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
Camera sliders are fun tools to use for making dynamic timelapse videos, and they come with some cool features. This is a clever little gadget that moves like a camera slider but folds much smaller. Eggtimers are also commonly used to make a similar effect. Some high-end gear can slide and rotate the camera at the same time for a particularly cool effect. But how do you guild one that one that could go up to 11?
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).
Wood burning is a popular hobby which can become quite expensive. A quality wood burning system consists of: 1. A pen or selection of pens and 2. A power supply (station). I decided to invest in a series of Razertip wood burning pens simply because they were available at a local Lee Valley Tools store (they also have a 1-year unconditional warranty – if I end up destroying a pen with a home-built supply then we will find out just how unconditional the warranty is). The pens are available for ~$30 each, which can become a significant investment if you want more than one or two. The stations run for $165 and up, which is the same price as six pens! So lets ditch the station.
2019-09-03: I’m considering manufacturing some sensor circuits and selling them for a reasonable price (probably ~$25 plus shipping for a pair). Eventually I will put a listing on tindie.com, but until then if you’re interested in building a ballistic chronograph and would like to buy a set of sensors, please contact me at email@example.com.
A ballistic chronograph is an instrument which measures the speed of very fast things (like bullets). I decided to build one which could be used for high-speed photography, such as glassware getting shot with an air-powered rifle (see my other post on this topic or my Flickr album). In order to take such a photo, you need to be able to trigger a flash at just the right moment, which will freeze all the juicy action.
There are numerous resources available which give very limited information on how to build such an instrument. Unfortunately all of the resources are incomplete or describe an instrument which only works for slower objects, such as paintballs or airsoft pellets. I designed and built this using the information available on the internet, my modest understanding of electronics, and many hours of trial-and-error. To somebody who has some knowledge of electronic components, this post can be used to build an instrument useful for measuring the speed of objects travelling up to 1,000 m/s (such as high-powered rifle bullets), and even photographing a projectile ‘interacting’ with other objects!
This obvious question was asked when my wife provided me with three wine glasses which were used to keep her Siamese Fighting Fish. She couldn’t bring herself to drink from them after their use as aquariums. So I decided to destroy them and make a few attempts at high-speed photography!
I’ve recently been keen on learning how to use and control stepper motors in a practical application. And it became apparent that the use of a stepper motor in a photographic slider (herein referred to as a PanoSlider) was an excellent challenge to start with. The reason? The PanoSlider had to provide fast, smooth, accurate, and powerful motion while being controlled by an intuitive user interface.
The actual design of the PanoSlider began in a typical fashion: by wandering around my collection of materials and devising a simple, easy, solid structure. I settled on a discarded construction level as a frame. 3/4″ PVC pipes were screwed onto the sides with sheet metal screws, and hot-melt glue (HMG) was added to prevent the pipes from rotating. HMG is a generally underrated material, and its use is often limited to children’s crafts (and results in many finger burns). In reality, it can be used as a fast-setting substrate with good strength, and its poor bond strength is useful in making temporary joints (for instance – I mounted the Arduino board to the PanoSlider assembly with HMG, then simply broke it off when it was no longer needed).
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.
Using a lightstand as a base, this Lego build was positioned above a glass bowl filled with water. An Arduino Uno board controlled the camera shutter, a flash, and the Lego ‘Dropper’. The time delay between the drop and the flash trigger was entered into a laptop. The results can be seen at: https://flic.kr/s/aHskhKLsh9. A video of the rig in action is shown below.
The camera and wireless triggers were controlled via a 4N35 Optocoupler circuit (keeping the Arduino and the equipment completely isolated). The shutter speed was quite slow (~1/10s). This was due to the inconsistent shutter lag that plagued the operation at speeds faster than 1/10s. No problem though, the flash stopped the motion better than the shutter could have.