Sharpstar SCA260 Aspherical Cassegrain Astrograph
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Sharpstar SCA260 Aspherical Cassegrain AstrographSharpstar SCA260 Aspherical Cassegrain AstrographSharpstar SCA260 Aspherical Cassegrain Astrograph
Sharpstar SCA260 Aspherical Cassegrain AstrographSharpstar SCA260 Aspherical Cassegrain Astrograph

Sharpstar SCA260 Aspherical Cassegrain Astrograph

£4,289.00
  (1 Review)
✓ 2 year warranty

:  

Out of stock due 15-20 working days

About this product

Model:  sharpstar_sca260

The SCA260 is the latest Astrograph from Sharpstar and offers a large aperture combined with a fast focal ratio and well corrected wide field.

Designed for use with camera sensors up to full frame.
 
Features
 
The SCA260 features an aspherical primary mirror and both primary and secondary mirrors feature enhanced 95% reflective coatings.
 
A 3" three element field corrector is incorporated into the optical path that ensures a well illuminated, wide and flat field.
 
The optical tube is made from carbon fibre for both light weight and rigidity with less thermal shift.
 
At the focal plane of the SCA260 is a heavy duty 3" rack and pinion focuser which has excellent load bearing capacity, a 1:10 dual speed mechanism and which provides very smooth performance free of image shift.
 
The two-section thread design of the focuser provides the telescope with popular M54×0.75 and M48×0.75 threads for most stock imaging cameras and accessories.
 
The focuser is compatible with popular motor focuser add ons including the ZWO EAF.
 
The SCA260 is a good alternative to an SCT instrument and benefits from not having a full aperture corrector liable to attract condensation,  and the provision of a high quality 3" focuser (instead of primary mirror focussing) which ensures collimation stability and focussing precision.
 
The SCA260 is ideal for both medium wide field imaging with full frame sensors and high resolution imaging of smaller galaxies and nebulae with smaller sensors.
 
Specifications
 
  • Aperture size:260mm
  • ​Focal length:1300mm
  • Focal ratio:f/5
  • Primary mirror type:aspherical reflective mirror
  • Primary mirror material:PZ33(similar to Pyrex glass)
  • Corrector:three-element air-spaced lens structure
  • Minor axis:120mm
  • Secondary mirror type:spherical reflective mirror
  • Image circle:80mm
  • Tube material:carbon fiber
  • Tube outer diameter:280.5mm
  • Tube length:712mm
  • Tube weight:15kg
  • Resolution:0.46
  • Focuser:3.2"
  • Limiting visual magnitude:13.8
  • Back-focus:75mm(start from the base of the mounting thread on the housing)

 
 
 

Customer reviews

Average Rating (1 Review):  
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IFirst few months with the SCA260
Saturday, 6 August 2022  | 

I have owned this telescope for a number of months now, although use has been restricted by the lack of astronomical darkness over the summer. This is the first large aperture telescope I have owned and I was concerned about my ability to collimate the optics. I can say with the correct tools this has been much more straightforward than I expected and even though I dismount the telescope after each imaging session, it has also held collimation well. The key tool for me was the Takahashi Collimating Scope. This needs to be screwed to the end of the focuser to prevent play. The main challenge was finding a ferule adapter to do this. Once done its is straightforward to center the secondary. The primary can also be adjusted using this, but I found it easier to use a TS Colli instrument that I owned. I have not needed to make further adjustments at night after confirming the set-up using a de-focused star.
The disappointing part of this scope is the focuser which exhibits noticeable play. This becomes worse as extended. I have minimized this by adding a manual rotator which means the focuser does not extend out much from the draw tube. The connecting threads of the focuser to the body are not standard and upgrading the unit would need a custom adapter. Despite these issues I am beginning to take some pleasing images. I think the fast optics and the good match of focal length to the pixel size of my camera have been factors. The total assembly with camera weighs in at 18kg. Using an OAG guiding performance has been good on my EQ6-R mount, sometimes with errors below 0.4 RMS.
Check out some of my more recent images on Astrobin to see what is possible with this scope. https://www.astrobin.com/users/Alistair/

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