The optics
The Omegon ED apo refractor has outstanding optics, a thoroughly though-out design and high-quality mechanical components. This very special telescope provides astrophotographers, visual observers or nature watchers with a unique source of pleasure when observing starry skies or nature watching. Pin-sharp stars, right out to the edge of the field of view, can be just as taken for granted as the outstanding mechanical precision.
The apochromat doublet
TrueColor lens elements are built into the objective lens of Omegon ED apochromat doublets. The two element objective lens is constructed of a clever combination of OHARA FPL-53 and S-NBM51 glass. These are special types of ED glass with high and low refractive indices and superior light transmission characteristics. A particularly special feature is the use of S-NBM51 glass, which is usually employed in the optics of apochromatic fluorescence imaging microscopes. The benefit to you is that the optics provide a particularly sharp and high-contrast image!
You will be able to see subtle detail on planets, using a Schmidt-Cassegrain telescope for example.
Carbon Fibre Tube
This apochromat is well suitable to visual observing but was, in fact, developed especially for astrophotography. Use the advantages of a carbon fibre tube: it is particularly light and so even perfectly suitable for using on smaller mounts. The tube also offers a very high inherent stability and only minimal thermal expansion. These advantages are particularly useful for astrophotography, as the focus remains stable for the whole night. The dew shield is also carbon fibre and can be extended easily. In addition, the tube is lined with black felt.
The Focuser
The telescope is equipped with a Crayford style focuser. It belongs to a new generation of drawtubes, which are patent pending. Absolute precision and enormous load bearing capacity are the main advantages of this focuser. It can carry accessories of even up to 10kg in weight by the use of an additional locking screw. Even under the application of extreme force, the drawtube will not move even by a millimetre: Once you have found focus, it will not change, even if you move where the telescope points to in the sky.
A 1:11 reduction ratio provides you with fine adjustment when focusing, allowing even more precision than with most telescopes. Do you use a full format chip for astrophotography, or do you intend doing this in the future? Even with full format cameras, images of objects are recorded free of vignetting. The complete focuser is freely rotatable: loosen the locking screw and the unit can be rotated through a full 360°.
Carrying case included
The aluminium case provided is ideal for storing your valuable optics. Extremely robust, with carrying handles and metal fittings, it can withstand some shaking around with no problem. The interior features accurately cut out foam mouldings which keep the telescope tube in exactly the same condition as when you last stored it there.
The advantages in a nutshell:
- all optical surfaces multi-coated
- refined baffle system to prevent reflections
- very high contrast and pin-sharp star images
- light and robust: telescope tube made from carbon fibre
- carbon fibre dew shield lined with felt
- fine focusing: focuser with 1:11 reduction and protective cap
Features:
- doublet design ED-Apo with 80mm aperture and 500mm focal length
- 360° rotatable 2“ focuser
- extended length 46cm, retracted length 39cm
- OTA weight only 2.8 kg, total weight with case 6 kg
- case dimensions 56x20x32cm
The Omegon field flattener - Provides perfect image flatness for your astronomy photos
Many refractors and reflector telescopes suffer from field curvature. A curved image field means that stars at the edge of the field of view no longer appear as pin-sharp points but as out of focus discs. But now the new Omegon field flattener will conjure astronomy photos with pin-sharp stars right out to the outer edge of the image field.
Bringing the problem under control
Field curvature is a common optical defect that is not noticeable with visual observing or photography using small chips. If, however, you use a large chip or a full-frame camera, then this defect becomes glaringly obvious. Of course you could always crop your images to remove the blurred outer region; but using a field flattener it is much more elegant solution for using your expensive camera with its large format chip.
Flat field over the entire field of view
The field flattener gives you an absolutely flat image over the entire photographic field of view. Also, the focal length remains the same when using the flattener.
Suitable for telescopes from f4 to f8
You can use the Omegon field flattener with any refractor with a focal ratio between f4 and f8.
M48 thread for better aperture illumination
The Omegon field flattener has an M48 thread on both sides - giving you complete aperture illumination. A T2 thread plus M42 would limit the incoming light beam and so not provide sufficient aperture illumination for telescopes with 2" focusers. But using only the M48 thread, you make use of the entire light entering the telescope.
Use additional accessories - 109mm of back focus
This field flattener has a very generous 109mm of back focus. This means that you need a spacing of 109mm between the lens plane and the camera chip. This is an advantage, as it means you can use other accessories in between - such as a filter wheel, a flip-mirror or an off-axis guider. Using the correct Omegon extension rings will let you set the optimum spacing - whether you use accessories in between or not. Please also note the adapter recommendations in our Expert's Advice.
The advantages in a nutshell:
- field flattener for refractors
- suitable for telescopes from f4 to f8
- M48 thread for complete aperture illumination at 2"
- room for accessories between - Backfocus from 108 mm, depending on telescope focal length. At 500mm → 118mm, at 600mm → 113mm
- excellent multi-coating on lenses
