Sun | September 2021

I have two new cameras I’d like to test with solar imaging, the ASI 533MC color camera and the ASI 174MM monochrome camera. Today, I tried using both to image the Sun, and while I am impressed with the ASI 174MM’s capture speed, sensitivity, and resolution, I can’t seem to remove the very subtle banding artifact in ASI 174MM. While I am learning how to use the ASI 174MM, I will be using the ASI 533MM as my main solar imaging camera.

Sun imaged with a 4 inch f/5.65 refractor, a Baader ND 5.0 solar filter, UV-IR cut filter, and an ASI 533 camera. Active regions AR2871 (lower center), AR2872 (center left), and AR 2873 (upper right) are visible in this image.

For a complete list of astrophoto images, click here.

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

M42 Orion Nebula| September 2021

The M42 Orion Nebula is now visible in the early morning hours. While the sky is still generally cloudy in the Philippines in September, the Orion nebula is bright enough to be captured through thin cirrus clouds, even with the moon at 97% illumination.

M42 Orion Nebula imaged with a 4 inch f/9 refractor with 0.63X DIY focal reducer (now at f/5.65), a UV-IR filter, and an ASI 533 astronomy camera

For a complete list of astrophoto images, click here.

Related link: Eastern Veil Nebula

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

Moon | September 2021

After having recently modified my telescope by installing a DIY 0.63x focal reducer, which involves cutting the optical tube assembly and reattaching the focuser, I took a test shot with the moon to determine if the optical elements are properly aligned (collimated) and whether or not the reducer lens introduces color (chromatic) aberration. The image appears sharp, and I did not notice any chromatic aberration (no chromatic aberration reduction applied on this image, not even RGB alignment). To further check proper collimation, I will need to perform a star test soon.

Moon | September 2021

For a complete list of astrophoto images, click here.

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

Horsehead Nebula| September 2021

The Horsehead Nebula (IC 434) imaged in September 2021 with a Sky-Watcher Equinox 100ED, ZWO duo nebula filter, and an ASI 533 astronomy camera at 565 mm focal length (using a 0.63x DIY focal reducer, guided with a DIY off-axis guider (OAG) and an ASI 174MM guide camera. A total of 20 minutes exposure stacked and processed in SIRIL without calibration frames.

The Horsehead Nebula in Orion

For a complete list of astrophoto images, click here.

Related link: Eastern Veil Nebula

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

Helix Nebula | September 2021

Helix Nebula imaged in September 2021 with a Sky-Watcher Equinox 100ED, ZWO duo nebula filter, and an ASI 533 astronomy camera at 565 mm focal length (using a 0.63x DIY focal reducer, guided with a DIY off-axis guider (OAG) and an ASI 174MM guide camera. A total of 38 minutes exposure stacked and processed in SIRIL without calibration frames.

Helix Nebula, a planetary nebula in Aquarius

For a complete list of astrophoto images, click here.

Related link: Eastern Veil Nebula

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

Eastern Veil Nebula | September 2021

First light image of a DIY off-axis guider OAG fitted to a Sky-Watcher Equinox 100ED using an ASI 174MM as a guide camera, imaging at 565 mm focal length (0.63x DIY focal reducer). This image was taken in September 2021 with an ASI 533 cooled astronomy camera and a ZWO duo nebula filter, for a total of 2.4 hours. Stacked and processed in SIRIL without calibration frames.

The Eastern Veil Nebula (Caldwell 33), a supernova remnant in Cygnus

For a complete list of astrophoto images, click here.

Related link: Western Veil Nebula

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

Transit of Europa, Ganymede, and Callisto| August 2021

When you look at Jupiter through a telescope, you usually see four moons lined up with the planet. From time to time, a moon may pass in front of Jupiter’s disc in an event called a transit. A transit is a rare event since it occurs only when at least one moon lines up with Earth and Jupiter. On August 15, 2021, however, three of Jupiter’s four largest moons—Europa, Ganymede, and Callisto—passed in front of Jupiter, a very rare event which I have observed and captured using a small telescope.

Three of Jupiter’s four largest moons passed in front of Jupiter on August 15, 2021 (Legend: 1-Europa, 2-Europa’s shadow, 3-Ganymede, 4-Ganymede’s shadow, 5-Callisto, 6-Io). Image taken with a 4 inch f/9 refractor and an ASI533 camera, Philippines.

Related link: View all posts about transit
For a complete list of astrophoto images, click here.

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

Clavius Crater | August 2021

Clavius crater imaged with a Sky-Watcher 4 in f/9 refractor, 25 mm eyepiece, and an ASI 533 camera. Registering and stacking done in SIRIL.

Clavius crater 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 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.

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.

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

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

Western Veil Nebula | September 2021

First light image of a DIY 0.63x focal reducer fitted to a Sky-Watcher Equinox 100ED. This image was taken in September 2021 with an ASI 533 cooled astronomy camera and a ZWO duo nebula filter, for a total of 14 minutes, tracked and unguided. Stacked and processed in SIRIL without calibration frames.

The Western Veil Nebula in Cygnus, a supernova remnant


For a complete list of astrophoto images, click here.

Related link: Veil Nebula (wide-field)

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.

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.

I had to shorten the optical tube by about 200 mm to reach focus, and then reattach the focuser. To see how long the telescope is prior to the modification, click here. 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 moved 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.

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

Related link:
Sky-Watcher Equinox 100ED (100 mm f/9 )
Vixen Achromat (80 mm f/11)

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.

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. The critical component in this DIY is a high-quality mirror, which 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 (webcam) in or out to achieve focus.

I have tested the off-axis guider to work with the SPC900NC web camera, Kenko NES mount, Sky-Watcher Equinox 100ED, and an ASI 533, with best guiding performance at 0.33″ (arcseconds) at 900 mm focal length. I tried using the ASI 533 as a guide camera and found out that the mirror fully illuminates the full width of the sensor, which means a dedicated OAG camera with large sensor (such as those using the Sony IMX 174 sensor) should be fully-illuminated as well.

To watch a video showing this DIY off-axis guider, click here. To view posts on DIY projects and astronomical equipment, click here.

Related link: Kenko NES Mount

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

Copernicus and Montes Apenninus | August 2021

Copernicus crater and the Montes Apenninus mountain range imaged with a Sky-Watcher 4 in f/9 refractor, 25 mm eyepiece, and an ASI 533 camera.

Copernicus crater and the Montes Apenninus imaged with a 4 inch f/9 refractor

For a complete list of astrophoto images, click here.

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.

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.

To watch a demo video about this DIY declination motor project, click here. To view posts on DIY projects and astronomical equipment, click here.

Related link: DIY Telescope Controller

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

Jupiter Opposition |2021

The best time to image and observe Jupiter (and Saturn or any other outer planet) is during opposition, when the planet, as viewed from Earth, is opposite the Sun (as the Sun sets in the west, the planet rises in the east), hence, the term opposition. Two conditions favorable to imaging happen during opposition: (1) Jupiter and Earth will be at their closest point in their orbits around the Sun, thus, making the planet appear largest when observed from Earth, and (2) Since the Sun is opposite Jupiter as viewed from the Earth, the planet is well-illuminated, thus, faster exposures can be taken resulting to sharper images. The Jupiter photo below was taken on August 7, two weeks before the 2021 opposition.

Jupiter imaged during the August 2021 opposition with a 4 inch f/9 refractor, 4x Barlow, and an ASI 533 camera. One of its large moon, Io, the cloud bands, and the Great Red Spot, are visible in this photo. Image processing done in SIRIL.

August is particularly rainy (and stormy) in the Philippines, and we seldom get treated with clear skies at this month.

For a complete list of astrophoto images, click here.

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

Saturn | Eyepiece Projection

In eyepiece projection, an image is projected onto the camera’s sensor using an eyepiece. In this Saturn photo, I used a 4 in f/9 refractor and a 25 mm eyepiece to project an image onto the sensor of ASI 533 astronomy camera. The magnification of the image depends on the focal length of the telescope, the focal length of the eyepiece, and separation between the eyepiece and the camera’s sensor. While longer telescopes, higher-power eyepieces, and wider separation between the eyepiece and the camera will produce more magnified images, the amount of detail that can be resolved will still depend on the aperture or the diameter of the telescope’s objective mirror or lens.

Saturn imaged through eyepiece projection during the August 2021 opposition with a 4 inch f/9 refractor, a 25 mm eyepiece, and an ASI 533 camera. Image processing done in SIRIL.

For a complete list of astrophoto images, click here.

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

Transit of Io | August 2021

The Galilean moons may sometimes cross the disc of Jupiter as viewed from the Earth in an event called a transit. This image of the moon Io transiting Jupiter was taken on August 8, 2021, from Bacoor, Cavite, using a 4-inch f/9 refracting telescope and an ASI 533 astronomy camera.

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For a complete list of astrophoto images, click here.

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

Moon | July 2021

This is probably my sharpest moon capture to date, taken with a ZWO ASI 533 camera and Sky-Watcher 100ED 4 inch f/9 refractor. This is a stack of 800 frames from a 25-second video, which I had to cut short since the file size is already 6 gig! Registered and stacked in SIRIL.

Moon imaged with an ASI 533 and a 4 inch f/9 refractor

For a complete list of astrophoto images, click here.

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.

Each counterweight measures 145 mm by 16 mm, and fabricated from unused plates I’ve found in a local metals supply shop.

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

Related links:
DIY Counterweights
Kenko NES Mount

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

DIY Electronic Microfocuser

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.

The focuser is ASCOM compliant and works with astronomy software such as the Nighttime Imaging N Astronomy (NINA) for automated focusing during unattended imaging. It runs on the firmware developed by R. Brown (2021). The modification should work with any lens with built in electronic focusers. To watch a demo video about this microfocuser project, click here.

To view posts on DIY projects and astronomical equipment, click here. To get a copy of the sketch, please email eteny@nightskyinfocus.com.

Related link: DIY Electronic Automatic Focuser for Telescopes

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