The SVBONY SV238 Off-Axis Guider delivers precise, reliable performance for astrophotography. Its large prism captures more starlight and widens the field for easier guide star acquisition. Dual helical focuser ensures ultra-fine, stable adjustments. Crafted from durable CNC aluminum, it resists outdoor deformation. Universal compatibility (M54, M48) and adjustable prism height allow flexible setup for clear, stable deep-sky imaging.
|
💡💡💡Note: |
Q&A: Q1: Which device models are compatible with SV238? A:1.Main camera: SV605CC, SV405CC, SV605MC, ASI 533MC Pro, ASI 260C Pro, ASI 2600 MC, ASI 662MC, Altair 294C, Altair 533M, Altair 26C, Uranus C-Pro, ATR294C, QHY5III585M 2.Guide camera: SV905CC, ASI 120MM Mini, ASI 220MM Mini, ASI 290MM Mini, GPM662M 3.Filter wheel/drawer: SV226P filter drawer, 7×36mm EFW 4.Adapter/spacer: Depends on configuration The above combinations come from actual customer feedback. In fact, SV238 has strong compatibility, and more combinations await discovery by enthusiasts. Q2: The main camera is in focus, but the guiding camera is always out of focus. What should I do? A: The key is to align the imaging planes of the two cameras. Procedure:1.First, focus only on the main camera to achieve precise focus. 2.Loosen the guiding camera's locking ring and use the sliding/rack mount to slowly extend or retract it until the star points become smaller and more solid. 3.If necessary, slightly adjust the height of the prism (by inserting or retracting a small amount). 4.Finally, "lightly lock - fine-tune - finally lock" to avoid rebound. It is recommended to mark the extension of the guiding camera for easy resetting next time. Q3: Can't find a guide star/the star is too faint, especially during narrowband imaging. What should I do? A: First, confirm that the OAG is placed before the filter wheel/filter (so that guiding does not pass through the narrowband filter). Then:1.Rotate the OAG (changing quadrants often helps to find a brighter star). 2.Slightly raise the prism (until a dark corner appears, then retreat). 3.Set the guiding camera exposure to 1-3 s, moderately increase the gain, or use 2×2 binning. 4.In urban light pollution, choose a brighter target area. 5.Check if the lens cap/cover is not removed and if the focal plane is close enough. Q4: Shadows/uneven dark corners appear in the main image. Is it because the prism is blocking the light? A: Very likely. Solution:1.Retract the prism by 0.5-1 mm. 2.Slightly rotate the OAG to change the light intake position. 3.Full-frame cameras are more sensitive; if dark corners still exist, consider an OAG with a larger aperture/prism or upgrade the camera port to an M54/M68 diameter. 4.Also, check if the back focus is correct (incorrect back focus can also exacerbate edge issues). Q5: Is there a recommended "first-time setup" checklist? A:1.Confirm the interface and thread pitch (M42/M48/M54) and target back focus. 2.Assemble in the order of "telescope → field flattener/focal reducer → OAG → filter wheel → main camera." 3.Focus the main camera. 4.Adjust the height of the guiding camera and prism to achieve simultaneous focus. 5.Rotate the OAG to select a brighter star field. 6.Calibrate the software, set the exposure to 1-3 s, and enable multi-star guiding. 7.Test shoot the corners to check for dark corners and star point shapes, make fine adjustments, and then start long exposures. Q6: I always get confused about the assembly order: where should the OAG be placed? Are there any exceptions? A: The general order is: telescope → (focal reducer/field flattener) → OAG → (filter wheel/drawer) → main camera. Reason: The guiding camera sees the corrected image field and is not obstructed by the main camera's filter. Exceptions: Ultra-short back focus systems (such as RASA/HyperStar) may not fit a conventional OAG and may require a dedicated ultra-thin model or omitting the OAG; in individual cases where a field flattener requires strict back focus, follow the manufacturer's linkage diagram. Q7: The guiding is always "drifting/unstable," and it's not a software issue. What else should I check? A: Prioritize hardware checks: 1.Ensure all threads are fully tightened and not "loosely tightened." 2.Check if cables are pulling on the guiding camera (use cable clips and leave some slack). 3.Check for radial clearance in the OAG/camera's sliding mount (apply moderate pre-tension). 4.Check the balance and backlash of the equatorial mount. 5.Check the stability of the tripod/wedge/ground. On the software side, start "conservatively": set exposure to 1-3 s, use multi-star guiding, set RA/DEC aggressiveness to medium, MinMo > 0, and calculate calibration step size based on focal length/pixel size. Q8: How do I choose an OAG for a full-frame camera + fast system + filter wheel? A: Select an OAG with a large aperture (larger prism/opening) and a large diameter thread (M54/M68), and minimize the number of unnecessary adapter rings. This reduces dark corners and leaves back focus space for the filter wheel/tilt plate. If the edges are still tight, consider using a thinner filter wheel/drawer or "subtract" from the optical train. Q9: What are the compatibility points for different telescope systems (SCT/RC/Newton/RASA)? A：SCT: The main mirror moves to focus, changing the focal length; refocusing is required after changing accessories. For long focal lengths, an OAG is highly recommended. |
Order Processing
Almost all of the standard orders are shipped within 1-2 business days, excluding weekends and holidays. The special orders for some customized products will take a little longer time, the specific time can be confirmed with our sales expert.
As soon as your order is ready, we’ll update the tracking number and inform you of the information. If the item you ordered is temporarily out of stock, our customer service team will reach out to you. You can choose to wait until the item is back in stock or cancel your order.
Delivery Time
Delivery time depends on destination, logistics mode and other factors.
If the products that you purchased are available in our local warehouses, we will ship them from there and it takes about 1-6 business days for delivery as usual.
If the product you purchased is in stock at our warehouse in China, we will ship it from there. Delivery time is usually 5-9 business days.
Thank you for choosing SVBONY! We have established a strict system to ensure product quality in a responsible manner. These products are safe and reliable, and you can buy them with confidence. Should you have any issues, feel free to contact us. Our professional customer support team will patiently help you resolve the problems. We sincerely apologize in advance for any trouble and inconvenience that caused you.
Return & Refund
We offer a 30-day unconditional return policy.
1. You can get a full refund when you return an undamaged product for any reason within 30 days. Just make sure all products are in original condition and provide us with relevant pictures or videos to prove it.
2. If you are not sure whether the product is in brand new condition, you can contact us first. We can help you confirm and provide a return label.
3. We will issue a refund immediately once the product arrives at our warehouse.Processing time usually takes 2-5 business days.
Warranty Time
We offer a 1-year warranty.
Guaranteed authentic, we are the official store of SVBONY brand, and the products sold are guaranteed to be authentic.
Guaranteed service, one-to-one exclusive customer service, answer all your questions and provide free professional technical support.
Guaranteed after-sales, all products purchased from SVBONY enjoy worry-free warranty, your product warranty period is one year.
If you have any questions or inquiries about our products or services, please feel free to contact us.
