Why is the Orion Optics UK OMC200 De-Luxe f/20?
The f/20 focal ratio is optimized for high-magnification planetary, lunar, and double-star observation. It provides a large image scale without the need for additional amplifiers like Barlow lenses, which simplifies the optical train and maximizes contrast and sharpness on fine details. This makes the OMC200 a specialized instrument, trading wide-field capability for exceptional high-power views.
What does the 1/8 PV wavefront of the OMC200 mean for views of Jupiter?
A 1/8 PV wavefront error is significantly better than the "diffraction-limited" standard of 1/4 PV. For an object like Jupiter, this translates to:
-
Higher Contrast: The boundaries between cloud belts and zones will be sharper and more defined.
-
Finer Detail: You will be able to more easily resolve small, low-contrast features like barges, ovals, and festoons within the cloud belts.
-
Better Color Fidelity: With less scattered light, the subtle color variations across the planet's disk are more apparent.
How does the OMC200 De-Luxe focuser prevent image shift?
The OMC200 uses a micrometer-style focuser that moves the secondary mirror, not the primary mirror. In many catadioptric telescopes, focusing is done by shifting the large primary mirror, which can cause it to tilt slightly, leading to "image shift." By moving the much smaller, lighter secondary mirror, the OMC200's mechanism provides precise, stable focus with zero lateral image movement, which is critical for high-magnification imaging.
Is the carbon fibre tube on the OMC200 De-Luxe a significant advantage?
Yes. Carbon fibre has a very low coefficient of thermal expansion, meaning it doesn't shrink or expand significantly as the ambient temperature changes throughout the night. At a long focal length of 4000mm, even a tiny change in tube length can shift the focal point. The carbon fibre tube ensures the focus you set at the beginning of the night remains sharp for hours, a crucial feature for long imaging sessions.
Can I use the OMC200 De-Luxe for deep-sky imaging?
While possible, it is not its primary design function. The very long f/20 focal ratio results in a narrow field of view and requires much longer exposure times for faint deep-sky objects compared to faster instruments. The OMC200 excels at imaging smaller targets like planetary nebulae and globular clusters, but it is not well-suited for large nebulae or galaxies.
What kind of mount is required for the 9kg OMC200 De-Luxe OTA?
While the tube itself weighs only 9kg, the 4000mm focal length acts like a massive lever, magnifying any vibrations from wind or mount drives. For visual use, a mount rated for at least a 15-20kg payload (e.g., EQ6-R Pro class) is recommended for stability. For astrophotography, a higher capacity mount is essential to ensure sharp, untrailed images.
