Zenithstar 73 APO
NOTE: 2" Rotolock and Guide scope showed on pictures are optional accessories.
ZenithStar 73 f=430mm
F/5.9 FPL53 doublet APO
Weight :2.5kg (5.5lb.)
2.5” R&P Focuser
OTA Package includes:
Vixen style Dovetail
Soft carry case $39
Flat73 1:1 Full frame flattener
2” Rotolock with M63 threads
50mm F/4 Rotolock Guiding scope
48mm T mount for Nikon or Canon
Free Shipping Worldwide
Frequently Asked Questions
Flattener or reducer: A flattener or reducer helps to correct for spherical aberrations in corners and reduce the focal length of the telescope for faster imaging. T-mount: A T-mount attaches to the camera body and allows you to connect the camera to the telescope. Camera: For astrophotography, you can use either a DSLR camera or a dedicated CCD camera. DSLR cameras are versatile and widely used for beginner astrophotographers, while CCD image sensor provide better sensitivity and image quality for more advanced users.
Here are the general steps to set up your William Optics refractor telescope for imaging without a photo adapter:
Set up your telescope as you would for visual observing, but make sure to attach the flattener or reducer to the focuser instead of an eyepiece. Attach the T-mount to the camera body. Connect the camera to the telescope by attaching the T-mount to the flattener or reducer. Adjust the focus of the telescope by using a Bahtinov mask or other focusing aid until the image appears sharp on the camera's live view screen. Take test shots of a bright star to check for any aberrations or distortion in the image. Adjust the position of the flattener or reducer and the focus as needed to correct any issues. With these steps, you should be able to set up your William Optics refractor telescope for imaging and start taking beautiful astrophotographs!
There are many accessories available that can enhance your viewing experience with a refractor
telescope. Here are a few of the most common ones:
1. Eyepieces: Eyepieces are the most basic accessory for a telescope, and they can greatly impact the magnification, field of view, and image quality. Investing in a variety of eyepieces with different focal lengths can give you more flexibility and control over the image you see.
2. Barlow lens: A Barlow lens is a type of magnifying lens that can increase the magnification of your telescope without requiring a longer focal length eyepiece. It can also reduce the impact of aberrations and distortion in the image.
3. Filters: Filters can be used to enhance or modify the colors and details in your images. For example, a moon filter can reduce the glare and brightness of the moon, while a nebula filter can enhance the details of gas clouds in deep space.
4. Finderscope: A finderscope is a small, low-power telescope that is attached to your main telescope and used
to help you locate and center objects in the sky more easily.
5. Guidingscope: A guiding scope is an accessory for telescopes that is used for astrophotography. It is a small telescope that is mounted parallel to the main telescope and is used to track and guide the telescope's movement during long-exposure imaging.
When taking long-exposure images of celestial objects, the Earth's rotation can cause the object to move across the field of view, resulting in a blurred or elongated image. To counteract this, the guiding scope is used to monitor the object's movement and send signals to the mount to make small adjustments to keep the object centered in the frame.
The guiding scope is usually a small refractor telescope with a short focal length and a wide field of view. It is often paired with a guide camera, which captures images of the object and sends them to the guiding software for analysis and tracking.
While a guiding scope is not necessary for all types of astrophotography, it can greatly improve the quality of
long-exposure images, allowing you to capture more detail and clarity in your photos.
6. Mount and tripod: A stable and sturdy mount and tripod are essential for a good viewing experience, as they can help reduce vibrations and keep your telescope steady.
7. Telescope cases: Cases and covers can help protect your telescope from dust, dirt, and other environmental factors when not in use.
8. Red light flashlight: A red light flashlight is useful for navigating in the dark without disrupting your
eyes' ability to adjust to the darkness.
These are just a few of the many accessories available for refractor telescopes. Choosing the right accessories depends on your individual needs and preferences, as well as the type of observing you plan to do.
There are several CCD cameras that can be used with a William Optics refractor telescope, and the choice will depend on your specific imaging needs and budget. Here are a few options:
-ZWO ASI series CCD cameras: ZWO ASI series cameras are popular among astrophotographers and are known for
their sensitivity and low noise. These cameras come in a range of resolutions and sizes to suit different
-QHY CCD cameras: QHY CCD cameras are also widely used by astrophotographers and offer good sensitivity and low noise. They come in a variety of sizes and resolutions.
-SBIG STF series CCD cameras: SBIG STF series cameras are designed specifically for astrophotography and offer high sensitivity and low noise. They come in a range of resolutions and sizes.
-Atik CCD cameras: Atik CCD cameras are known for their excellent image quality and low noise. They come in a variety of sizes and resolutions to suit different telescopes.
When selecting a CCD camera for your William Optics refractor telescope, it's important to consider factors such as resolution, sensitivity, and noise performance. Additionally, make sure that the camera is compatible with your telescope's focal length and has the appropriate back focus distance.
Here are the general steps to align your telescope:
Set up your telescope on a level surface and make sure your mount is polar aligned.
Find a bright star or planet that you can see with your naked eye and center it in your telescope's field of view. You can use a star chart or a mobile app to help you identify celestial objects.
Use a low-power eyepiece to locate the object and center it in the field of view.
Adjust the focus until the object appears sharp and clear.
If neccessary use the telescope's slow-motion controls to keep the object in the field of view.
If your telescope has a motorized mount, turn on the motor and use the hand controller to adjust the telescope's movement to track the object.
Once you have the object centered in your telescope, you can use its coordinates to locate other objects. For example, if you want to observe a specific deep-sky object, you can use its right ascension and declination coordinates to find it.
Repeat these steps for other objects you want to observe.
It may take some practice to get used to aligning your telescope with celestial objects, but with patience and persistence, you will be able to enjoy the beauty of the night sky with your William Optics refractor telescope!
Focusing your refractor telescope using a diagonal and eyepiece is an essential step in obtaining a clear and crisp image of the celestial objects you want to observe. Here are the general steps to focus your telescope:
Insert an eyepiece into the diagonal and insert the diagonal into the telescope's focuser. Make sure the
diagonal is securely in place.
Point your telescope at the object you want to observe. If you're not sure where to point your telescope, you can use a star chart or a mobile app to help you identify celestial objects.
Look through the eyepiece and use the telescope's focus knob to adjust the focus until the image appears sharp and clear.
If necessary, use a focusing aid such as a Bahtinov mask to achieve precise focus. A Bahtinov mask creates a diffraction pattern that helps you adjust the focus until the pattern is symmetrical.
Once you have achieved focus, you can adjust the telescope's magnification by switching to an eyepiece with a different focal length.
Repeat these steps for other objects you want to observe.
It may take some practice to get used to focusing your refractor telescope using a diagonal and eyepiece, but with patience and persistence, you will be able to enjoy the beauty of the night sky with a clear and crisp view.
Cleaning the lens of your William Optics refractor telescope is an important task to ensure that you get the best possible image quality. Here are the general steps to clean the lens of your telescope:
Check the lens surface for any debris or dust. If there is any visible dust or debris, gently brush it off with
a soft-bristled brush or a blower brush.
Use a lens cleaning solution and lens tissue to clean the lens. Apply a small amount of the cleaning solution to the lens tissue and gently wipe the lens in a circular motion, starting from the center and working outward.
If there are any stubborn spots or stains on the lens, you can use a specialized lens cleaning pen or lens cleaning solution to remove them. Follow the manufacturer's instructions carefully when using these products.
Once you have finished cleaning the lens, use a fresh piece of lens tissue to wipe away any excess cleaning solution or moisture.
Repeat these steps for the other lens of the telescope.
It is important to be gentle and careful when cleaning the lens of your William Optics refractor telescope, as any scratches or damage to the lens can significantly impact image quality. With regular and careful cleaning, you can ensure that your telescope continues to provide clear and crisp images of the night sky.
When selecting eyepieces for your William Optics refractor telescope, it's important to consider the telescope's aperture, focal length, and your observing goals. Generally, it is recommended to use high-quality eyepieces that are compatible with the telescope's focal length and provide the desired magnification range.
For William Optics refractor telescopes, which typically have focal ratios between f/5 and f/7, it is recommended to use eyepieces with a focal length between 8mm and 40mm. This will give you a good range of magnifications for observing celestial objects.
Eyepieces with a larger apparent field of view (AFOV) can provide a more immersive observing experience, as they allow you to see a wider area of the sky. Wide-angle eyepieces with AFOVs between 60-80 degrees are ideal for this purpose.
For higher magnifications, you may want to consider using eyepieces with shorter focal lengths, such as 6mm or 4mm. However, be aware that using very short focal length eyepieces can result in a dimmer image and may require higher-quality optics to avoid distortion.
Ultimately, the best eyepiece for your William Optics refractor telescope will depend on your personal preferences and observing goals. It's a good idea to invest in high-quality eyepieces that provide clear and sharp images of the night sky.
To calculate the magnification of your refractor telescope, divide the focal length of the telescope by the focal length of the eyepiece being used.
To maintain your refractor telescope, you should:
-Keep it covered when not in use to protect it from dust and moisture.
-Regularly clean the lens or mirrors with a soft brush or lens cloth to remove dust and debris.
-Store it in a cool and dry place to avoid damage from temperature and humidity changes.
-Check the alignment and collimation of the telescope regularly to ensure optimal performance.
-Avoid touching the lens or mirrors with your fingers as oils and residue can damage the surface.
-Lubricate any moving parts, such as the focuser, as needed with appropriate lubricants.
-Follow the manufacturer's instructions for any specific maintenance or cleaning procedures.
1. Collimation: Make sure that the optics are properly aligned and the collimation is accurate. If the
telescope is not properly collimated, the image will be blurry and stars not round shape (coma
2. Focusing: Achieving proper focus is essential for clear and sharp images. Adjust the focuser slowly to get the best focus.
3. Diagonal and Eyepiece: Use high-quality diagonal and eyepiece that are compatible with your telescope to achieve the best image quality.
4. Barlow lens: Consider using a Barlow lens to increase magnification without sacrificing image quality.
5. Filters: Use filters to improve the contrast and reduce glare, especially when observing bright objects like the Moon and planets.
6. Mount: Use a sturdy mount to reduce vibrations and increase stability, which will result in sharper images.
7. Light pollution: Avoid observing from areas with high light pollution, as it can reduce the image quality.
8. Atmospheric conditions: Wait for good weather conditions, such as clear skies and steady air, to get the best images.
By following these tips, you can improve the image quality of your William Optics refractor telescope and enjoy stunning views of the night sky.
The William Optics refractor telescope is a high-quality instrument that is suitable for observing a wide range of celestial objects. Some of the best objects to view with this telescope include:
Moon: With its high-quality optics and sharp images, the William Optics refractor telescope is ideal for
observing the details of the lunar surface, such as craters, mountains, and valleys.
Planets: The telescope's high-resolution optics make it perfect for observing the planets of our solar system, including Jupiter, Saturn, Mars, and Venus.
Double stars: The telescope's high contrast and sharp focus make it great for observing double stars, which appear as two stars very close to each other in the sky.
Nebulae: The telescope's wide field of view and excellent light gathering ability make it perfect for observing bright nebulae, such as the Orion Nebula and the Lagoon Nebula.
Star clusters: The William Optics refractor telescope is great for observing open and globular star clusters, such as the Pleiades and the Hercules Cluster.
Overall, this telescope is versatile and can be used to observe a wide range of objects in the night sky.
1. Cover the telescope: When storing the William Optics telescope, it is important to protect it from dust and
moisture. Use a dust cover or a soft cloth to cover the telescope and protect it from dust.
2. Store in a dry place: Store the telescope in a dry place to avoid damage from humidity. Moisture can damage the lenses or mirrors and cause mold growth, which can be difficult to remove.
3. Store in a cool place: Store the telescope in a cool place to avoid heat damage. Avoid storing the telescope in a place that is exposed to direct sunlight or high temperatures, such as a car trunk or attic.
4. Disassemble the telescope: If you have to store the telescope for a long time, it is best to disassemble it. Remove the eyepiece, diagonal, and any accessories, and store them separately in a dry and cool place. William Optics telescope comes with a soft carry bag.
5. Store the mount and tripod: If the telescope has a mount and tripod, store them in a dry and cool place as well. Make sure to remove any batteries from the mount to avoid battery leakage.
By following these tips, you can ensure that your William Optics telescope is stored safely and properly when not in use, which will help prolong its lifespan and maintain its performance.