The Sky Rover 130 GPS is a serious deep-sky imaging platform: 130mm aperture, 910mm focal length, a Super ED triplet, and a 3.7-inch focuser that gives you the precision and stability that long focal lengths demand. At 910mm f/7, the scope is built for planetary nebulae, galaxies, and tight star clusters — the kind of targets that reward native focal length and careful focus. But like all refractors, the 130 GPS has inherent field curvature. At the eyepiece, your eye adapts to it instantly. Behind a camera sensor, it becomes visible: stars in the center are tight and round, while stars at the edges of an APS-C frame or larger sensor start to elongate. That's not a flaw — it's the optical reality of refractor design — and it's exactly what the SR130GPSFF 1× field flattener is designed to correct.
The flattener maintains the 130 GPS's native 910mm focal length and f/7 ratio. It changes nothing about the focal length or speed — it simply flattens the curved focal plane into a flat one that matches your camera sensor. The result is sharp, round stars from center to corners at the full 910mm focal length. For a scope this capable, adding a matched flattener completes the system: you get the full resolving power of 130mm aperture at the native focal length, with corrected stars across the entire sensor.
Flattener, Not Reducer
This is a 1× flattener — it preserves the native 910mm focal length and f/7 ratio of the 130 GPS. If you want the full imaging power of this scope at its native focal length with a corrected field, this is the accessory. The field of view, star size, and exposure times all remain the same — you just get flat, well-corrected stars across the sensor instead of curved, elongated ones at the edges.
If you prefer a shorter focal length and faster system instead, Sky Rover offers the SR130GPSRFF 0.8× reducer, which yields 728mm f/5.6. The choice is yours: native focal length with the flattener, or shorter focal length and faster speed with the reducer.
Camera Connection
The camera side of the flattener connects to your imaging equipment via standard threads. DSLR and mirrorless cameras connect via a T-ring for your specific camera mount (sold separately). Dedicated CMOS and CCD astronomy cameras typically have 48mm T-threads built in and connect directly without a T-ring.
What's Included
- Sky Rover SR130GPSFF 1× field flattener for 130 GPS
Features
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1× field flattener — no focal reduction. Maintains the 130 GPS's native 910mm f/7. Corrects field curvature for flat, sharp stars across the sensor without changing the imaging characteristics.
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Designed for 910mm deep-sky imaging. At this focal length, field flatness is critical for planetary nebulae, galaxies, and other compact objects. The flattener is optimized for the 130 GPS's optical prescription.
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Transforms the 130 GPS into a complete imaging system. The 130 GPS's 130mm aperture, 910mm focal length, and 3.7-inch focuser are built for precision imaging. The matched flattener gives you flat-field performance at the native focal length — exactly what deep-sky imaging at this scale demands.
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APS-C and larger sensor coverage. Field flatness extends across the entire width of full-frame sensors and larger formats, not just APS-C.
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Standard camera-side threading. DSLR and mirrorless bodies connect via a T-ring (sold separately); dedicated CMOS/CCD astronomy cameras attach directly — 48mm T-threads are standard on most.
Frequently Asked Questions
Do I need this flattener for visual observing?
No. Field curvature only affects imaging — your eye naturally accommodates the curved focal plane during visual observation. The flattener is specifically for camera work.
What's the difference between this flattener and the SR130GPSRFF reducer?
The flattener (this product) preserves the native 910mm focal length and f/7 ratio while correcting field curvature. Use it if you want the full 910mm focal length and 130mm resolving power at native speed. The SR130GPSRFF 0.8× reducer shortens the focal length to 728mm and speeds up the system to f/5.6, making exposures faster but reducing magnification. Choose based on your target scale and exposure time preferences.
Will this fit any other Sky Rover scope?
No. The SR130GPSFF is designed specifically for the 130 GPS's optical prescription and mechanical connection. Using it on a different scope will not produce correct results. Each Sky Rover scope has its own matched flattener.
What cameras does this work with?
DSLR and mirrorless cameras connect via a T-ring for your specific camera mount (sold separately). Dedicated CMOS and CCD astronomy cameras typically have 48mm T-threads built in and connect directly without a T-ring.
Final Thoughts
The 130 GPS at 910mm f/7 is built for the kind of deep-sky work that demands precision: tight star clusters, planetary nebulae, galaxy details. The matched SR130GPSFF flattener gives you the flat-field performance that matches the scope's optical and mechanical quality. It turns a capable imaging platform into a complete one. That's the essential pairing for 130mm refractor work.
