Brief Review - Celestron C70 and C50 Spotting Scopes (1 Viewer)

Earlier today (Eastern Standard Time) I got the opportunity, graciously facilitated by Eric Briggs of Khan Scope Centre in Toronto to review in-store the new Celestron C70 and C50 Maksutov spotting scopes.

These are spotting scopes with one very useful feature; the supplied 3x zoom eyepieces are removable by unscrewing, revealing a male thread (may be T2) that allows the attachment of a supplied 1.25" eyepiece holder (visual back). This allowed for testing with a 25mm plossl as well as de-facto eyepieces.

Celestron C70. The image holds up well with the zoom eyepiece (25-75x with this scope) but the view with the plossl was clearly superior. Focusing on a cable box on an outside cable against a bright sky gave a very clear, sharp image with no false color.

Celestron C50. This scope is so light it feels like a kids toy, but the view proved othewise. The de-facto eyepiece performed well enough at 25x, but there was some image softness at full zoom. This scope was transformed with the 25mm plossl; I had reservations about the contrast given the small diameter of the objective that appears to be less than the advertised 50mm, but the view was crystal clear and again, no false color.

These two scopes present a unique opportunity for birding and digiscoping. The ability to use astro eyepieces means the user can determine the optimal magnification for viewing and otherwise and also the quality of the eyepiece; imagine using one of these with a Televue or other high quality eyepiece.
Lastly, the cost is the best part of this review. Both scopes are priced less than $150 Can but can give Apo-like performance.

Rmel66.

Thanks for posting that review.

I've been looking at these scopes for a while (I have a bias to Maks from astro days).

I was curious why Celestron seemed to have so many Mak soptting scopes in this "region": C50, C65, C70 and up .... An aperture every 10mm or so! And waterproof or not-waterproof versions. I suspect some of the older non-waterproof designs are close to EOL.

It seems to me that the C50 is based on an OEM design e.g. compare to the now discontinued Barska Contour 20-40x50 Waterproof 580 Maksutov Spotting Scopes. The C50 to be the same body with, I presume, a different eyepiece. It also quotes eye relief at both ends of the zoom: 25mm at 20x; 20mm at 40x. Good for eyeglass wearers.

http://www.celestron.com/c2/product.php?CatID=30&ProdID=512

http://www.opticsale.com/barska-con...maksutov-angled-eyepiece-multi-coated-wi.html

Amazon have it for cheaper than the C50: the Barska for $68 and the C50 for $93. And its a bit more reasonable that its only 20-40x zoom with a 50mm object (with an obstruction in the middle of it!). Also comes with a 1.25" adaptor so there is some flexibility in eyepiece choice too.

I suspect the C70 is an in-house design. Looks more "Celestrony". And is not much more expensive, especially from the usual optics outlets, and only a little heavier, at 2.0lb, than the 1.3lb C50.

http://www.celestron.com/c2/product.php?ProdID=513

Any other reviews or experiences?

The only one I've found are on Cloudy Nights to which Rmel66 (the OP) added his review -- the most useful contribution!

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/2460479/Main/2412104

The posters mostly drop back to talking about the C90. With a much longer focal length a consequence of an long focal length astro scope forced into a spotting scope role the C90 has some "issues". These Mak spotting scopes seem to have a "better" (shorter) focal length for the spotting scope role so lower magnification is available with "normal" shorter focal length (12mm to 25mm) eyepieces.

I put a Barska on order to try it out. I'll post more when I try it out.

Mak Spotting Scopes

I too have a liking for Mak Scopes; I own a LOMO Astele 60 that has a focal length of 1147mm, effectively making it a F 19.5 scope and this poses a few challenges, although it performs very well as a spotting scope with the right eyepiece. Given the maxim of optimal exit pupil for daytime viewing being 2mm or greater, the maximum magnification for the LOMO is 30x, meaning that an eyepiece of 40mm fl or greater is required; I found this out the hard way after realizing that the views through the supplied 25mm eyepiece were sub-optimal and only improved when I substituted a 40mm plossl.
The focal length of mak scopes needs to be taken into consideration when choosing eyepieces given the long focal length per body size; the views will probably be best when exit pupil is kept at 2mm or greater and this is especially important given the central obstruction.
The focal length of the C50 is 580mm and 750mm for the C70.

I believe that the much maligned Celestron C65 mini-mak spotting scope could be transformed with the substitution of a better eyepiece; 30-90x is a ridiculous magnification range for almost any scope especially a sub $100 spotting scope. This scope however does not allow for easy eyepiece substitution as the supplied eyepiece is fixed, but I am sure there are enterprising persons reading this forum who could take up the challenge.

Rmel66.

The Meade XTX 90 with a 32mm eyepiece gives 39x with 2.3 exit pupil, weighs about 54 oz. with eyepiece if I remember right as an OTA.Not WP not wide view, no CA.
Regards,Steve

rmel66 said:

[...] Given the maxim of optimal exit pupil for daytime viewing being 2mm or greater, the maximum magnification for the LOMO is 30x, meaning that an eyepiece of 40mm fl or greater is required; I found this out the hard way after realizing that the views through the supplied 25mm eyepiece were sub-optimal and only improved when I substituted a 40mm plossl.
The focal length of mak scopes needs to be taken into consideration when choosing eyepieces given the long focal length per body size; the views will probably be best when exit pupil is kept at 2mm or greater and this is especially important given the central obstruction.
The focal length of the C50 is 580mm and 750mm for the C70.

I believe that the much maligned Celestron C65 mini-mak spotting scope could be transformed with the substitution of a better eyepiece; 30-90x is a ridiculous magnification range for almost any scope especially a sub $100 spotting scope. This scope however does not allow for easy eyepiece substitution as the supplied eyepiece is fixed, but I am sure there are enterprising persons reading this forum who could take up the challenge.

Rmel66.

Click to expand...

For the 50mm C50 the magnification should be x25 or less to keep the exit pupil at 2mm or larger requiring an eyepiece of 23.2mm or longer.

For the 70mm C50 the magnification should be x35 or less to keep the exit pupil at 2mm or larger requiring an eyepiece of 21.4mm or longer.

Much more reasonable. Perhaps increasing them a bit (to x30 for the C50) wouldn't be pushing it too hard with a 20mm Plossl.

BTW, which particular 25mm Plossl EP did you use when you tested them out in the store?

Do either of these scopes start to suffer problems from the objective "obstruction" (the Cas mirror) at these low magnifications. It seems that Mak Cas scopes can do a lot better with higher magnifications in daylight even if it means a smaller exit pupil (though one that will fit completely inside the entrace pupil of the eye).

Given the price of the C70 (with the removable EP) and the C65 without I suspect the better deal is the C70.

The 25mm eyepiece is presumably a LOMO (it came with the Astele 60). In testing, I did not notice any obstruction artifacts but these as you rightly stated are manifest at lower magnifications. There is a hint of it in my LOMO setup (40mm eyepiece) but I guess one learns how to look around it and it does not hinder my viewing.
I note in another post that you have received the Barska Contour 20-40x Mini-Mak. Awaiting your evaluation.

Rmel66.

I found the "mini-review" of the Celestron C70 by rmel66 interesting I haven't found any reviews yet by someone who has owned the scope.

I'm considering buying the C70 for casual viewing of the moon and the sun (with a full aperture filter, of course), plus any daytime opportunities that might present themselves. Big pros are the tiny size and, of course, the possibility of using higher quality 1.25" eyepieces. In this respect, I wonder if it can handle e.g. a 32 or 40 mm eyepiece with a moon filter attached at the bottom? I hope it'll focus properly ... I too think that low mag (and higher quality) eyepieces are the way to go with these scopes.

BTW, how is the focusing knob? Apart from the crappy image in the included zoom eyepiece, the older C65 model got lots of complaints regarding the focusing.

[reusing some text! But I need to post something]

I have a "Celestron C50" or rather the Barska Contour 20-40x Mini-Mak. Different eyepiece but the same body. Both are OEMed (ODMed?) by Bosma in Ghuanzhou.

OK, it's the cheaper and discounted Barska 20-40x50 version with a different lower mag eyepiece on a small SLIK 450G tripod that weights about 1lb. Total weight of scope and tripod is about 2.4lbs (1.1kg). It's lightish, perhaps it's best point as I stick it in a backpack - the main reason for getting it that with the low CA from the catadioptic optics.

It does "bring the bird closer" but it's not great. The provided zoom 15mm to 30mm EP is not the best especially for setting the correct eye placement and ER with the rubber eyecup. I find the best setting for the eyecup is halfway rolled up for use with eyeglasses. They don't provide a cap for the ocular but I found that one of the spare caps I had around fit the partially rolled down eyecup perfectly.

Pushing up the zoom of course the scope dims out and at x40 I find setting the focus to be a problem with a sort of mushy feeling of not quite knowing if you've hit focus. Not too sure how different the quality is between this EP and the one Celestron provide (which goes to way too short a focal length IMHO).

I suspect the view will be rather better with a wider AFOV fixed EP with set and perhaps a bit better ER (as the OP says). So I still want to try the "C50" with a fixed astro eyepiece: 25mm probably, for about x25 sounds about right. Though that may make the scope not waterproof (I think anyone know for sure - I couldn't see a window inside the scope and waterproofing is a bit of an issue in PNW).

With the small SLIK tripod pointing an angled scope is more of an issue than I though it would be. But that might just be me and some practice and determining the right body position to get comfortable. It didn't help that the first place I tried it on birds was looking down from a hillside to the birds on the reservoir below perhaps 15 to 20 degrees below the horizon. In this case a straight scope would have been better.

As one can see from other posts here I'm rather better at doing bin reviews than scope reviews but I really need to take this scope and the Celestron Ultima 65 I bought from FrankD to Greenlake to check out the ducks for real rather than just checking out the crows around a local reservoir. For that the "C50" did OK. It's better than nothing (or better than bins) though it seems more fiddly than it should be.

BTW, how is the focusing knob? Apart from the crappy image in the included zoom eyepiece, the older C65 model got lots of complaints regarding the focusing.

Click to expand...

I found it OK but on the stiff but rather rather wimpy tripod and head (the C50 + scope only weights a couple of pounds) one can move the scope off target. Again a little more experimentation to get the right friction settings on the pan axis would help this.

More as I play with it more.

Would any of these scopes work for digiscoping with a canon SLR camera ? Would I need a brand specific adapter ?

Thanks to rmel66 for review and sorry for digging up such an old thread, but I think this is a good place for this question as many noobs like me would probably ask the same thing... I'm considering buying an entry level scope for all-around use - probably 80% usage would be birding/terrestrial and 20% glancing at the night sky if something interesting is up.

I already have Opticron Discovery WP PC 8x42 which I am very happy with. Now I'd need something with higher magnification to put on a tripod and C70 looks like a good option. Unfortunately I don't have any experience with these Maksutov designs compared with traditional refractors and there is no local store I could visit to test it myself. So, basically I'm asking if Celestron C70 would be a good choice or would it be wiser to choose refractor design - I've looked into Celestron Ultima 80 (non-ED) and Helios Fieldmaster A90 as alternatives to C70.

Size and weight in all three are ok for me. On plus side C70 takes normal 1.25" EPs (with adapter which is not optimal for field use, I've read) while Ultima 80 is only compatible with some 1.25" EPs like Baader Hyperion series (for some reason I don't understand, you would think 1.25" is 1.25"...) Haven't found any info if Helios Fieldmaster has changeable EP or not - it seems very much like Ultima 80 but with larger aperture. Is there some aspect I have missed totally or do you think there is any big difference no matter which of the three I choose?

Thanks in advance - any insight and voice of experience is greatly appreciated. I know many of you have higher requirements for your optics, but I'm more looking into staying on budget while getting the best all-around scope with good enough capabilities for my use.

Rob

Interesting this should come up again. I've been looking for a cheap, light scope for travel use, and last week I ordered the C70, along with a Celestron X-Cel LX 25mm eyepiece that will yield 30x. Obviously I have no idea how good it will be yet, but scope and EP came to $145 so it's definitely cheap. At about 2 pounds it should also be light. Being a Mak, it should also be compact.

It's no Nikon ED50, no doubt, but then again it's not $800 either. And my hunch is that with the fixed EP it might hold its own.

The zoom, from what I can tell, has a very narrow FOV, which is why I also got the comparatively wide-angle X-Cel.

I should be able to report back in a few days.

Mark

In terms of cost/performance there is nothing to beat a good maksutov scope and from other reviews at optics retail sites, the C70 is a very good performer. One of the chief advantages of a 'mak' is the absence of chromatic aberration. If you have used an achromat refractor you may have noticed colour fringing around high contrast objects. With a mak this is almost totally eliminated and heightens the viewing experience.

As with everything else in life however there is no free lunch. Maks suffer from slightly reduced contrast due to the central obstruction imposed by the secondary mirror and do not perform very well at low magnifications due to the secondary mirror blocking the centre of the visual field.

That being said, I employ the use of both types of scopes when birding. My mak (LOMO Astele 60, no longer in production) is set up with a 32mm eyepiece for 37x magnification for distance viewing. I have a diy 50mm refractor set up with a Paradigm 15mm eyepiece for 15x magnification for in-close viewing. Sometimes I will switch the 15mm eyepiece to the LOMO for 77x identification viewing.

Rmel66.

`Ultima 80 is only compatible with some 1.25" EPs like Baader Hyperion`

far as i know there is no adapter that fits the ultima 80 that alows 1.25@ eps use. The baader zoon scres onto an external thread, which connects the factory shipped zoom. In theory an adapter could be made, but i havent heard of anyone trying so far.

Ive found a problem with the c70. when using eps with fov greater than 55deg, i get a square sided image on the lower half of the view....top half is fine. I have the meade 5000 plossl 26mm, 60deg fov. Have had the same problem with other eps.

DUnno if others have found the same?

I can recommend the acuter 80+baader hyperion, but its alot heavier. The c70 wins for lightweight+cheap. Helios Fieldmaster A90=NO!

can you stretch to ....Helios Fieldmaster ED60DS ?

Thanks for comments and advise!

I guess I was confused with this EP stuff - now I understand the Baader zoom is only compatible because it has some special threading which fits to some spotting scopes like Ultimas. Unfortunately normal 1.25's do not fit, so the idea of using some higher-quality fixed focal EPs is out of question - and shelling out the price of Baader zoom to be used with lower quality refractor does not sound sane.

It's good to know CA is not such a bad issue with Maks - especially in birding high contrast object situation is very common. Too bad larger aperture maks like C90 have a bit long focal length (and therefore high magnification factors) for birding use.

Mark, while being green with envy about prices in US (in Europe you can get only the scope for that price!), I'm looking forward to hear about your experiences with C70 and X-Cel EP.

Rob

rob sent you a pm.

Well, I've had the C70 for a couple days and I have to say I am not overly impressed. I wanted to be because out of the box I thought, "That's it!" It's light, compact, seemingly rugged, well-armored. The focus on this sample is nice--no slop, no backlash.

Mind you, we've had nothing but gloom around here the past two days so I'll wait for a sunny day before deciding whether to send it back, but here's my impressions.

For a 70mm aperture, it is not very bright and the contrast is poor, especially as you zoom. The central obstruction is at fault I guess.

It is not particularly sharp either. There is, for me, a frustrating lack of detail. Zooming makes things bigger, but doesn't add much detail.

At 25x it's actually usuable, but anything above maybe 40x strikes me as superfluous. Too dark and low contrast. I put a 17mm Baader Hyperion on it (44x) and the view wasn't very good.

I put the 25mm Celestron X-Cel LX on it (30x) and that's the best view I got. It's better than the zoom and might actually be good on a sunny day. The bottom edge of the view was cut off, but I'd settle for that if the view was sharper.

The eye relief is remarkably consistent throughout the zoom range--great for glasses.

I'll wait for a sunny day and see how it does, but my gut is telling me it's going back.

Incidentally I put the 25mm X-Cel on my 80mm Celestron Regal and compared it to the 17mm Hyperion. The Hyperion is noticably better to my eyes, and worth the difference in cost. The X-Cel has quite a bit of pincushion. It is a very easy view though, with excellent eye relief. It seems like more than the 16mm ER it's rated for.

Hah, maybe I'll just pack the Celestron Regal and the Manfrotto 055 and pay the checked bag surcharge when I travel.

Or maybe I'll let my wife get me the Nikon ED50 for Christmas. Hey, she keeps asking me what I want.

Mark

`I put a 17mm Baader Hyperion on it (44x) and the view wasn't very good.`

agreed, I found anything under 21mm was rubbish viewing. This scope is only useful when weight is an issue. Its a real shame, but tis no world beater(

maybe worth getting the 22mm baader hyp and try that?

Or maybe I'll let my wife get me the Nikon ED50 for Christmas. Hey, she keeps asking me what I want.

Click to expand...

If she gets it for you then I am jealous. You definitely found a good one there. I don't think my future Mrs. would be willing to spend that kind of money especially with us just finishing the new home.

I found your comparison of the Celestron X-cel LX and the Baader to somewhat mirror my own experiences. I compared the Celestron with an Orion Stratus 21 mm and came to a similar conclusion. The Celestron holds its own very well. The Orion has a flatter field and slightly better contrast. Now if I could just reach infinity focus with it in either of my 80 mm scopes.

Interestingly I did just pick up a Pentax XW20 to try out in both scopes. I received it yesterday and only had a brief time to play with it outside in the darkness of these late fall days. I am looking forward to playing with it on both scopes in daylight. I can say though that it won't reach infinity focus in either scope at this point...unless I cut a half inch or so off of the barrel.

I am getting off track Mark and I apologize but am glad you posted this information. I ran into a similar conclusion when I tried one of the smaller Celestron reflectors last spring.

Not a problem, Frank. I'll pony up about $500 for the ED50. I wouldn't let her pay for the whole thing. I just listed my beloved 8x32 SE's in the classifieds to help defray the cost! Hate to part with them, but I've been using the SV pretty much 100% these days.

It is a shame about the C70 because it is a "just right" size for travel. Woodhornbirder, I think I'm destined for the ED50, something I've been trying to avoid ($$$).

The 17mm Baader on the big Celestron is just a great combo at 28x. Of course the scope and EP are both simply huge! The Baader doesn't quite seat all the way either--maybe 2-3mm to go--but it does reach infinity. What affect does that have on the actual magnification I wonder?

Ah, well, the quest for the "poor man's ED50" continues. I started a thread on the 26 ounce Nikon Prostaff 16-48x60 spotter. The weight on that is sweet. It's big brother, the 80mm version, is listed at 35 ounces. Something tells me those weights don't include EP's, but I could be wrong.

Mark

Celestron C65 - eyepiece removal

rmel66 said:

I believe that the much maligned Celestron C65 mini-mak spotting scope could be transformed with the substitution of a better eyepiece; 30-90x is a ridiculous magnification range for almost any scope especially a sub $100 spotting scope. This scope however does not allow for easy eyepiece substitution as the supplied eyepiece is fixed, but I am sure there are enterprising persons reading this forum who could take up the challenge.

Rmel66.

Click to expand...

Hi, I am not an enterprising person, however I have done the above (yesterday!), and thought I would reply to your post for anyone else reading and wondering the same!

PS I am brand new to scopes, and so bought very cheaply in case I wasn't interested, I prefer photography and binoculars !

I have the Celestron C65 30-90x, and was very disappointed with its clarity, focus, and zoom, in fact the only thing I actually liked was the tripod, which although basic, was ideal for home table top use !

As such I decided to make the above alteration, to see whether or not it improved -it did !

Basically I took off the eye piece with shear grunt, removing carefully the rubber eye cup (used later), and then butchering the 30-90x eyepiece with pliers until I had it mostly off.

I then used my dremel drill to reduce the inner plastic ring, so that a standard eyepiece could be inserted into the outer lower plastic bevel which remained on the body.

I then used electrical tape to pad out the inner space so that the new eyepiece could be inserted, and using friction stay in place

To tidy up the appearance, and hold the tape firm, I then stretched the original eyepiece rubber cup, upside down, over the lower plastic ring (the piece with just the single white alignment line still painted on!) which went on great, and makes it all look slightly less amatueristic

I then tried a couple of eyepieces which I had from a Celestron starter kit I had also bought, namely a 12.5mm and 6mm

If I have my facts right, the focal length of the scope is 835mm, and so using the 6mm gave me an unusable 139x !!!

I then tried the 12.5mm which I believe gives me 67x magnification, and I found that this worked better than the original 30x-90x eyeiece when it was only on the 30x setting, and so a vast improvement in light, focus, and image quality, at close distances (under 300m it is very clear, over a 1000m it is still useable, and works OK up a few miles

However, I think that 67x is still way too much for this little scope, and so I have ordered a better quality 40mm plossl eyepiece, which should give me 21x mag

I will post back out this performs when I have it, and if it is much better, I may invest in a 25mm eyepiece for 33x

Thus I would have

6mm = 139x
12.5mm = 67x
25mm = 33x
40mm = 20x

If the scope doesn't perform, then at least I have a few eyepieces for my next scope, which reading here will be a much better make!

hope this info is of use to someone