Posts Made By: Roland Christen

And here is your result from last night - image by Gilles Cohen, IC1318, reduced to 1/4 size...

Rolando

Maybe: Lots of people bought cheap binoviewers, which were really intended originally for microscope objectives and are not well corrected internally. As such the views are less than great. The really good binoviewers are very expensive to make, and thus do not appeal to the average buyer with a limited budget. We do sell quite a few Baader Mark V binos and those who have them are using them, me included.

Rolando

We have shipped some already.

Although it was designed primarily for astronomy, this scope is turning out to be a superb daytime birding and long distance telescope. With a pair of 19mm Panoptics installed in my Mark V binoviewer, the views are incredibly sharp and saturated with color. We watched tiny insects crawling on cone flowers on our prairie restoration here next to our factory. About 1/4 mile distant, I was watching red wing black birds eating mulberries. The feather detail, beaks and claws were easily resolved, as were the individual polyps of each berry. The original 105mm Traveler was quite a nice daytime telescope, but this one easily exceeds it in every respect.

Rolando

But, hold on to your hat because the mighty Mak can do both wide field and closeups in one shot. Stars overall measured around 1.8 arc sec FWHM.

(next couple of days I will add color to this if the skies hold up)

Rolando

Anybody know where the name Gran Turismo was first used?

Rolando

How big?

There is a real difference between these two optical systems. Although both are SCTs, the Meade has an aplanic coma-free design, whereas the Celestron is an all-spherical mirror design similar in performance to a Dall-Kirkham along with characteristic off-axis coma.

What does this mean to you the average telescope user? Well, having a coma-free design puts other restraints on the optics. The corrector of the Meade ACF is twice as strong as the Celestron, resulting in more sphero-chromatism on axis. The result is lower performance on-axis but better off-axis images for the Meade. The Celestron all-spherical design theoretically would have better on-axis performance and worse off-axis.

Can you see the difference normally? Visually there is little benefit to the off-axis coma-correction of the Meade. Only when using it for CCD imaging with big chips would you see the benefit to the wider corrected field of the ACF. Stars are sharp over a wide CCD field, whereas the celestron shows quite comatic stars not too far off-axis. One can tame these somewhat with certain telecompressor accessories, but not fully supress them.

There are other considerations besides this if you are primarily a visual user. An 11" scope has more light grasp than a 10". Mechanically there are differences also. Mirror shift, collimation shift, focus shift as you move the scope around the sky can put a real damper on your observing pleasure (these are real problems and all these scopes have them to some degree - minor in some, major in others). The Celestron design certainly is fussy with collimation, but the ACF design with its hyperbolic secondary is many times more sensitive to miscollimation. You should check these scopes out before you buy.

Rolando

You can get Barry Greiner of D&G Optical to make you a 12". Go for it. The views will be awesome.

Rolando

Excellent sharpness! Lots of resolution for sure.

Rolando

If in doubt, buy Televue.

Rolando