UPDATE: I made a new adjustable adapter that I think is better, check it out here: https://www.printables.com/model/1180078-zwo-seestar-s30-s50-equatorial-eq-wedge-adapter-ad
This adapter aids in balancing a ZWO Seestar S30 or S50 smart telescope over the center of gravity of the tripod when used in equatorial (EQ) mode using an adjustable EQ wedge.
Say goodbye to field rotation and hello to zenith imaging when using the equatorial (EQ) mode of the Seestar, which should be officially supported soon via firmware update. The Seestars can be used in EQ mode unofficially now using various methods including seestar_alp.
If you have an EQ wedge to adjust the angle of the Seestar, it leans and at lower latitudes, could make your tripod tend to tip over. This adapter puts and offset and will allow you to balance the Seestar directly above the center of gravity of your tripod making it a more stable system.
I've tested this using the excellent William Optics Vixen-style Base as well as the iOptron Adjustable Base #3327, which comes with the iOptron Skyguider Pro package. I formerly had the Sky-Watcher Star Adventurer Latitude (EQ) Base, but sold it when I bought the premium William Optics base. I now wish I had it to test. Now that I have both a Seestar S50 and a S30, I ordered what appears to be a nice aluminum base from ebay that is branded as Aktuhrashid, so will update when I get that in a few weeks. The premium aluminum iOptron Precision Base #3328 also appears to be an excellent premium choice. Any adjustable base will work with this adapter, as long as they use Vixen-style dovetails. I have two sets of adapters, ones with 60mm Vixen dovetails which can be used with most of the EQ bases and ones with 90mm Vixen dovetails, which can be used in the William Optics base since it has a long 90mm dovetail clamp.
I have adapter arm offset lengths ranging from 15mm to 155mm in 10mm increments. I've included two charts to help determine which adapter to use. The factors that affect this are primarily your latitude above or below the equator, but also which EQ base you have as well as which Seestar version you have. I've tested all of the models with both the S30 and S50 Seestar models on both the iOptron #3327 base as well as the William Optics base and the latitude range works from as low as 34° to as high as 71°. Use the chart to estimate, but ultimately you need to balance your Seestar yourself and might need to use another adapter model. I'm planning a different solution for low latitudes nearer the equator that offsets the wedge to the side of the tripod so the arm doesn't have to be so long.
Note: I initially made the mistake of thinking the markings on the wedge indicate latitude, but actually they measure degrees from horizontal. To use the scale on the side of the bases, you need to take 90°-latitude to match the scale. For example, if you live at 55°, then the scale would read 35° (90-55=35). For my 43° latitude, it almost doesn't make a difference as I'm very near the break-even point and a couple of degrees out of level could compensate for that.
I measured the center of gravity for both Seestar S30 and S50 models and surprisingly, there isn't much difference in height between the two models (see photo). I simply balanced them on a pencil and notated the center of gravity using a post-it note. The center of gravity of the Seestar was then balanced directly over the centerline of the EQ base and tripod.
You'll need a 3/8"-16 x 1.25" UNC socket head cap screw to screw the Seestar to the adapter.
I live at 43° North latitude, so for my Seestar S50 and my William-Optics Base, I used the 90mm Vixen dovetail model and 125mm offset arm length to achieve balance. For my Seestar S30 using the iOptron #3327 base, I used the 60mm Vixen dovetail model with 95mm arm offset length to balance it.
I decided not to make these longer than 155mm offset due to it getting pretty long. They become difficult to make on the print bed of my Prusa MK3S, but also the Seestar sits fairly high above the wedge. I think for these very low latitude angles I will make a different design that offsets the wedge itself to the side.
Additionally, I will try to come up with a laser holder to mount a laser in the vixen dovetail to align it to the Polaris to help with polar alignment, although I believe that ZWO will offer some sort of EQ aiming assistance in the software.
I've added a 3mm spacer for use with the S50 so that the small rubber feet clear the adapter. The S30 doesn't need this.
The author marked this model as their own original creation.