Is the 10mm eye relief on the Tele Vue Nagler T5 16mm sufficient for eyeglass wearers?
The 10mm eye relief is considered short for observers who need to wear glasses to correct for astigmatism. While some may be able to see most of the field, many will experience vignetting (a restricted field of view). Eyeglass wearers should look for 15mm to 20mm of eye relief, such as the Delos line's 20mm.
How will the Tele Vue Nagler T5 16mm frame globular clusters like M13 in my 8-inch f/10 SCT?
In a typical 8" f/10 SCT with a 2032mm focal length, the 16mm Nagler provides 127x magnification. That power resolves stars across much of the Hercules Cluster (M13), with the cluster well inside the 0.62° true field.
Do I need a Paracorr with the Tele Vue Nagler T5 16mm for my f/4.5 Dobsonian?
It helps. An f/4.5 parabolic mirror produces coma that no eyepiece removes. A Tele Vue Paracorr Type-2 eliminates it; scopes faster than f/5.0 see the greatest results.
What makes the Tele Vue Nagler T5 16mm's 82° field a "spacewalk" view?
The 82° apparent field is wide enough that you look around inside it rather than seeing the whole edge at once, which observers describe as a spacewalk. Al Nagler's guide gives Plössls 50° by comparison.
How does the Tele Vue Nagler T5 16mm compare to the 17.3mm Delos eyepiece?
The primary difference is the trade-off between apparent field and eye relief. The 16mm Nagler T5 offers a more immersive 82° field with short 10mm eye relief. The 17.3mm Delos has a 72° field, 20mm of eye relief and Dioptrx readiness, which suits eyeglass wearers.
What is the exit pupil of the Tele Vue Nagler T5 16mm in an f/7 refractor?
In an f/7 telescope, the 16mm Nagler T5 produces a 2.3mm exit pupil (16mm ÷ 7). Tele Vue's chart gives the same 2.3mm, a useful size for galaxies and planetary nebulae.
Can I use standard 1.25" filters with the Tele Vue Nagler T5 16mm eyepiece?
Yes. The 1.25" barrel of the Tele Vue Nagler T5 16mm is threaded to accept standard 1.25" astronomy filters, such as Tele Vue's BandMate Nebustar, O-III and H-Beta nebula filters.
How many lens elements does the Tele Vue Nagler T5 16mm have?
Six elements in four groups. No further details of the design are published for this model.
Is the Tele Vue Nagler T5 16mm a good choice for planetary viewing?
In long focal length telescopes it gives medium-high power, for example 127x in an 8" SCT. With a Tele Vue Barlow or Powermate it reaches higher powers.
What is the warranty on the Tele Vue Nagler T5 16mm eyepiece?
Tele Vue eyepieces, including the Nagler T5 16mm, carry a Lifetime Limited warranty against defects in material or workmanship.
