Celestron CGX Equatorial 925 HD Telescope

CGX 925 HD combines Celestron's all-new state of the art CGX computerized equatorial mount with its acclaimed EdgeHD optical system. With over 9 inches of aperture and our premium StarBright XLT coatings, the CGX 925 HD gives you over 1000 times the light gathering power than the unaided eye. Designed to give diffraction limited performance and offer more resolution than the 800 with less weight than the 1100, the CGX 925 HD is a premier astroimaging telescope made for remote operation.

See the Universe in HD

EdgeHD is an aplanatic, flat field Schmidt-Cassegrain telescope that produces aberration-free images across a wide visual and photographic field of view. The optical system was designed to reduce more than just off-axis star coma; it also provides an astrograph-quality flat focal plane all the way to the edge of the field of view.

True Astrograph Quality
Many optical designs that advertise themselves as "astrographs" actually only produce pinpoint stars across a curved focal plane. While this may be acceptable for some visual observing, stars will appear out of focus at the edge when used with the flat chip sensor of a digital camera. EdgeHD optics produce a focal plane more than three-times flatter than a standard Schmidt-Cassegrain telescope and dramatically flatter than competing coma-free designs. This guarantees you visibly sharp stars across some of the largest CCD chips available today.

Improved Performance
Superior edge performance not only creates rounder, more pleasing stars, but actually improves the resolution and limiting magnitude when compared to telescopes of equal aperture. With Celestron’s StarBright XLT optical coatings on every surface, EdgeHD optics gives you maximum light throughput across the widest visual and photographic spectrum.

Mechanical Features
In addition to EdgeHD’s optimized optical design, the telescope tube has been redesigned to make sure you get the most from your optics each and every night.
Mirror clutches - Flexible tension clutches hold the mirror in place and reduce image shift when taking long exposure astro-images. Once focused, the flexible rods allow the mirror to be held in place without putting any force or pressure on the mirror assembly, keeping the image centered in the eyepiece (or on the sensor).
Tube vents - Cooling vents located on the rear cell allow hot air to be released from behind the primary mirror. Each vent has an integrated 95-micron micromesh filter guaranteed to let warm air out without letting dust in.
Fastar versatility - EdgeHD is the most versatile imaging telescope available today. At its native f/10, you can achieve the image scale necessary to capture the smallest of deep sky objects. A Barlow gives you added power for high-resolution planetary, lunar and solar imaging. All EdgeHD optical tubes are Fastar-compatible, allowing the secondary mirror to be removed and replaced with a third party lens accessory for ultra-fast f/2 wide field imaging.

Individually Tested
Every EdgeHD that ships has been tested not only for the surface quality of each optical component, but also with a camera and artificial star to ensure the imaging system meets our rigid quality assurance. This “final acceptance test” confirms the EdgeHD will perform in the field and deliver high-quality astroimages.

CGX Mount

Celestron’s workhorse CGEM mount lineup has been the German Equatorial backbone for telescopes ranging from 6 to 11 inches of aperture. Since that time, many more astro-imagers and planetarium controlled setups have emerged as backyard telescope technology has evolved. Celestron’s engineering team applied their years of experience designing German Equatorial mounts to the all-new CGX EQ, a culmination of all the advancements made to our technologies, value, and ease-of-use.

The new CGX was designed to better support your telescope for both visual and astro-imaging pursuits. Key design goals included a lower profile EQ head, which provides a more compact and therefore more stable setup; a better drive system; remote operation-friendly with home and limit optical sensors; easier polar alignment adjustments; and better cable management. In addition to that, we’ve made mechanical and ergonomic improvements throughout to make the mount sturdier, easier to use, and transport. The CGX is our new Equatorial backbone to support a wide range of telescopes.

Features:

9.25" HD Optical Tube Assembly
CGX EQ Mount and Tripod
Celestron’s premium StarBright XLT coatings provide maximum light transmission
A 9x50 finderscope, 2” mirror diagonal for more comfortable viewing, and wide-angle 23 mm Luminos 2" eyepiece are all included
HD Features

Experience our best optical performance with EdgeHD’s flat-field and coma-free optics for pinpoint stars all the way to the edge of today’s largest imaging sensors and widest eyepieces
Aluminum optical tube with tube vents featuring an integrated 95-micron mesh filter allows hot air to be released from behind the primary mirror. Mirror support knobs hold the mirror in place and reduce image shift during imaging
Versatile design accommodates 2 focal ratios: native f/10 or ultra-fast f/2 imaging with a removable secondary mirror and third-party accessories
Computerized Mount Features

All-new design. Sturdier and more rigid with quicker dampening time
Increased load capacity to 55 lbs.
Improved motors provide more torque, better slewing and tracking under heavy loads
Heavy Duty belt-drive system minimizes backlash while providing smooth motor operation under heavy loads
Spring-loaded brass worm wheel and stainless steel worm gear reduce friction and provide optimum gear mesh
Internal cabling for worry-free remote operation. Power input and accessory ports remain stationary while the mount slews to avoid snags
Internal hard stops for both axes prevents cable tension and tripod strike
Internal optical sensors on both axes for simple and safe remote operation
Home sensors allow the mount to always start in the index position regardless of orientation before a power reset
Limit sensors automatically shut off slewing or tracking before reaching the hard stop fail safe
Brand new control software developed in conjunction with PlaneWave Instruments for professional level control operation and imaging
Software includes multi-point mount modeling for extremely precise pointing accuracy and many more additional features for remote astroimaging
Wider tripod stance for improved stability
Adjustable EQ head position to optimize center of gravity over the tripod and fully utilize the increased 3º-65º latitude range
Dual-fit CG-5/Vixen and CGE/Losmandy dovetail saddle
Improved tripod includes:

2" steel legs with height index marks for quick leveling
"Jack of all trays" can hold three 1.25" eyepieces, two 2" eyepieces, your smartphone, or other accessories
+20º of additional tracking past the meridian on either side
Tripod legs can be collapsed with accessory tray installed for faster setup and transport
Improved ergonomics:

Two handles for easy pickup and transport
All-new ergonomically designed dovetail clamping knobs
Innovative and improved polar alignment adjustment system
All-new ergonomic latitude adjuster for smooth and easy adjustment under full loads
Optional add-on polar axis finderscope - coming soon
Electronics:

All-new NexStar+ hand control with USB port
Two AUX accessory ports to support wireless/WiFi alignment and operation with StarSense AutoAlign and SkyPortal WiFi Module accessories (sold separately)
USB 2.0 port, used to connect directly to PC with included software
Autoguider port
PPEC ready
Threaded 12VDC power input barrel connector
Internal Real Time Clock (keeps time and site information saved)
Specifications:

Optical Tube
Optical Design: EdgeHD
Aperture (mm): 234.95 mm (9.25 in)
Focal Length: 2350 mm (93 in)
Focal Ratio: 10
Focal Length of Eyepiece 1 (mm): 23 mm (0.91 in)
Magnification of Eyepiece 1: 102x
Finderscope: 9x50
Star Diagonal: 2" w/ 1.25" adapter
Optical Tube: Aluminum
Highest Useful Magnification: 555x
Lowest Useful Magnification: 34x
Limiting Stellar Magnitude: 14.4
Resolution (Rayleigh): 0.59 arc seconds
Resolution (Dawes): 0.49 arc seconds
Light Gathering Power (Compared to human eye): 1127x
Secondary Mirror Obstruction: 3.35 in (85 mm)
Secondary Mirror Obstruction by Diameter: 36%
Secondary Mirror Obstruction by Diameter: 13%
Optical Coatings: StarBright XLT
Optical Tube Length: 22 in (559 mm)
Optical Tube Weight: 21 lbs. (9.53 kg)
Dovetail Compatibility: CGE Mount
Mount
Mount: German Equatorial Mount
Instrument load capacity: 55lbs
Tripod height adjustment range: 47.25” to 77.5” including EQ headA
Tripod leg diameter: 2"
Latitude adjustment range: 3º-65º
Tripod Weight: 19.2 lbs.
EQ Head Weight: 44 lbs
Max Slew Speed: 5º/second (4º/second is default)
Tracking Rates: Sidereal, Solar and Lunar
Number of Auxiliary ports (for hand control and accessories): 2
Autoguide Port: Yes
USB Port: Yes
Software: New telescope control PC software
Included Items
CGX Equatorial Head
CGX Tripod
Accessory Tray
One 17 lbs counterweight
NexStar+ Hand Control
DC Power Cable (plugs into cigarette lighter socket)

Some items that are showing as in stock are in stock at our holding warehouses, not at the shop. To double check the stock levels at the shop, please contact us on 01909774369 or sales@rothervalleyoptics.co.uk.

The delivery times for most items is 1 - 2 days but again, please double check stock levels on important orders before placing an order via the website.

The delivery costs for courier next day are for mainland UK only. If you live in the Scottish Highlands/Islands, Channel Islands or Northern Ireland, then a shipping surchage will apply. please contact us for prices. Smaller items can still go 1st class via Royal Mail.

Please note that if you are wanting to take advantage of our Saturday and Sunday timed services or next day pre 12 or pre 10:30 services, you MUST check that the stock is here at the shop before placing orders. Also, orders using the Saturday and Sunday services must be placed before 1pm the previous working day. Also, please remember to check that the stock is here at the shop before placing orders. If the stock is not at the shop, we won't be able to ship on any of the timed services. 

Please note International customers will need to contact us for a shipping price prior to ordering via the website. We don't ship all items internationally. It is at our discretion what we ship outside of the UK. This all depends on the size and weight of the items. Please get in touch with us for any postage costs. Please note we do NOT ship telescopes or heavy items outside of the UK. This is due to massive postage costs and problems regarding returns.

If you have any questions regarding stock levels or delivery, please get in touch.

Zygo Interferometer Testing For ED Refractor Telescopes!

We are extremely pleased to announce our Zygo Interferometer is now installed and ready for use! Our experienced staff can test refractor lenses up to 120mm aperture and provide a comprehensive 2 page report showing the optical quality and Strehl ratio, plus much more information. We are using the very latest Zygo MX software to provide a more detailed report compared to other standard reports.

The interferometer is essentially a measuring instrument. Within the interferometer is a calibrated laser that is pointed through the optical test surface, then onto a high quality reference sphere, then back through the test subject then to an internal camera which gives us the measurement on the screen. From this, we can adjust the position of the test optic and the reference sphere to obtain a perfectly calibrated system. The more central the laser to the test optic and then on return, the better and more accurate reading and measurement we can take. This takes a lot of adjustment to get the best results from the optical surface. Once the measurement has been taken, we are provided with a series of results that show the optical quality of the surface plus other information. Continue reading for an explanation of the individual values and you can also see a test report that was done on one of our RVO Horizon 60 OTAs. 

We are offering certain telescopes with a Zygo test at an extra cost. Mainly ED doublets and triplets. All available telescopes with a Zygo test report are listed here. Just select Zygo Test Report from the drop down box at the top of the listing and we will test the optics in house and provide a full 2 page report with your scope. This will show you the optical quality of your telescope optics. We can also offer this service on your refractor telescope. Please get in touch for more details about this. 

At Rother Valley Optics, one thing we pride ourselves on is customer service and quality of our equipment. When we test your telescope, we will ensure that it is of the highest quality otherwise, we will reject the scope under our strict quality control and test another model for your peace of mind. One of the main values to look at when testing a refractor is the Strehl ratio. The higher this number, the higher quality lens you have. At Rother Valley Optics, we will guarantee the highest possible Strehl ratio for your telescope.  We will aim to provide 0.95 Strehl or higher on Takahashi, RVO Horizon, William Optics and many more! Generally, the higher the Strehl ratio, the lower the Astigmatism and Coma meaning a better image quality from your instrument. 

Other measurements such as the PV and RMS are important too. With these measurements, the lower the number the better as it shows less curvature on the lens. The flatter an optical lens, the better it will perform. The PV rating (Peak To Valley) is a measurement from the highest point (Peak) to the lowest point (Valley). From this we get the RMS (Root, Mean, Square). This is a similar figure to the PV and measured exactly the same way. The RMS is basically an average height difference from the PV so again, the lower the better. As you can see form the example below, we measured an RMS of just 0.027 wave which is a very good value.

We also measure the Power with our systems which is essentially the error from the reference sphere to the test optic. The reference sphere we use on our system is a very high quality sphere so the closer to zero the Power, the less error between the 2 elements thus ensuring a higher quality optical surface. 

You will also see some more values such as Astigmatism and Coma. Again, these are measured by the interferometer when we take measurements of the optical surface after adjustment. These are values which ideally would be at 0 but as our test optics are all curved lenses, there will always be astigmatism and coma present. The lower the number, the less of these aberations you will effectively see but with most refractors, you can buy field flatteners which will compensate for the coma anyway. The astigmatisms value is explaining the error between the symmetrical curvature of the lens. Basically, no lens will be perfectly symmetrical, the lower the astigmatism, the more symmetrical the lens surface is. 

Once the Zygo test report has been completed, the optical alignment is thoroughly tested and tuned to ensure they are spot on before they leave us. 

All available telescopes are on the website at the link below and ones we've tested already that are available straight away are also listed.

https://www.rothervalleyoptics.co.uk/zygo-tested-refractors.html

Here is an example of the test what we provide. This was a test on one of our Horizon 60 ED OTA's.

For any questions about this amazing new service, please either call 01909774369 or email sales@rothervalleyoptics.co.uk.

Are you interested in this product but would like to speak to someone with some more information? Simply fill in the form below and we will get back to you as soon as we can!

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