Is it a finderscope or a telescope?
Can it be both?
The SkyWatcher EvoGuide is a stand-alone purchase without accessories because it’s often picked up by users as a replacement for their inferior finderscope.
So, can you use the small aperture scope as a telescope as well?
While the aperture is small, you can take advantage of its wide field of view and wide-angle photography benefits.
✔️ Best Feature: Semi APO doublet
❌ Worst Feature: Can’t use diagonal
👌 Ideal For: Celestial Viewing, Stargazing, Lunar & Planetary Observation, Bright DSO Viewing, Astrophotography, Beginners, Intermediates, Experts
- Optical Design: Refractor
- Aperture: 50 mm
- Focal Length: 242 mm
- Focal Ratio: f/4.8
- Eyepieces Included: None
Our Verdict: The EvoGuide 50 APO telecope is a buy for every astronomer regardless of skill level. For the beginner, they’ll learn how fast optics work and how it can provide wide-field viewing and fast exposure imaging benefits. For the expert, they’ll use the telescope as a finder scope to find objects easier and faster, view with incredible seeing quality, and take wide-angle photos of sky bodies. What makes it superior to its small aperture refractors is its ED optics. The EvoGuide is a keeper.
Who is the SkyWatcher EvoGuide 50 APO Best Suited to?
The SkyWatcher telescope is a telescope that is suitable for all. It’s attractive to experts and intermediates for its compact and portable design. Users with experience will pick the EvoGuide as a supplementary telescope to mount atop their large refracting scope.
Beginners may be intimidated by the fact that this is a stand-alone purchase. There is no mount and tripod included in the buy, and in fact, there are no included eyepieces. This is a tube-only purchase that is often marketed as a finderscope as a secondary optic for a primary telescope a user already owns. But, a beginner may want to start with wide-field astrophotography with the EvoGuide regardless of its small aperture.
How Does the SkyWatcher EvoGuide 50 APO Perform?
The EvoGuide is a very fast telescope with its small aperture, short focal length, and fast focal ratio of f/4.8. Its specs imply that it’s a scope designed to supplement much larger telescopes as a finder or guider scope.
It performs excellently as intended, but it can also perform well as a small aperture astrophotography telescope for wide-angle shots and deep-sky astrophotography. It will take some experimentation to achieve focus with the right equipment for the brightest targets the aperture can resolve.
You can view the moon and planets with color fidelity, contrast, and resolution, but pushing the magnification above 100x will push its optical limits since it is restricted by its small aperture. Bright DSOs can be viewed and captured with a camera, but it will take additional investment to acquire the setup you’re after.
Features & Benefits
Semi APO Doublet
The EvoGuide is marketed as an APO refractor that is typically indicative of a 3-lens optical assembly. However, this is actually an ED (Extra-low Dispersion) doublet that incorporates an achromatic optical system with its double lenses. Although SkyWatcher isn’t as transparent as many would like them to be about their glass, it’s assumed they use FPL-53 glass that provides the ED benefits necessary for aberration-free seeing and imaging. It’s not unusual to hear many satisfied users speak to capturing point sources with pinpoint sharpness free of color fringing.
However, there is some coma visible beyond the center of the field of view. Due to the extremely wide field of views the EvoGuide is capable of providing with the appropriate eyepieces, the distortion can easily be cropped out leaving a reasonable wide-angle image. You can also purchase a field flattener for the telescope to compensate for this type of aberration.
The EvoGuide has a 1.25” helical focuser. It’s a great match with use of a CCD camera as it provides smooth movement and no backlash. This allows for the fine type of focusing a CCD requires. This model provides independent focusing without changing the orientation of the camera or eyepiece. This may be an essential feature for astrophotographers.
Additionally, helical focusers are known for the ability to stay in place. It has a locking ring that allows for steady and stable positioning even under heavy loads, so you can have confidence that it’s not going to creep during imaging.
Finder scope & Telescope
The EvoGuide is marketed as a finder scope to be attached to a much larger telescope for astrophotography, guiding, and more. Its designed to be an excellent finder scope with its 50 mm aperture and dovetail mounting shoe. It’s not too heavy weighing in at approximately 2 lbs and can easily be used with a 1.25” crosshair eyepiece.
The EvoGuide can also be used as a telescope for wide field viewing and imaging. While it can provide very wide fields of view, it doesn’t have the aperture to reach out to faint DSOs. Only the brightest DSOs will be seen. If using the EvoGuide as a telescope, you’ll find that it lacks a finder scope in the package. The short focal length means it’s a finder scope in itself, so you won’t have to worry about this as you’ll find objects easily enough with the wide fields and the low power.
Apparently, new models have seen an upgrade. It has a 45 mm dovetail bar for mounting to a mount and comes with a 1/4” 20 thread for mounting to a photography or field tripod. It also comes with a finderscope dovetail bracket for mounting into a finderscope shoe.
The EvoGuide can be used as-is for astro-imaging typically with a guide camera. Images of the moon are excellent and can provide high-contrast and sharp detail of its surface. There’s also plenty of field of view to capture an entire image of the full moon. Faint DSOs will be difficult to identify and image due to the small aperture, but bright nebulae like M42 can be captured.
To image with a DSLR, you’ll need a T-ring specific to your camera to mount it. Mirrorless cameras may be able to obtain focus with the very short focal length. There is rumor of a field flattener that allows focus for a mirrored camera that is in the works if you can’t reach focus even by removing the extension sleeve to add another 40 mm to backfocus.
Can’t Use a Diagonal
Unfortunately, if you use the EvoGuide strictly as a finder, it will only provide straight-thru seeing and is not compatible with a diagonal. You will not be able to reach focus. However, some have experimented using a right-angle star diagonal and removed the extension sleeve to just barely reach focus. An Amici prism is not recommended for this setup.
What Accessories are Included with the EvoGuide 50 APO Telescope?
The telescope is an OTA-only purchase, so you will have to purchase additional items separately, and by accessories, I mean eyepieces. What does come with the scope is a 1.25” helical focuser, guide rings, a mini dovetail bracket for mounting to a finderscope shoe, and a 45 mm dovetail with ¼” 20 threading.
What Eyepieces Can be Used with the SkyWatcher EvoGuide?
This will depend on what you have and what you want to use. Because of the small aperture and fast focal specs, it will work best with low power eyepieces with wide fields of view. Its useful optical magnifying limit is 100x, so it’s intentionally designed as a low-power telescope. If using very short eyepieces, be sure that it provides adequate eye relief and has quality glass to take advantage of the ED optics in the system. With this type of setup, you can achieve aberration-free images and improved seeing quality.
Do You Have to Use a Field Flattener with the EvoGuide 50 APO Telescope?
Short focal length refractors suffer terribly from field curvature. This makes objects like stars that are further away from the center of the field of view look distorted in some form. For example, stars can look like elongated blobs. To correct for this off-axis aberration, a field flattener helps with “flattening” the view so that objects maintain their shape with resolution, contrast, and sharpness. It is highly recommended to use a field flattener with this EvoGuide.
Is the EvoGuide Portable?
With the new improvements, the EvoGuide would make a great, portable telescope. It weighs only 2 lbs and is 10.5” long. Since it can be mounted to a standard tripod, it can be as portable and lightweight as you want.
If you’re using this telescope as a guiding scope, you’ll have to determine how portable your setup is as it will depend on the size and weight of your primary scope, mount and tripod, and additional gear needed to get set-up and observe or image.
The EvoGuide is on the smaller side for telescope-only use, but it can be done and is more than adequate for astro-imaging.
It won’t be your do-all astrophotography telescope, but it performs well and provides better-than-expected imaging quality due to its ED optics.
As a finder, it makes finding objects far easier due to its better image quality and 50 mm aperture with a great helical focuser.
It’s a win-win buy for any user of any skill level.