• Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.

    Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
Where premium quality meets exceptional value. ZEISS Conquest HDX.

celestron mini mak 70 (1 Viewer)

If you do a search in this forum, you will see where I posted a brief review on the C70 and its sibling, the C50. That being said, the C70 should serve as a good/very good first scope. I swear by another Cat scope (the LOMO Astele 60) that is unfortunately no longer available.
 
seems interesting.

whats max magnification on the 70 before the image starts to go dull?

am guesssing 12/14mm ep ?? ~50x

i have a williams optics swan 20mm ep= 66deg fov.

wonder if a meade5000 UWA would be over kill for this scope )
 
Dn't forget these are Maksutov scopes so they have an obstruction in the objective of about 20mm or so that gives a doughnut shaped exit-pupil.

A useful estimate of "equivalent" aperture is objective diameter - obstruction diameter. About 50mm or so in the C70. The C50 is even smaller (I have one!).

On that basis I wouldn't use them above 25x. And perhaps push them to 40x at most.

The reason they have high magnification is the catadiptric telescopes tend to have rather long focal lengths (especially for their package size). With fairly standard focal length EPs they tend to have rather too much magnification.

The other issue when you go to low magnifications if you can see the hole in the exit pupil.

This scope is probably best between 20x and 30x.

I note the scope is backordered and I think no longer sold by Celestron. Will they have any more?
 
The C70 I tested in-store was with a 25mm eyepiece I brought along specifically for the purpose. With the C70 it gave a magnification of 30x and a fine view to my recollection, much better than the supplied zoom eyepiece. That said, I have carried my LOMO Astele 60 Mak to 77x (15mm Astro-Tech Paradigm eyepiece) with no ill effects.
The scope that is no longer sold by Celestron is the C65, not the C70.
 
Ah, I'm confusing the model numbers.

The LOMO's are well made (Russian?) with an astro background so I wouldn't be to surprised you could push them.

The upside of the cats is they do have good CA performance (it's pretty much all lateral CA in the EP) but have a dip at low F in the MTF curve but the curve comes back to the line at high frequency i.e. you still get the fine detail.
 
`a dip at low F in the MTF curve but the curve comes back to the line at high frequency `

...again...this time using english plz )


I have a baader hyp mk2 zoom. AM interested to see what this mm70+bhzoom would be like.

assume 18-20mm on zoom would be the sweet point.

Got a nipon mak(cheap chinese thing) which has similar focal length. 17mm is about max before image starts to get dim. OPtics on this scope are ok, but the focus is awful, keeps going out of focus; its like the scope has its ownlittle imp of optical illwill :p
 
Last edited:
Poorer contrast for larger objects compared to the ideal telescope.

That's as good as I can do if you don't know how to read MTF curves.
 
The apparent improvement in contrast at high spacial frequencies for obstructed optics is an anomaly of the MTF diagram that results from so much light being thrown into the diffraction rings that the central disc shrinks to a size that mimics a larger aperture (see Suiter, "Star Testing Astronomical Telescopes", p. 155). The larger the obstruction the better the MTF looks up to almost a full aperture obstruction where the curve at high spacial frequencies looks better than a perfect aperture, but of course the actual image looks terrible. So, there is nothing good about a large central obstruction at any magnification.
 
I hate to say it...but yes this scope struggles over 40x.

19/20mm is borderline, 18mm and beyond and it starts to go fuzzy city. Maybe the erecting prism in this scope isnt the best? Ontop of the mak design problems mentioned above.

Scope sits best at 30xwide. Acceptable for general use.
 
I am thinking of getting 40mm eyepiece, Omni Series 1.25" 40mm. My goal is to get lower magnification for general use. Am I pushing the limits, will the image suffer from the "doughnut" effect?

Thank you!
 
I hate to do this because it seems like propaganda...

But I saw this promotion on optic planets. Basically $20 off on anything above $150.

And their C90 kit is exactly around $150.

So basically you get celestron c90, 2 plossl... and a cheap tripod.

Be aware that the tripod alone costs $27, so it is probably the worst tripod you will ever see in your life.

But anyway it is very cheap and seems ok, specially for people who already have fine eyepieces.

I will probably order it myself. It is so inexpensive. Even for those who don´t like catadioptrics. Its focal lengh is huge... 1250mm. So it is like a huge barlow =P to test eye pieces.
 
I spoke with celestron tech support. They tried 40 and 32 mm eyepiece and reported some vignetting in the lower left corner presumably from the prism that is not large enough. They did not report "doughnut" like effect.

It seems that magnification of 25x with a 30mm eyepiece is the lowest that can be used with no vignetting.

They recommended Ultima 65 with magnification of as small as 18, They said that the image quality should be better in comparison with C70. Now I am not sure if they meant at 25x magnification or with the 40mm eyepiece. I am reading that Ultima 65 suffers from some CA where C70 doesn't.

I am thinking of getting 40mm eyepiece, Omni Series 1.25" 40mm. My goal is to get lower magnification for general use. Am I pushing the limits, will the image suffer from the "doughnut" effect?

Thank you!
 
C70 review

Greetings all

after a long time reading, I thought I'd finally try and contribute to these forums myself.
And what better way to start as with a review, so here it goes:

I'll start off by stating that my experience with scopes is rather limited; I've had brief looks through other (better) scopes, but I won't be comparing it with anything, just a plain old 'monograph'.

I've had this scope for about 3 years now, bought it maybe a bit impulsively because it was rather cheap, there aren't many scopes around in the proximity and well I wasn't really ready to splash out for a scope since I had never used one.

So I'll start off with a 'technical' description of the C70 followed by some experiences in the field.

Eyepiece:
Having never used a scope before, the view initially pleased me, but as stated by others, zooming in results in fast image degradation
after reading this thread as wel as another (http://www.birdforum.net/showthread.php?t=116740&highlight=C70+mak) I decided to try out a Plössl eyepiece(25mm), and is has never left the scope since. It's a no-brand eyepiece but still provides a wider FOV and increased brightness.

Focussing:
the focussing mechanism is an sich smooth, but it is laggy so getting the focus right does require some getting used to. This also means focussing can be slow and difficult. Furthermore it takes quite some turning to go from near to far focus and vice versa.

Image Quality:
overall, I've always been able to see what needs to be seen, so I find it a good tool for the job. What I find a real plus is there is no CA, something the C70 has over other low budget scopes (or at least I think so, I haven't found others reviewed or had the occasion to look through any). But it has to be said that the view is more like looking at something rather than experiencing it, if that makes sense. Contrast, resolution and sharpness are sufficient, though not super, as you would expect.

In the field:
it has been used mostly on the local patch (lake, marsh, forest/park) which has allowed me to see things I would have never seen with binoculars only, so it has been, as stated above a tool for the job.
I used it one time for seawatching on a field trip but the cloudy conditions didn't work too well with the far off smudges with which I have little experience.
On occasion I try to digiscope a bit as well, without adapter or anything, I'll add some examples
Ideal conditions: summer, bright, subject not too far (sharpened in post-process)
Buteo buteo digiscoped by Boris Flaccus, on Flickr

Not so ideal: winter, subject farther off and smaller
IMGP3936 by Boris Flaccus, on Flickr

Regrettably I tried using it with a DSLR + T2 ring + adapter, I advise against this, the results are terrible

In conclusion, after 3 years of use it has served me well, but I'm starting to yearn for a true high quality view, to really enjoy what I see rather than just being able to ID it.

phew, een hele boterham
 
Plössl eyepiece(25mm),

am sure you can improve on the fov.

plenty of eps out there with 55/58 deg fov. I tried a 60deg 25mm in this scope and was annoyed to find the bottomn of the image was squared off.

tbhi havent played around withthis scope for while......dont have spare cash to exp with eps on a scope which is very borderline quality.

you can even get 2" eps and use an adapter so they fit in the mak. might find that a 30mm 2" ep gets you over the 60deg fov. Widefield is only really useful for seawatching/raptors.
 
Last edited:
Warning! This thread is more than 12 years ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.

Users who are viewing this thread

Back
Top