DIY Microfocuser for a Telephoto Lens

I’ve built an electronic automatic focuser (EAF) for my Tamron 80 to 210 mm telephoto (zoom) lens for automated and precise focusing. The focuser was built with a stepper motor, an A4988 stepper motor driver, an Arduino Uno, and a repurposed azimuth adjustment mechanism of an old Vixen mount.

DIY microfocuser for a telephoto lens

Vixen’s alt-az mount azimuth lock mechanism happens to be wide enough to fit a telephoto lens. It allows fine movement using the fine adjustment knob attached to a stepper motor with 60:16 pulley and belt system. It features a clutch mechanism that allows for manual focusing. The lens and the camera are held in place with mounting rings from an old 80 mm Vixen refractor. An aluminum baseplate is used to mount together as a unit the lens, camera, focuser, finder scope, and guide scope. The controller for the focuser was housed in a project box. A dovetail bar connects the whole assembly to the telescope mount.

I have tested the focuser on several imaging runs now and it appears to be working fine, especially with wide-field targets such as the Lagoon and Veil Nebula. To watch a video showing the microfocuser in action, click here

Related links:
DIY Electronic Automatic Focuser (EAF) | Refractor
DIY Electronic Automatic Focuser (EAF) | Reflector

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Polar Scope for Vixen GP Mount

I have installed a Kenko polar scope to a Vixen Great Polaris (GP) mount. I modified the polar scope’s coupler to fit the Vixen GP mount. Instead of the standard threaded coupling, I used three screws to attach the polar scope onto the mount. A separate set of centering screws allow alignment of the star map overlay with that of the actual stars in the sky.

Kenko polar scope to a Vixen Great Polaris (GP) mount

A polar scopes is helpful in aligning the mount’s polar axis with that of the Earth’s axis of rotation, but it lacks the precision required for astrophotography. When imaging at longer focal lengths, I recommend not relying on a polar scope, but instead use the declination drift alignment method for polar alignment. It looks at two stars, one in the eastern or western horizon, and another in the celestial equator, allowing for better polar alignment even without the view of Polaris.

Star chart from a 1990 polar scope still works!

Related link: Kenko NES Mount

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Upgrades for a Newtonian Reflector

This post features all the DIY modifications I have made with a Vixen R114 Newtonian reflector on a Grand Polaris equatorial mount.

Buying a Telescope in the Philippines
Acquiring a telescope for astrophotography may be very costly if it is to be purchased brand new, with prices usually costing (in the Philippines) more than 35,000 pesos (more than $700) for the telescope and mount only, cameras not included. For an aspiring astronomy enthusiast, a low-cost alternative would be to purchase one from a local surplus store. Such stores are popular in the Philippines, selling relatively low-cost second-hand telescopes in good condition, mostly imported from Japan. A few months ago, I purchased a Vixen Newtonian reflector (year 1990, model Vixen R114) with 114 mm diameter 900 mm focal length, on a non-motorized equatorial mount. This telescope was initially purchased by a fellow astro-enthusiast but was offered to me instead for 7,500 pesos ($150) when it was discovered that the telescope has to be repaired as it could not reach focus. I found out later that the optical elements were not properly installed. The telescope does not have a tracker, and thus, is not equipped for deep-sky astrophotography (such as for taking images of galaxies, nebula, and star clusters).

Vixen R114 on a modified Vixen Great Polaris mount

Importance of a Tracking Mount
As the Earth rotates, the apparent position of sky objects changes. Pointing with a telescope would have been easy if sky objects are stationary. But the Sun, planets, stars, galaxies, and nebulae, they all move across the sky at a rate of about 15 deg per hour from east to west. To follow a moving target, the telescope uses motors and controllers that move the telescope at a very precise rate in order to keep an object centered. A tracking mechanism compensates for the Earth’s rotation by moving the telescope just right to negate the effects of Earth’s movement. This capability of a telescope to track is what makes it suitable for taking long-exposure images, a basic requirement in astrophotography.

Building a DIY Go-To Telescope Controller
Telescopes on equatorial mounts without trackers may still follow objects manually by rotating the RA fine adjustment knob. To be useful in astrophotography, tracking must be done with precision. Telescopes with trackers are available, but are costly. An alternative would be to build a tracker using parts that can be purchased online or taken from old appliances (such as printers). There are various open-source projects on the internet about building trackers, one of which is a system called OnStep (which stands for On Cue, On Step). It allows not only tracking but also automated finding of objects in the sky. It can be installed on any telescope, even on a year 1990 model Vixen R114 that I have purchased.

OnStep Telescope Controller

In my particular OnStep build, I used an Arduino Mega 2560 as the main controller board as I am already familiar with it. I also used a pair of LV8729 stepper motor driver and an HC-05 Bluetooth module. For the motor drive mechanism, I used a pulley-and belt system.

OnStep with Smart Hand Controller

I used a pair of 200-step-per-revolution stepper motors paired with 60-teeth and 16-teeth pulley and belt drive system to motorize the Vixen Great Polaris mount with 144:1 worm drive. In this configuration, the total steps are 200 steps * 60/16 reduction * 144/1 teeth worm drive = 108,000 steps per 360 degrees at full stepping. Actual testing showed that accurate tracking is possible at 1/64 microsteps (60 second unguided exposures at 900 mm focal length) . This brings the total steps per revolution to 6, 912, 000 per 360 degrees, or 19,200 per degree (you need to configure this in the OnStep code).

OnStep Telescope Controller

The OnStep telescope controller can be connected to an Android smartphone (using the app OnStep) via bluetooth connection or to a laptop computer via USB connection, running the software Nighttime Imaging N’ Astronomy (NINA) to enable automatic slewing to targets. It also connects with Stellarium to display real-time the telescope’s current position. It uses plate-solving (with ASTAP) to validate and refine its pointing accuracy.

Right-Ascension Motor
Declination Motor

During start-up, the telescope begins with the alignment process in which it will point to a star and ask you to validate that the correct star is shown on the screen or eyepiece. Once successful, the telescope will be capable of finding almost any sky target such as planets, galaxies, and nebulae. The telescope will have very accurate pointing and tracking if properly polar-aligned.

Unguided 60 sec exposures at 900 mm with an OnStep-controlled mount, Dumbbell Nebula (1 hour)

Attaching a Motor to the Focuser
Precise focus is essential in capturing sharp images. Focusing is done by moving the draw tube that holds the eyepiece or camera. This is usually done by looking at the eyepiece or screen to assess focus while rotating the focuser knob. A motor may be attached to the focuser knob to automate this process. Precise focusing can be done by manually operating the controls and stopping when the view is sharp, or by using a software to check proper focus. The software will move the motor and stop at the position where there is good contrast and pinpoint stars. In the Vixen R114, I attached a motor on the focuser and use an Arduino Uno and an A4988 stepper motor driver to control it. The focuser is ASCOM compliant and works with astronomy software such as NINA for remote and automated focusing.

DIY Electronic Automatic Focuser installed on a Vixen R114

Using Laser as Finder

The telescope comes with a 6 by 30 mm finder scope which is adequate for pointing at bright targets. To add to it, I also installed a laser pointer as a tool for locating objects. The laser pointer is mounted on a spare finder scope holder with collimation screws to enable alignment with the telescope. It has a toggle switch that allows the laser to be turned on and off. To find an object such as a galaxy or nebula, I turn the laser on and point the telescope to the target’s approximate location as indicated in a star map. I then use a pair of binoculars to spot the target. Since the laser allows me to know precisely where the telescope is pointed at, I could use it to guide the telescope to the target. Observe safety precautions when using laser pointers (also, laser pointers are usually not allowed in star parties!)

A laser pointer attached to a telescope allows easy star-alignment for an accurate go-to system

Installing a Polar Scope
Most second-hand telescopes do not come with complete accessories. The mount the Vixen R114 came with (Vixen GP mount) does not have a polar finder scope. Polar finder scopes help in precise alignment of the equatorial mount’s RA axis with the Earth axis of rotation. I do happen to have a polar scope from a smaller mount that I no longer use. I transferred the polar scope from the other mount into the Vixen GP mount. The polar scope has three centering screws which is needed for calibrating the polar scope’s star map with the actual position of Polaris in the sky. I have tested the polar scope and it works well.

Polar scope upgrade
1990 star chart reticle still works

Preventing Collisions with a Pier Extension
Automated telescopes must be able to point anywhere in the sky without the risk of collision between the telescope and the tripod legs. One solution to this is to elevate the telescope on to a pier. Pier extensions can be purchased, but I opted to build one since it is not difficult to do and I happen to have the parts needed. I used three L-bars to lift the tripod head. The pier extension allows unattended imaging without the risk of damage due to collision, to the mount or telescope.

DIY pier extension

Home-brewing Astronomical Equipment
You will learn many things as you engage more with home-brewed projects. Do not be afraid to modify or improve your existing equipment. Building equipment does not necessarily mean low-cost though, it can sometimes be costly and there is always a risk of damage to equipment. Building DIY equipment, however, can be a worthwhile activity for astronomy enthusiasts. If you want to learn more about improvised astronomical equipment that you can build at home, you may check out my other home-brewed projects here.

Trifid Nebula imaged with a Vixen R114 on Vixen GP mount with home-brewed tracking system

Related link: DIY Astronomical Projects

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Tamron to Astrocam Adapter

I have a 1980 Tamron 80 mm to 210 mm telephoto (zoom) lens that I intend to use for astrophotography. I could not find a dedicated astro camera adapter for this particular lens so I just improvised one. I used epoxy to connect a Tamron to Canon EOS adapter and an M42 connector for my ASI 533 astro camera.

After several imaging sessions with the Lagoon and Veil Nebula, the DIY adapter appears to work.

Related links:
Universal Camera Adapter
DSLR to Telescope Adapter

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Electronic Focuser | Reflector

I’ve built an electronic automatic focuser (EAF) for my Vixen R114 reflector for automated and precise focusing. The focuser was built with a geared stepper motor, A4988 stepper motor driver, and an Arduino Uno.

DIY Electronic Focuser for a Vixen R114 reflector

The focuser is ASCOM compliant and works with astronomy software such as the Nighttime Imaging N Astronomy (NINA) for automated focusing during unattended imaging. To watch a video showing the focuser’s movement, click here.

Related links:
DIY Electronic Automatic Focuser (EAF) | Refractor
DIY Electronic Automatic Focuser (EAF) | Telephoto Lens

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Pier Extension for EQ Mount

I have built a DIY pier extension to allow my DIY go-to telescope to move without hitting the tripod legs. It consists of three 12-inch L-bars (which I later shortened to 7.5 inches, after measuring the minimum clearance required) that lift the tripod head. I repurposed a tripod head from an old and unused tripod to serve as the base where the L-bars and the tripod legs connect to. The pier extension allows unattended imaging without the risk of damage to the mount or telescope.

DIY Pier Extension

To watch a video of the telescope performing a successful meridian flip without hitting the tripod legs, click here.

Related link: Converting the Vixen Great Polaris mount into a Go-to mount

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Telescope Controller | OnStep

I have built a controller for my Vixen Great Polaris mount using the OnStep go-to telescope controller. I used an Arduino Mega 2560 as the main controller board, a pair of LV8729 stepper motor driver, and an HC-05 bluetooth module (which connects to the OnStep Android app).

I also built a Smart Hand Controller (SHC) using an ESP32 module, an OLED display, and a button array. The SHC connects to the same serial communication lines (Rx and TX pins) used by the HC-05 bluetooth module. I use a toggle switch to select between the HC-05 Bluetooth module for the Android controller and the Smart Hand Controller with ESP32 module.

OnStep Telescope Controller

I used a pair of 200-step-per-revolution stepper motors paired with 60-teeth and 16-teeth pulley and belt drive system to motorize the Vixen Great Polaris mount with 144:1 worm drive. In this configuration, the total steps are 200 steps * 60/16 reduction * 144/1 teeth worm drive = 108,000 steps per 360 degrees at full stepping. Actual testing showed that accurate tracking is possible even at just 1/64 microsteps (as evident in a 60 second unguided exposures at 900 mm focal length). This brings the total steps per revolution to 6, 912, 000 per 360 degrees, or 19,200 per degree. You need to configure these values in the OnStep code.

The OnStep telescope controller can be connected to NINA to enable automatic slewing to targets and use plate-solving to validate and refine its pointing accuracy. It also connects with Stellarium to display real-time the telescope’s current position.

Unguided 60 sec exposures at 900 mm with an OnStep-controlled mount, Dumbbell Nebula (1 hour)

OnStep will have very accurate pointing and tracking even with just one-star alignment, if properly polar-aligned.

OnStep Telescope Controller


Related links:
Trifid Nebula imaged with the OnStep DIY Go-to Controller
OnStep Main Page
Smart Hand Controller Main Page
Schematic Diagram OnStep Main Board and Smart Hand Controller

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

Vixen R114 on Great Polaris Mount

I have recently acquired a Vixen R114 Newtonian reflector (114 mm aperture, 900 mm focal length at f/7.9) on a Great Polaris equatorial mount. The mount does not have motors, but I have converted it into a fully-automated go-to and tracking mount capable of unguided exposures of at least 60 seconds (field-tested without guiding).

Vixen R114 on Great Polaris Mount

The reflector has a very good primary and secondary mirror cells which allowed precise collimation and prevent strained optics. The stock focuser is a 0.965 in barrel which I modified and converted to the 1.25 in standard. The rack-and-pinion focusing mechanism is very precise and sturdy enough to hold an ASI 533 astronomy camera even without using the focuser lock. It comes with a 6 x 30 mm finder which is adequate for pointing at bright targets.

Trifid Nebula M20, 1.7 hours exposure

The Vixen R114 on Great Polaris equatorial mount now serves as my long focal length telescope both for visual observation and imaging.

Related links:
Converting the Vixen Great Polaris mount into a Go-to mount
DIY Upgrades for a Vixen R114 on GP mount
Sky-Watcher Equinox 100ED

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

Portable Telescope Setup

I have a TravelScope70 which has served as a guide scope for my imaging setup for many years. Now that I have shifted to an off-axis guider (OAG) setup, the TravelScope70 is now being repurposed back to a grab-and-go travel light telescope setup, to be used particularly in astronomy outreach events and visual observations.

Aluminum-lined hard case for the Celestron TravelScope70

The TravelScope70 is a good small-aperture low-magnification telescope, if paired with a good diagonal and set of eyepieces. It will show good views of the moon and allow decent moon photography. Due to the short focal length, small aperture, and lack of a dedicated and more robust mount, the TravelScope70 may be limited to moon viewing and other large and bright targets such as star clusters and nebula.

Related link: Celestron Travel Scope 70

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Projector Lens Telescope

Projectors have lenses that may be used to build low-magnification telescopes. I happen to have found an old 70 mm diameter LCD projector lens with focal length of 105-210 mm which I paired up with an eyepiece to build a DIY telescope.

DIY projector lens telescope

This projector lens, while not designed to be used as a telescope lens, may still provide good views. I measured the proper focus distance and used a DIY adapter to attach a 2-in diagonal mirror and a 40 mm lens to it. This combination produced a 2.6 by 70 to 5.25 by 70 finder scope (wide field of view with ability to zoom). Focusing is done by sliding the eyepiece in and out of the diagonal’s eyepiece holder. I then made an improvised reticle (cross hair) to finally complete the setup. I will be using this DIY projector lens telescope in star-hopping to deep-sky targets and scanning large areas of the sky.

Related link: View all home-brewed DIY astronomy equipment

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Focal Reducer

I have built a DIY focal length reducer (focal reducer) by inserting a converging lens from an old telescope along the optical system of a Sky-Watcher Equinox 100ED . The telescope’s native focal length is 900 mm at f/9. With the DIY reducer, the focal length is reduced to 565 mm at f/5.65 (actual focal length as measured by SIRIL’s plate solver function). The lens used was the objective of a Vixen 80 mm f/11 achromat, reducing the native focal length of my telescope by 0.63x.

DIY Focal Reducer

Focal reducers are optical elements (usually a convex lens or lens group) that converge light from a telescope’s objective. It shortens the focal length and in effect, produces a faster telescope (lower f/ratio) and widens the field of view (larger portion of the sky is seen or captured). Any decent quality converging lens should work as a focal reducer. It works opposite to a Barlow lens which increases the focal length by using a concave lens or diverging lens. Unlike dedicated focal reducers designed to maintain optimal image quality, DIY focal reducers may introduce aberration and must be considered when attempting this modification.

Orion Nebula M42, imaged with the DIY focal reducer

I had to shorten the optical tube by about 200 mm to reach focus, and then reattach the focuser. The focuser’s draw tube was also shortened by 55 mm to prevent it from obstructing the light and stopping down the objective lens when the draw tube moves inward. The telescope’s optical tube has an inner diameter of about 100 mm which has enough space to accommodate the lens cell of the Vixen 80 mm lens. Only the central 60 mm part of the reducer is used due to the presence of a light baffle in the telescope’s optical tube assembly.

Related link: View all home-brewed DIY astronomy equipment

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Off-Axis Guider (OAG)

I have built a DIY off-axis guider (OAG) using a mirror from a DSLR camera, some tube extenders (2 in and 1.25 in diameter), and a webcam. Best guiding performance currently at 0.33″ (arcsecond) RMS error, at 900 mm focal length, using a mount with DIY controller.

DIY Off-Axis Guider (OAG)

In off-axis guiding, the telescope functions both as an imaging scope and a guide scope. In this configuration, a mirror or a prism receives a portion of the light without blocking the main imaging sensor, sending the light to a guide camera. In this build, I used a high-quality mirror I happen to have found in a non-working Canon 1100D. To build the OAG, I removed the lens from a Barlow so I could get a 1.25 inch barrel for the webcam attachment, and then fastened it perpendicular to a 2 inch extender, where an appropriate side hole has been made. I then fabricated a small mirror mount (like a secondary mirror mount in a Newtonian) using some brass material, to send the reflected light on to the side. The placement of the mirror and the proper spacing to achieve focus required trial-and-error. To use the OAG, focus the main camera first, and then slide the guide camera in or out to achieve focus.

M51 Whirlpool Galaxy, imaged with the DIY Off-Axis Guider

Related link: View all home-brewed DIY astronomy equipment

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Declination Motor

Using a gearbox from an electronic screw driver and a stepper motor from a printer, I’ve built a declination motor drive (direct drive and using gearbox).

The electronic screw driver has a DC motor which I removed and swapped with an old printer’s stepper motor. The gearbox attaches to the declination worm screw using an improvised coupler. I designed it to feature a clutch knob to disengage the motor drive in case I need to slew manually, using the fine adjustment knob.

DIY Declination Motor

The stepper motor is driven with an A4988 stepper motor driver board and controlled with an Arduino Uno microcontroller. Two push buttons are used to slew the telescope north or south. I had to perform a field test in order to correctly set the motor’s speed to match the slew speed of the RA motor. The declination motor can be used for declination guiding. I have also tested it to work with a DIY go-to controller.

Related link: View all home-brewed DIY astronomy equipment

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Counterweights Set

Equatorial telescopes near the equator have polar axis with very low elevation and as a result, the counterweights may hit one of the tripod legs. With this new set of DIY counterweights, I was able to reposition the weights just enough distance to clear the north-side tripod leg, while at the same time, shift the weights closer to the polar axis, making the whole system more stable.

Custom counterweights for a Kenko NES mount

Related link: View all home-brewed DIY astronomy equipment

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Microfocuser | Canon 50 mm f/1.8

When imaging targets using a DSLR lens, achieving proper focus may be difficult even when using a Bahtinov mask. Focus adjustments involving very small and precise steps can be achieved using a microfocusing mechanism. In this DIY project, I have modified a Canon 50 mm f/1.8 lens and tapped onto its built in electronic microfocuser. It uses an L293D stepper motor driver and an Arduino Uno.

The focuser is ASCOM compliant and works with astronomy software such as the Nighttime Imaging N Astronomy (NINA) for automated focusing during unattended imaging. The modification should work with any lens with built in electronic focusers. To watch a demo video about this microfocuser project, click here.

Related link: View all home-brewed DIY astronomy equipment

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Equatorial Wedge

I have fabricated a customized equatorial wedge for a colleague. An equatorial wedge is simply a platform that is tilted to precisely match the latitude of a place. When used with a wedge, an altitude-azimuth telescope mount may be used in equatorial configuration.

Plans for building the equatorial wedge

Equatorial wedge fabricated at a local machine shop

Related link: View all home-brewed DIY astronomy equipment

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

Baader ND 5.0 Solar Filter

I have been using a Baader Neutral Density (ND) 5.0 Solar Safety Film filter for several years now in solar photography and visual observation. According to the specifications, it reduces solar intensity by a factor of 100,000.

Baader film solar filter mounted on a telescope

The filter looks like a thin reflective plastic sheet, about A4 size (20 cm by 29 cm). When used with binoculars or telescope, it must be cut to the right size to cover the whole aperture of the optical instrument and installed securely on a rigid frame. Alternatively, the filter may be used without a telescope. Based on my experience, while the solar film may look very delicate and fragile, it is very durable and does not easily get damaged. Special attention, however, must be given to ensure that the film does not get stretched or folded to retain its properties.

Sunspot AR12192 | Sky-Watcher 4 in f/9 refractor

The Baader ND 5.0 solar filter produces sharp images with good contrast without changing the white balance. The filter I purchased in 2011 which has been used extensively in almost every solar event visible in my locality is still in excellent condition.

To view posts on DIY projects and astronomical equipment, click here.

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

Celestron OIII Narrowband Filter

The 2-inch Celestron OIII (oxygen III) band-pass filter that allows the 496 nm and 501 nm lines emitted by planetary and emission nebula. The filter looks like a polished mirror that allows some green light that corresponds to the light emitted by emission and planetary nebula to pass through but blocks everything else including most light pollution.

Celestron 93624 OIII filter

I used this filter extensively in visual observation by ‘blinking’ it in and out between the eye and the eyepiece, a technique used in observing O-III planetary nebula. The use of the filter results in enhanced contrast between the sky and the nebula.

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Electronic Focuser | Refractor

I’ve built an electronic automatic focuser (EAF) for my Sky-Watcher Equinox 100ED refractor for automated and precise focusing. The focuser was built with a stepper motor from an old printer, a gearbox from an electronic screwdriver, A4988 stepper motor driver, and an Arduino Uno.

DIY Electronic Focuser for a refractor

The focuser is ASCOM compliant and works with astronomy software such as the Nighttime Imaging N Astronomy (NINA) for automated focusing during unattended imaging. When the autofocus command is called, NINA takes a series of photos (with a Canon 50D DSLR) at various focus distances and measures the diameter of stars for star fields or the highest contrast for moon and planets. It then calculates the proper distance travel for best focus, and then moves the focuser to focus. An automatic focuser ensures that stars remain focused during unattended imaging runs while you are away from the telescope.

Autofocusing with a DIY Electronic Focuser

This DIY electronic focuser attached to a standard Crayford focuser features 50,000 focus positions, with buttons for manual focus adjustment and calibration. The controller keeps track of the draw tube’s current position and saves this information even when the focuser is powered off.

Precise focusing of Jupiter using an Electronic Auto-Focuser

I have tested the focuser on several imaging runs now and it appears to be working fine, especially with planets in which I image at 3600 mm focal length.

Related links:
DIY Electronic Automatic Focuser (EAF) | Reflector
DIY Electronic Automatic Focuser (EAF) | Telephoto Lens

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Intervalometer

I’ve built a simple DIY intervalometer for deep-sky imaging, to enable my DSLR camera to take a series of photos of galaxies and nebula. It features a rotary dial with preset exposure times. When used with an autoguider setup, the intervalometer allows taking unattended exposures, while the telescope tracks a galaxy or nebula.

DIY Intervalometer for a Canon 50D

Related link: View all home-brewed DIY astronomy equipment

Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines