Celestron C6 Review: A Goldilocks Scope?
Updated: Jan 31, 2021
Good optics in a compact, highly portable form factor at a great price.
I've purchased over a dozen telescopes over the last 15 years, though I usually only keep 2-3 at any given time, selling or trading the others. Part of the reason for the frequent telescope swapping is to try out other types and sizes of scopes for a while, and part is to determine what telescopes best fit the my lifestyle. Since I have a family and also work long hours at my day job which requires a 4 am start time, nighttime observing sessions tend to be short-lived or happen during weekend trips and vacations. So, I've found that size, weight, and ease of use are critical factors to maximizing the number of observing sessions. If it is going to take me more than a couple of minutes to get the scope out the door, set up, and start observing, then often I'll skip out on many of those 10-20 minute observing sessions before bed. So, after trying out everything from longer refractors to 10" dobsonians, I keep gravitating back to shorter refractors and SCTs. I had a 6" SCT just like the one in this review a few years ago but sold it to go back to a mid-size refractor. I decided I wanted to maximize the amount of aperture on a lightweight mount, so I decided to try out the C6 once again.
This go around, I purchased the scope from Highpoint Scientific for $399 (though the MSRP is $649). You can find links below to the OTA as well as other configurations with mounts at the bottom of the article. The $400 price point for 6" of aperture is one of the key selling points to this scope. You are not going to buy a quality new ED or APO refractor of 4" or larger aperture for $400, and while you could pick up an 8" dobsonian for a similar price, you would give up the excellent compact size, low weight and fantastic ergonomics of the C6.
The C6 arrived well protected in form-fitting foam packaging material. This foam that the scope ships in can be removed from the box and used inside carrying cases of similar size to the box. However, I prefer to use as small a case as possible to make travel more manageable, and you can find camera bags or other gear bags that work well and keep the total volume smaller.
The fit and finish of the scope are excellent, and the Celestron lettering looks to be screen printed in some manner and is nice and crisp. One Celestron scope I owned in the past had stick-on letters that made the OTA look very cheap. The optics were clean and focuser operation smooth. While the focuser turns smoothly, precise focusing can be challenging since small turns of the focuser are often needed. So, you have to hunt around a bit to get the best focus. You can help improve focusing precision by fitting a rubber or foam donut over the knob which helps to increase the size of the knob. That, in turn, makes small turns of the focuser knob easier. Alternatively, you can spring for a feather touch focuser that gives you both coarse and fine focuser adjustments, though that will set you back a few hundred dollars.
Being an SCT, the scope does have the usual SCT drawbacks. The complex light path through the scope is prone to disruption by tube currents while the scope is cooling down. Also, SCTs usually have good optics, but since they are mass-produced, they often don't have the same quality optics as higher prices telescopes. Still, what is often forgotten is that aperture rules more times than not, and a 6" SCT is going to show you a lot more objects in the night sky than a great 3" refractor will. Yes, the views through a good 4-5" refractor are going to beat those through the C6 on most objects, but such scopes will also be longer, heavier, and cost much more than the C6 will. One thing a refractor will almost always win out on though is the field of view, and so I complement this C6 with a 3" refractor for when I want to take in large star clusters or want even more portability than the C6 offers.
Despite the potential issues with turbulent views while the scope is cooling, the small size of the scope does allow it to cool quickly, much faster than an 8" or larger scope would. Any turbulence while the scope is cooling can impact the views of planets and double stars, though some users have found wrapping the scope in an insulation material to slow the cool down can help keep the views crisp. Alternatively, setting the scope outside a half hour or so before you plan to use the telescope can allow it to reach equilibrium before you are ready to observe. However, the slow cooldown doesn't really impact views much of nebula or most other deep-sky objects. So, if your high power view of Saturn is wavering quite a bit, look at something else for 10-15 minutes while your telescope settles down.
During the few weeks I have been using this C6, I've had lovely views of Saturn and Jupiter with the Great Red Spot easily visible, and the Cassini Division in Saturn's rings also prominent. The 6" aperture shows a lot of deep-sky objects, and while they all show more detail than in my 3" refractor, they do fail to keep up with views through 8" or larger scopes as would be expected. Globular clusters are partially resolved in the 6" scope, but not nearly to the extent as in an 8" or larger scope. But, they are far better than in a 3" scope. The main area the 6" SCT lacks in terms of deep-sky objects is a wide field of view. Being limited to around a 1.1-degree field of view means you won't get the sweeping vistas of the Milky Way or capture the full extent of the Andromeda galaxy, though the core of the galaxy does look nice through the scope.
Overall, I highly recommend the Celestron C6 if you are looking for a medium aperture scope that is lightweight, compact, easy to move around, and won't break the bank. Yes, you can get much better 6" telescopes, but not for $400 (prices vary and can be over $600 at times though) and weighing only 7 lbs with a 14" length. The C6 probably shouldn't be your only telescope, but it is a good all-around scope and can serve that purpose well if need be. But, pair it with a moderately priced 3" refractor, and you have a nice setup that can show you a lot of the night sky. While I'd like a nice 12" or larger dobsonian reflector to bring in the views on deep-sky objects, the reality is that I'm just not going to get a scope that big out under the stars very much. So, I can't justify the cost to keep something around that might only get used once or twice a year. So, if you are in a situation like me, consider the C6, it can help you get out under the stars more often.
Here are some links to where you can buy the C6 OTA by itself or with the SE or Evolution go-to mounts that will give you tracking and additional functionality, but with a much higher price. Keep in mind you will need to spend at least a couple hundred dollars for a mount capable of handling the C6 without shaking and frustrating you (though perhaps much less on the used market), so the 6SE can be a nice package option. However, while go-to and tracking are nice to have, it does take a little longer to start observing, and you have to worry about things like battery levels that can derail your observing session. I was able to pair the $400 C6 with a $200 Twilight 1 mount, saving a good bit over the 6SE setup. However, if the C6 is priced at $600 or higher when you are looking to purchase, then it is probably worthwhile to buy the 6SE setup, and sell the mount if you don't need or want it.
Note: As an Amazon Associate I earn from qualifying purchases made through Amazon links.
Celestron C6 bare OTA
From Highpoint Scientific: https://bit.ly/2wSwGTj
From Amazon: https://amzn.to/2M6iDOW
From Astronomics: https://bit.ly/2oV5lM9
Celestron 6SE (scope plus SE mount)
From Highpoint Scientific: https://bit.ly/2NWgDdO
From Astronomics: https://bit.ly/2Q6QASJ
Celestron Evolution6 (scope plus higher-end evolution mount)
From Highpoint Scientific: https://bit.ly/2Qd0v99
From Amazon: https://amzn.to/2NrS23A
From Astronomics: https://bit.ly/2wRDH73
Some Mounts for the C6
Explore Scientific Twilight 1 Mount: https://amzn.to/2oPzA72
Stellarvue M2 Mount: https://bit.ly/2NwsbYo
Celestron AVX Mount: https://amzn.to/2Qdt6va
Other accessories for the C6
Focal reducer (drops scope from f10 to f6.3): https://amzn.to/2x0s4tR
50mm correct image finder: https://amzn.to/2wU7xa3
Red dot finder: https://amzn.to/2MXC2H5
Dew Shield: https://amzn.to/2NTWi8P
Orion 32mm Plossl: https://amzn.to/2MUjeIG (about 47x magnification)
Use the 25mm Plossl included with scope (about 60x magnification)
Agena Dual ED 12mm: https://amzn.to/2M7BtFf (about 125x magnification)
Agena Dual ED 8mm: https://amzn.to/2wU81Np (about 188x magnification)
Televue 24mm Panoptic: https://bit.ly/2CvISyL (about 63x magnification)
Televue 13mm Nagler: https://bit.ly/2oMgGxP (about 115x magnification)
Televue 9mm Nagler: https://bit.ly/2oVSlWB (about 167x magnification)
Televue 7mm Nagler: https://bit.ly/2Cykxbq (about 214x magnification)
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