Celestron C90 Mak (1 Viewer)

yossi · Jun 25, 2004

Just out of curiosity and testing for my local photography forums, I've purchased last week this scope. It's about $185 at Adorama. You get quite a package for this money - including a case, an eyepiece, a small directing scope, a prism and a nice scope. I already have several scopes, but this one is worth checking. I shot through it with my CP4500 with various eyepieces and with my D100 - directly as a 1200mm lens and via a 45mm mm lens and the Maxview eyepiece. The scope is rubber coated, sealed and nitrogen filled. The focus button is a bit flimsy, but it delivers very good images. The problem is it's focal length which is 1200mm, and even with a 40mm eyepiece you obtain a X30 magnification.
The best eyepiece tested so far with it is the Pentax XW 21mm. It allows fully zooming with the CP4500, resulting in a combined focal length of 2170-8685mm. At the 8000mm end it's quite soft, but anywhere between 2170 and 4500mm the images look very good. It also works nicely as a 1200mm tele lens for the D100 (with manual exposure and focusing) and I've ordered a proper T connector for the camera, as I was using an improvised combination.
The bottom line - worth checking!

Here is a shot using the CP4500 + Pentax eyepiece - at a combined focal lenght of 2170mm:

http://www.kramery.com/digitalphoto/gallery/Celestron/cel_4500_21mmPTX_2170.jpg

And another one, the moon taken with the CP4500+Scoptronics Maxview at a combined focal lenght of 4140mm:

http://www.kramery.com/digitalphoto/gallery/Celestron/cel_4500_40mm_4140.jpg

william j clive · Jun 25, 2004

I believe the Celestron C90 is a clone of the Konus MotorMax 90 to which has been added rubber armouring and waterproofing. I have a Konus with which I am pleased, as it is a dual purpose scope that can be used for birding and astronomy. I bought it used as an OTA for peanuts. It is not as bright, and has a narrow FOV compared with my Nikon 78ED, but it cost a fraction of the price of a Nikon, even at clearance prices.

You can get up to 172x depending on conditions, and you cant do that with the Nikon. I also have an Opticron MM2 with 15-40 zoom lens. The zoom has an outside diameter of 1.25", so fits tightly into the eyepiece socket of the Konus and becomes a 64-172x zoom!

I have obtained a 1.25" adapter from Markus Ludes of APM telescopes in Germany to convert the Nikon 78ED lenses for use in the Konus. The 25/38/75x eyepieces become 57/87/172x on the Konus. The last two have 72* FOV, that is of advantage in the narrow field Konus. The eyepiece I use as a finder is the 30mm Orion Ultrascopic (40x). I would like to try a focal reducer on the Konus to widen the narrow FOV, but I dont know whether this would work in a Maksutov, so it would be risky to buy one.

Konus = the poor man's Questar!

Clive

Jay Turberville · Jun 26, 2004

yossi said:
J
The best eyepiece tested so far with it is the Pentax XW 21mm. It allows fully zooming with the CP4500, resulting in a combined focal length of 2170-8685mm. At the 8000mm end it's quite soft, but anywhere between 2170 and 4500mm the images look very good. It also works nicely as a 1200mm tele lens for the D100 (with manual exposure and focusing) and I've ordered a proper T connector for the camera, as I was using an improvised combination.
The bottom line - worth checking!

You might want to check my article. on the pros and cons of catadioptrics for digiscoping.

http://www.jayandwanda.com/digicat/digicat.html

yossi · Jun 26, 2004

Jay Turberville said:
You might want to check my article. on the pros and cons of catadioptrics for digiscoping.

http://www.jayandwanda.com/digicat/digicat.html

A very interesting article. Thanks for posting.
I have a Lomo 60 and a 70 too, but the image quality of the C90 looks better. The Lomo 60 I have is the WA version that is not sold out of Russia, and was purchased directly at the factory in St. Petersburg. It has a 600mm focal length (in contrary to the standard 900mm of this scope), and it's easier to handle and shoot.
The C90 is a very good solution for someone who can't invest in a Swarovski or a Leica. Also, Plossls are usually cheaper than the refractors eyepieces. The C90 doesn't perfectly conform to the WYPIWYG rule (Whay You Pay...) and is a good value for money.

Jay Turberville · Jun 26, 2004

yossi said:
A very interesting article. Thanks for posting.
I have a Lomo 60 and a 70 too, but the image quality of the C90 looks better. The Lomo 60 I have is the WA version that is not sold out of Russia, and was purchased directly at the factory in St. Petersburg. It has a 600mm focal length (in contrary to the standard 900mm of this scope), and it's easier to handle and shoot.

Interesting about the Lomo 60. As my tests show, the Lomo 70 does not match the quality of the Rubinar and the Swarovski. But it is surprisingly close and I've taken some of my best shots with it. From a practical standpoint, its range is limited. This makes sense due to its limited aperture. But as you know, it is very compact and lightweight.

I also have a Lomo 95 that I didn't test but my experience says is a small notch below the Rubinar. It and the C90 probably deliver similar results. The larger aperture does matter.

yossi said:
The C90 is a very good solution for someone who can't invest in a Swarovski or a Leica. Also, Plossls are usually cheaper than the refractors eyepieces. The C90 doesn't perfectly conform to the WYPIWYG rule (Whay You Pay...) and is a good value for money..

I would think so. I did some research before writing the article and was surprised to find the C90 in a waterproof model. This answers one of the biggest complaints that some people have about a catadioptric.

Yes, the "you get what you pay for" is an overused maxim. All too often you pay a premium for very little benefit. And sometimes a particular design or approach can have benefits that buck the general rule. If the "you get what you pay for rule" were really true, then the concept of a bargain would be a myth (which sometimes it is). The truth is somewhere in between.

The Plossl design is an inherently well corrected design because it is symmetrical. Its biggest drawback is its limitation of a 50 degree AFOV. That's actually fine and in some way very good for digiscoping. But its on the average to narrow side for a scope. The TeleVue 32mm Plossl that I am using does have a clear edge over the low priced Plossls that came with my scopes. So to does the 50mm military surplus Plossl that I used with my Lomo 95.

I find the flip mirror system very interesting. You could leave your camera permanently mounted to the 90 degree viewer and switch back and forth between an erected view. That sounds great.

I've been thinking about selling my Lomo 95 since the Rubinar makes it redundant. Maybe I will and get a C90 so that I can check it out.

yossi · Jun 26, 2004

Jay Turberville said:
I've been thinking about selling my Lomo 95 since the Rubinar makes it redundant. Maybe I will and get a C90 so that I can check it out.

It would have been interesting to test their new refractors - like the Ultima 100ED, which costs less than $600 including a x22-66 eyepiece, a third of the price of a Swarovski 80HD, and it's 56% brighter.
It seems that Celestron have lifted the glove to make inexpensive spotting scopes. I'm sure Meade will follow.
Their C65 mini Mak costs $75 only - and is a 30-90x65mm scope. I've checked with them - the eyepiece of this version can't be removed, so it may not be good for digiscoping, but just for watching birds or wildlife it should be fine. Good days for scopers.

Jay Turberville · Jun 26, 2004

yossi said:
It would have been interesting to test their new refractors - like the Ultima 100ED, which costs less than $600 including a x22-66 eyepiece, a third of the price of a Swarovski 80HD, and it's 56% brighter.

I agree that it would be interesting, but I would guess in advance that all of the top birding scopes will give a superior image. But its hard to say until someone does the testing. I also get a bit annoyed when makers and distributors fail to give important information about their products. What is the eye relief, AFOV and can the eyepieces be changed?

yossi said:
It seems that Celestron have lifted the glove to make inexpensive spotting scopes. I'm sure Meade will follow.
Their C65 mini Mak costs $75 only - and is a 30-90x65mm scope. I've checked with them - the eyepiece of this version can't be removed, so it may not be good for digiscoping.

the Mini Mak might be a fine scope to carry around in the car just in case. But I've gotta think that zoom eyepiece is mediocre at best and that at the price they have an inexpensive roof prism in there.

FWIW, while I am a fan of cats for digiscoping, I think they do less well for most visual observation. They probably do their best for high magnification observation where the donut shaped exit pupil is less bothersome and where you can get an eyepiece that gives you a pretty wide AFOV. That's not to say that they don't represent an incredible bargain for someone who can't or won't pay the price of a top end scope. But at 20-30X, I think the better birding refractors really shine and show the benefits of a "made for the purpose" design.

ssemone · Mar 16, 2005

Shooting directly through a C90?

I know this is an old post, but I wonder if you might talk more about your experience in shooting through the C90 "directly" with your D100. Was this with the Celestron T-Adaptor and a T-Rign for your D100?

Cheers,

Sean

yossi said:
Just out of curiosity and testing for my local photography forums, I've purchased last week this scope. It's about $185 at Adorama. You get quite a package for this money - including a case, an eyepiece, a small directing scope, a prism and a nice scope. I already have several scopes, but this one is worth checking. I shot through it with my CP4500 with various eyepieces and with my D100 - directly as a 1200mm lens and via a 45mm mm lens and the Maxview eyepiece.

Humboldt Jim · Mar 16, 2005

ssemone said:
I know this is an old post, but I wonder if you might talk more about your experience in shooting through the C90 "directly" with your D100. Was this with the Celestron T-Adaptor and a T-Rign for your D100?

Cheers,

Sean

yossi said:

Just out of curiosity and testing for my local photography forums, I've purchased last week this scope. It's about $185 at Adorama. You get quite a package for this money - including a case, an eyepiece, a small directing scope, a prism and a nice scope. I already have several scopes, but this one is worth checking. I shot through it with my CP4500 with various eyepieces and with my D100 - directly as a 1200mm lens and via a 45mm mm lens and the Maxview eyepiece.

Click to expand...

I have the previous C-90 (1000mm and have taken some digital pictures directly (no prism) through a 30mm celestron ultra eyepiece. Very sharp and no CA. If you can tolerate an inverted image, avoid using the erecting prism. It makes a difference. Photograph lore alludes that composition on view cameras was better because it was upside down.

ssemone · Mar 18, 2005

The big question is...

Do you think I would be able to use that setup as a method to reduce vignetting with a 40mm eyepiece (say the maxview or others) and an FZ20? probably no great way to test this other than to try it out at my local astonomy shop. I do know that the conventional wisdom is the lens on the FZ20 is too big for digiscoping.

It seems that the Maxview 40mm
http://scopetronix.com/maxview40.htm

or perhaps even the
Maxview II (which is a 2" and would require the Large Accessory Ring on the C90) and has a 58mm thread would be a good way to go.

Of course prism or not isn't so much the issue (other than I'd be getting better light, right). Would it change in any other ways how I would go about focusing/scoping?

I already have an adapter tube for my Minolta 1.5x , so in addition to the above I'd need a 55-58 step up ring. Assuming the tube I had would give me adequate relief.

Anyway, just bouncing around ideas. If I get a chance to try this out at the astro shop perhaps I'll post a fresh thread on the topic. Certainly there are a lot of FZ20 owners that would like to get into digiscoping with a minimum of vignetting.

Cheers,

Sean

Humboldt Jim said:
I have the previous C-90 (1000mm and have taken some digital pictures directly (no prism) through a 30mm celestron ultra eyepiece. Very sharp and no CA. If you can tolerate an inverted image, avoid using the erecting prism. It makes a difference. Photograph lore alludes that composition on view cameras was better because it was upside down.

Humboldt Jim · Mar 18, 2005

ssemone said:
Do you think I would be able to use that setup as a method to reduce vignetting with a 40mm eyepiece (say the maxview or others) and an FZ20? probably no great way to test this other than to try it out at my local astonomy shop. I do know that the conventional wisdom is the lens on the FZ20 is too big for digiscoping.

It seems that the Maxview 40mm
http://scopetronix.com/maxview40.htm

or perhaps even the
Maxview II (which is a 2" and would require the Large Accessory Ring on the C90) and has a 58mm thread would be a good way to go.

Of course prism or not isn't so much the issue (other than I'd be getting better light, right). Would it change in any other ways how I would go about focusing/scoping?

I already have an adapter tube for my Minolta 1.5x , so in addition to the above I'd need a 55-58 step up ring. Assuming the tube I had would give me adequate relief.

Anyway, just bouncing around ideas. If I get a chance to try this out at the astro shop perhaps I'll post a fresh thread on the topic. Certainly there are a lot of FZ20 owners that would like to get into digiscoping with a minimum of vignetting.

Cheers,

Sean

You have two strikes against you with your proposed set up:

1. A long eyepiece may cause problems in a Mirror scope due to the center obstruction of the mirror causing a black spot in the middle of the image.

2. Your camera lens is bigger in diameter than the eyepiece lens. (assuming its just a few mm larger than the lens)

You could use a "T" mount and use the the scope as a prime lens or accept the vignetting and crop it out.

If your actual camera lens diameter is smaller than the eyepiece occular diameter, you just need the right step ring to adapt.

Try scopetronics.com

Good luck

ssemone · Mar 18, 2005

Jim, thanks for the continuing advice. I've done a bit more research and I think that the 2" moonfish viewer mentioned here:

http://groups-beta.google.com/group...6a93?q=moonfish+celestron+2"#d4a21cf18c566a93

...might do well with a C90 with a Large Accessory Ring (from scopetronix). I've sent an email to the moonfish folks asking them about that setup. That eyepiece is a 2" and has a 49mm ring on it.

http://moonfishgroup.com/GBP2Commer...id=50&osCsid=16634b96fb42f2269f5fa8eface74626

I am currently using an adapter tube and a 55mm to 49mm step down (handy since that is what the moonfish requires) for use with my Minolta 1.5 teleconverter. Vignetting is not apparent with that setup after about 3x or 4x (optical) zoom. I don't know if that is comparing apples to apples, though. I suspect it might not be?

When I start to think about the economy of it all though, I might still be better off getting a camera more suited to digiscoping instead of going through all the hard work of mating the FZ20 to the task. Of course selling the idea of *two* cameras might be a hard thing to do as well.

Cheers,

Sean

birdeast · Aug 13, 2005

Jay,

Can you explain this statement you made above:

"I find the flip mirror system very interesting. You could leave your camera permanently mounted to the 90 degree viewer and switch back and forth between an erected view. That sounds great."

I am not very familiar with scopes (actually not at all) and I was wondering if you mean you can somehow look through the scope while the camera remains attached or if you mean you can invert the image while viewing it through the camera?

I am seriously considering the C90 MAK. I want to give digiscoping a try without making a huge investment. I read your comparison of the different scopes above and found it very interesting. I would also be interested to know what the difference would be in the four images if the Phred had been 150 or 200 ft away instead of 50 ft.

Lastly, I am thinking of using a Sony W-5, and a couple of fixed focus tele vue (or good quality generic equivalents ?) eyepieces with the scope. I am in Singapore and most of my shooting would probably be in semi-sunny to cloudy conditions. From your experience, would this combination of equipment and environment conditions allow for the possibility of good quality shots in the 150 - 200 ft range?

Thanx in advance
Scott

Jay Turberville · Aug 16, 2005

birdeast said:
Jay,

Can you explain this statement you made above:

"I find the flip mirror system very interesting. You could leave your camera permanently mounted to the 90 degree viewer and switch back and forth between an erected view. That sounds great."

I am not very familiar with scopes (actually not at all) and I was wondering if you mean you can somehow look through the scope while the camera remains attached or if you mean you can invert the image while viewing it through the camera?

Yes. That is essentially what I meant. You could conceivably switch back and forth from visual use to camera use by just flipping the mirror. I haven't tried it, but I find the idea interesting. I am so used to photographing with a reversed and inverted image, that having the image inverted but not reversed on the camera side isn't that important to me. But that's not to say you or someone else wouldn't prefer that.

birdeast said:
I am seriously considering the C90 MAK. I want to give digiscoping a try without making a huge investment. I read your comparison of the different scopes above and found it very interesting. I would also be interested to know what the difference would be in the four images if the Phred had been 150 or 200 ft away instead of 50 ft.

As with any digiscoping rig, the further the scope to subject distance, the more you are at the mercy of air quality issues such as haze, and turbulence. At such distances, you are usually tempted to push the limits of scope magnification as well which will compound the problems.

If you want the very best in image quality on a consistent basis, you will shoot at shorter (50-75 foot distances). Of course, everybody shoots over longer distances at times. Just expect the image to get a bit softer as you extend the reach.

birdeast said:
Lastly, I am thinking of using a Sony W-5, and a couple of fixed focus tele vue (or good quality generic equivalents ?) eyepieces with the scope. I am in Singapore and most of my shooting would probably be in semi-sunny to cloudy conditions. From your experience, would this combination of equipment and environment conditions allow for the possibility of good quality shots in the 150 - 200 ft range?

I have no knowledge of whether or not the W-5 is a good digiscoping camera. It might be, but since you are on a tight budget, why take a chance. Others have reported good results with the Canon A95 which has the tilt swivel LCD that I really like. There is also the Kyocer SL400R which is getting good reviews. Personally, I just move to the Olympus C7070 and was very impressed with the image quality as compared to my Nikon CP5000. It tends to give somewhat sharper and clearer images as well as more detail. The entrance pupil of that lens moves around a bit more than most cameras and it really "wants" a scope eyepiece with longer eye relief than most scopes. I think this camera would be a particularly good match for the C90.

Jacek Zarzycki · Oct 10, 2005

One can buy many different eyepieces for c90 mak - do you think that zoom eyepiece ( 50-150 x ) is of any use ? Or is it better to buy serveral eyepieces and change them in a case one needs better magnification ?

Jacek Zarzycki · Oct 11, 2005

anybody here ? ;-)

Aryanto · Oct 11, 2005

Hi Jacek. I am Aryanto, a new member.
I am also trying to find out if there are people who has experienced celestron mak c90.

I saw owner's picture in www.buytelescopes.com:
http://www.buytelescopes.com/product.asp?m=1&pid=7098&display=gallery#gallerynav

Looks decent enough for beginner.
However without real people to communicate with, I tend not to believe whatever on the internet.

This thread looks old already. May be we can bring it to live.

birdeast · Oct 11, 2005

Maybe Jay will have this thread marked and get notification that this thread is alive again. He is very helpful and seems to be one of the few that would even consider using this scope (or any other astro scope) for digiscoping.

I have moved on a bit and have been considering the Televue 60. This scope has the same eyepiece flexibility, but costs a lot more. However, it appears to quite portable and should provide very good images.

Good luck with getting your questions answered |=)|

yossi · Oct 13, 2005

Hi Jacek,

I think the you shouldn't invest too much in this scope. A fixed 30-40mm eyepiece will do for learning and experimenting. I do not believe that this scope can output very good quality shots at very high maginifications.

Jacek Zarzycki · Oct 13, 2005

actually I had an idea to use it for WATCHING birds but not for digiscoping . Is this scope good enough for watching birds ?

Celestron C90 Mak (1 Viewer)

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