Carbon Fiber Tube Upgrades For Celestron® C-14 SCTs
 "C-14 with replacement carbon tube and dew shield from CST")
Photo by: Simon Kfir
Stay Focused
For applications where maintaining image quality in changing temperatures is crucial, as in astrophotography, a carbon fiber optical tube is a reliable solution. Aluminum tubes tend to shrink as temperature decreases, which will cause the primary and secondary mirrors to move closer together, resulting in a shift of the focal plane off the imaging chip and producing blurry images. Carbon fiber tubes, on the other hand, have a significantly lower shrink rate, which allows for longer imaging periods without the need for frequent refocusing. In fact, carbon fiber has a shrink rate that is at least one-fifth that of aluminum, which can result in a five-fold increase in the amount of time that can be spent imaging before refocusing is required. However, it is important to note that focus may still need to be adjusted when changing filters and that temperature changes can vary from night to night."Before upgrading my C-11* to a carbon fiber telescope tube, I had trouble with narrowband exposures of over 45 minutes on a typical Michigan night, as the temperature can easily drop 2 degrees per hour. In just these few minutes, my aluminum OTA would shrink enough to defocus my system. However, with the carbon fiber tube upgrade, I'm now able to image for longer periods without needing to re-focus. As you can see in the M-27 image I posted here, I used a series of 90 minute H-alpha sub-exposures (plus RGB). I've even been able to take 120 minute narrowband exposures, which would have been impossible for me without the carbon fiber tube upgrade."
---Frank
*CST no longer makes upgrades for the C-11 or any other specific brand or model except the C-14. The reason is that the C-14 tube has not changed since the 70s, while all other scopes now have far too many variations to track.
Swapping out the tube
Swapping out the tube is very straight forward...
• Turn the focus knob to move the mirror as far back as it will go.
• Lay the scope on it's side for the rest of the process and roll it as needed.
• Remove the screws that hold the corrector, then remove the corrector.
• If you are nervous about touching or damaging the mirror surface during this procedure, then it would be best to disassemble the focuser assembly, remove the stop ring from the baffle tube, and remove the mirror altogether.
• You now have access to the nuts and bolts holding the tube to the cells. Remove the nuts and bolt and then the tube.
• This is a good time to clean your optics and re-lube the scope.
• Reverse the process using the new tube.
• Minor collimation will be needed to complete the process.
Stay focused!
CarbonScopeTubes.com
CarbonScopeTubes.com
We do not stock the Celestron® C-14 telescope tubes on a regular basis.
When a production run is planned, we typically post a classified ad in the "Telescope-Catadioptric" catagory of the very popular Astromart astronomy website. Or you can simply add your name to the notification list linked below.
If the tube you need is currently sold out, please
add your name to our notification list
for an up coming run. Next run in late 2024.
add your name to our notification list
for an up coming run. Next run in late 2024.
