Despite numerous alternatives, I continue to employ my Celestron Zoom 8-24 Eyepiece due to its versatility and performance.
Revamped Review:
Experience the universe up close with the Celestron 8-24 zoom eyepiece - a versatile, budget-friendly gem in your astronomical arsenal! This babyman's got you covered, whether you're a beginner or an advanced stargazer, with its ability to provide a range of magnifications that'll put your single-focal-length eyepieces to shame.
Like a sprightly zoom lens on your precious Canon or Nikon, the telescope zoom eyepiece offers an array of magnifications, but don't be too quick to judge all zoom lenses equally. Some can be disappointing, sporting low quality or a narrow field of view. However, the Celestron 8-24 mm zoom holds its own, delivering image quality comparable to the good ol' Plossl eyepieces. I've yet to find a zippy zoom under $100 that outperforms this delightful little number!
One eyepiece, paired with a Barlow lens that matches your telescope's focal length, can take the place of 4-6 traditional eyepieces, giving you the chance to perform astral feats that would be otherwise impossible with solitary, stationary eyepieces.
The Nitty-Gritty
I've tested the Celestron zoom on a variety of scopes, including 80 mm refractors, 125 mm Maksutov-Cassegrains, 203 mm Newtonians, 250 mm Newtonians, and a 203 mm Schmidt-Cassegrain. The image quality was on par with the Plossl eyepieces in these scopes, showing occasional aberration around the outsides in focal ratios of f/6 or lower. However, I wouldn't be overly concerned - the aberrations are minor, and you'd likely need a pricier telescope zoom eyepiece to eliminate these pesky edge effects.
The Celestron zoom is my preferred eyepiece for outreach events where folks line up to ooh and ahh at my telescope. It's a breeze to share the view when using the zoom, as I hand over the telescope at low magnification, allowing the target to remain in sight for longer. Kids particularly love the zoom effect - I'll start with the Moon at low power, let them take a peek, then guide them on how to turn the barrel to zoom in, always eliciting a resounding "WOW!"
Magnification, Simplified
Rather than investing in the typical 24 mm, 14 mm, 10 mm, and 8 mm eyepieces for a selection of magnifications, the zoom offers the whole shebang. It even provides magnifications in between those sizes, so you don't have to fret about needing that 11.5 mm eyepiece - you've got it! Just tweak the barrel of the Celestron zoom eyepiece, and you're good to go.
The barrel has handy markings for focal lengths, primarily useful when recording observations for a report. But don't worry about keeping track of these numbers in real-time - why bother when it's the image that truly matters?
When I use single-focal-length eyepieces, I'm acutely aware of the focal length because I need to figure out my next move. With the Celestron zoom, simply twist the barrel and enjoy the celestial show without a care in the world. The eyepiece seems to just vanish, allowing you to focus on the rings of Saturn or the stars in a globular cluster - 'tis a truly magical experience!
The zoom isn't perfectly parfocal throughout the range, but it's darn close. Focus adjustments are minor, just like when using single-focal-length eyepieces. It's customary to make these adjustments due to the change in magnification, even in cases where eyepieces are parfocal.
A Thought about the Tube Size
Ninety-nine percent of modern telescopes accept 1.25" eyepieces, so the zoom will fit them all. You'll find adapters for older designs that use the obsolete 0.965" eyepiece size if you still somehow possess one of these dinosaurs.
Growing Field of View with Decreasing Focal Ratio
Running from 40 degrees to 60 degrees AFOV (apparent field of view), the Celestron zoom offers a widening field of view as you decrease the focal length. In comparison, Kellner and Modified Achromat eyepieces, usually found in the cheaper packages, provide around 40 degrees AFOV, while Plossls, typically provided with better packages, provide around 50 degrees AFOV. The benefit of increasing AFOV at lower focal lengths is that, as magnification increases, the true field of view naturally narrows. With the widening of the AFOV on the Celestron zoom, you get a more expansive view at the higher 8 mm setting where it's much needed.
Eye Relief: A Must for Glasses Wearers
The Celestron zoom's 15 to 18 mm eye relief is important for all, but especially for folks who wear glasses. Eye relief is the distance you must place your eyeball from the top lens to see the full field of view. Typically, anything over 10 mm is comfortable, with 13 - 15 mm being preferable. If you wear glasses, you'll need to determine if the Celestron zoom's eye relief is sufficient for you.
Glasses wearers will have to ascertain if the 15 to 18 mm range is workable for them. I wear progressive lens glasses, and I find it sufficient, though I tend to remove my glasses when observing. The primary value of the glasses I wear is to bring images into focus - a function that's already handled by the focuser on the telescope. However, if you have other visual issues like astigmatism, you might be better off keeping your glasses on.
Weight and Balance Considerations
At 8 ounces, the Celestron zoom is larger than the average Kellner, Modified Achromat, or Plossl eyepiece, which typically weigh in at 3 - 5 ounces. On smaller scopes, the weight of the zoom might cause an imbalance in the optical tube. I've yet to encounter this issue with my 80 mm scopes. Larger 1.25" eyepieces that weigh more than the zoom are common, so it's just something to be aware of.
Greater Magnification Possibilities
Let's explore magnification in simpler terms. The formula is straightforward:
- Focal length telescope / focal length eyepiece = magnification or power
For instance, let's consider two typical eyepiece focal lengths from beginner telescope packages: 25 mm and 10 mm. With a 1000 mm focal length scope, the 25 mm will offer 40 times magnification, while the 10 mm will provide 100 times magnification.
The Celestron zoom will deliver 41.67 times to 125 times magnification, boasting a significant advantage in this regard. However, it's not just the sheer variety of magnifications that sets the zoom apart – but the fact that it offers all these magnifications in between as well. Normally, you'd need multiple eyepieces to fill this gap, but the zoom covers the entire range.
When paired with a 2X or 3X Barlow, the zoom provides double or triple the magnification, respectively. Depending on your scope's aperture, this may cover the full range and capabilities of the scope. But, on larger aperture scopes, you might match the zoom to a 3X Barlow for 125 times to 375 times magnification. One eyepiece and a single Barlow can give you this impressive range!
Just remember to have a low-power wide-field-view eyepiece in the 28 to 40 mm range for targets that benefit from lower powers or wide fields of view.
And there you have it! The Celestron 8-24 zoom is an exceptional performer in its price range. Recommended for newbies on a budget and those seeking to expand their magnification range, this zippy zoom delivers the goods without breaking the bank!
Other Quality Affordable Zoom Eyepieces:
- Baader Zoom Mark IV
- Quality: Excellent with sharp, clear images
- Field of View: Wide field of view for a better observing experience
- Eye Relief: Good eye relief, comfortable for glassess wearers
- Meade Variable Zoom Eyepiece
- Quality: Good optical quality, though it may not match the high-end features of Baader or Celestron
- Field of View: Decent field of view, suitable for general observing
- Eye Relief: Acceptable eye relief, may vary depending on the zoom setting
- Orion Variable Zoom Eyepiece
- Quality: Acceptable quality and affordable
- Field of View: Moderate field of view suitable for most astronomers
- Eye Relief: Sufficient eye relief for comfortable use
When choosing a zoom eyepiece, keep these factors in mind:
- Quality: Look for eyepieces with high-quality glass and smooth zoom mechanisms
- Field of View: Wider fields of view offer a better observing experience
- Eye Relief: Comfortable eye relief is essential for glasses wearers
- Durability: Consider the build quality and its ability to withstand frequent use.
Ultimately, the choice depends on your budget, desired level of optical quality, and the type of telescope you own. Find the right balance between quality, price, and functionality, and immerse yourself in the wonders of the cosmos!
- The Celestron 8-24 zoom eyepiece can be a game-changer for astrophotography, offering a range of magnifications, comparable image quality to Plossl eyepieces, and a widening field of view as you decrease the focal length, making it a versatile gadget in the field of technology.
- The Celestron 8-24 mm zoom eyepiece can replace up to 4-6 traditional eyepieces, making it a valuable investment for both beginner and advanced stargazers due to its affordability and convenience, putting multiple magnifications at your fingertips like various gadgets do for other fields.
- For glasses wearers, the Celestron zoom's 15 to 18 mm eye relief is a significant advantage, allowing them to view the entire field of view comfortably without the need to constantly adjust their position or take off their glasses.
- The Celestron 8-24 mm zoom eyepiece, when paired with a Barlow lens matching the telescope's focal length, can provide double or even triple the magnification, opening up greater possibilities for exploration with just one eyepiece and a single Barlow, streamlining the process of astronomical observation.
