14" Celestron EdgeHD versus 12.5" Planewave CDK

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Nov 25, 2024 · Edited: Nov 25, 2024

I've run a number of C14 Edge scopes and a CDK 20 (obviously bigger) but that's enough to know the basic differences. The optical quality can be similar but neither supplies a test report so it's hard to tell what you'll get up front–in either case. The focusing system on the Celestron is poor but it's fixable; whereas, the PW doesn't even come with a focusing system. You'll have to add it to the PW and you'll need something like a SMFS from Optec for the Celestron so that's a bit of a wash. The advantage of the PW is that it's optically faster with a larger FOV. However, if you want to shoot smaller objects like galaxies, the longer EFL of the Celestron is an advantage. And then there's the price. Fully configured, the Celestron will be less expensive than the PW but I'd recommend a beefier mount so the entire system (mount+OTA) may not be that far apart–depending on the components that you choose. One other thing to consider is that the 12" system will be a bit more portable if you don't have a place to mount your scope. The C14 is "moveable" but I wouldn't call it portable.

In my view, they are both good scopes and you can get great results with either one.

John

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Yuxuan

Dec 7, 2024

Actually the PW 12.5” does come with a focuser.

Ani Shastry

Dec 7, 2024

That’s correct, the CDK12.5 comes with the Hedrick focuser (no rotator though).

And for the Celestron, I would recommend the Moonlite litecrawler over the Optec SMFS as it avoids weight and cabling on the front of the scope (from personal experience it wasn’t terrible, but I would have preferred having a focuser at the rear end), plus it has a built-in rotator.

The other thing you will have to deal with on the PW side is the Delta T for dew management, and EFA for focuser operation and temp sensors.

My personal vote would be the PW12.5, given my experience with the EdgeHD 11 from Celestron and CDK14 and now CDK24 from PlaneWave, but either of those scopes should serve you well.

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AstroRBA

Dec 9, 2024 · Edited: Dec 9, 2024

I've been running an Edge 14 with an ASI6200MM for just over a year now after taking some very good advise from John Hayes.

I run the setup at the full F11 (3910mm) focal length and also use an On Axis Guiding system from Innovations Foresite; I also have the Optec Secondary Focuser (but haven't yet been able to install it) - I'm not far from Ingersol in Mississauga (in a really bad Bortle 8 zone with horrible seeing most of the time). I think that the 3910mm FL is a good match under these my sky conditions.

I find that keeping this unit set up outside permanenty also works well.

Just my two cents …

Edit: I also have a Hyperstar for my Edge 14 to achieve F2 (about 780mm FL) wide(r) field BUT, I have not used it as of yet .. (I had one on a previous Edge 11 but wasn't very impressed, likely due to the massive light pollution in my area);

Dec 9, 2024 · Edited: Dec 9, 2024

Depends on your objective. One is medium field and the other longer, for DSO.

a few notes on the EDGE series:

I use a EDGE 925 with stock focusing and have never had a problem with it. The electronic focuser gets the image sharp and holds it. Some worry that leaving the mirror locks loose for the EF will introduce mirror flop (which is why they opt for an external focus mechanism), but I’ve not seen it.

One thing to note is that an EDGE scope is mostly sealed, so it doesn’t tend to accumulate dust on the mirror…nor does it produce spikes on stars. Mine stays outside and is ambient temperature, so it doesn’t need active ventilating. But the stronger 14” EDGE you’re considering may show temp variations more readily and benefit from faster temp stabilization. (The 925 is 2350mm)

the EDGE also collimates very easily and rarely needs adjustment more than 1-2 times a year (can’t speak to the PW).

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Brennan Jontz

Dec 9, 2024

I've had my CDK12.5 for a couple years now, no complaints on my end. I shoot with the .66x reducer so my effective focal length is around 1670mm. I had a custom imaging train made to accommodate a OAG with the reducer as that can be a challenge with the backfocus requirements. I shoot with an ASI2600MM and the scope is permanently mounted in my ROR observatory. Can't say much about the EDGE 14, but just that I really enjoy the PW.

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Dec 9, 2024

Personally speaking, I would go for the CDK simply due to the fact that it's a CDK, it's Incredibly sharp.

Kay Ogetay

Dec 9, 2024

Personally speaking, I would go for the CDK simply due to the fact that it's a CDK, it's Incredibly sharp.

I wonder if there is a side-by-side comparison under the same conditions (time, location, etc). I'd like to see that.

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Dec 9, 2024

Just last week there was a test published with several scopes pointed at Crescent Nebula…and now I can’t find it!

sharpest was PW Delta Rho, followed by one of the Edges (I think 14”) then others.

the point was that scopes of all kinds are absolutely amazing and produce very fulfilling results. The group included reflectors and refractors.

Will keep looking.

Anderl

Dec 9, 2024

Dave Rust:
Just last week there was a test published with several scopes pointed at Crescent Nebula…and now I can’t find it!

sharpest was PW Delta Rho, followed by one of the Edges (I think 14”) then others.

the point was that scopes of all kinds are absolutely amazing and produce very fulfilling results. The group included reflectors and refractors.

Will keep looking.

I have not seen that comparison but i can remember this one done by timothy martin.

cdk 12.5 and edge hd 11 are part of this comparison. The differences are very subtle between the scopes. The price and size difference between an redcat 71 and the cdk 12.5 is definitly bigger than the small difference in the resulting images.

https://www.astrobin.com/3853td/

Dec 9, 2024

Thanks, Anderi!

Well, I’m an idiot. This is indeed the post I remember, although quite inaccurately! But the conclusions are the same. I don’t know know why the Z61 looks so bad.

Josh Breezy

Dec 9, 2024

Just pull up images taken by CDK sharp sharp sharp

Dec 10, 2024

Honestly I can't imagine buying a scope like a Edge 11 or Edge 14 and thinking that it remotely compares optically to a Planewave CDK 12.5.

How many SERIOUS professional observatories have a Celestron SCT parked in them vs a Planewave CDK?

I'd happily buy a 2010 vintage CDK 12.5" or old RCOS 12.5" over a brand new Celestron SCT any day…

Caveat: This is coming from the perspective of using the scope for purely deep sky imaging. if you're doing 50/50 planetary imaging, or even doing some visual observation at times, then the SCT is definitely worth a look.

Dec 11, 2024 · Edited: Dec 11, 2024

That's mostly because Celestron doesn't manufacture $50,000 scopes.

On the other hand, given the nearly equivalent performance of the two, as demonstrated above, I think the extra expense for the PW would give me marginal returns. I'm impressed at how the demo shows that 33 hours is a great leveler among scopes of many types, including small diameter refractors.

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Gregory Terrance

Dec 11, 2024

My two cents – I would be heavily biased toward the C-14 (but I am a planetary imager). Even if planetary and lunar imaging were secondary to the choice, I think I'd still go for the C-14. Easier to find a used OTA, less expensive, better light grasp and IMO, more flexible. There are also dozens of options for the C-14 including various focusers, reducers, etc.

Regards,
Greg

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Dec 11, 2024

Alex Nicholas:
Honestly I can't imagine buying a scope like a Edge 11 or Edge 14 and thinking that it remotely compares optically to a Planewave CDK 12.5.

How many SERIOUS professional observatories have a Celestron SCT parked in them vs a Planewave CDK?

I'd happily buy a 2010 vintage CDK 12.5" or old RCOS 12.5" over a brand new Celestron SCT any day...

Caveat: This is coming from the perspective of using the scope for purely deep sky imaging. if you're doing 50/50 planetary imaging, or even doing some visual observation at times, then the SCT is definitely worth a look.

1). You might go review the interferometric test report that I published on CN here: https://www.cloudynights.com/articles/cat/articles/interferometrically-testing-two-celestron-c14-edge-telescopes-r3095. The first telescope is every bit as good optically as the CDK20 that I used to own. The test results for that 20” telescope are posted on my image page. Neither manufacturer supplies test data and I’ve seen as many marginal SCTs as CDKs and in most cases the optics can be quite good in either case.

2). I am currently sitting in Santiago on my way home from visiting Obstech to work on my scope. Planewave scopes are the overwhelming favorite for remote installation but the number of Celestrons operated by one research group has grown quite a bit. I agree that Celestrons are not the top choice but they are still selected by some operators. Heck, I even ran a C14 Edge remotely for 5 years and I got superb results from it. Go check out the images from it in my gallery.

John

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Dec 11, 2024

John Hayes:
Go check out the images from it in my gallery

I'm well aware of your magnificent gallery, John. Arguably, some of the most incredible work on Astrobin.

Whilst I'm not saying that the Edge 14 is a 'bad' telescope. I just believe that it is in a different class to something like a Planewave CDK or a high quality RC optical system.

I've not owned a planewave myself, but I lusted after them, as they were released in my country shortly after I bought my 10" RCOS in ~2009, and from what I could see then, it was a superior telescope to the RCOS 10" I had just purchased...

To that point, I've also not owned an Edge HD telescope of any aperture, but I do understand the optical system well, and have a good understanding of it...

I will say this, and perhaps that will make a little clearer what I was trying to say in my previous post.

I would personally prefer a CDK or RC over an SCT in a purely imaging only situation... Not because I think the SCT is a bad telescope, but because I feel that the CDK or RC optical system is designed from the ground up as an imaging system, with no regard for its visual performance. The SCT is still, at its heart, an SCT.

I live in sub-tropical climates, and I can assure you that no amount of dew shield and heater bands would prevent the corrector on my C11 XLT from fogging up eventually at any time of the year where I live... this is not a concern with a CDK/RC, as the primary and secondary can be very lightly warmed with a low power heating element...

For me, the decision is simple, and if the price was the same or even close, there is no way I'd be buying a Celestron 14" over a PW CDK 12.5, or a similarly high quality RC telescope for an imaging rig.

Kay Ogetay

Dec 12, 2024 · Edited: Dec 12, 2024

John Hayes:
...but the number of Celestrons operated by one research group has grown quite a bit. I agree that Celestrons are not the top choice but they are still selected by some operators.

Just wanted to add. Like 10-15 years ago, my college had Meade LX series telescopes, three different versions 12", 14", and 16". And they were actively publishing research on binary stars, flares, etc. Anything can be used for research depending on what the goal is. Most of the important scientific research was done with scopes that none of us would use today.

I didn't use any telescopes at this focal length other than my observatory experience for research, but I know at that focal length atmospheric conditions matter the most. That's why I asked for a scientific comparison because this has been on my mind for quite a while and I still have not seen any serious comparison. Sorry if I missed it.

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Dec 12, 2024

Alex Nicholas:
John Hayes:
Go check out the images from it in my gallery

I'm well aware of your magnificent gallery, John. Arguably, some of the most incredible work on Astrobin.

Whilst I'm not saying that the Edge 14 is a 'bad' telescope. I just believe that it is in a different class to something like a Planewave CDK or a high quality RC optical system.

I've not owned a planewave myself, but I lusted after them, as they were released in my country shortly after I bought my 10" RCOS in ~2009, and from what I could see then, it was a superior telescope to the RCOS 10" I had just purchased...

To that point, I've also not owned an Edge HD telescope of any aperture, but I do understand the optical system well, and have a good understanding of it...

I will say this, and perhaps that will make a little clearer what I was trying to say in my previous post.

I would personally prefer a CDK or RC over an SCT in a purely imaging only situation... Not because I think the SCT is a bad telescope, but because I feel that the CDK or RC optical system is designed from the ground up as an imaging system, with no regard for its visual performance. The SCT is still, at its heart, an SCT.

I live in sub-tropical climates, and I can assure you that no amount of dew shield and heater bands would prevent the corrector on my C11 XLT from fogging up eventually at any time of the year where I live... this is not a concern with a CDK/RC, as the primary and secondary can be very lightly warmed with a low power heating element...

For me, the decision is simple, and if the price was the same or even close, there is no way I'd be buying a Celestron 14" over a PW CDK 12.5, or a similarly high quality RC telescope for an imaging rig.

Alex,
Thanks for that explanation and I can appreciate your comments, but I want to clarify two things.

1) The Celestron Edge HD scopes were optically designed specifically for imaging. I agree that the mechanics leave a lot to be desired, but the optics can cover a 42 mm (even up to 52 mm) image circle with round, pinpoint star images. Even though I had to fix the mechanics, I ultimately justified moving beyond my Celestron mostly because I wanted a larger aperture; not because the optics weren't good.

2) I disagree about your feelings about dew prevention. With the correct configuration, dew can be successfully prevented up to within just a couple of degrees of the dew point even in "tropical conditions". Warm air can hold a lot more water than cold air so things just get a lot wetter if the surfaces of the optics are not carefully temperature controlled. Dew control is all about keeping the optical surfaces at or above the ambient air temperature no matter how much water is in suspension. When the dew point spread goes below 1-2 degrees, the conditions are on the hairy edge of fog and the atmospheric transparency starts to go way down so that's when you should just give it up anyway.

John

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ScottF

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Dec 12, 2024

Alex Nicholas:
John Hayes:
Go check out the images from it in my gallery

I'm well aware of your magnificent gallery, John. Arguably, some of the most incredible work on Astrobin.

Whilst I'm not saying that the Edge 14 is a 'bad' telescope. I just believe that it is in a different class to something like a Planewave CDK or a high quality RC optical system.

I've not owned a planewave myself, but I lusted after them, as they were released in my country shortly after I bought my 10" RCOS in ~2009, and from what I could see then, it was a superior telescope to the RCOS 10" I had just purchased...

To that point, I've also not owned an Edge HD telescope of any aperture, but I do understand the optical system well, and have a good understanding of it...

I will say this, and perhaps that will make a little clearer what I was trying to say in my previous post.

I would personally prefer a CDK or RC over an SCT in a purely imaging only situation... Not because I think the SCT is a bad telescope, but because I feel that the CDK or RC optical system is designed from the ground up as an imaging system, with no regard for its visual performance. The SCT is still, at its heart, an SCT.

I live in sub-tropical climates, and I can assure you that no amount of dew shield and heater bands would prevent the corrector on my C11 XLT from fogging up eventually at any time of the year where I live... this is not a concern with a CDK/RC, as the primary and secondary can be very lightly warmed with a low power heating element...

For me, the decision is simple, and if the price was the same or even close, there is no way I'd be buying a Celestron 14" over a PW CDK 12.5, or a similarly high quality RC telescope for an imaging rig.

I've looked at RC scopes, but I always shied away from them due to complaints about collimation difficulties. What company would you consider that makes "high quality" RC scopes? I assume once you go over 10" you are into truss tubes only?

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Dec 12, 2024

Alex Nicholas:
John Hayes:
Go check out the images from it in my gallery

I'm well aware of your magnificent gallery, John. Arguably, some of the most incredible work on Astrobin.

Whilst I'm not saying that the Edge 14 is a 'bad' telescope. I just believe that it is in a different class to something like a Planewave CDK or a high quality RC optical system.

I've not owned a planewave myself, but I lusted after them, as they were released in my country shortly after I bought my 10" RCOS in ~2009, and from what I could see then, it was a superior telescope to the RCOS 10" I had just purchased...

To that point, I've also not owned an Edge HD telescope of any aperture, but I do understand the optical system well, and have a good understanding of it...

I will say this, and perhaps that will make a little clearer what I was trying to say in my previous post.

I would personally prefer a CDK or RC over an SCT in a purely imaging only situation... Not because I think the SCT is a bad telescope, but because I feel that the CDK or RC optical system is designed from the ground up as an imaging system, with no regard for its visual performance. The SCT is still, at its heart, an SCT.

I live in sub-tropical climates, and I can assure you that no amount of dew shield and heater bands would prevent the corrector on my C11 XLT from fogging up eventually at any time of the year where I live... this is not a concern with a CDK/RC, as the primary and secondary can be very lightly warmed with a low power heating element...

For me, the decision is simple, and if the price was the same or even close, there is no way I'd be buying a Celestron 14" over a PW CDK 12.5, or a similarly high quality RC telescope for an imaging rig.

I've looked at RC scopes, but I always shied away from them due to complaints about collimation difficulties. What company would you consider that makes "high quality" RC scopes? I assume once you go over 10" you are into truss tubes only?

Unfortunately, there aren't many premium ones around any more at reasonable apertures and prices...

Rcos/deep sky instruments were the gold standard back in the day.

Today, It looks like you're either buying an Officiana Stellare or Planewave, at a minimum aperture of 20", or you're looking at one of the GSO or rebranded options.

I guess the thing here is price to performance. You could buy the gso 14" truss tube RC, and factor in all the required extras like an essato 2 focuser, instrument rotator, optics heaters etc and still be at 1/3 the cost of the planewave. And cheaper than the c14 even...

but I'd place a budget rc in the same category as an sct in my mind though. If you have the money for the premium instrument, buy it.

if you can find a used RCOS 10" or 12.5" OTA, I'd be doing some serious thinking between that and a planewave... id happily run an upgraded gso 14" rc before getting a c14, even if, just for the fact that I don't like corrector plates.

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Dec 12, 2024

Alex Nicholas:
Unfortunately, there aren't many premium ones around any more at reasonable apertures and prices...

Rcos/deep sky instruments were the gold standard back in the day.

Today, It looks like you're either buying an Officiana Stellare or Planewave, at a minimum aperture of 20", or you're looking at one of the GSO or rebranded options.

I guess the thing here is price to performance. You could buy the gso 14" truss tube RC, and factor in all the required extras like an essato 2 focuser, instrument rotator, optics heaters etc and still be at 1/3 the cost of the planewave. And cheaper than the c14 even...

but I'd place a budget rc in the same category as an sct in my mind though. If you have the money for the premium instrument, buy it.

if you can find a used RCOS 10" or 12.5" OTA, I'd be doing some serious thinking between that and a planewave... id happily run an upgraded gso 14" rc before getting a c14, even if, just for the fact that I don't like corrector plates.

Perhaps you are forgetting about ASA. I paid a bit less for my ASA60 than a similarly equipped CDK24 from Planewave would have cost. Unfortunately, ASA as moved away from building smaller telescopes, but there are a number of them (small ASA scopes) at Obstech and they sometimes come up on the used market. Don't take this comment to mean that I don't like Planewave products or CDK systems in general . They are very good and I do like them. If you want a smaller RC today, the manufactures are limited to: GSO, iOptron, RC Optical (if you can find one), Takahashi, and TPO. Planewave makes RCs but as I recall, they are all larger aperture. For small RC scopes, in the range of 8"-12", GSO is probably the most widely available choice.

John

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