Comparing the Innorel RT90C and the ZWO TC40 tripods

When I decided to fully migrate to harmonic mounts and get ZWO AM3 in addition to the AM5 I had already used for a while, I was thinking if it makes sense to invest in a second TC40 tripod from ZWO. Eventually, I decided to get Innorel RT90C (also known as LT404C). It seemed to be in use for astrophotography by several folks, but the information about this was scattered. I thought I should close the gap 🙂

Both tripods are very similar in their design and construction. These are the main functional differences:

The similarities in the dimensions, materials and the mechanical design of the leg mounting on the top as well as of the first (and last for TC40) two leg sections make you think that the mechanical stability for astrophotography should be the same. And I believe it actually is. Most astrophotography users will extend only one leg section on Innorel RT90C, but others can still be used for regular photography. You certainly can extend more sections for astrophotography as well, but each next one will reduce the total mechanical stability and rigidity.

The picture on the top of the page shows that Innorel RT90C tripod (on the right) is slightly higher than ZWO TC40, even though its leg sections are slightly shorter. This comes through additional retracted leg sections.

Most of the 557 g of additional weight should also come from those additional leg sections.

Innorel RT90C uses the popular 85mm size for the insert diameter of the mounting plate. This plate holds a double-sided 1/4-3/8″ mounting bolt and a hook. BTW, this hook is fixed with a small recessed screw, which you have to unlock before trying to remove the hook.

The side shapes of these mounting plates are totally different. Innorel uses a lock button on the side (pressed by the finger on the picture below). This prevents the plate from falling out (together with precious equipment) if the main lock screw is not tightened.

ZWO uses the same 85mm so that you can insert the mounting plate from the ZWO TC40 into the Innorel RT90C and tighten it well with the main lock screw.

You can do the same with Innorel plate in TC40. On this picture both mounts now sit on different tripods but with other mounting plates:

Well… They sit there… and you still have an impression that the original mounting plate would be better. The side shapes and the different locking mechanics make this difference.

I guess ZWO saves this more sophisticated locking and invests in the leg spreader which is not available for Innorel RT90C.

There are other differences in the mounting plates (also called “pans” for some reasons) which are important for AM3 and AM5 users. The version from ZWO comes with three mounting holes which fit their counterparts on the bottom sides of the AM3 and AM5 mounts. These two pictures show the one from ZWO on the left side:

With this, you can only use the 3/8″ screw provided with the Innorel RT90C to attach the AM3 or AM5 mount to the tripod, whereas the ZWO plate is mounted with three M6 screws directly to the bottom side of the mounts. This is a more solid approach since the connection cannot come untightened by accidentally rotating the mount on the plate. This happened to me a few times and I was wondering why the mount started to wobble a bit. To compensate it, I created an adapter which can be inserted into the mounting Innorel RT90C mounting plate and mounted onto AM3 and AM5 mounts the same way as the original ZWO plate:

It is possible to order the Innorel RT90C tripod with a 75mm leveling “bowl” and an adapter for it. On this picture, both are mounted into one unit and placed into the tripod instead of the plate discussed above:

At first sight, it does not look that this would work well for astrophotography, but I was really surprised how stable and rigid this contraction is. It makes it very easy to level the mount. I’m sure it will work well with small refractors.

The mount was leveled here really in seconds. The leveler on the picture has precision of 20-25″ and it still was easy to find the right spot. BTW, this leveler as well as the cable management guides are from the kit available in the Photastro shop.

Conclusions

If you already own a setup with the ZWO TC40 tripod, Innorel RT90C is a better choice than a second ZWO TC40 tripod, if you are also doing regular photography. Innorel RT90C is an excellent photography tripod for large equipment. It is still stable and rigid enough to carry small to mid-size refractors. A leg spreader would fully close the gap to TC40 in that sense. ZWO TC40 should still be the first choice if you do astrophotography only. It brings things astrophotographers need and omits those which they do not care about.