Many people are astounded that they can buy such a powerful instrument for so little, but that’s exactly why we sing the praises of John Dobson – the man who revolutionised affordable big telescopes for amateurs!
The benefit of a 302mm primary mirror will be obvious the first time you look through the eyepiece of this telescope. Enjoy seeing globular star clusters resolved into myriad pin point stars against a velvety black sky. Observe faint wisps of nebulosity not even visible in smaller scopes.
Fine planetary detail comes into view under steady seeing due to the much better resolving power of a large aperture.302mm mirror diameter with a 1500mm focal length (f/5).
Like any Dobsonian, the Bintel BT302-B provides more light grasp for your money than any other telescope type. We are often asked “what telescope is the best for an avid beginner?” Of course the answer depends on how you plan to use your telescope, but if we were to suggest just one telescope for starting your adventures in astronomy – this would be it!
The BT302 12″ Dobsonian features an 12″ (300mm) diameter parabolic mirror with aluminium coatings providing ~93% reflectivity providing bright detailed images. The telescope’s optics and long focal length will provide night after night of great observing performance. You can expect sensational views of celestial objects like the Moon and planets, plus with its considerable light grasp you can delve into more distant treats such as cloudy star forming nebulae, globular star clusters and galaxies far far away.
Bintel’s Dobsonians feature quality components and accessories that will make your viewing experience both rewarding and enjoyable. These include:
Precision figured primary and secondary mirrors
Telescope optics have to be ground and polished to a very accurate shape to ensure the finest images. Bintel’s telescope mirrors are ground and polished to exacting tolerances and checked by laser interferometry to guarantee outstanding performance.
The mirrors are made of BK7 “water white” optical crown glass that is free of internal stress and striae. The thermal stability of BK7 glass is generally better than other glass used for the mirrors of most reflectors in this price range. The optics are then coated with 91% reflectivity aluminium, and overcoated with a protective layer of silicon dioxide (quartz) for long life.
If you’re curious how the optical quality of our telescopes compares to other “big” names we say the others are nearly as good. With thousands of Bintel telescopes in use around Australia we are confident there is no telescope that even comes close when comparing performance and value.
Knurled collimation knobs on the primary mirror cell making precise optical alignment much easier – no more fumbling with tools in the dark.
A cooling fan mounted to the telescopes main mirror cell to achieve faster cool down of the optics. A telescope will produce its very best performance when the optics have cooled to within 1°C or so of the ambient air temperature. To help this process our larger telescopes are fitted with 12V battery powered cooling fan helping the mirror come to equilibrium faster.
The views will still be great even if the fan is not used…but if you are looking to coax the upper limits of resolution out of your telescope the fan should be run for a period of 30-60minutes when setting up.
A fully adjustable four-vane spider supporting the secondary mirror. The spider uses very thin steel vanes (only 0.75mm thick) maintaining excellent image quality and minimising unwanted diffraction effects. Beware of budget Dobsonian telescopes that use thick posts to support the secondary mirror (or even thicker cast metal spiders) – they degrade images and are not even adjustable.
The image above was taken using a home built 8″ Newtonian Astrograph. The optics used are the same as those in every Bintel Dobsonian, and show the beautiful star images expected from a Newtonian telescope. Note the almost text book perfect thin diffraction spikes around the brighter stars.
BINTEL Dobsonians are equipped with a CNC machined 2″ Crayford focuser allowing extra smooth 10:1 fine focus control without backlash. The focuser comes with a 1.25″ adapter so both sizes of eyepieces can be used without the need for special adapter tubes. Non-marring brass compression rings are standard and large “easy grip” locking screws are used so your precious oculars are held securely in place. The brake system with roller bearings makes the Dobsonian easier to balance and easier to use. First the side bearing can be moved back and forth allowing it to be positioned and set at the exact balance point of the telescope tube. Then the new large smoothly-knurled black plastic knobs can be tensioned to the perfect level for easy, precise movement of the telescope. If heavy eyepieces are being used simply apply a little more tension. If you prefer light, fluid movement you can back the brake off.
The included 8×50 finder scope is a premium right-angle model presenting a correct left/right and up/down oriented image for easy aiming of your 12″ Dobsonian telescope.
Standard accessories in the box include:
30mm Superview (2″) Fully Multi Coated Eyepiece – 68° Field Wide Field!
15mm and 9mm (1.25″) Fully Multi Coated Plossl Eyepieces
1.25″ Moon filter
8×50 Right Angle Correct Image Finderscope
Base carry handle
Eyepiece rack for 2″ and 1.25″ eyepieces
Snap-on dust cap and focuser dust plug.
– Aperture: 302mm
– Focal length (f/#): 1500mm (f/5)
– Limiting magnitude: 14.9
– Resolving power: 0.38 arc sec.
– Weight: 22kg OTA, 17.4kg Base
– Dimensions: OTA 1450mm long ~ 450mm diameter including tube bearings