Celestron CPC 925 Review & (c8 vs c9.25)

By: Vlad Fedosov
12/06/2017

Intro:

I have been a Meade LX-200 user for many years having owned an 8”, 10”, and 12” variants. I have always loved the fork mounted design SCT's for their simple setup and portability. For one reason or another, I have always seen Celestron offerings of the fork mounted scopes as a bit sub-par. When I came across a local CPC 925 I could not resist the chance to finally test out one of Celestron's modern GOTO fork mounted SCT’s(as well as have the perfect chance to compare my excellent c8 to a c9.25 that I was considering upgrading to). The CPC 925 weights in at 58lb, and has a focal length of 2350mm.

Testing:

I had the opportunity to try out the CPC 925 on one of the rare clear nights that we get here in the northwest in early December. The scope was setup in my mag 4 backyard with a ¾ full moon that rose about an hour after sundown. For a comparison, I had my c8 setup next to the CPC. Both scopes have the XLT coatings. The setup of the CPC was easy to do with one person. It has a nice handle on the side of the fork, and a grove on the bottom of the opposite fork for your fingers to slip into. It is quite comfortable to grab the CPC, and I find a bit easier than the Meade LX scopes. I must say that this is a fairly large scope and you do need to be in good health if you want to set this up by yourself(similar size to the Meade 10” LX-200).

Physically the CPC 925 is an impressive looking scope. For one reason or another, I do still prefer the aesthetics of the fork design on the Meade LX-200 scopes. I guess to me they just look more professional with the more angular all-metal design of the fork. I was eager to find out if the CPC forks would live up to the more professional look of the Meade’s.

Once sundown came I turned on the CPC and was greeted with a screen on hand controller that asked to enter the time. By the time I pulled out my phone to check the current date and time the built-in GPS had already auto input all of the required data and the hand controller now displayed a message that I was ready to align the scope. This seems 2-3 minutes faster than the GPS locked-on on several Meade scopes I have tested. I did the 3-star SkyAlign that the CPC features. If you are not familiar with this alignment procedure, all you do is point the scope to any 3 bright stars in the sky and the alignment is done. The first time I read the instructions on doing this I did not believe that it could be that simple… It was. You do not need to know the names of the stars, and from what I understand you can even use the bright planets. Brilliant! This is far superior to what I’m used to doing on the Meade LX-200 scopes as well as my LXD-75 mount.

It came time for me to test the CPC mount and see how it fared compared to the Meade’s. With my heavy 25mm Explore Scientific 100° eyepiece in the diagonal producing about 94x I thumped the side of the OTA with my palm. Much to my surprise, the vibrations were settled in under a second. I was impressed. In use, the scope felt very well planted and very stable. I’m now confident that this mount is at least as good as the Meade LX scopes!

I next turned my attention to the optics of the c9.25 as I was very interested to see how much better it was compared to my c8 OTA that I use on my LXD-75. I turned both the scopes towards the double-double in Lyrae. To keep the view as fair as possible I used the same 25mm ES 100° eyepiece in both the scopes. It did produce 14x more in the c9.25 but I did not have any better-matched eyepieces to test with. The first look at this showcase object revealed that the seeing was not going to cooperate this night for close double star work. Neither of the stars pairs was close to being split and I could tell that more magnification would not help. Taking a look through the c8 confirmed what was seen in the c9.25. I was next excited to see if what people say about the c9.25 having a flatter field would be obvious compared to my c8. I pointed the scopes at Albireo in Cygnus and was greeted by this beautiful easily split wide double(it was easily split in the 50mm finder of the CPC). I noted the surrounding star field in the c9.25 and then proceeded to compare the view that the c8 produced. I could tell that the field was a bit flatter in the c9.25 at the edge of FOV but honestly, to me, this was not a huge difference and something that I really had to look for. I’m still in my 30’s and from what I understand folks that are a bit older can notice this difference more easily.

Next, I turned both the scopes to m57, the ring nebula. I already had the 25mm eyepiece in the c8 so I looked through the smaller scope first. The view was not too impressive in these less than ideal viewing conditions. But the ring was clearly visible and I could see the darker central area. Contrast this night was less than average in the c8 probably as the moon was already rising. I next took a look through the c9.25. I was greeted by a similar but clearly brighter ring nebula. I was honestly surprised by how much brighter the nebula looked through the slightly larger scope. It was not the view that I get from my 16” Lightbridge but clearly brighter. The central area of the nebula was also darker(perhaps because of the slight magnification increase). I also tried to note the surrounding stars to evaluate the flatness of the field and again did not discern a large difference.

I wound down the night by observing some wide doubles in Cygnus and Pegasus. The GOTO of the CPC 925 did excellent the entire night. At one point I went inside to warm up for about an hour and spend some time with my family. Once back outside the double, I was observing was just where I had left it in the FOV. The tracking looked spot on. The operation of the motors is not quit but is quieter than the Meade LX line. It is however not quite as quiet as the Losmandy g11 that I own. I don’t find the noise level objectable though.

Conclusion:

I found the CPC 925 an overall pleasure to use! I think this is about as big of a scope that I would setup and not consider it a complete drag such as is the case for my Meade 12” ACF on g11 or my Meade 16" Lightbridge. I do find that my c8 on the LXD-75 mount gives very similar performance in a package that is much smaller and lighter. From my time spent with both these setups, I decided to stay with my c8. I can carry the scope out fully setup on the mount where’s the CPC 925 requires multiple trips. I was also considering upgrading my c8 OTA to a c9.25 OTA to ride on the LXD-75. From doing a comparison of the scopes the c9.25 does pull in more light but I think it would really tax my LXD-75 mount too much and make it quite a bit harder to carry out in one go(although I’m sure it’s doable). The conclusion that I came to is that if I’m going to spend the extra effort to setup the CPC 925 I might as well setup my Meade 12” or 16”. If you, however, do not own a larger scope I think the upgrade from a c8 to the c9.25 would be much more tempting!

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