DIY Portable Star Tracker

I have built a lightweight portable DIY star tracker for DSLRs. It uses a worm drive from an unused equatorial mount I have found in a local surplus shop. I used a geared stepper motor and an Arduino controller to spin the RA axis at the correct tracking rate to match the apparent movement of the sky. The setup was housed in a metal box that fits in a small camera bag. It mounts on a standard camera tripod. I have tested it to track accurately with a DSLR with an 80 mm to 210 mm telephoto lens.

Lightweight portable DIY star tracker for DSLRs

Related links:
DIY Ultra-Portable Tracker
DIY OnStep Go-To Telescope Controller

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

Running Man Nebula

Running Man Nebula S279 in the constellation Orion imaged with a Vixen R114 reflector at 900 mm focal length, an ASI 533MC cooled astronomy camera, dual band H-alpha and O-III filter, with an ASI 174MM guide camera.

Running Man Nebula S279, 1 hour exposure

For a complete list of astrophoto images, click here.

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

Horsehead Nebula

Horsehead Nebula IC 434 in the constellation Orion imaged with a Vixen R114 reflector at 900 mm focal length, an ASI 533MC cooled astronomy camera, dual band H-alpha and O-III filter, with an ASI 174MM guide camera. The nebula is not visible in small telescopes and requires a camera sensitive to H-alpha to reveal the deep-red ionized hydrogen gas obscured by an opaque cloud of dust and gas.

Horsehead Nebula IC 434, 1 hour exposure

For a complete list of astrophoto images, click here.

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

Orion Nebula M42

Orion Nebula M42 imaged with a Vixen R114 reflector at 900 mm focal length, an ASI 533MC cooled astronomy camera, dual band H-alpha and O-III filter, with an ASI 174MM guide camera. M42 is visible even with binoculars or small telescopes.

Orion Nebula M42, 1 hour exposure

For a complete list of astrophoto images, click here.

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

Total Lunar Eclipse | 08 November 2022

Totally-eclipsed moon imaged with a 114 mm f/7.8 reflector and an ASI 533MC astronomy camera on 08 November 2022 in Bacoor City, Philippines. The bright object near the moon is the planet Uranus during its conjunction with the moon coinciding with the total lunar eclipse. The moon and Uranus appear close together in this photo due to a chance alignment of Uranus, the moon, and the Earth. Uranus is much farther behind the moon, by a distance of about 2.7 billion kilometers.

Totally-eclipsed moon with Uranus imaged with a 114 mm f/7.8 reflector and an ASI 533MC astronomy camera on 08 November 2022 in Bacoor City, Philippines. To watch our guided lunar eclipse observation (livestream), click here.

For a complete list of astrophoto images, click here.

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

Jupiter | November 2022

This is my first test image of Jupiter using a Vixen R114 telescope on a tracking mount. I used a stack of two 2x Barlows to magnify the image. This is a stack of 2000 frames imaged with an ASI 533 camera and a UV-IR filter.

Jupiter, 2000 frames stacked

For a complete list of astrophoto images, click here.

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

Rosette Nebula | Travel Scope 70

Rosette Nebula imaged in October 2022 with a Travel Scope 70 at 400 mm focal length, ASI 533MC cooled astronomy camera with dual-band OIII and H-alpha filter, and an ASI 174MM guide camera.

Rosette Nebula imaged with a Celestron Travel Scope 70, an ASI 533 astronomy camera, and a Vixen GP tracking mount

For a complete list of astrophoto images, click here.

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

Flame and Horsehead Nebula | Travel Scope 70

Flame and Horsehead Nebula imaged in October 2022 with a Travel Scope 70 at 400 mm focal length, ASI 533MC cooled astronomy camera with dual-band OIII and H-alpha filter, and an ASI 174MM guide camera.

Flame and Horsehead Nebula imaged with an inexpensive refractor

For a complete list of astrophoto images, click here.

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

Triangulum Galaxy

Triangulum Galaxy M33 imaged with a 4 in refractor at 565 mm focal length, ASI 533MC cooled astronomy camera with UV-IR filter, and an ASI 174MM guide camera. Use the three prominent stars of the Triangulum constellation to find M33.

M33 Triangulum Galaxy, 44 minutes exposure

For a complete list of astrophoto images, click here.

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

Pleiades

Pleiades M45 star cluster imaged with a 4 in refractor at 565 mm focal length, ASI 533MC cooled astronomy camera with UV-IR filter, and an ASI 174MM guide camera. This target is very prominent and can be seen very easily with the unaided eye, binoculars, and small telescopes.

M45 Pleiades, 1 hour exposire

For a complete list of astrophoto images, click here.

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

NOAA 15 Satellite | August 2022

NOAA satellites 15, 18, and 19 transmit weather images in APT format at 137 MHz which may be received using a DIY non-tracking circularly-polarized VHF antenna, an AirSpy Mini software-defined radio (SDR), and a decoder such as the NOAA-APT.

NOAA 15 weather satellite image decoded on 03 August 2022 as it passes over the Philippines

To watch a video of a signal received from a NOAA satellite, click here. To view all posts about amateur radio, click here.

Related link: My First NOAA Satellite Image

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

Sunspot AR 3057 and AR 3059

This is an image of the Sun showing two prominent sunspots AR 3057 (upper right) and AR 3059 (lower left), imaged with a Vixen R114 reflector, ASI 533 MC camera, and a Baader ND 5 solar filter. Never observe or image the Sun without the proper solar filters.

Sunspot AR 3057 and AR 3059

For a complete list of astrophoto images, click here.

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

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

Automated Station ID with ISD1820

The ISD1820 is a sound recorder and playback module capable of storing 20-second audio recordings. It features the ability to initiate playback with a button press or a pulse, which is very useful in automated transmissions. The playback signal can be generated manually by tapping the playback button onto a radio’s PTT button, or by using a dedicated controller (such as a timer or an Arduino) for sending transmissions at regular intervals. To send the module’s audio signal to a radio transmitter such as a VHF radio on FM mode or an HF radio on SSB, connect the speaker out to the microphone line input of the radio. This module can be used to send repeated transmissions such as station IDs or for calling a CQ.

ISD1820 is sound recorder and playback module

To view all posts about amateur radio, click here.

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


Moon | Sky-Watcher Equinox 100ED

The moon imaged with a 4 in Sky-Watcher Equinox 100ED refractor at 0.65X DIY focal reducer and an ASI 533MC camera. Registering and stacking done in SIRIL.

The moon imaged with a 4-inch telescope and an astronomy camera

For a complete list of astrophoto images, click here.

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 attached 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.

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

Veil Nebula

Veil Nebula in the constellation Cygnus imaged with an 80-210 mm Tamron telephoto lens set at 210 mm f/5.6, an ASI 533MC cooled astronomy camera, dual band H-alpha and O-III filter, with an ASI 174MM guide camera on a 30 mm f/4 guide scope. I used the StarNet++ to reduce the stars and highlight the nebula.

Veil Nebula, 1 hour exposure

Related link:
OnStep DIY Go-to Telescope Controller

For a complete list of astrophoto images, click here.

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

Lagoon and Trifid Nebula

Lagoon M8 and Trifid Nebula M20 imaged with an 80-210 mm Tamron telephoto lens set at 210 mm f/5.6, an ASI 533MC cooled astronomy camera, dual band H-alpha and O-III filter, with an ASI 174MM guide camera on a 30 mm f/4 guide scope. This photo was imaged and tracked using a DIY go-to telescope controller.

Lagoon and Trifid Nebula, 2 hours exposure

Related link:
OnStep DIY Go-to Telescope Controller

For a complete list of astrophoto images, click here.

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