The Celestron EdgeHD 9.25" is an aplanatic astrograph lightweight and compact. Compared to 200mm model in diameter, on visual observations it generates brighter and more detailed images. In photography it's excellent, especially for those who want to devote himself to high resolution photography of the planets and the moon, where it excels thanks to the special optical design with the two mirrors to a focal ratio slightly longer than the other EdgeHD. In this the user will get a better optical correction and a higher contrast of the images. The difference in price is justified not only by the larger diameter but also for the higher quality standard accessories, such as the eyepiece Luminos 23mm ideal for deep-sky viewing Wide Field and diagonal 50.8 mm in diameter ( which also accepts eyepieces 31.8 mm). 3 years of warranty on the optical tube!
Celestron EdgeHD 9.25" telescope has an internal focuser without micrometric focus and that generates image shift, the movement of the image during focusing. This special version of the Celestron EdgeHD 9.25" adds ESATTO 2", the new generation robotic focuser that you control by any Windows computer by connecting it to a USB port, or via WiFi by using ESATTO app on your smartphone or tablet with the Virtual HandPad! The 2” version of the ESATTO 2" has a depth of 67mm, it has 15mm of focuser tube travel, a 5kg payload capacity and an incredible resolution of 0,04 micron per step (and this is why we call it ESATTO)! And you can also expand ESATTO features by adding the ARCO robotic camera rotator! EdgeHD telescopes are equipped with two primary mirror lock knobs: thanks to the ESATTO you can lock the primary mirror (this way you avoid any mirror shift) but you can always focus the telescope.
Celestron EdgeHD 9.25" has a long backfocus, 146mm from the 3,3" SC thread on the back of the telescope. ESATTO 2" is 67mm thick and the adapter to connect it to the telescope is 2mm then you still have 77mm that are more than enough to connect cameras also with accessories for astrophotography (like off axis guiders or filter wheels). These values are still the same if you use the 0,7x focal reducer for EdgeHD that is threaded on the telescope rear side before the ESATTO.
The Celestron challenge was to further improve their famous Schmidt-Cassegrain telescopes and the intention of creating a instrument without compromise, it brought the realization of these aplanatic optics, that return a stellar image comparable only to the famous RC or the CDK. The EdgeHD optics in fact guarantee perfect images, both in color level and in big 42mm circle field correction. Maintaining the same high quality standards, Celestron has succeeded in creating a new generation telescopes at a very affordable price. The construction of these optics is done by the combination of the best features of CDK and SCT. EdgeHD in fact are made with primary and secondary spherical mirrors. But, unlike the Schmidt-Cassegrain telescopes, in the optical path two lenses that correct aberrations are installed, in addition the stars appear perfectly point, without coma or field curvature.
The high performance of this instrument can be noticed immediately during an observation, thanks not only to the optical design, but also to the great optical correction that offer results hat only few instruments can provide. Even with wide-field eyepieces, stars appear perfectly pinpoint from the center to the edges of the field of view. The resolution capabilities of this instrument is amazing, you can perform very high quality observations or imaging of double stars or planets. More, thanks to the large diameter, you can observe and take picture of many deep-sky objects, like galaxies, nebulae or star clusters. Thanks to a big 42mm diameter flat field, this telescope is ideal in astrophotography even with large sensor camera. Celestron also created dedicated accessories in order to be able to use this instrument with the maximum performances, such as the focal reducers and photographic adapters made specifically for the EdgeHD. In addition, these optics are compatible with the Hyperstar system, which leads the focal instrument from f/10 to f/2, much brighter and greatly reducing the exposure times. Photographically they are comparable only to high-level instruments with much higher costs.
- Celestron EdgeHD 9.25" optical tube
- ESATTO 2" robotic microfocuser
- Adapter ESATTO 2" for telescopes with large 3.3" SC thread
- 50,8mm and 31,8mm visual back
- Plossl 40mm 51x eyepiece (diameter 31,8mm)
- Mirror diagonal 90° (diameter 31,8mm)
- View-finder 9x50
- Dovetail bar Losmandy type
|Optical Design||Aplanatic Schmidt-Cassegrain|
|Optics||Primario e secondario sferici, con lastra correttrice e gruppo spianatore|
|Focal Length (mm)||2350mm|
|Field flattener/corrector||Included and not removable|