Explore Scientific iEXOS-100 2.2 lb Counterweight

Product Overview

This is a supplemental 2.2 pound counterweight for Explore Scientific iEXOS mounts. It slides onto the counterweight shaft and is held by the locking knob supplied with it. The finish is black with a silver stripe, matching the iEXOS-100 hardware.

A counterweight has one job: to sit on the opposite side of the right-ascension axis from the telescope so that the loaded mount balances. A balanced mount asks its motors for the least torque, tracks more evenly, and does not run away when the clutches are released. Adding weight is what extends the range of telescope, camera and accessory loads a given mount can carry in balance — and it is usually the cheapest change that improves how a mount behaves.

This piece is supplied as an addition, so it is bought either to supplement the weight already on the shaft or to replace one that has gone missing.

Who It's For

• iEXOS mount owners who have added weight to the telescope end: a heavier camera, a guide scope, a dew heater battery or a larger tube all move the balance point outward, and more counterweight brings it back.
• Anyone running out of shaft: when the existing weight is already pushed to the end of the shaft and the setup still tips telescope-heavy, a second 2.2 lb weight is the answer rather than a longer shaft.
• Observers who swap payloads: having a second weight means rebalancing between a visual setup and an imaging setup is a matter of sliding weights rather than compromising.
• Owners replacing a lost or damaged weight, where matching the original iEXOS hardware matters.
• Imagers who want the small deliberate east-heavy bias that keeps the RA gear teeth engaged on one flank throughout an exposure sequence.

Key Features & Design

• 2.2 pounds of published mass: a useful increment — large enough to make a real difference to balance, small enough to fine-tune with rather than overshoot.
• Locking knob supplied: the weight arrives with the means to clamp it in position on the shaft, so nothing else is needed to fit it.
• Made for the iEXOS counterweight shaft, which is the mount family Explore Scientific specifies it for.
• Black finish with a silver stripe, matching the rest of the iEXOS-100 hardware.
• Supplemental by design: it is intended to be added to a shaft, either alongside an existing weight or in place of one.

Recommended Uses

• Rebalancing an iEXOS mount after adding a camera, guide scope, filter wheel or heavier eyepiece.
• Bringing a telescope-heavy setup back into balance when the existing weight has reached the end of the shaft.
• Keeping a second weight in the case so a visual and an imaging configuration can both be balanced properly.
• Replacing a counterweight that has been lost or damaged.
• Setting a deliberate slight east-heavy bias for guided imaging runs.

Compatibility and Accessory Notes

• Mount family: Explore Scientific specifies this weight for iEXOS mounts, and the finish is matched to the iEXOS-100.
• Shaft diameter: Explore Scientific does not publish the bore diameter of this weight or the shaft diameter it is cut for. If you are considering it for a mount outside the iEXOS family, send us the shaft diameter of your mount and we will put the question to our Explore Scientific representative before you order.
• Locking knob: included, so the weight is ready to fit as supplied.
• Stacking weights: two weights on one shaft is normal practice, with the outer one doing most of the work because its leverage is greater. Balance is weight multiplied by distance from the axis, so moving a weight along the shaft has as much effect as changing its mass.
• Shaft capacity: the number of weights a given shaft will take is a function of shaft length and thread, and that varies by mount. Tell us the model and we will work out what fits.

Good to Know Before You Order

• Explore Scientific does not publish dimensions, bore diameter or a shaft thread specification for this counterweight, so those rows read as not published in the table below rather than being estimated. If a physical measurement is decisive for you, ask us and we will confirm it with Explore Scientific first.
• This is a counterweight only. The counterweight shaft itself is part of the mount, and a shaft is not included here. The locking knob is.
• Balance is about position as well as mass. 2.2 lbs near the end of the shaft counteracts far more telescope than the same 2.2 lbs sitting near the axis, so a single weight often covers a wider range of payloads than the number alone suggests.
• A counterweight does not raise a mount's payload rating. It lets a mount carry its rated load in balance; the rating itself is set by the bearings, gears and motors. If you are near the limit of what your mount is rated for, we can talk through what the next mount up would give you.
• The published figure is 2.2 pounds, which is the mass of the weight itself rather than a shipping weight, and it is the number to work with when planning a balance.

Frequently Asked Questions

Is it difficult to set up?

No. The weight slides onto the counterweight shaft and the supplied locking knob clamps it in place. Balancing afterwards is a matter of releasing the right-ascension clutch with the shaft horizontal, sliding the weight until the assembly stays put on its own, and locking it. It takes a couple of minutes and no tools.

Which mounts does it fit?

Explore Scientific lists it for iEXOS mounts and finishes it to match the iEXOS-100. The bore diameter is not published, so for anything outside that family we would rather confirm the shaft diameter with Explore Scientific than guess — send us your mount model and we will find out.

Do I need a second counterweight?

If your existing weight is already at the far end of the shaft and the telescope end still drops, then yes. If the setup balances with room to spare on the shaft, a second weight is not doing anything useful yet.

Does adding weight let me carry a heavier telescope?

It lets you balance a heavier telescope, which is a necessary condition but not the whole story. The mount's rated payload is set by its mechanics, and staying inside it is what keeps tracking and pointing reliable.

Is a locking knob included?

Yes. The counterweight ships with its locking knob, so there is nothing else to buy to fit it.

How exact does balance need to be?

For visual observing, close enough that the telescope stays where you leave it with the clutches loose. For imaging, many people leave the mount very slightly east-heavy so the right-ascension gear stays loaded on one side of the tooth through the whole run, which shows up as smoother guiding.

Bottom Line

In short: a 2.2 pound iEXOS counterweight supplied with its locking knob, in the black-and-silver finish that matches the iEXOS-100 — the straightforward fix when a camera, guide scope or heavier tube has pushed the balance beyond what is already on the shaft. Tell us which mount and what you are putting on it and we will confirm the fit and how many weights the setup wants.