RASA 6 vs IRDK17: Fast Imaging Telescope Showdown
By Cloud Break Optics | Published: 2026-10-25
Category: Comparisons
Compare the RASA 6 and IRDK17 catadioptric telescopes for fast astrophotography. See which suits your imaging goals and budget.
Quick answer
Choose the RASA 6 for portable, ultra-fast deep-sky imaging with minimal exposure time. Choose the IRDK17 for specialized infrared research where on-axis performance is paramount.
Speed vs Specialization
The RASA 6's f/2.2 optics are designed for speed, allowing you to capture deep-sky images with shorter sub-exposures and less total time. This makes it ideal for mobile setups and beginners in astrophotography.
The IRDK17, with its f/6.8 Dall-Kirkham design, prioritizes on-axis performance and infrared optimization. It's a specialized tool for research applications, not for general wide-field imaging.
Trade-offs at a glance
- Speed vs. specialization: The RASA 6's f/2.2 system captures images in minutes; the IRDK17's f/6.8 is slower but optimized for infrared. Choose speed for broad deep-sky, or specialization for infrared research.
- Portability vs. size: At 8.4 lb with a CG-5 dovetail, the RASA 6 is highly portable. The IRDK17 is a 17-inch tube requiring a permanent setup and separate shipping arrangements. If you need to move your setup frequently, the RASA 6 is the clear winner.
- Cost vs. research capability: The RASA 6 is priced at $1,206.29 (catalog price $1,699), while the IRDK17 costs $19,220 (catalog price $31,000). The IRDK17's cost is justified only for dedicated infrared research. For most hobbyists, the RASA 6 offers better value.
Product facts
- RASA 6 Optical Tube Assembly (91071): The RASA 6 features ultra-fast f/2.2 optics for deep-sky imaging with briefer sub-exposures and less total exposure time, often eliminating the need for autoguiding. This means you can capture high-quality images faster, even from less stable mounts or under light pollution.
RASA 6 Optical Tube Assembly (91071) - IRDK17 (Infrared Optimized): The IRDK17 is a 17-inch infrared optimized optical tube with a Dall-Kirkham design and focal length of 2,939 mm (f/6.8), optimized for on-axis performance. Its specialized coatings and design make it ideal for infrared research, but its narrow field and slower speed limit its use for general astrophotography.
IRDK17 (Infrared Optimized)
Which one fits you?
Best for
- Portable deep-sky astrophotography with fast results
- Beginners and intermediate imagers on a budget
Not for
- Infrared research requiring specialized coatings and on-axis performance
