Celestron C11 at almost 1200X mag !

[jordan20]

Used a C11 yesterday at my local astro shop during the day to align the finder and managed to get 1191x out of the scope with tolerable dimming and very little image graining or degradation. i used a Meade 4.7 mm with a Celestron ultima Barlow. I was amazed by this cant wait to use it soon on the night sky especially the MOON!

[nightfisher]

wow, thats some magnification, will be interesting to see how it does on lunar

[jordan20]

just worked out its just a tad over 108x per inch ! and i will report back and take a few images

[saturn10]

Very impressive.

[Stargazer Jack]

Wow! That is a lot and can't wait to see images of the moon

[Merlin]

Using very high magnifications won't show any more detail in extended objects than lower magnifications, so there's no real gain.

A simple rule is to use the lowest magnification that shows the greatest detail.

Very high magnifications can be useful for splitting close doubles because here we are only dealing with point sources.

[kniclander]

Using very high magnifications won't show any more detail in extended objects than lower magnifications, so there's no real gain.

is that assuming you've reached the "Dawes" limit of resolution for the particular aperture? IIRC it's a fairly simple equation?

[jordan20]

Using very high magnifications won't show any more detail in extended objects than lower magnifications, so there's no real gain.

A simple rule is to use the lowest magnification that shows the greatest detail.

Very high magnifications can be useful for splitting close doubles because here we are only dealing with point sources.

i know what i saw if you get the chance to use a c11 at over 1000x you will change what you think

[riklaunim]

Theoretically max magnification with C11 is 560x. Above that you don't get more details on the image. Second - atmoshpere rarely allows to use ~500x magnifications.

[John]

i know what i saw if you get the chance to use a c11 at over 1000x you will change what you think

Reading your original post, your experience was in daytime or terrestrial objects I believe. You may find that nighttime viewing of astro objects is a different matter.

It's fun trying very high magnifications from time to time though

As Rik says, with apertures over 6" or so it's usually the seeing conditions that limit the useful magnification rather than the scope.

[michael.h.f.wilkinson]

As I have posted before, much also depends on your visual acuity. If, like me, you have sharper than average vision (60% sharper in my case), you will see blurring very clearly well below the theoretical limit of 560x. If your visual acuity is lower than average, you can tolerate more than 560x on a C11. As others have said, daytime viewing is very different from nighttime.

[jordan20]

it seems im just going to have to prove it when i get the chance to use it for the night on the moon and shoot a video

[riklaunim]

The same is true for prime-focus imaging - the image quckly degrades down just after the optimal f-ratio giving max scope resolution.

[John]

it seems im just going to have to prove it when i get the chance to use it for the night on the moon and shoot a video

That would be very interesting

It would be worth capturing the views at 300x and 600x as well so the sharpness and resolution could be compared to the higher magnification.

[jordan20]

That would be very interesting

It would be worth capturing the views at 300x and 600x as well so the sharpness and resolution could be compared to the higher magnification.

I will be doing at least 5 diffident mags.

[ollypenrice]

i know what i saw if you get the chance to use a c11 at over 1000x you will change what you think

I have and I don't agree! If you were looking at a relatively nearby terrestrial target then you were looking through very little atmosphere. When you look at an astronomical target you are looking right through the atmosphere and, with all its changes of temperature and density, it has much more time to disturb the image through turbulence or bad 'seeing.'

You need to keep your magnification within what the seeing will allow.

However, big SCTs are great on the moon and planets and I reckon you'll have a ball.

Olly

[Stu]

Amazing images Rik ;-)

[Stu]

On a slightly more serious note, I've seen just what Olly had described quite a few years ago when trying out a small apo refractor in the day. You are able to maintain a higher magnification in daylight than translates in to practical use at night looking through the full thickness of the atmosphere.

We would all love to be able to use very high magnifications, and I'm sure many people will have tried combinations of lenses and barlows which give x 800 or so just to try it out.

I have a high spec 8" mak, f 20 designed for high mag planetary viewing. I rarely use above x250 with it but still get cracking views

Cheers

Stu

[Klesk14]

My C11 EdgeHD only has a maximum of 661x useful magnification, according to the specs in the book.

[RobH]

i know what i saw if you get the chance to use a c11 at over 1000x you will change what you think

Done it with a 14 inch scope.....no more detail than around 500x, but the lower magnification is a lot crisper.

For imaging the planets and moon though, many folk get great results using barlow lenses and webcams.....these magnification are very high....an SPC900 webcam can be equated to a 6mm eyepiece....I've seen images done with 14 inch scopes and x5 barlows, giving a magnification of around x3000, but long video sequences of thousands of individual frames, which are then stacked and filtered to remove the effects of the atmosphere.

Rob

[johninderby]

When I had a C11 I found that around 300x was the most useful higher mag and sometimes up to 550x when the seeing was really good. I did try over 1100x on the moon just to see how far I could push it, but really there was no more detail than at 500x.

With the light levels available in daylight observing it's a very different situation to the low levels of light available at night. Have you ever tried a cheap pair of binoculars that seemed passable in the daytime but turned out to very poor at night with dim fuzzy images?

John

[Klesk14]

So you'll be able to view the sun at higher magnifications? Say... 400+?

[johninderby]

So you'll be able to view the sun at higher magnifications? Say... 400+?

When viewing the sun you're still subject to atmospheric seeing conditions which will limit the maximum usable mag much more than with daytime terrestrial viewing. Unstable seeing during the day caused by atmospheric heating has a big effect on observing the sun.

John

[Klesk14]

Ah that's too bad. But the sun is big I'm sure it'll still have great images.

[kniclander]

is that assuming you've reached the "Dawes" limit of resolution for the particular aperture? IIRC it's a fairly simple equation?

quoting myself () so is it anything to do with the dawes limit?