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.

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

DIY SARCNET Satellite Tracker

I have built a DIY satellite tracker based on the SARCNET project. It is a simple Arduino-based motorized azimuth and elevation rotator that uses DC motors to move the antenna, and gets position feedback using an accelerometer and compass.

The tracker receives satellite’s azimuth and elevation info using the tracking software Gpredict. Hamlib is then used to establish a link between the computer and Arduino through USB connection via EasyComm II protocol.

To view all posts about amateur radio, click here.

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

DIY Flat Field Panel

I’ve built a DIY dedicated flat field panel using a repurposed LED light fixture. The flat field panel is a light source with relatively uniform brightness. The panel attaches directly onto my telescope and can be used for taking flat frames.

DIY LED fixture for taking flat frames

If a telescope with camera captures a target that is known to have a uniform brightness or illumination (such as this DIY flat field panel), the unevenness in the illumination of the field such as vignetting or presence of dusts are revealed. When a flat frame is applied to an image, any variation in brightness or illumination across the frame is leveled out, thus, vignetting and dusts are removed in the image.

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© Anthony Urbano | Manila, Philippines

Cleaning Telescope Lenses or Mirror

To clean the telescope’s lens or mirror, disassemble the lens or the mirror from the cell, making sure to mark the sides of the glass elements as it is necessary to reassemble them following the correct orientation as determined by the factory. In this video, I used my Sky-Watcher 100ED as an example. Follow these instructions at your own risk and exercise outmost care when cleaning telescope lenses.

Related link: View all home-brewed DIY astronomy equipment

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© 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. It runs on the firmware developed by R. Brown (2021).

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 link: View all home-brewed DIY astronomy equipment

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© 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

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© Anthony Urbano | Manila, Philippines

DIY Shutter Switch | Canon 50D

I’ve built a remote shutter switch for my Canon 50D to enable it to take exposures longer than 30 seconds, which is essential in astrophotography. Since the camera already has a battery grip, I just bypassed the battery grip’s shutter button and put an external switch. To make it removable, I used a wire that plugs into a socket hidden neatly in the battery compartment.

DIY remote shutter switch for Canon 50D

Related link: View all home-brewed DIY astronomy equipment

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© Anthony Urbano | Manila, Philippines

DIY Straight Key and Dual-Paddle with Iambic Keyer

I have built a Morse code straight key and iambic keyer for Morse code communications.

The straight key was made from brass bars, some bearings, and screw. It was then mounted on the same aluminum plate with my home-brewed electronic keyer with paddles and desk microphone.

Home-brewed straight key and dual-paddle with an iambic keyer

The keyer uses an Arduino Uno and a few components such as a potentiometer for adjusting the words per minute (WPM), a small speaker, some resistors, and LED indicators.

To view all posts about amateur radio, click here.

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

DIY Planetary Camera

By attaching a webcam or a dash cam to a telescope using a special type of adapter, it is possible to take up-close photos of planets.

Web Camera

Replace the webcam’s lens by a special type of adapter called a webcam-to-telescope adapter. Insert the webcam with an adapter into the eyepiece barrel of the telescope’s focuser.

Dash Camera


I repurposed my old dash camera as a planetary camera. The lens was removed and replaced with a webcam-to-telescope adapter and then mounted on to a telescope.

Related link: View posts on camera modification projects

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

DIY Satellite Antenna DU1AU

A satellite antenna can be made from 3 mm copper or aluminum elements, PVC boom, and some parts you may already have at home. This antenna has been tested to work with the Philippine Oscar (PO)-101 satellite Diwata 2.

DIY Satellite Antenna

To view all posts about amateur radio, click here.

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

DIY SATNOGS Satellite Tracker

I’ve recently finished building a satellite traker based on SATNOGS satellite tracker. The automated tracker uses an Arduino to control a pair of stepper motors that move two cross-yagi antennas (VHF and UHF).

DIY SATNOGS satellite tracker

The Arduino receives satellite’s azimuth and elevation info using the tracking software Gpredict. Hamlib is then used to establish a link between the computer and Arduino through USB connection via EasyComm III protocol. The tracker uses two A4988 stepper motor driver, and two geared stepper motors. A weatherproof metal box is used as a case, and rubber seals prevent water from entering.

To view all posts about amateur radio, click here.

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

DIY Portable Satellite Radio Setup

This battery-operated radio setup can be easily carried to any remote location. Connect a satellite antenna, turn the radio on,  select the pre-programmed uplink and downlink frequencies, and you are ready to make contact!

A portable satellite radio setup

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

DIY Arduino TNC

I have finished building and testing a DIY Terminal Node Controller (TNC). With a TNC, any radio may encode and decode signals in the Automatic Packet Reporting System (APRS) format. This TNC is based on the home-brewed TNC project by VK3DAN.

Arduino-based TNC

The TNC requires a smart phone with APRSdroid connected via bluetooth. It taps directly to a radio through the dedicated audio line-in and line-out ports. I’ve tested this TNC to work with the International Space Station’s (ISS) digipeater at 145.825 MHz, using the digipath: ARISS.

To view all posts about amateur radio, click here.

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

DIY DSLR Filter Modification

I have performed filter modifications on a number of DSLR cameras (Canon 450D, 700D, 1200D, 500D, 1000D, 1100D, Nikon D3100, and Fuji X-A1) for me and my colleagues. It involves the removal of the stock UV-IR filter, making the camera more sensitive to H-alpha wavelengths. This modification is helpful only when shooting targets with H-alpha emissions, as most DSLR camera’s standard (stock) filter blocks this part of the spectrum.

Take note of the shift in white balance (reddish hue), which is to be expected in this type of modification. Focus will be affected, your camera may no longer focus with compatible lenses unless you add a filter between the lens and the sensor, to address the shift in focus and to filter out UV-IR. If used with telescopes, you need a DSLR-to-telescope adapter and achieve focus using the telescope’s focuser.

Daytime images before and after the filter modification

Here are sample images taken with the cameras I have modified (posted with permission).

Horse head and Flame Nebula by Kennerton Agresor, 1.5 hours exposure, imaged with a modified Canon 700D, SVBONY 70ED, 0.8X reducer-flattener, tracked and guided with Sky-Watcher AZGTi and ASI120mm mini with ZWO 30mm f/4 guide camera
Rosette Nebula by Kennerton Agresor, 1.5 hours exposure, imaged with a modified Canon 700D, SVBONY 70ED, 0.8X reducer-flattener, tracked and guided with Sky-Watcher AZGTi and ASI120mm mini with ZWO 30mm f/4 guide camera
Orion Wide-Field by Luis Angelo Rafael imaged with a modified Canon 1200D and Samyang 135mm at f/4, tracked with EQ mount with a Celestron RA Drive
Orion Nebula by Pierre Paulo Sebastian imaged with a Canon 500D and a 3M-6A 500 mm lens, total 6.9 hours exposure
Trifid and Lagoon Nebula by Pierre Paulo Sebastian imaged with a Fuji X-A1 and a Tair 3s 300mm lens, 1.8 hours exposure
Orion Nebula by Anthony Guiller Urbano imaged with a modified Canon 450D and Sky-Watcher Equinox 100ED f/9, tracked with a Kenko NES mount, 1 hour exposure

If you are interested in this kind of camera modification (Philippines only), send an email to du1au@nightskyinfocus.com.

Related link: View all home-brewed DIY astronomy equipment

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© Anthony Urbano | Manila, Philippines

DIY Guide Scope Rings

Guide scope rings or guide rings are mechanisms used for mounting guide scopes. A guide scope is a telescope used to monitor tracking accuracy while a main telescope takes a long-exposure photo. Errors in tracking are detected with a guide scope by monitoring a guide star. Corrections are made by the mount to keep the guide star centered, and thus, keeping the main imaging telescope pointed at a target for the whole duration of an exposure.

DIY guide scope rings

This DIY guide scope rings set is used with a 60 mm f/5 guide scope and a 114 mm f/8 imaging telescope.

Related link: View all home-brewed DIY astronomy equipment

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

DIY Smartphone-to-Telescope Adapter

Smartphones can be used to image the moon by holding it next to the eyepiece of a telescope. For smart phone cameras, a mid-power eyepiece such as a 25 mm eyepiece yields good results. To hold the phone camera steady while taking a photo, a smartphone-to-telescope adapter may be used.

This imaging method is called afocal imaging, in which a camera with its lens is mounted next to another image-forming optical system such as a telescope or a pair of binoculars.

DIY Smartphone-to-Telescope Adapter

Related link: View all home-brewed DIY astronomy equipment

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© Anthony Urbano | Manila, Philippines

DIY Dew Heater

Dew heaters or heater pads are telescopes accessories used to prevent dew from forming on the telescope’s lens. During long imaging sessions, it is not uncommon for the main lens of refractors and SCTs to form dew. A heater is used to keep the objective lens at a temperature a few degrees C above the dew point to prevent the formation of dew.

I used nichrome wires from a local electronics store to build several DIY heater pads for my telescope, which I find useful in keeping the lenses free from dew especially when imaging in remote observing sites.

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

DIY Plate for Telescopes

I’ve built an aluminum plate for my equatorial mount to allow it to carry the main telescope and the guide scope for autoguiding purposes. In autoguiding, it is important to minimize flexing between the imaging telescope and the guide scope, thus, a plate with suitable thickness helps address this problem. This DIY plate measures 12 cm by 20 cm by 1 cm and made from a solid aluminum plate from a local metals supply shop. Holes have been drilled on the plate to allow attachment of various loads such as DSLR cameras and different telescopes.

Kenko NES mount with a DIY aluminum plate

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

Related link: Sky-Watcher 100ED Refractor

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

Peltier-Cooled DSLR Project

During an exposure, the imaging sensor of a DSLR warms up, resulting to noisy images. By cooling down the sensor, it is possible to eliminate or somehow minimize this thermal noise.

Cooling the camera’s sensor using a Peltier module

I have made a number of attempts to accomplish this with a Canon 450D and a Peltier module, however, it appears it is very difficult to implement without running into problems such as condensation and frosting.

M42 imaged with a Peltier-cooled filter-modified Canon 450D. No dark frames were used in this image. Image processed in SIRIL. The DSLR’s stock filter was replaced with a Baader UV-IR blocking filter.

Related link: View all home-brewed DIY astronomy equipment

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

DIY Logitech 4000 Guide Camera

The Logitech 4000 webcam is capable of imaging planets and can be modified to take long exposure images to serve as a guide camera. The modification requires a serial port to externally control the camera’s exposure time using a guiding software such as GuideMaster and PHD Guiding.

Modified Logitech 4000 Guide Camera

The long- exposure modification allows the camera to detect faint guide stars, which is a useful feature for a guide camera. The diagram shown here was a modified version of M. Burri’s (2002) parallel port interface for a Logitech 3000 which I have adapted to work with the newer Logitech 4000 and a serial port.

Related link: View all home-brewed DIY astronomy equipment

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