But there’s one other factor that you have to consider: the Earth’s rotation. The Earth is constantly spinning. While it’s difficult to observe this movement with the naked eye, it’s very evident with astrophotography. Exposures longer than 30 seconds or so result in visual distortion like star trails. So, how do astrophotographers overcome the Earth’s spin? They use a telescope guide scope!
What is a Telescope Guide Scope?
To put it simply, a guide scope is a special optical device that’s designed to track your target star. It looks similar to a traditional finder scope. However, finder scopes are meant for manual tracking with the human eye. Guide scopes, on the other hand, work with a camera and computer to track your target automatically.
This process is known as auto-guiding. It’s an essential practice for astrophotographers.
In the early days of astrophotography, this type of technology didn’t exist. So, astronomy buffs had to manually track stars on their own. This involved finding reference stars and nudging the telescope’s mount to reduce image distortion. As you can imagine, this was a difficult process. Not only that, but it was in the imperfect process. Even with seasoned star trackers, images rarely came out as intended.
Guider scopes eliminate a lot of the guesswork. There are other types of guiding devices. But, guider scopes are more efficient and accessible than things like off-axis guiders or dual-chip cameras.
These scopes are very easy to use. They attach directly to the optical tube of your primary telescope. This ensures that the guide scope is always pointing in the same direction as the telescope. Once you connect the scope to an auto guider camera, computer, and star-tracking software, it handles all of the hard work.
Whenever the stars “move,” the guide scope will automatically adjust your equatorial mount to keep your telescope and astrophotography camera lined up.
Is a Guide Scope Necessary?
If you plan on taking highly detailed shots, a guide scope is a must-have.
Simple sub-frame shots won’t require a guide scope. While the Earth is still rotating, its movement is not going to affect a single frame or short exposure. But with long-exposure shots of 30 seconds or more, it’s a different story.
The Earth rotation is constant. Unless you work to accommodate this rotation, your images are going to look like a mess of color and light. The guide scope and accompanying software will track the night sky forward. It makes astrophotography simple enough for even amateur astronomers to try out!
The Best Telescope Guide Scopes Reviewed
The key to getting some amazing shots is to have the right equipment. While the quality of your camera and telescope is going to have a greater impact on the final composition of your photos, none of that is possible without a good guide scope!
We’ve taken the liberty of finding some of the best guide scopes on the market. To complete your setup, we’ve chosen some great brackets, too. Take a look at our top choices below. Don’t forget to check out our buying guide to learn more about choosing the right guide scope.
SVBONY SV165 Mini Guide Scope
The SVBONY SV165 is a flexible imaging scope that works with most modern guiding cameras. It’s a robust optical device with a relatively wide aperture and appropriate focal length. Inside, you’re getting multi-coated optics, too. This helps to provide a crystal-clear image for better data collection.
The scope is made out of milled metal. It’s beautifully crafted and feels sturdy in the hand. But, it only weighs approximately 12 ounces. Thanks to the included bracket rings and dovetail foot, you can easily secure it for distortion-free tracking.
Key Features:
- 30mm aperture
- 120mm focal length
- Multi-coated optics
- Dovetail bracket
- Nylon-tip screws
AVAILABLE ON AMAZON
SVBONY SV106 Guide Scope
Also from SVBONY, this guide scope is a bit more capable than the other. It has an impressively wide aperture, allowing light to pour in. This particular unit is also sporting a helical focuser. It’s similar to what you would see on a microscope or other delicate optical device.
The drawtube housing allows you to physically move the optics for greater eye relief and focus. Despite the moving parts, the system is very stable. There’s even a copper rim to protect the camera and guide.
Key Features:
- 60mm aperture
- 240mm focal length
- Helical focuser
- Copper eyepiece rim
- Dovetail bracket rail
AVAILABLE ON AMAZON
Astromania 50mm Compact Deluxe Finder & Guide Scope Kit
If a standard helical focuser is good, a double focuser is even better! This unit from Astromania has two separate focuser tubes that let you make fine-tuned adjustments. The mechanics all have a set orientation. As a result, you can move the focuser without having to worry about throwing off alignment.
This guide scope is a bit on the heavier side. But, the metal bracket system does a fine job of keeping it stable. It features two rings with multiple thumbscrews to help you get the positioning just right.
Key Features:
- 50mm aperture
- 190mm focal length
- Double helical focuser
- Aluminum housing
- Stable metal bracket
AVAILABLE ON AMAZON
Orion 60mm Multi-Use Guide Scope
This unit from Orion is an excellent addition to your astrophotography setup. It’s designed to work with Orion StarShoot Autoguider models. However, the unit is flexible enough to work with other imaging cameras and telescope accessories, too. You can even attach an illuminated eyepiece or Barlow lens to use it as a standard straight-through finder scope.
The scope has a helical focuser. The focusing system has a fixed orientation to prevent alignment issues with your guide stars. The bracket and mount are stable, too, to prevent unwanted rotation.
Key Features:
- 60mm aperture
- 240mm focal length
- Helical focuser
- Compatible with several eyepieces
- Multi-use design
AVAILABLE ON AMAZON
Astromania Camera Easy Autoguiding Set60
Want a complete kit to start your astrophotography journey? Astromania has you covered. This set includes a full imaging telescope and all the accessories you need to get started. You’re getting the guide scope, a high-resolution CMOS camera, and guiding software.
The guide scope itself is very robust. It has a 60mm aperture to let light pour in. Pair that with the helical focuser and you have a fully capable scope for tracking. The system even comes with a doublet ring bracket for added stability.
Key Features:
- 60mm aperture
- 240mm focal length
- Comes with CMOS camera and software
- Dovetail bracket rail
- Nylon-tip thumbscrews
AVAILABLE ON AMAZON
Solomark F60 60mm Guide Scope
This compact guide scope from SOLOMARK offers precise focusing abilities and a super-bright image. Despite its small size, this unit has a wide aperture. Plus, it has multi-coated optics. Even the inside of the optical tube has a matte finish to reduce reflections as much as possible.
The guide scope is compatible with a wide range of telescopes. It uses a universal saddle design. You can use it with mounts from Celestron, Skywatcher, Vixen, GSO, and more.
Key Features:
- 60mm aperture
- 215mm focal length
- Multi-coated optics
- Anti-reflection finish
- Micro-focuser ring
- Helical focuser
AVAILABLE ON AMAZON
Orion 30mm Ultra-Mini Guide Scope
Looking for a lightweight guide scope you can take anywhere? This model from Orion weighs less than 8 ounces! It’s a sleek scope that’s even more compact than the Orion Mini. You can easily carry with you to your favorite stargazing spot.
Even with its small size, the scope has all the capability you need. There’s a precision helical focuser. It uses a locking thumbscrew to help you maintain focus at all times. The mount is robust, too. Overall, the scope is great for both polar alignment and continual tracking.
Key Features:
- 30mm aperture
- Ultra-compact
- Precision focuser
- Wide compatibility
AVAILABLE ON AMAZON
Orion 13022 Deluxe Mini 50mm Guide Scope
If you need to upgrade your telescope’s focuser, the Orion 13022 is a model worth checking out. This versatile focuser fits onto most units thanks to its dovetail bracket.
The unique thing about this focuser is that it has a helical focuser. Instead of fiddling with distance markers or finicky rack and pinion models, you can simply turn the focuser with your fingertips. The helical design is reminiscent of what you’d encounter on binoculars or a camera, so it’s pretty easy to use even if you don’t have tons of experience.
The Orion focuser works well on its own. However, it’s also compatible with astrophotography accessories. It works best with Orion’s StarShoot AudoGuider, but you can also use it with additional adapters. Either way, it helps you get the perfect shot.
Key Features:
- 50mm aperture
- 1500mm focal length
- Helical focuser
- Versatile setup options
- Dovetail bracket
AVAILABLE ON AMAZON
Orion 8891 Mini 50mm Guide Scope
Here’s another fantastic focuser from Orion. This one is the 8891 model, and it’s much smaller and more compact than some of the alternatives. It’s plenty big enough to give you impressive focal length and a relatively wide objective lens. However, it’s not as bulky as other premium focusers.
This has a couple of advantages. The first is that you can easily take it with you to remote viewing sites. No need to lug around a separate case just to keep it safe! Secondly, the lightweight build ensures that you’re not adding tons of weight to your astrophotography setup. It won’t ruin your dovetail or tip your setup to one side.
But it will help you get some amazing photographs. Like before, this Orion focuser is compatible with a wide range of accessories and mounts.
Key Features:
- 50mm aperture
- 1500mm focal length
- Wide-field optics
- Dovetail bracket
- Compact design
AVAILABLE ON AMAZON
Best Guide Scope Brackets
SVBONY SV116 Guiding Scope Ring Kit for Telescope
Check out this mounting kit from SVBONY. It’s a versatile kit that works with a wide range of different guide scopes. The kit includes a separate mounting rail and two bracket rings.
You can position the rings as needed on the rail. There are several screw holes to accommodate short and long scopes. Even the rings are adjustable. They can fit optical tubes between 43mm and 70mm wides. Use the included thumbscrews to secure the tube. Thanks to the nylon tips, you don’t have to worry about marring up the surface of your scope.
Key Features:
- Fits tubes between 43mm and 70mm wide
- Nylon-tipped screws
- Solid metal construction
- Versatile ring placement
AVAILABLE ON AMAZON
Astromania Universal Quick Release Finder Shoe Base
If you own multiple scopes, you may benefit from a quick-release mount like this one from Astromania. The mount attaches to the optical tube of your telescope. It fits most dovetail feet and secures them into place with two screws. When you want to swap out your guide scope, just unscrew the foot. It’s as easy as that!
The mount uses the Vixen format. Not only is it compatible with Vixen telescopes, but it also works well with models from Celestron, SkyWatcher, GSO, and more.
Key Features:
- Solid aluminum
- Quick-release design
- Vixen mounting format
- Knurled screws
AVAILABLE ON AMAZON
Astromania Adjustable Guiding Scope Rings
This bracket set includes two rings. It doesn’t come with a base or mount. But, the rings are compatible with most dovetail rails and mounting systems. It uses simple screws to attach to a custom mounting rig.
The rings are compatible with a wide range of guide scopes. The screws can secure optical tubes between 48mm and 100mm in diameter. Each screw features a Teflon inlay. The material protects the finish of your guide scope while also improving grip.
Key Features:
- Wide diameter
- Teflon inlays
- Solid metal construction
AVAILABLE ON AMAZON
Guide Scope Buying Guide
Guide scopes are a unique optical accessory. They’re not as widespread as traditional refractor finders. As a result, you’re going to have to dig a bit dip deeper to find accessories that will work for your astrophotography needs. Here are some things to keep in mind as you search.
Wide Aperture
A wide aperture can improve the overall performance of the auto-guider you use with the guide scope. The aperture refers to the diameter of the objective lens. With any optical device, a wider aperture results in more light exposure.
In the world of astronomy, a wide aperture can mean the difference between seeing a target and not. You want your guide scope to let as much light in as possible to the auto-guider can pick up the information it needs.
There’s a fine balance here. A large-diameter guide scope is necessary if you want to track deep-sky objects like nebulae. It can even fare better for relatively nearby targets like planets. But, you don’t want to get a scope that’s so large it becomes taxing on the mount.
Moderate Focal Length
The focal length is the distance between the objective lens of the scope and the focal plane. A longer focal length is going to provide greater magnification.
Like aperture, finding the right focal length is a bit of a balancing act! You need to have adequate magnification so that the auto-guider camera and software can discern those minute movements. But, you also want to maintain a wider field of view. More on that in a bit!
In the past, high magnification was necessary. But today’s tracking software is much more astute. Generally, the rule of thumb is to get a guide scope with a focal length that’s about a fifth of the focal length on your primary telescope.
Short Optical Tube
The focal length and size of the optical tube go hand-in-hand. However, it’s important to aim for a relatively short tube to avoid differential flexure. This is an issue that occurs when the weight of the scope causes it to shift away from the primary telescope.
A lighter and more manageable optical tube will hold steady regardless of how the telescope mount moves.
Wide Field of View
The field of view is another important factor to consider. The guiding software is more accurate when it has more guide stars to pick up. A wider field of view opens up the data field, which can improve the accuracy of the software.
A wider field of view is achieved with a shorter focal ratio. The focal ratio is the relationship between the focal length and aperture. A shorter ratio means a wider field of view and less magnification.
Reliable Focuser
Like any other optical device, a focuser helps to produce a clear image for the viewer. In the case of a guide scope, the focuser will be supporting the camera.
A solidly built focuser is essential, as it prevents sagging or slipping during tracking. There are a few different types of focusers available. You can have a pin-based focuser system or a simple ring on the eyepiece. Whatever the case may be, make sure it’s stable and secure!
Mounting System
Your guide scope needs a mount and bracket to sit on the optical tube of your telescope. Mounting systems can vary from brand to brand. But, most telescopes use a simple dovetail mount.
The key is to choose a bracket that fits into the dovetail mount while also supporting the scope. Ring brackets are the most common. They feature several adjustable screws that you can use to fine-tune the scope’s position.
Using a Telescope Guide Scope
Implementing the guide scope into your astronomy setup isn’t too difficult. We won’t get into the technical weeds here, but the process involves attaching the bracket and mounting it to your telescope.
Before you start working, you need to line the scope up to ensure that it’s pointed at the same spot as your telescope. You can do this manually by using a reference star. However, most auto-guiding software has some kind of alignment feature built-in.
To complete the setup, attach your camera and connect it to your computer. The guide camera may use USB or other similar interfaces. Once everything is ready, you can run your software!
There are several applications available. Some are more feature-rich than others. But all titles should be able to receive and analyze data from the camera and scope.
Conclusion
A guide scope is only one piece of the puzzle. But, it’s an important one! The right guide scope will make it possible for your accompanying auto-guide camera to gather the data it needs. In turn, your software can run efficiently.
The finished results speak for themselves. Guide scopes are a necessity if you want to take breathtaking photos of the cosmos above. Give one of our recommended picks a try. The difference a good guide scope can make will surprise you!