SE mount
This time the device in question was just a bit too valuable to dispose of despite fairly extensive damage.
Living in the islands provides excellent observing for an amateur astronomer such as myself, but there are drawbacks. I do miss the large star parties, getting together with hundreds of other observers to see other telescope setups, to learn, and to share the sky.
The 10″ f/4.5 travel scope Holoholo
Thus I have made a habit of traveling to the mainland once in a while to attend one of the larger star parties. This year I will again attend Oregon Star Party. It has been a while, the last time was 2017, the year of the total solar eclipse.
Traveling from the islands to a star party makes it a challenge to bring a large telescope. Last time I borrowed an 11”, not a bad solution, it worked, but it was not my ‘scope. This time I was determined to realize a long considered idea, to build a substantially sized travel telescope. Thus Holoholo was designed and built, a 10.1” f/4.5 travel ‘scope.
This has been a bit of a design challence for me… Just how small, how simple, can I make a focuser and yet still provide excellent usability. My latest Helix 1-14 design is my best yet.
A simple helical crayford focuser
As my 3D printer design skills improve I applied lessons learned and the unique capabilities of an FDM printer to the problem of a focuser. After a bit of a journey I have arrived at a design I can consider finished. Is it the final design? I may tinker some more, but I am satified for the moment.
The design is based on a few ideas from here and there, products I have seen or used, internet postings from others faced with the same challenge. I am not one for just printing someone else’s design, I rarely do that, I want to do my own, and maybe make it better.
For the last couple years I have been exploring 3D printed telescope designs. The latest result of this oddessy is Kinipōpō, a 4.5″ f/4 Newtonian using a entirely 3D printed ball mount design.
Kinipōpō ball telescope 3D model
The Hawaiian word kinipōpō translates as ball or sphere.
A ball telescope offers a number of advantages, the first of which is ease of use. It is simplicity itself to aim at a target, no odd controls, no weird angles, just freely push the ‘scope to the target. As the tube can be freely spun the eyepiece can always be positioned for easy viewing.
The design is an RFT, or Rich Field Telescope. This type of ‘scope is designed to be a low power, wide field ‘scope ideal for enjoying sweeping the sky and providing views rich with innumerable stars. It is not a good ‘scope for planets, the magnification is far too low. It’s prey is large, bright targets, star clusters, bright nebulae, or even the dark nebulae silhouetted against the rich starfields of the Milky Way.
Another ideal target is bright comets. My prototype providing pleasing views of comet C/2022 E3 ZTF a month before preihelion and maximum brightness.
The short focal length does create coma issues around the edge of the field, stars near the edges of the field smear a bit and will not focus. The problem does not seem too objectionable, but it is there.
The design is inspired in part by the classic Edmunds Optics Astroscan telescope, in being both small, portable, and simplicity to use. On the other hand the design offers a number of improvments over the Astroscan. Primarily the ‘scope offers an increased aperture of 114mm compared to the Astroscan’s 105mm, while being very close to the same overall size.
The scope costs about $200 to assemble, the largest chunk of that being the primary mirror. While the needed plastic filament for the 3D printer is cheap, it does take quite a bit of time to print. The largest part, the spherical shell requires over 60 hours on the printer, with many of the other parts being overnight prints. Assembly is not difficult, mostly cleaning up the plastic prints, heat setting a number of brass threaded inserts, and a bit of epoxy here and there.
Three of these little telescopes have been built, and three have been given away. I get photos of them every now and then, fun little telescopes under a dark sky.
As I have observed lately, most of the small telescope mirrors available right now are out of China, most of those produced by one company, Guan Sheng Optical or GSO. If you want a small mirror, say a 6″ or 8″ mirror, there is not a lot of choice, the mirror makers in the US generally do not do anything smaller than 10″.
A textbook Foucault knife edge test image on a 6″ f/4 mirror
The GSO mirrors range from decent to pretty bad, with no way of knowing what you will get when you order, just luck of the draw.
With the big wall completed along the driveway, and a bit of a break over a hot muggy summer, I am again building walls.
Excavating for a series of terrace walls in the back yard.
This is not the sort of wall between people, I detest those, but rather a real rock wall, terracing the backyard to make the space available for landscaping and other projects. This puts into action a plan that has been brewing for years.
Part of the impetus is that I have a source of rock secured, a very large pile of very nice rock found in a Waimea backyard. One of my co-workers casually mentioned he needed to rid himself of a pile of rock, to which I quickly asked… How much rock?
The classic Cave Astrola telescope has become my roll-out, quick observing session ‘scope, often found in my driveway. I have also used it a few times at darker sites when I expect the weather to be damp or dewy as a Newtonian is more protected.
The restored 8″ f/6 Cave Astrola under a dark sky at Kaʻohe
While the restoration job was finished some time ago, I never got around to re-coating the optics. Meanwhile the telescope has seen good service on many occasions as I enjoyed this fun-to-use instrument.
The optics did need some attention… The primary mirror from the Astrola appeared to have not been re-coated since it was made in 1978. Thus the aluminum coating was over 40 years old. While the coating looked bad, it was still serviceable, producing reasonable images.
Still, the loss of light due to the old aluminum coating was probably reducing the effectiveness of this 8″ telescope to something more like a 6″ telescope. I had meant to get it re-coated some time ago, but we know how these things work.
