CEO, Tele Vue Optics
If you have an 8" f/10 SCT with the 1¼" diagonal, as I've had since the early '70s, you can simplify your eyepiece collection while gaining dramatically better viewing experiences with a few Tele Vue eyepieces.
You basically need only 3 eyepieces to cover the range from low power with maximum field to high power for planetary viewing.
For low power viewing, you may already have a 25mm or 26 mm Plössl eyepiece that came with the scope. These will likely give you a fairly decent image and field of view with a 1¼" diagonal. But the superior coatings, construction and edge sharpness of Tele Vue's 32mm Plössl will yield better performance, especially for those who wear eyeglasses and need long eye-relief. If you must wear glasses to correct astigmatism and know the astigmatism value, it's best to call Tele Vue for specific advice. However, you can gain maximum field, sharpness and contrast with a wonderful 68° field by using the 24mm Panoptic. The expansive view, darker sky background and higher magnification yields more detail and more exciting low power viewing.
Note, you can further dramatically increase low power viewing by adding the 2" Everbrite mirror system with its 1/10 wave, 99% reflective broadband dielectric coating. With appropriate 2" Tele Vue eyepieces, your maximum field can be increased from 0.76° to 1.3°, (three times the area). If you stay with a 1¼" diagonal, you may find that replacing your stock 1¼" prism or mirror diagonal with a 1¼" Tele Vue Everbrite diagonal will give noticeably sharper, brighter images.
At medium and high power viewing, 82° Nagler or 100° Ethos eyepieces yield "spacewalk" viewing for open and globular star clusters, planetary nebula, and galaxies.
And for high power viewing you'll see more field viewing the moon, planets such as Jupiter with its entourage of moons using Nagler and Delos eyepieces, all with far more comfortable eye-relief than the "peep-hole" eyepieces usually supplied with your scope.
| Power | Field | ||
| 1. Low Power, Maximum Field for 1¼" Diagonal | Either 32
Plössl or 24mm Panoptic |
63x 85x |
0.76° 0.76° |
| 1a. Low Power, Maximum Field for 2" Diagonal | Either 55
Plössl or 41 Panoptic or 31 Nagler |
37x 50x 65x |
1.30° 1.30° 1.20° |
| 2. Medium Power, for 1¼" Diagonal |
Either 15mm DeLite or 14mm Delos or 13mm Ethos or 13mm Nagler Type 6 |
133x 145x 156x 156x |
0.46° 0.49° 0.64° 0.50° |
| 2a. Medium Power for 2" Diagonal | 17mm Ethos | 120x | 0.83° |
| 3. High Power for 1¼" or 2" Diagonal* |
Either 10mm Ethos or 10mm Delos or 9mm Nagler Type 6 or 9mm DeLite |
203x 203x 226x 226x |
0.50° 0.36° 0.35° 0.28° |
| *Use 2" - 1¼" adapter. |
You're welcome to call our staff for more in-depth, personal advice to fit your needs and budget. If you have 10" or larger-size SCT's you'll want to discuss the important field size advantages of 2" eyepieces, and the possibility of needing only 2 eyepieces to meet all your needs.
