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Zhumell Z12 Dob.

Posted by Larry Beach   03/06/2011 12:00AM

I have been in the Astronomy hobby since the early 70's and have either owned or looked through nearly every type/size and brand of scope.

I did fix the collimation issue by replacing the springs in the primary mirror cell with heavier ones from the hardware store!

The scope does not ship with instructions but they are available online. There are also several good u-tube videos for help with the alignment procedure.

Mine did not have the cluch slip issue some have had but, even if it did, a washer fixes that.

First of all, at full aperture, the views are crisp with high contrast. I have made a 4 1/2" off axis mask for high power planetary viewing, this is as good as I have seen with APO refractors.

The Primary mirror is made of pyrex and not crown or bk7 glass that some others have used, it also has a layer of MGF3 for higher light transmission. Mine shows a very good figure and good coatings optically.

Deep sky items are contrasty with an inky background sky.
The secondary holder's veins are very thin which, in my opinion, helps with the contrast. I may get a curved holder though...

On one exceptional seeing night I was able to see the elusive "spiking" of Saturns rings, Jupiter shows so much detail it is mind blowing. It seems my mirror is not the exception but the rule for figure, I would guess it is at least 1/8th wave! objects SNAP into focus, it is as good as a research grade Meade I looked through some years past.

The clutch at the pivot points on the rocker box are adjustable allowing for better balance with heavy eyepieces.
The cooling fan helps remove tube currents and is essential for visual use, only goofy thing is there is no place to put the battery box??. The 2 speed crayford focuser is silky smooth, but the finder is on the cheapish side, yet is nice for correct images - seeing things as they are in the star charts. A telrad would be good in this case.

The included 2" 30mm lens is ok, nothing spectacular as is the 9mm 1-1/4. Also included is a glass 1-1/4 green Moon
filter, nice because viewing the moon at full aperture can be painful!

The laser supplied for collimation is ok, if it is properly lined up itself, It can be "tweeked" by small screws on the side.

The scopes are not packaged very well and some have reported receiving theirs damaged.

This beautiful scope is the best buy in my opinion and everyone I have seen used for sale have been snatched up rather quickly on the classified sites
for used equipment.

I lucked out and found mine at a "truckload liquidation sale" at a ridiculous price!!!

clear skies,
Larry Beach.