In daily astronomical shooting, the backfocus will have an influence. Astronomical photographers are often frustrated by the change of backfocus due to various reasons such as refraction of filters or when using some products with sensitive backfocus. To solve this problem, ASKAR launched the backfocus adjuster, (providing the adjustment range from 16mm-20mm), which can be adjusted ± 2mm of the backfocus. We offer two specifications for the backfocus adjuster, the camera side adapter M54 and M48, which are convenient for users to choose from.

The M54 backfocus adjuster's front telescope interface is female thread M54x0.75 and the rear camera interface is male thread M54x0.75, the overall thickness is 18mm and offers ± 2mm adjustment range.

 The M48 backfocus adjuster's front telescope interface is female thread M54x0.75 and the rear camera interface is male thread M48x0.75, the overall thickness is 18mm and offers ± 2mm adjustment range.

The backfocus adjuster is CNC machined. Each unit is a 0.05mm precision adjustment, the surface is printed with a scale for easy adjustment and to save the position. There are two holes for fixing screws, which make the adjuster easy to use with different products.

 By rotating the backfocus adjuster, it can be adjusted between ±2mm to match the backfocus requirement, and to solve the various imaging problem caused by the backfocus.

 Users just need to choose according to their product's rear adapter.