Astrophotography is a bit of a money pit. I recently delved into it with my 80-200 f/2.8L and a home-built tracking mount. It was so much fun that I decided to buy a telescope! So my entire budget went into an 80mm APO.
The problem was that a telescope alone is useless for star pics – some quality infrastructure is needed. This post is about my attempt to affordably build the following components:
High-precision Tracking Mount with an ASCOM-compliant driver
Guide camera and scope to help the tracking
Portable Power supply
Telescope Focusing motor with an ASCOM-compliant driver
The V2.1 update produced a working mount, but it unfortunately was not very user friendly. I made a few modifications to improve the setup and aiming time, as well as its ability to disassemble and stow in a modest-sized wood box for storage and transport.
V2.2 (codename: HoLi) is the mount’s final design, as I’m very happy with it and have moved on to building the V3.0. See the photo of Orion’s Nebula below taken using this mount, I’ve been happy with its performance using lenses as long as 300mm.
Most DIY astro-tracking mounts can be described as either low-quality barn-door mounts (with questionable door hinges used as pivots) or high-cost and effort equatorial mounts (typically equipped with complex drive systems). The original Tracker V2 was designed to be an attempt to combine low-cost and high-quality elements in a single mount. The basic design could be described as a hybrid barn-door/equatorial style mount.
That said, Tracker V2 was tested using a 250mm lens on a cropped-sensor camera and did not produce sharp OR consistent images! Further examination at the shop revealed that the 10-32 nut and threaded rod caused the arm to advance erratically. There was no way to eliminate or even mitigate the issue, so a bit of an overhaul was in order. Enter: Tracker V2.1!
NOTE: While the V2.1 modification corrected the drive issue and made the device useful for unguided DSO astrophotography, it suffered from usability issues which made setup and targeting very difficult. Improvements were made for the V2.2 upgrade, which concludes this project. I currently building a V3, which will be another screw & arm-driven equatorial. It will have 2-axis auto-guiding among other improvements over the V2.x design (which has admittedly been a product of evolution rather than design and planning).
NOTE: The Tracker V2 I described below had a major flaw: the curved threaded rod. It was removed from the design and replaced with a straight section of Acme rod in Tracker V2.1, which works very well. See Tracker V2.1 for more information and be aware that using a curved section of standard threaded rod is a bad idea! Further improvements and a paint job were added for Tracker V2.2.
Having finished a first attempt at building a working Star Tracker, I’ve recently set out to build a second (final) version. The goal was to use scavenged (read: FREE) mechanical components and cheap electronics from eBay China to build an automated tracking mount which could be used to capture high-quality DSO (Deep Space Object) and Planetary images. I’ve also made an attempt to make it look nice.
The main body of the tracker was based around the pivot assembly – a modified treadmill roller. Treadmills contain a large amount of useful mechanical and electrical components, so I try to pick up any old treadmills being given away on the local classifieds. After disassembling the roller, I shortened the shaft and body to a practical and aesthetically pleasing length.