Celestron has just dropped a new addition to its popular RASA lineup, and it’s exciting news for the astrophotography community. The RASA 6, a compact 6-inch Rowe-Ackermann Schmidt Astrograph, promises ultra-fast imaging in a lightweight, travel-friendly package.
For those unfamiliar, the RASA series is all about speed. These scopes are designed to gather light fast—we’re talking f/2.0 and f/2.2 fast. That means shorter exposures, less time fiddling with gear, and more time actually capturing the night sky.
So How fast is this?
Let’s break it down. A telescope with an f/2.0 focal ratio collects light about 25x faster than a standard f/10 system. That’s huge. With the RASA 6, a 30-second exposure can reveal more detail than a 10-minute shot on a traditional setup. It’s a game-changer for anyone who’s tired of long imaging sessions or dealing with autoguiding headaches.
And it’s light—just 8.4 lbs (3.8 kg). That makes it a true “grab-and-go” scope. Whether you’re imaging from your backyard or heading out to a dark-sky site, the RASA 6 is built to move.
The Journey from RASA 11 to RASA 6
The RASA story started back in 2014 with the RASA 11, a big, pro-level scope used by satellite trackers and even some government agencies. Then came the RASA 8, which brought that same speed to amateur astronomers. Now, the RASA 6 continues the trend—smaller, lighter, and more affordable.
It’s optimized for modern CMOS and mirrorless cameras, especially those with sensors up to 22mm diagonal. APS-C sensors can work too, though you might see a bit of vignetting. Standard DSLRs? Not really compatible—they’re just too bulky for this design.
RASA 6 vs. RASA 8: What’s the Difference?
Here’s the quick rundown:
- RASA 6: 6″ aperture, f/2.2, 335mm focal length, 3.8° field of view, $1,699.
- RASA 8: 8″ aperture, f/2.0, 400mm focal length, 4.6° field of view, $2,199.
The RASA 8 also has an Ultra-Stable Focus System, which helps eliminate image shift—super helpful when you’re working at f/2.0. But it’s heavier (17 lbs) and more expensive. So it really comes down to what you value more: portability or performance.
| Feature | RASA 6 | RASA 8 |
|---|---|---|
| Aperture | 6″ (152mm) | 8″ (203mm) |
| Focal Ratio | f/2.2 | f/2.0 |
| Focal Length | 335mm | 400mm |
| Resolution | 0.76 arcsec | 0.57 arcsec |
| Weight | 8.4 lbs (3.8 kg) | 17 lbs (7.7 kg) |
| Sensor Support | Up to 22mm | Up to 32mm (APS-C ideal) |
| Focus System | Standard | Ultra-Stable Focus System |
| Price (approx.) | $1,699 | $2,199 |
A Few Caveats
As cool as these scopes are, they’re not exactly plug-and-play. Both the RASA 6 and 8 are very sensitive to backfocus and sensor tilt. You’ll need to dial in your spacing carefully, and maybe invest in a tilt adjuster or electronic focuser.
Also, dew can be a problem. The big front corrector plate tends to fog up, so you’ll probably want a dew shield or heater. And since the camera sits right at the front of the scope, cable management is a thing—messy cables can cause diffraction spikes in your images. Curved routing helps.
And while the fast optics reduce the need for long exposures, you’ll still need a solid equatorial mount and good polar alignment. Some folks even “over-mount” their RASA for extra stability.
Final Thoughts
The RASA 6 is a seriously exciting option for astrophotographers who want speed, portability, and performance without breaking the bank. It’s not without its quirks, but for those willing to put in the effort, the results can be stunning.
If you’re just getting into deep-sky imaging or looking to upgrade your setup, this might be the scope that finally gets you those crisp, wide-field shots you’ve been dreaming of.
