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Eyepiece Selection:
Daystar Recommends the DayStar 25mm Plossl, or
Tele Vue Plossl series eyepieces of 25mm, 32mm,
and 40mm.
Remember that at long focal ratios, a high powered
eyepiece can exceed Dawes' limit. Observers will
find best results with an eyepiece which is 32mm or
greater to avoid this. Eyepieces of higher power will
result in a fuzzy disk without the ability to focus well.
We have tested a number of eyepieces over the years. We performed a
comprehensive eyepiece comparison between various brand names and
eyepiece styles. Naglers, zooms, radians and other "fast" eyepieces
typically perform very badly on DayStar applications.
Other brands do offer Plossl eyepieces in 32-40mm and they can give a
respectable performance in lieu of a DayStar or Tele Vue. We have
also found some of the very old wide field "Erfle" eyepieces aren't bad for
an experienced observer. It should be noted that repeatedly in side-by-
side tests, we found Tele Vue brand Plossl eyepieces to offer the highest
contrast, most even view and widest exit pupil. In Solar Observing,
contrast is achieved by control of scattering. Tele Vue Plossls stand out
in superior design. DayStar uses these same designs. Furthermore, the
adjustable eye cup offers additional contrast by allowing the user to dark
adapt during sunny days.
Eyepiece features we found to increase performance include:
- "Fully Multicoated" - Of those eyepieces which did better than others,
those marked "fully multicoated" offered better views from less internal
scattering.
- Blackened optical edges - Tele Vue and other eyepieces which
performed better all had blackened edges of their optical elements. This
also reduces internal scattering within the eyepiece.
TeleVue Plossl owners who do not use eyeglasses may benefit from the
TeleVue Eyeguard Extender, as the point of best view will be elevated
above the eyepiece cup.
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