The Zhumell Z12 is just about the biggest telescope we would recommend to beginners, and we would only recommend it to be your only telescope if you are strong and in good health, or if you can keep the scope on a dolly or hand truck to roll outside. Otherwise, you are going to end up missing out on clear nights due to the sheer bulkiness of the scope and you’ll need a smaller instrument to complement it. This being said, you simply can’t get more bang for your buck than the Zhumell Z12.
The Z12 is more or less a scaled up version of the Z8 and Z10. If you are unwilling or unable to deal with the size and mass of the Z12, our comments here mostly apply to those two smaller scopes as well, and we love all of the Z series Dobsonians equally. If the Zhumells are not available in your region, the Orion SkyLine, Apertura AD, GSO Deluxe and Bintel Dobsonians are all pretty much the same both in design and accessories.
Overview Of Zhumell Z12
- The Optical Tube
The Z12 is a 12” f/4.9 Newtonian reflector. While a 12” f/4 would be better portability-wise, the designers at GSO elected to make the scope as close to f/5 as possible so that you could get away with not using a coma corrector at first. We would recommend eventually obtaining a coma corrector for the scope as it is definitely visible at the edge of the field of view with low-power eyepieces such as the 30mm SuperView.
The primary mirror sits on a 9-point floatation-support mirror cell. Like with the other Zhumells the Z12 comes with 3 pointless locking bolts which can be removed to no adverse effect – they directly contact the glass and could crack your primary mirror if you drop the scope by accident with them left in, and serve no functional purpose in the scope.
The cell also has a cooling fan which is powered by an AA battery pack which plugs into the fan. I’m not sure where one is supposed to attach the battery pack – no instruction on that is given as far as I’m aware – but I wound up using Velcro to stick it onto the back end of the one I used.
The focuser on the Zhumells is a high-quality dual-speed 2” Crayford unit, a must for such a large scope with a fast focal ratio.
Unlike with the Z8 and Z10 the dust cap on the Z12 actually has raised areas near the middle for you to lift it off the tube, a nice bonus.
- The Z12 Dobsonian Mount
The Z12’s mount works much like the Z8’s – the altitude bearings are small, adjustable ball bearings that can be slid up and down the optical tube to help with balance, while the azimuth bearing runs on rollers. The whole thing is constructed out of laminate-covered particle board and can be assembled with an Allen key in minutes – something you may need to do more than once if you plan on frequently transporting it.
The Z12, like the Z10 and Z8, comes with a 30mm SuperView eyepiece (51x), 9mm Plossl eyepiece (169x), a laser collimator, and a 9×50 right-angle correct image finderscope.
The 30mm SuperView is decent, providing a 70-degree apparent field of view (so about 1.375 degrees true field with the Z12). However, in addition to the obvious and inevitable coma you’ll see at the edge of the field of view, the SuperView design suffers from a fair amount of edge-of-field astigmatism as well – though coma is a far bigger problem and a far more solvable one.
The included 9mm Plossl is short on eye relief and has a narrow apparent field of view (I question if it’s even 50 degrees). It’ll work, but a few decent medium- and high-magnification eyepieces should definitely be on your radar if you purchase the Z12.
The included laser collimator works quite well, provided the laser itself is aligned. Unfortunately, this rarely proves to be the case, but aligning the laser is rather simple and can be done with an Allen key and a makeshift V-block in just a few minutes.
The included 9×50 RACI finder works great, but you may want to use a Telrad or Rigel QuikFinder in conjunction with it.
Transporting & Setting Up The Z12 - Important Notes
The Z12’s optical tube is so large (at 14” across and 58” long) and heavy (at about 48 pounds) that careful considerations must be taken in moving it.
For one, unlike with the Z8 and Z10 the Z12’s tube will not fit across the back seat of most cars – fold-down seats are required. While the weight may not be bothersome to some people, the sheer width and length means you are going to have trouble “bear hugging” the scope to move it and there aren’t really any handles on the tube. Setting the scope precisely on the base without dropping it can also be a little tedious due to the small size of the altitude bearings and the precision at which they must be inserted into the base. The best option is to obtain aftermarket tube straps, or plan on hauling the tube (or entire scope) on a dolly or hand truck.
The particle board base of the Z12 weighs in at 38 pounds. Moving the base is awkward more than anything else, and the odd position your arms may need to take to lift it may cause you to get tired of carrying the base around after a while. You can buy or make a plywood base to significantly reduce the weight for a relatively low cost, and I would highly recommend doing so.
Again, if the prospect of all this scares you, you’re probably best with one of the smaller Zhumell or other Dobsonians instead of the Z12. But if you’re not concerned with these increased transport challenges, then go right ahead!