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Celestron C90 vs the usual spotting scope (1 Viewer)

George_T

New member
Hello guys,

I am new to birding and I want to buy a scope. Because of the passion for astronomy, I was thinking about a Celestron C90 with a zoom eye-piece to use mainly for birdwatching and sometimes for planets view.
Another option is Celestron Trailseeker 80.
These are cheap options, but in my country this money means something. I've researched the forums and haven't found something about this option.

Celestron C90 + zoom eyepiece will have a great zoom - but it will have great quality?

For which I should go and why?

Sorry for my English |>|
 
Hello George!

I´m no english language virtoso either :)

Two and a half year ago I was in exactly the same position as you are today. I needed relatively low cost, good performing spotting scope mainly for birding and occasional observing of the moon and planets. After searching the internet and reading tons of reviews and forums I decided to buy Skywatcher Maksutov telescope MC 90/1250 SkyMax (https://www.astroshop.eu/telescopes...mc-90-1250-skymax-ota/p,5020#tab_bar_0_select). This telescope is optically same telescope as Celestron c90 (produced by same factory), but it has less bulky and lighter housing. Maksutov type spotting scope is a great birding instrument, but like any other optical device, it has some PROS and some CONS.

PROS:
+ Extremely high magnification capabilities. For me the closer view on birds is the better view. Maksutov telescopes have starting magnification where image of majority other spotting scopes will start to deteriorate. This telescope can produce sharp image up to 250x (maybe more) which is useful for moon and planets observing and rarely for birding. With my 22,5 – 7,5mm zoom eyepiece I get 55x to 166x magnification which is useful if conditions are right (plenty of light).
+ Sharpness. Scope producces sharp high quality image and you can use all 1,25˝ eypieces on the market.
+ You can use 90° amici prism for comfortable viewing of celestial objects (see photos)
+ Portable, small in size.
+ Sturdy, well built.

CONS:
- No low magnification capabilities. You are restricted to lowest magnification of 39x (using a 32mm SuperPlossl eyepiece). This magnification is too high for scanning the surroundings for birds, which means that you must first see a bird with naked eyes or through the binocular and then point the telescope at the bird.
- The image has slightly less contrast than refractor type spotting scopes.
- It is not weather sealed. No problem if you use it in dry weather like I do.

You will need a good finder. I mounted cheap Chinese made 4x32 Riflescope (see photos) and it works like a charm. With this combo aiming scope even at distant flying birds is easy. You will get your view faster on target than with any other spotting scope. Red dot finder, that comes with the scope is also quite good.

For tracking birds in flight, and other movable objects you will need a sturdy tripod and good fluid video head, preferably with longer mounting plate, so you can balance scope well (I use Manfrotto MVH500AH).

I managed to save a little fortune for buying Kowa TSN-883 spotting scope, so I have an intend to sell my well preserved Skywatcher MC90 Skymax. If you are interested let me know and if you have any other questions I will gladly answer to them. On the photos scope is wrapped in Camo tape and equipped with a 32mm SuperPlossl eyepiece.

Bye!

Astrobird69
 

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I've used a C90 for digiscoping "on the cheap" and it worked okay; you can see my rig here. I've had a chance to peek through much nicer scopes, but those scopes cost alot of money.

I did/do have plans to resurrect this setup for astrophotography some day.

I do recommend the dew shield and upgraded Plossl (TeleVue in my case) if you can afford them, they made the scope much more flexible for daytime use.

These things are quite large compared to the nicer spotting scopes, but I suspect you know that going in.

The stock Plossl is good for sunny day photography out to 125m or so, viewing definitely out to 200m or more.
 
Astrobird69, Great!

Thanks for your reply and such details, it will help me a lot with my future decision. A very nice rig you have there.
And here are some questions also:
1. Does it need a lot more light than a usual spotting scope?
2. As I had read on the internet, because of climate conditions more than 60x-80x magnification on the ground (birding) makes no sense, is that true?

Thanks, George
 
Kevin...Have you used also in just watching birds?
A little bit, but mostly for digiscoping.

It's too bulk and heavy in my opinion for the whole "leave it on the tripod and tote it around" thing. I tended to take it to a location, set it up, and then not move it from that spot for a couple hours and just watch/photograph whatever was nearby/within range.
 
Astrobird69, Great!
1. Does it need a lot more light than a usual spotting scope?
2. As I had read on the internet, because of climate conditions more than 60x-80x magnification on the ground (birding) makes no sense, is that true?
Thanks, George

1. The higher is magnification, the smaller is exit pupil and the dimmer is image. So for high magnification observing you need alot of light (sunshine) and scope with big aperture to catch more light. Aperture of this type maksutov telescope is 90mm minus about 10% of secondary mirror obstruction. This means that in terms of light gathering capabilites this scope is exactly the same as usual spotting scope with about 80mm aperture.

2. Depends how far is the object that you look at and how strong is the heat haze. If you look at 40m distant bird in the middle of summer day at 150x magnification you will get very nice closeup view, but if you look at 400m distant bird and the conditions are the same you will get very blurry, unusable image due to heat haze. One summer morning I´ve ID species of gull at the distance of 1,4km away. This was possible because conditions were excelent and I used 250x magnification. In general you will observe mostly with magnifications up to 80x, because they do not require such good conditions.
 
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