ES127CF 127mm f/7.5 ED triplet refractor, with carbon fiber body

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  • This 5" Explore Scientific ES127 apochromatic carbon fiber refractor has:

    • 127mm f/7.5 fully multicoated triplet optics using a Hoya FPL51-equivalent ED element
    lightweight low thermal expansion carbon-fiber body
    • dual-speed 2” Crayford focuser with 10:1 ratio fine focusing
    • 2” dielectric star diagonal with 2” and 1.25” brass compression ring eyepiece holders
    • dual split mounting rings with dovetail for use on a Vixen-style altazimuth or German equatorial mount
    • flight-ready travel case
    • extended  lifetime warranty

    With a 5" (127mm) aperture, this Explore Scientific ES127 CF ED triplet refractor gathers 55% more light (with nearly 25% higher resolution) than the more common size 102mm (4") doublet and triplet refractors that often cost nearly as much as the ES127 CF.

    The Explore Scientific ES127 CF uses a premium Hoya ED glass element and state-of-the-art optical multicoatings in its apochromatic air-spaced ED triplet optics. The result is images that are essentially free of the annoying halo of unfocused violet light (chromatic aberration) that mars the view of bright stars and solar system objects in lesser scopes, despite the scope’s relatively large aperture, and even at very high magnifications.

    The 127mm Explore Scientific triplet optics are even more appealing when you consider that this Explore Scientific apo is loaded with features other manufacturers charge extra for (or don’t even have available) – such as a 2" dielectric star diagonal with 1.25" and 2" compression ring accessory holders, and a flight-ready carrying case.

    The body and dew shield of the 127mm Explore Scientific are made of high strength, low weight, low thermal expansion carbon fiber. This keeps the scope light in weight and sharply focused as the ambient temperature changes during critical long-exposure CCD imaging.

    The Explore Scientific ES127 CF is a natural on an equatorial mount as the heart of your primary observing system. In addition, it’s an excellent astrograph for serious wide field imaging, as well as crisp solar system imaging. Considering its surprisingly reasonable price for a 5" apochromatic triplet, adding in the extra features you get at no extra cost, and in view of the great optical performance that comes as standard equipment, the 5" Explore Scientific ES127 CF is a terrific buy!

Features of this Telescope . . .

  • ED triplet refractor optics: 127mm (5") aperture, 952mm focal length, f/7.5 focal ratio three-lens air-spaced optical system. The optics use a center lens element of Hoya FCD1 (Dense Fluor Crown) glass, the Hoya equivalent of FPL-51 ED (Extra-low Dispersion) glass. This ED element produces superior sharpness and color correction by minimizing the chromatic aberration, the “false" color fringing seen around bright objects when light rays pass through standard crown-and-flint doublet objectives, particularly those with apertures in the 127mm class. The result is to reduce spurious color halos and fringing to vanishingly low levels.

  • Fully multicoated optics: The triplet objective lens of the ES127 CF has EMD™ (Enhanced Multilayer Deposition) antireflection multicoatings on all air-to-glass surfaces for high light transmission, minimal light scatter, and excellent contrast.

  • Internal light baffles: Contrast-enhancing internal light baffles and a specially darkened tube interior provide dark sky backgrounds and high terrestrial contrast.

  • Collimatable optics: One of the bonuses of owning a refractor is that, compared to standard reflector telescopes, they almost never require realigning of the optics (collimation). However, any air-spaced refractor telescope may require optical recentering if the lens elements are knocked out of alignment by a heavy blow during shipping or use. Removing the dew shield will give you access to the lens centering screws in the sides of the lens cell, which you can then adjust yourself by referring to the supplied instructions. You can also send your scope to Explore Scientific’s Service Center for precision alignment. A standard service charge applies for factory realignment.

  • Carbon fiber body: The body and dew shield of the 127mm Explore Scientific are made of woven carbon fiber fabric, encapsulated in epoxy. Carbon fiber, the same material used to fabricate much of the fuselage and wings of the new Boeing 787 Dreamliner passenger jet, has a high strength-to-weight ratio to keep the scope almost 20% lighter than comparable aperture aluminum-body scopes. In addition, it has low thermal expansion characteristics when subjected to temperature variations. This helps to keep the instrument sharply focused as the ambient temperature changes, which is particularly important during critical long-exposure CCD imaging.

  • Dew shield: The supplied removable carbon fiber dew shield slows the formation of dew on the lens in cold weather to extend your undisturbed observing time. It also improves the contrast, similar to the effect of the lens shade on a camera lens, when observing during the day or when there is excessive ambient light at night, such as a neighbor’s backyard security light. A slip-on metal dust cap is standard.

  • Dual speed 2" Crayford-style focuser: The precision-made no-backlash focuser has dual-speed focusing. There are two coarse focusing knobs. The right knob also has a smaller concentric knob with a 10:1 reduction gear microfine focusing ratio. This provides exceptionally precise image control during high magnification visual observing and critical 35mm or CCD imaging. The large focus knobs have ribbed gripping surfaces so they are easy to operate, even while wearing gloves or mittens in cold weather. The focuser drawtube has a scale marked in centimeters and 1mm increments. This lets you note individual focuser positions for easy return to the correct focus when switching between visual use and photography. Two knobs underneath the focuser lets you adjust the tension on the drawtube to accommodate varying eyepiece/photo accessory loads, as well as firmly lock in a photographic focus.

  • 2" dielectric star diagonal and compression ring eyepiece holders: The supplied standard equipment 2" mirror star diagonal of the ES127 CF slips into the focuser drawtube’s 2" eyepiece/accessory holder. The 2" diagonal has 99% reflectivity dielectric mirror coatings for high light transmission. The star diagonal uses a non-marring soft brass compression ring to hold 2" eyepieces in place. The compression ring won’t scratch the barrel of your 2" eyepieces as an ordinary thumbscrew can. A supplied 1.25" accessory adapter slips into the 2" diagonal to let you use 1.25" eyepieces in the 2" diagonal. The 1.25" accessory adapter can also be inserted into the 2" accessory holder on the focuser drawtube to let you use a 1.25" image erecting diagonal, or 1.25" photographic accessories. Like the 2" eyepiece holder on the diagonal, the 1.25" adapter also uses a non-marring soft brass compression ring to hold 1.25" star diagonals and accessories in place.
  • Mounting rings and dovetail: The ES127 CF has dual split mounting rings with a dovetail plate that fits the Vixen-style dovetail slot on the head of many of the most popular medium capacity German equatorial mounts. Such mounts include the Celestron Advanced VX go-to equatorial, the Meade LXD-75 go-to equatorial, and the Vixen Sphinx and Great Polaris Deluxe equatorial mounts, among others. A spacer/stabilizing bar on the top of the rings provides a carrying handle that makes it easy to transport the optical tube and install it on your equatorial mount.

  • Extended lifetime warranty: This individually serial numbered Explore Scientific telescope is backed by a limited one year warranty, which will be extended to an Explore Scientific transferable lifetime limited warranty when its warranty card is registered with Explore Scientific within 60 days of purchase. Full details on this unique transferable lifetime warranty.
Highest Useful Magnification:
This is the highest visual power a telescope can achieve before the image becomes too dim for useful observing (generally at about 50x to 60x per inch of telescope aperture). However, this power is very often unreachable due to turbulence in our atmosphere that makes the image too blurry and unstable to see any detail.

On nights of less-than-perfect seeing, medium to low power planetary, binary star, and globular cluster observing (at 25x to 30x per inch of aperture or less) is usually more enjoyable than fruitlessly attempting to push a telescope's magnification to its theoretical limits. Very high powers are generally best reserved for planetary observations and binary star splitting.

Small aperture telescopes can usually use more power per inch of aperture on any given night than larger telescopes, as they look through a smaller column of air and see less of the turbulence in our atmosphere. While some observers use up to 100x per inch of refractor aperture on Mars and Jupiter, the actual number of minutes they spend observing at such powers is small in relation to the number of hours they spend waiting for the atmosphere to stabilize enough for them to use such very high powers.
271x
Visual Limiting Magnitude:
This is the magnitude (or brightness) of the faintest star that can be seen with a telescope. The larger the number, the fainter the star that can be seen. An approximate formula for determining the visual limiting magnitude of a telescope is 7.5 + 5 log aperture (in cm).

This is the formula that we use with all of the telescopes we carry, so that our published specs will be consistent from aperture to aperture, from manufacturer to manufacturer. Some telescope makers may use other unspecified methods to determine the limiting magnitude, so their published figures may differ from ours.

Keep in mind that this formula does not take into account light loss within the scope, seeing conditions, the observer’s age (visual performance decreases as we get older), the telescope’s age (the reflectivity of telescope mirrors decreases as they get older), etc. The limiting magnitudes specified by manufacturers for their telescopes assume very dark skies, trained observers, and excellent atmospheric transparency – and are therefore rarely obtainable under average observing conditions. The photographic limiting magnitude is always greater than the visual (typically by two magnitudes).

13
Focal Length:
This is the length of the effective optical path of a telescopeor eyepiece (the distance from the main mirror or lens where the lightis gathered to the point where the prime focus image is formed). Focallength is typically expressed in millimeters.

The longer the focallength, the higher the magnification and the narrower the field of viewwith any given eyepiece. The shorter the focal length, the lower themagnification and the wider the field of view with the same eyepiece.

952mm
Focal Ratio:
This is the ‘speed’ of a telescope’s optics, found by dividing the focal length by the aperture. The smaller the f/number, the lower the magnification, the wider the field, and the brighter the image with any given eyepiece or camera.

Fast f/4 to f/5 focal ratios are generally best for lower power wide field observing and deep space photography. Slow f/11 to f/15 focal ratios are usually better suited to higher power lunar, planetary, and binary star observing and high power photography. Medium f/6 to f/10 focal ratios work well with either.

An f/5 system can photograph a nebula or other faint extended deep space object in one-fourth the time of an f/10 system, but the image will be only one-half as large. Point sources, such as stars, are recorded based on the aperture, however, rather than the focal ratio – so that the larger the aperture, the fainter the star you can see or photograph, no matter what the focal ratio.

f/7.5
Resolution:
This is the ability of a telescope to separate closely-spaced binary stars into two distinct objects, measured in seconds of arc. One arc second equals 1/3600th of a degree and is about the width of a 25-cent coin at a distance of three miles! In essence, resolution is a measure of how much detail a telescope can reveal. The resolution values on our website are derived using the Dawes’ limit formula.

Dawes’ limit only applies to point sources of light (stars). Smaller separations can be resolved in extended objects, such as the planets. For example, Cassini’s Division in the rings of Saturn (0.5 arc seconds across), was discovered using a 2.5” telescope – which has a Dawes’ limit of 1.8 arc seconds!

The ability of a telescope to resolve to Dawes’ limit is usually much more affected by seeing conditions, by the difference in brightness between the binary star components, and by the observer’s visual acuity, than it is by the optical quality of the telescope.

0.91 arc seconds
Aperture:
This is the diameter of the light-gathering main mirror or objective lens of a telescope. In general, the larger the aperture, the better the resolution and the fainter the objects you can see.
5"
Weight:
The weight of this product.
18 lbs
Telescope Type:
The optical design of a telescope.  Telescope type is classified by three primary optical designs (refractor, reflector, or catadioptric), by sub-designs of these types, or by the task they perform.
Refractor
 
Based on Astronomy magazine’s telescope "report cards", scopes of this size and type generally perform as follows . . .
Terrestrial Observation:
Observing terrestrial objects (nature studies, birding, etc.) is usually possible only with refractor and catadioptric telescopes, and convenient only when the scope is on an altazimuth mount or photo tripod. Most reflectors cannot be used for terrestrial observing. Scopes with apertures under 5" to 6" are generally most useful for terrestrial observing due to atmospheric conditions (heat waves and mirage, dust, haze, etc.) that degrade the image quality in larger scopes. 
No
Lunar Observation:
Visual observation of the Moon is possible with any telescope. Larger aperture scopes will provide more detail than smaller scopes, thereby getting a higher score in this category, but may require an eyepiece filter to cut down the greater glare from the Moon's sunlit surface so small details can be seen more easily. Lunar observing is more rewarding when the Moon is waxing or waning as the changing sun angle casts constantly varying shadows to reveal craters and surface features by the hundreds.  
Great
Planetary Observation:
Very Good
Binary and Star Cluster Observation:
Very Good
Galaxy and Nebula Observation:
Good
Photography:
Yes
Terrestrial Photography:
Photographing terrestrial objects (wildlife, scenery, etc.) is usually possible only with refractor and catadioptric telescopes, and convenient only when the scope is on an altazimuth mount or photo tripod. Most reflectors cannot be used for terrestrial photography. Scopes with focal ratios of f/10 and faster and apertures under 5" to 6" are generally the most useful for terrestrial photography due to atmospheric conditions (heat waves and mirage, dust, haze, etc.) that degrade the image quality in larger scopes.
No
Lunar Photography:
Photography of the Moon is possible with virtually any telescope, using a 35mm camera, DSLR, or CCD-based webcam (planetary imager). While an equatorial mount with a motor drive is not strictly essential, as the exposure times will be very short, such a mount would be helpful to improve image sharpness, particularly with webcam-type cameras that take a series of exposures over time and stack them together. Reflectors may require a Barlow lens to let the camera reach focus. 
Yes
Planetary Photography:
Yes
Star Cluster / Nebula / Galaxy Photography:
Yes
Warranty:
1 year, extendable to lifetime
Reviews from Cloudy Nights (www.cloudynights.com)
These reviews have been written by astronomers just like you and posted on the Cloudy Nights astronomy forums . . .
Explore Scientific 127mm APO Triplet

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Overall Product Rating: AstronomicsAstronomicsAstronomicsAstronomicsAstronomics(4.67)   # of Ratings: 3   (Only registered customers can rate)

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1. ERIC on 5/18/2014, said: AstronomicsAstronomicsAstronomicsAstronomicsAstronomics
I have been using this telescope for a couple of years, on a Vixen GPD2 German equatorial mounting, and can attest that it does everything you would expect a 5-inch triplet to do. Being an older model, it does have the 6 x 50mm correct image finder (which I rarely use, other than with a solar filter to put the Sun in the center of the field, after using the shadow of the finder's rings for general location - mostly I use Telrads). The only negative is the rings of the finder have too little leeway (internal circumference of the rings is limited), but easily altered. Optical performance is fine, Crayford focusser ditto, tremendous deal.
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2. Michael on 4/30/2013, said: AstronomicsAstronomicsAstronomicsAstronomicsAstronomics
This is my first 5" APO. I have had several other scopes from 4" refractors, SCT's, and Dobs. My first night out was a star test and a look at Jupiter. From what I can tell, perfect in/out focus and perfect collimation. I'm far from an expert but in comparing at the eyepiece to the Internet star test diagrams, these optics are as good as I have had. All my other scopes would not look the same on each side of focus. CA is very well corrected, as I can see but maybe, and I mean maybe, a trace of color, only off-center, and only on a very bright star. No color on Jupiter. This may be due to the eyepiece.

Looking at Jupiter confirmed that this is a great scope. For the first time, I was able to discern detail in the bands. Best view I have had of Jupiter hands-down.

Construction is great. Explore Scientific has listened and changed the dew shield to be retractable and improved the focuser. Overall the construction is excellent and the case is pro.

At 11lbs and $2499, this is in the price and weight league of 4" refractors. And though I have read many don't feel a 5" offers much more than a 4", I disagree. The 5" optics really do go the extra and worth it if you have a mount that will handle it. The handle on the tube rings make the scope easy to handle.

Finally, the included accessories make this an even better value.

Highly Recommended.
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3. Steve on 4/30/2013, said: AstronomicsAstronomicsAstronomicsAstronomicsAstronomics
4 stars because nothing is perfect, but this telescope is pretty close!

What I like:
*The weight...18 pounds with all my imaging gear including cameras, guide scope, etc.
*Carbon Fiber...I have yet to have the objective dew over.
*The carry handle...Seems to be standard on all ES scopes. Love it!
*The optics...absolutely spectacular! You'll have to spend twice as much to get optics that are just a little bit better.
*The focuser...smooth and solid Crayford style focuser. Not a Feathertouch, but still good.
*The finder scope...good quality, solid, and the polar alignment marks are a nice touch.

What I don't like:
*The case...when I pack it up, I have to turn the scope upside down in the rings because of the way the case foam is cut.
*The objective cover...the threads are rougher than I would like to see on a scope at this price point.
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Showing comments 1-3 of 3
We haven't recommended any accessories for this product quite yet... check back soon or call one of our experts (1-405-364-0858).
  • Dual tube rings with Vixen-style dovetail and carry handle
  • 2" dual speed Crayford focuser
  • 2” dielectric star diagonal with 2” and 1.25” brass compression ring eyepiece holders
  • Carbon fiber body and removable dew shield
  • Dust covers
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Explore Scientific - ES127 127mm f/7.5 ED triplet refractor, with carbon fiber body

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Explore Scientific - ES127 127mm f/7.5 ED triplet refractor, with carbon fiber body
 AstronomicsAstronomicsAstronomicsAstronomicsAstronomics (Average: 4.67 | Users: 3)  Only registered users can submit ratings - Register Here
Our Product #: ES127CF
Manufacturer Product #: EDT-127075-CF
Price: $2,499.99  FREE ground shipping - Click for more info
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MSRP: $5556.99
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This optically excellent 127mm (5”) carbon fiber body Explore Scientific air-spaced ED triplet apochromatic refractor is loaded with features other manufacturers charge extra for and is superb for critical long-exposure CCD imaging . . .





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