Daystar Interference Eliminator (T mount)

Daystar Interference Eliminator - T-mount

This version has the T-Mount / T2 / M42 Female thread on one side and a male thread on the other. It is the most flexible model.

Please note, the C-Mount only version of this product is quite limited in it's scope, and it's better to order this T-Mount version for better flexibility and wider aperture for cameras like IMX533 or larger, and DSLRs.

You can still convert this into C-Mount format with an adaptor, and therefore enjoy both types of connection with either 1.25" or 2" push-fit, M48, etc. by ordering the following accessories: 

For the Quark / Telescope side: 
- Altair Hypercam 1.25 inch Nosepiece - Straight Sided Barrel (Product code: ALTAIRH-125IN) which fits the standard Daystar Quark.
- Altair Hypercam 2 inch Nosepiece -Straight Sided Barrel (Product code: ALTAIRH-2IN) which fits Daystar Quantum series or the Quark with 2" push-fit adaptor.

For the camera side: 
- If you have a Hypercam series camera, then no adaptors are required, it will fit directly.
- If you have a DSLR, you can attach a standard DSLR T-Mount / M42 / T2  adaptor directly without additional adaptors.
- For GPCAM with C-Mount thread you need the Altair 2mm M48 Male to T2 Female Converter Spacer Ring - Easy Grip (Product code: M48M-2-T2F) and the M48 to C-Mount Adaptor Converter for GPCAM (Product code: M48-5-CMOUNT)

Why do you need the Interference Eliminator? Photographers imaging in monochromatic light, such as Hydrogen Alpha, using an electronic sensor frequently encounter a wavy pattern of light and dark lines superimposed over their images. These lines are called interference fringes, interference patterns, or Newton´s Rings. In long focal ratio applications, the nearly parallel light can internally reflect inside the image sensor or camera, causing an addition or subtraction of the light waves, resulting in the observed pattern.

The Interference Eliminator solves this problem by tilting the camera off normal while keeping the centre of the image sensor stationary, so that focus, framing, and vignetting are not changed with the tilt. The tilt changes the angle of incidence and optical path lengths relative to the image sensor, mitigating the interference.

Installation & Use:
Installation: The Interference Eliminator should be placed directly in front of the camera in the optical train. For proper operation, the distance from the flange of the male T thread to the camera focal plane should be 55 mm. On a DSLR with a T ring, no spacers are required, the T ring sets the distance to 55 mm. On a CCD camera or Webcam, male to female T ring spacers may be required to bring the distance to 55 mm. If the distance is significantly different from 5 5mm, the camera will move off boresight and the focus position will shift while adjusting the Interference Eliminator tilt setting.

Use: Slightly loosen the thumbscrews and slide the two halves of the Interference Eliminator apart, such that the camera tilts. Take a few images with the camera to check for the interference pattern. Slide further apart if the pattern is still evident. Tilt it the minimum amount to eliminate fringes - too far and focus could be lost at the top and bottom of the image, especially in fast focal ratio systems. If maximum tilt is reached without satisfactory effect, try full tilt in the opposite direction. In some severe instances the interference pattern may not be completely removable, but it will be reduced to where other techniques such as flat-fielding or compositing can make the image acceptable.

Notes: On large sensors such as full frame 36x24 mm DSLR cameras, some vignetting is possible at full tilt due to the camera structure and the inside diameter of the T thread. For an example of a full frame Canon EOS 5D image at full tilt, click here. With webcams or 1.5-1.6x crop digital SLRs no vignetting will occur.