William Optics High Latitude Base Review

November 24, 2019  •  9 Comments

William Optics High Latitude Base Review

While I was reviewing the Space Cat, AgenaAstro was kind enough to send me a William Optics Latitude Base to test out.  This base comes in two different configurations – High Latitude (32-59) and Low Latitude (7-34).  You should choose the base depending on your shooting location.  For example, I normally take my photos in North America, which ranges from roughly 30 N to 45 N.  Therefore, the High Latitude base works well for me.  However, if you live closer to the equator, you should consider the Low Latitude base instead.

Before I get into the main review, I want to touch on the default iOptron and Sky-Watcher bases that come with the SkyGuider / SkyTracker Pro and the Star Adventurer / Star Adventurer Mini.  The iOptron bases are not well made. Almost everyone I talk to complains about the imprecise adjustments and flimsy design.  I’ve gotten used to the relative inaccuracy of the altitude and azimuth screws, and have learned to work around them.  However, I still get frustrated when I try to make precise adjustments during my polar alignment. 

The Sky-Watcher base has a few improvements over the iOptron base.  If you've read my Star Tracker Buying guide, then you know I tend to recommend the Sky-Watcher base, even if you have an iOptron SkyGuider Pro.  The most noticeable change is that the Sky-Watcher base goes from 0 to 90 degrees!  That means it will work anywhere in the world.  Like the iOptron base though, the azimuth / altitude screws could be more precise.  One problem that I've noticed with both the Sky-Watcher and iOptron bases is that the altitude knob tends to break off.  I've had multiple students lose their altitude knob, which renders the base completely useless!  There is a way to fix this, but you will need a very small allen wrench, which you likely won't have on you when you need it.

The William Optics base is in a whole new league!  The entire base is 100% CNC constructed.  The base itself is beautifully designed, and comes in three colors – Red, Blue, and Gold

Unlike the Sky-Watcher and iOptron bases, which are mainly plastic, the William Optics base is constructed from a very dense metal of some sort.  This makes it noticeably heavier and a bit bulkier too.  According to the specifications, the William Optics base weighs over 2 lbs!  (990 grams)  Meanwhile, the iOptron base weighs about 1 lb and the Sky-Watcher base weighs roughly 1.7 lbs.  If you are hiking into your location with a star tracker, you will notice the extra heft of the William Optics base.

The WO latitude base also has a very large locking knob.  I’m sure this will be nice on cold winter nights, when you are using gloves, but I really don’t understand why it’s so large.  I’m no engineer, but it just seems unnecessary to me, and it increases the size and weight.

Next, let’s talk about the most important part of any latitude base – the adjustment screws.  The WO base has very smooth and precise screws for both altitude and azimuth.  If you have the Sky-Watcher or iOptron base, you are used to adjusting the altitude with one large knob and the azimuth with two screws.  The WO Base is a bit different; the altitude and azimuth are both controlled with two screws.  This takes a little getting used to, but it works much better! 

I was really impressed by just how smooth the adjustments were.  Whenever I use the iOptron or Sky-Watcher bases, I’m used to everything jumping around in the polar scope, especially when I adjust the altitude.  However, the William Optics base provides smooth adjustments at all times!  This will make a precise polar alignment much easier to achieve!

When I was comparing the iOptron base with the WO base, I noticed a big difference in the azimuth screws.  The iOptron screws are much harder to get a grip on, and the range is fairly short.  Therefore, if your polar alignment wasn’t that close, you may not have enough room to turn the screws.  This happens to me quite often.  The North Star will get close to the correct position in the reticule, but not close enough.  Since the screws have reached their limit, I have to pick up the whole tripod (with everything attached!) and move it very slightly to the left or right.  Now I need to try the polar alignment again, and hope I can get the azimuth perfect.  The William Optics base makes this much easier, as the screws have more range.  If your polar alignment was a quite a ways off, you should be able to correct the azimuth without having to pick up the whole tripod.

I do have one problem with the William Optics base, and that is the limited range.  As I mentioned earlier, the base comes in two versions - High Latitude and Low Latitude.  I normally do my astrophotography between 30N and 45N.  However, I recently went down to Florida to teach an astrophotography workshop.  The latitude was 27 N.  The High Latitude Base is marked from 60 to 10, however you cannot access that full range.  Once I adjusted the altitude to 30, I reached a hard stop.  I was unable to lower the altitude any further!  Therefore, I could not do a polar alignment during the workshop!  The online specifications clearly state the range, but I had hoped you could lower the altitude a bit further.  Thankfully, one of my students mentioned that there was a workaround. 

After doing some research, I found this video.  Thanks to Orion2400, I was able to take apart the High Latitude Base, and essentially convert it into the Low-Latitude base.  Now that I could reach 27 N, I was finally able to do my polar alignment in Florida! 

One look at the William Optics Latitude Base and you can clearly see this is high-end product!  If you’ve been having trouble with your current base, this may make for a great investment.  Just keep in mind that the WO Base is noticeably larger, heavier, and bulkier than either the iOptron or Sky-Watcher bases.  It’s also not cheap, as it usually retails around $188.  The default bases for the Star Adventurer / SkyGuider Pro usually cost around $65.  Is the extra cost justified?  That really depends on your intended use.

First, remember the latitude problem I discussed earlier.  If you buy the High Latitude base and ever find yourself below 30 degrees, you will be unable to do a polar alignment.  If you have the right tools though, you can take apart the base and convert it to the low-latitude version.  This will allow you to use the High Latitude Base throughout most of the world. 

If you plan to do a lot of deep space astrophotography, the William Optics base will the polar alignment process much easier.  You can get very precise adjustments now, and you don’t have to deal with anymore flimsy plastic screws and knobs.  However, if you are just shooting with a wide-angle lens, your polar alignment doesn’t have to be perfect.  In fact, I can usually shoot 4+ minutes with a very rough polar alignment.  With that in mind, I think the William Optics base is overkill for wide angle astrophotographers, especially those hiking into their shooting locations and traveling across the globe. 

Having struggled with the poorly designed iOptron base for the past 2 years, I'm looking forward to getting my own William Optics High Latitude Base to complete my 2020 astro setup!


Peter Zelinka
Hi Pablo,

To be clear, you can use this base in both High-latitude and low-latitude situations. You'll need to take it apart and re-configure a few pieces though, as I mentioned in this article.

If you'd rather have something a bit lighter and cheaper, then the SkyWatcher Star Adventurer's latitude base would work well. That one can go from 0 - 90 degrees without any fussing around:


Pablo Yanez(non-registered)
Great review Peter... it almost tempted me to get one. Honestly though as someone that would like to be able to use the same equipment in the mid-latitudes N hemisphere and near tropics of the S Hemisphere (18-26) this would get quite expensive. Do you have any recommendations for something able to cover the entire range of latitudes?

Thanks for the great work!
I just picked up a Star Adventurer Pro Pack 2i. I shoot with my Canon 135mm F2L and soon will pick up a Canon 200 F2.8. Do you think it would be worth my money to pick this base up? I also have an old Skytracker Pro and I know the base on it left a lot to be desired. Thanks for all you do.
Richard Jakobson(non-registered)
I have purchased the Williams Optics Base to replace the base on my Star Adventurer Pro. It is well engineered but it should be at that price. It is much easier to make precise adjustments. However one gripe I have is the size of the level bubble. A level base is crucial for accurate tracking. The Williams Optics bubble is difficult to see if your mount is raised to a reasonable height making a level base not at all easy to achieve which somewhat negates its purpose. Am I missing something?
Brian Schumacher
I am pleased that I replaced my stock Sky Adventurer Pro latitude base with the William Optics base. I have a dedicated concrete pier for deep space photography along with a ZWO 120 mini guide scope and ASI air. With the stock base it was difficult and time consuming for an accurate polar alignment required for long exposure deep space photography. With the William Optics base dialing in polar alignment is much easier, more accurate and much less time consuming. Thanks Peter for brining us good information on equipment that performs well that is reasonable on the pocketbook.
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