One of the most
common gripes I hear is that the finderscope supplied with the telescope
is not very easy to use, most commonly this dissatisfaction is with
the red-dot finders, which a number of people find difficult to use.
I will also add that a number of experieced astronomers swear by them,
but having said this these astronomers often use a combination of two
types of finders to locate their object, using the red-dot finder for
the initial targeting, and then a another to home in on the object.
a number of choices when you want to change your finder-scope,
first of all you need to get one that will fit your scope and
also one that can be attached and detached easily. Sometimes,
with some telescopes such as Sky Watcher you have a standard fitting
so that the new finder can easily fit into the 'shoe' you already
have fitted to the telescope. This makes life easy, of course.
Finderscopes come in different magnifications and my advice is
to always go for the larger. Two common sizes are 6 x 30 and 9x
50, the latter being the better if your budget will allow, they
both have cross-hairs to accurately target your object.
If you already
have one of these, you can improve on this and get a 'right-angled
and right-way-up side corrected finderscope' like the one in the
illustration opposite which greatly improves your comfort when
viewing and will save time if like me you always nudge the scope
in the wrong direction because the view through a reflector telescope
for example is back-to-front and upside down, it makes life so
You will often
find that different makes have a standard fitting, so you can,
for example, fit an Orion finderscope to a Sky Watcher telescope
(as I have done), but always check with the retailer first.
The cost of
telescopic finderscopes is around £70-£80
9x50 Right-Angled, Erecting Finderscope
has two choices of battery power, the small lithium type or
a pair of double 'A's. The image shows QuikFinder with optional
AA battery-holder for up to 2700 hours of operation from 2x
AA alkaline batteries
QuikFinder Compact Reflex Sight
design is a clever one that can only be used on larger scopes,
very easy to use and can interchanged between more than one
telescope by the addition of extra baseplates
design lets you use both eyes.
Aiming your telescope is easy with its wide-open right-side-up
Projects 1/2 and 2 degree red circles onto the night sky
- what you see in the red circles is what you get in your telescope.
Pulsed or continuous illumination of the reticle is a
standard feature on the QuikFinder.
Includes two baseplates, one for apertures around 5",
the other for larger apertures. Easy clip on/off mounting to
baseplate (no screws to fumble with).
Other Features: Rugged construction, an ultra-efficient LED
and lithium battery (included) for long life. QuikFinder attaches
without drilling and is easily removed from its baseplate for
storage. Additional baseplates are available for using QuikFinder
on more than one telescope.
is 2.5 inches long, 2 inches wide and 1/2 inch high.
is 4.5 inches tall, 1.4 inches square
Costs around £39
can be employed as the sole or primary sight of a telescope to
help you "star hop" using visible stars to find and
center objects that would be invisible to the naked eye or in
other small finder telescopes. Or, you may choose to use a Telrad
in combination with a second conventional magnifying finder telescope.
The Telrad is the innovative, dominant choice of finder sights
by the amateur astronomy community, and it is not uncommon to
find a Telrad on professional observatory telescopes too!
It is a particular
favorite among experienced amateurs using deep sky telescopes
(particularly larger "Dobson" style telescopes) where
aperture and the ability to find faint deep sky objects are concerns.
. The Telrad is often the choice to replace economical finders
sights provided on telescopes.
is often the most commonly desired finderscope.
with furnished Quick Release Platform - viewed from right rear.
Note three control knobs at rear for adjustment of reticle pattern
onto display window and on the right side at the rear is the on-off
and brightness adjust dial lever
Notes on using
a Telrad can be found HERE
that is frequently considered is an upgrade on the focuser of
your telescope, upgrades can be done on Newtonians or refractors,
the only disadvantage is sometimes the prohibitive cost of the
upgrade, but well worthwhile, as a standard rack-and-pinion focuser
is often unsatisfactory for fine adjustment and especially so
opposite is one of many on the market, this is dual-speed focuser
for a Newtonian telescope with a compression ring eyepiece clamp.
The beauty of an upgrade like this is the smooth fine adjustments
that can be made, but this comes at cost. Equally, upgrades can
be obtained for refractor telescopes of similar quality and price!
Please note that prices for various upgrades vary greatly, but
all tend to be expensive!
Dual-speed Crayfords seem to be the most commonly desired upgrade
and can greatly add to your enjoyment of astronomy, especially
if you are a deep-sky observer. Always discuss an upgrade like
this with the retailer to ensure you get the right upgrade for
your type of telescope.
Many new premium
grade telescopes now come with these as standard.
CR Dual Rate tri-knob Crayford Focuser for Newtonians
Available from First
three: Nebula Filters
Nebula filters help
you identify and see nebula in deep sky observing, and are essential
for the serious deep sky observer, for example, the Great Orion Nebula
looks fantastic using a nebula filter, which helps bring out all the
whispy clouds within and allows you to explore deeper into Trapeziam.
There are two main types of nebula filters as follows:
High Contrast) Filter
If you only
get one filter this is the one to buy as it suits all telescope
apertures, the UHC has good transmission and can be used in any
UHC filter, like the O-III filter, isolates the two doubly ionized
oxygen lines (496 and 501nm) in addition to the hydrogen-beta
line (486nm) emitted by planetary and most emission nebulae.
The UHC filter
permits superb views of objects like the Orion, Lagoon, Swan and
other extended nebulae. It performs well in smaller aperture instruments
owing to its greater light transmission than the O-III, yet still
suppresses light pollution well.
The UHC filter
is the best all-round dark-sky nebula filter.
The only drawback
with any filter is their cost, because a good filter can cost
as much as a medium range eyepiece, and if you are new to astronomy
you may feel it is more prudent to invest in a new eyepiece rather
than a filter. Filters always come in the two most common barrel
diameters as follows:
O-III narrowband filter is specially designed for the observation
of diffuse and planetary nebulae.
narrow band-pass filter isolates just the two doubly ionized oxygen
lines (496 and 501nm) emitted by diffuse, planetary and extremely
are suited to telescopes with of any aperture 90mm and above and
can produce near-photographic views of the Veil, Ring, Dumbbell,
Orion and many other nebulae in larger apertures.
under even heavily light-polluted skies!
analysis on the performance of filters please click HERE
four: Variable Polarizing Filters
is a suitable upgrade from a standard ND96 Moon filter, though
it would not and should not replace it altogether, as it is
important to have a Moon filter that has a standard one-off
density that you can rely on and place in your eyepiece quickly.
However, many amatuer astronomers say the 'variable' is the
best thing since sliced bread and it is therefore worth looking
at this clever little filter.
polarizing filter made from anodized aluminium and optical glass
allows you to progressively reduce the amount of light entering
whilst increasing contrast so perfect for observing bright objects
such as the Moon or certain planets.
can be varied from 40% down to as little as 1%.
Will not change
the colour of the object being viewed.
fatigue and loss of night vision.
set consists of two polarizing filters, one which can be rotated
in its cell to adjust the brightness.
used as single elements, can also be used for daytime terrestrial
use for reducing sunlight glare from lakes oceans or window glass.
in two sizes, threaded to fit either standard 1.25 or 2
five: Collimating Eyepiece
eyepiece is essential, and not just an accesory, if you own a
reflector telescope. The reason is that the primary and secondary
mirrors need aligning from time to time and a collimating eyepiece
allows you to correct the angle of the mirrors.
several types available, the main two are the manual (Cheshire)
collimater, reviewed here, and the laser collimator.
eyepiece is a combination of a sighting tube and Cheshire eyepiece.
The sighting tubes narrow field of view and crosshairs provide
a centering reference for the telescopes optical elements.
The Cheshire eyepiece has a means of providing illumination to
a target face (set at 45 degrees to the illuminating hole) that
will be used to collimate the primary mirror.
Page for tutorials on collimation.
In summary, if you
can, always talk to other amatuer astronomers about thier experiences,
you can learn a lot from talking to other people, or join the
Stargazers Lounge, a huge resource of information!