How to See Comets With A Telescope?
Comets are a mixture of ice, frozen gasses, dust, and rocks. Scientists think that comets are the debris from materials that formed the solar system initially around 4.6 billion years ago. Comets follow elliptical orbits around the sun. The more it gets closer to the sun, the faster it is pulled in. Some comets fall into the sun and others break up before they reach the sun. Comets are heated up by the sun which makes the volatile materials into the nucleus spout and escape away from the sun.. This makes the signature appearance of the comets a glowing coma with a tail of dust and gas. This tail can stretch over 1 million kilometers out in space.
What are Comets?
Comets are frozen leftovers from the formation of the solar system composed of dust, rock, and ices. They range from a few miles to tens of miles wide. When a comet’s orbit brings it close to the Sun, it heats up and spews dust and gases into a giant glowing head larger than most planets, forming a tail that stretches away from the Sun for millions of miles. There are likely billions of comets orbiting our Sun in the Kuiper Belt and even more distant Oort Cloud. The current number of known comets is about 3,910.
How far are Comets from planet Earth?
The distance between comets and Earth can greatly affect their visibility and brightness. The average distance between comets and Earth can range from 50 million kilometers to 6 astronomical units. The distance from Earth affects the brightness of comets, with closer comets appearing brighter due to the heat causing vaporization of ice in the nucleus. The distance of the comet from Earth can also play a role in its brightness, as seen with Halley’s Comet and Comet Hale-Bopp, which were both exceptionally bright due to their close proximity to Earth during their respective apparitions.
Can you see Comets with a telescope?
Yes, a small telescope will show the brighter comets very well, because the wide field of view is advantageous. As long as they have a high enough surface brightness and are not very faint, from a dark area there should be at least one comet you can see with a small telescope at any one time. The distinguishing features of comets that make them visible through a telescope include their long orbital periods, origin from the Oort Cloud, hyperbolic orbits, comet nucleus composition, and outgassing creating a glowing coma and tail. The size of a comet can affect its visibility through a telescope by influencing its apparent magnitude, overall brightness, and the amount of gas and dust it releases. The ideal focal length for viewing comets with a telescope can vary depending on the specific comet and the level of detail you want to see. The best telescopes for viewing comets are typically at least 5 inches (125 mm) aperture and 1250 mm focal length or more. The recommended magnification for viewing comets with a telescope is around 50x per inch of aperture, with a maximum usable magnification of 200x for a 4-inch telescope. The larger the comet’s nucleus, the more light it can gather and the brighter it will appear through a telescope. This dust, along with gas, forms the comet’s tail, which can be seen through a telescope. The role of aperture in determining the visibility of comets through a telescope is to limit the cone of light that enters the system, thus affecting the brightness and resolution of the image. The visibility of a comet through a telescope can also depend on its distance from Earth. The closer the comet is to Earth, the brighter and more detailed it will appear.
Quick Guide to Observe Comets
Get the position and time of a comet’s appearance using a star chart. Move the scope slowly in search of a bright, spherical, fuzzy object. Higher magnifications can be tried because they occasionally make the comet appear. Limit the amount of light to no more than one-fourth of the viewing area. Otherwise, it will be challenging to find. Start with an eyepiece with a 50x magnification. Traditional wide-bandwidth deep-space filter (Baader UHC-S): If there is a lot of light pollution, which makes it harder to see the comets, this method still works.
Before starting make sure to choose a star app.
Use a star chart to get the location and time a comet will appear. There are several star apps like Stellarium available online.
How to find Comets in the sky?
- Gently move the scope and look for a bright round fuzzy object.
- You can try higher magnifications as sometimes it helps the comet to appear.
- Do not spread the light over more than ¼ of the field of view. Otherwise, it will become hard to detect.
What is the best time to observe Comets?
The table below shows what comets are visible in December 2022 and January 2023. You can visit comet calendars online to find out more information about it.
| December 2022 | |||
| Comet | Magnitude | Highest Altitude | Best Seen |
| C/ 2022 E3 (ZTF) | 9 | 21 | Evening |
| C/ 2022 P1 (NEOWISE) | 10 | 12 | Evening |
| C/ 2020 V2 (ZTF) | 10 | 17 | Evening |
| C/ 2020 K1 (PanSTARRS) | 12 | 18 | Evening |
| C/ 2021 Y1 (ATLAS) | 12 | 12 | Evening |
| 73P/ Schwassmann- Wachmann 3 | 13 | 19 | Evening |
| 118P/ Shoemaker- Levy 4 | 11 | 28 | Midnight |
| C/2021 Y1 (ATLAS) | 12 | 77 | Midnight |
| 29P/ Schwassmann- Wachmann 1 | 13 | 58 | Midnight |
| January 2023 | |||
| Comet | Magnitude | Highest Altitude | Best Seen |
| C/ 2022 E3 (ZTF) | 9 | 2 | Evening |
| C/ 2020 V2 (ZTF) | 9 | 44 | Evening |
| C/ 2022 P1 (NEOWISE) | 10 | 2 | Evening |
| C/ 2021 Y1 (ATLAS) | 12 | 57 | Evening |
| 29P/ Schwassmann- Wachmann 1 | 13 | 22 | Evening |
| C/ 2022 U2 (ATLAS) | 13 | 41 | Evening |
| 118P/ Shoemaker- Levy 4 | 11 | 50 | Midnight |
| C/ 2019 L3 (ATLAS) | 11 | 9 | Midnight |
| C/ 2022 A2 (PanSTARRS) | 12 | 2 | Midnight |
| 29P/ Schwassmann- Wachmann 1 | 13 | 84 | Midnight |
| C/ 2021 Y1 (ATLAS) | 12 | 66 | Midnight |
| C/ 2022 U2 (ATLAS) | 13 | 24 | Midnight |
| C/ 2021 E3 (ZTF) | 13 | 1 | Midnight |
3 Tips to observe Comets in the best way.
- Clear dark sky is a must to see comets.
- The new moon phase is the best time to observe comets.
- You can use various filters to get a sharp image.
What Comets can you see with a telescope?
- 19P/BORRELLY: The closest approach to the earth of this comet will be on 11 December 2022.
- ATLAS (C/ 2019 L 3 ) , a small bright comet will appear near Gemini this winter and remains visible throughout this spring.
- LEMMON-PANSTARRS (C/2021 F1): It will appear on Feb. 12, 2022, and remain visible only for a week before it is lost in the sun’s glare.
- COMET ATLAS (C/ 2019 L3) and 104P/KOWAL: They will both appear in the same part of the sky from the end of March till early April.
- COMET PANSTARRS (C/ 2017 K2)
- 29P/SCHWASSMANN- WACHMANN
- COMET PANSTARRS (C/ 2021 O3)
- COMET ZTF (C/2021 E3)
- 73P/SCHWASSMANN- WACHMANN
- COMET ATLAS (C/ 2021 P4)
- COMET ZTF (C/ 2022 E3)
What telescope to see Comets?
Celestron 114AZ-SR, Orion SkyScanner 100mm Tabletop, and Orion StarBlast II 4.5 EQ are great telescopes to see Comets. A list of telescopes to see Comets has more telescope options that can see Comets very clearly.
What size telescope to see Comets?
The comets have much less limiting magnitude than the stars. For example, 13.8 magnitude stars are easily visible with a 6-inch telescope whereas you can not see a comet fainter than 12 magnitudes. This table describes the limiting magnitude for comets in different aperture telescopes:
| Aperture (inches) | Mag Limit |
| 6 | 12 |
| 8 | 12.6 |
| 10 | 13.1 |
| 12 | 13.6 |
| 16 | 14.1 |
| 18 | 14.4 |
| 20 | 14.6 |
| 24 | 15.0 |
What magnification is required to see Comets?
Higher magnification with smaller focal length will provide more contrast as the sky background becomes darker that makes it easier to find objects. You can start with a 50x magnification eyepiece. If needed you can increase the magnification later. 135x is best for most comets and sometimes 200x magnification makes some comets easy to detect and observe.
What Filters are recommended to see Comets?
- Classic broadband Deep Sky Filter (Baader UHC-S): This works if there is a lot of light pollution that makes the view of the comets fainter.
- The Swan Band filter enhances the contrast of gas-rich comets. It darkens the sky and increases coma diameter and makes it more visible.
- Moon & Skyglow filters like Baader neodymium filters with UV/IR blocker works better to decrease the moon glow on moonlit nights. However, the Baader Semi-APO filter performs better than the previous one.
- Baader FringeKiller filter suppresses the blue atmospheric glow. At the same time, it maintains full transmission for OIII and Cyan which is necessary for gas tails.
Enjoying Comets? Here are other things to see with your telescope.
Comets are wonderful to see with a telescope. There are many other objects that you can see with the same telescope. The planets of the solar systems with their moons appear with amazing views in the telescopes. Viewing a Nebula Through A Telescope can guide you to see colorful nebulae in the sky. There are also galaxies, star clusters, and myriads of stars to view. List of things to see with a telescope provides a shortlist of the night sky objects that you can observe with your telescope.
