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| Calibrating the scale and weighing the 10mm EP gives .97oz., exactly as specified by Svbony |
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| Compare 23mm to 23mm, the fat Celestron Luminos EP setting on the scale is an irregular shaped massive overweight boat anchor that was not usable on smaller telescopes. On larger scopes it upset the counter- balancing significantly. Seen here, the Luminos EP overloaded the 10,000 gram scale. The aspheric 23mm eyepiece is seen at top left. |
These aspherics are the Cat's Pajamas!
Different lens designs have different performances with various telescope mirrors. Some oculars will set you back $600 to $1200 and yet perform poorly on half of the telescopes you may own. Others, like the aspheric design, may cost $9.50 and give phenomenal performance!
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| Nice Big Lenses The aspheric design has large diameter lenses ideal for both visual eyepiece projection and astrophotography. At left, the lens is .87 inch in diameter and at right .39". Their EP lengths are 2.36" and 1.69" and adapt well to projection with the Apple iPhone camera. The exit pupil is generous and considered just right. The barrel construction is from very light weight materials trimmed in gold, chromed on the lower half, engraved with a flat black interior. |
As an optician, experimenter and inventor, I like to try new lens combinations and see how they perform. Thus far, the aspheric oculars were tested on the f/3.9 2.99-inch diameter Celestron FirstScope and perform as real winners. The light weight of these EPs are idea for small telescopes that have no means to tube balance. Aspherics are somewhere in between complicated lens designs with many lens elements and a simple one lens. However, it works to correct aberrations such as spherical and astigmatism, and maximizes light transmission.
— if the single aspheric lens is ground and polished to 1/4th wave, then having an eyepiece with 6 or 7 lenses all at 1/4th wave adding their defects together is absolutely not preferred —
The asphere's more complex surface profile can reduce or eliminate spherical aberration and also reduce other optical aberrations such as astigmatism, compared to a simple lens. A single aspheric lens can often replace a much more complex multi-lens system. Wiki
My set of aspherics range in cost from free to about $14. I have dedicated a 10mm 62 degree and 23mm 62 degree to the FirstScope as the best oculars for this telescope. In the future, I will definitely expand on my collection of this eyepiece type. Getting complete sets of aspherics can save thousands of dollars over other eyepieces. The images are bright and sharp with a compatible exit pupil due to a welcomed large lens diameter. No squinting necessary. The rubber top insulated eye stop protects the eye from bad weather that's to hot or too cold. The simplicity of performance is outstanding and ideal for EP projection and astrophotography or visual observing. They have a wider FOV compared to popular Plossls and these are the lightest weight EPs in my collection. The 10mm is 428 grams (15oz) and the 23mm is 666 grams (23oz). By comparison, the massive 23mm Celestron Luminos overloaded the 10,000 gram scale! According to Celestron, it weighs 1lb 13.3oz or 29.3oz. That's 30 times heavier than the aspheric eyepiece! Comparing both 23mm EPs, aspheric to Luminos, the aspheric has a much larger lens. The aspherics have a set of 4mm, 10mm, and 23mm as offered by Svbony for about $9.90 each. The weight is listed as 1.48oz, .97oz and 1.69oz respectively. Svbony has provided fast outstanding service.
In summary, the 1.25" aspherics are the bargain of the century, come fully packed in their own bags and boxes, are attractive with gold and chrome, low cost, high on performance, give bright images, have a wide FOV, perfect exit pupil (10 and 20), light weight, fully coated, have a rubber top eye stop/protector, are engraved, threaded for filters, and include full lens caps, plus they are sold online by Svbony, an excellent provider of astronomical telescopes and supplies.
