Telescopes
We are authorised dealers for ATIK Instruments, Ba'ader, Celestron, Ferrari, Guan Sheng
Optical, Long Perng, Lumicon, Saxon, Skywatcher, Tasco,
William Optics and many other brands...and Lay-By is available!
We have far more stock than
any other telescope or binocular dealer in Australia...for your
convenience! Immediate delivery on most models!!
***AUSTRALIA'S PREMIUM TELESCOPE IMPORTER AND STOCKIST***
New CCD cameras
simple
comparison chart is on our Atik page!
New 150mm and 200mm telescope OTA comparison
charts below...
See
www.atik-instruments.com
for more Atik astrophotograhy info...
We stock many hundreds of telescopes and thousands of
accessories!
Why wait weeks or
months elsewhere - only to pay far, far more?
Most products ship same day from us
We mail order worldwide - contact us now to order!
| Telescopes, cameras and spotting scopes |
| Telescope accessories and eyepieces |
| Used and Surplus Stock |
| Andrews 150mm telescope OTA-only comparison chart OTA = Optical Tube Assembly |
|
| Type | Price $(AUD) |
| BOSMA 150mm x 1800mm Maksutov-Cassegrain | $799.00 |
| CELESTRON OMNI 150XLT 150mm x 750mm Newtonian | $399.00 |
| CELESTRON C6N 150mm x 750mm Newtonian | $699.00 |
| CELESTRON C6S 150mm x 1500mm Schmidt-Cassegrain | $999.00 |
| GSO 150mm x 750mm Newtonian | $249.00 |
| GSO 150mm x 1000mm Newtonian | $349.00 |
| GSO RC 6" 150mm x 1360mm Ritchie-Chretien - super flat field | $999.00 |
| SKYWATCHER 150mm x 750mm Newtonian w/dovetail bar (light blue) | $249.00 |
| SKYWATCHER 150mm x 1000mm Newtonian (light blue tube colour) | $299.00 |
| SKYWATCHER Black Diamond N150 150mm x 750mm Newtonian | $349.00 |
| SKYWATCHER 150mm x 1200mm achromatic refractor | $799.00 |
| SKYWATCHER PRO-MAK150 150mm x 1800mm Mak. (gold colour) | $799.00 |
| SKYWATCHER Black Diamond MAK150 150mm x 1800mm MAK | $1199.00 |
| We believe our new chart should make it easier for you to choose the 150mm (6") OTA best suited to your requirements! Please compare the overall quality levels and types of focusers fitted, too! | Please call us for more info |
| Andrews 200mm telescope OTA-only comparison chart OTA = Optical Tube Assembly |
|
| Type | Price $(AUD) |
| CELESTRON C8N 200mm x 1000mm Newtonian | $899.00 |
| CELESTRON C8S 200mm x 2000mm Schmidt-Cassegrain | $1399.00 |
| GSO RC 8" 200mm x 1600mm Ritchie-Chretien | $1699.00 |
| GSO SDX 200mm x 1000mm Newtonian | $449.00 |
| SKYWATCHER BD-N200 200mm x 1000mm Newtonian | $499.00 |
| SKYWATCHER 200mm x 1000mm Newtonian (light blue colour) | $399.00 |
| We believe this new chart should make it easier for you to choose the 200mm (8") OTA best suited to your requirements! You should also compare the overall quality levels and types of focusers fitted, too! | Please call us for more info |
REFRACTOR BASICS
A single objective lens is the most basic lens for a refracting telescope.
Most refractors have a "compound" (two lenses grouped together) objective lens and these will provide improved image quality with reduced optical aberrations (e.g. chromatic aberration, in particular) than a cheap single lens
refractor.
A "doublet" (two lenses spaced apart) objective lens refractor performs better than a compound lens refractor.
A "triplet" (three lenses spaced apart) objective lens is
generally regarded as the best lens system for a refractor.
"ED" means "extra-low dispersion" of light. ED lenses reduce light
scattering, resulting in improved contrast.
There are several grades of ED lenses - the best being FPL-53 which is the highest grade of fluorite ED lens. FPL-51 is a more common, slightly lower grade, but lower cost ED lens. Incorporating an ED lens into a triplet lens design is generally regarded as providing the best possible optical performance in a refractor, at reasonable cost.
APO = apochromatic = colour free.
OTA = optical tube assembly.
Magnification may be calculated simply by dividing the focal length of the telescope by the focal length of the actual eyepiece in use.
E.g. a telescope with a focal length of 900mm fitted with an eyepiece of
10mm will deliver a magnification factor of 90x. In this example, adding a 2x Barlow
lens will double magnification to 180x.
A Barlow lens effectively reduces the focal length of the eyepiece in use,
therefore increasing the magnification. Barlow lenses can reduce some
optical aberrations. Barlow lens have negative optical characteristics. They
act similarly to a magnifying lens. Telescopes have positive optical
characteristics.
The maximum recommended/advisable/useable magnification for most telescopes is generally regarded as being double the aperture (in mm). E.g. a telecope of 100mm aperture would have a maximum recommended magnification factor of about 200x.
Low quality telescopes often advertise high magnification levels on their boxes - beware of them! Generally speaking, the higher magnification printed, the lower the quality of the telescope. Often, the first thing to throw away is the Barlow lens...
Lee's blog
We offer our technical expertise to those
who purchase products elsewhere (often from overseas). Our optical manager,
Luke, has a university degree in Cosmology.
Does your telescope supplier have such qualified and also well-proven expertise?
We import and supply only high quality products at the best prices in
Australia.
We retain the services of two
outstanding optical technicians, one of whom has for many years successfully repaired
telescopes for numerous east coast telescope shops when those shops'
in-house technicians could not successfully repair some telescopes.
The other is contracted to ExtraVision, the previous Celestron telescope
distributor.
We continually export to New Zealand and many other countries and, in fact, also sell our goods in New Zealand personally by regularly visiting field days there! We also have a truly outstanding New Zealand agent, ensuring our New Zealand customers enjoy excellent product support. We offer genuinely friendly and helpful service to all!
|
Mr Lee Andrews with Mr Jim Sheng of the world famous Guan Sheng Optical Company on Lee's second of many visits to the GSO factory in Taiwan |
|
The Arctic Moon at Kakslauttanen, 250klm north of the Arctic
Circle, near Ivalo, northern Finland, at 6pm on 5th January, 2010.
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Andrews Communications Systems
Shop 8, 41-51 Bathurst St, Greystanes, NSW 2145
Telephone: (02) 9636 9060, (02) 9688 4301