Bahtinov Focusing Mask 250
Bahtinov Telescope Focusing Mask 250 for telescopes with a lens diameter usually around 250mm (dew cap = 289mm, such as Celestron or SkyWatcher Newton)
The LACERTA Bahtinov Focusing Masks are made from a lightweight, sturdy but still flexible plastic material (special material: Kö-Ma, produced in Hungary).
Use: just like a solar filter, place the Bahtinov mask in front of the telescope tube. With the help of the resulting diffraction pattern of a star a precise focus can be determined. From the star’s diffraction spike there are three rays formed; when the distance between them is the same then the optimum focus is reached.
This can be used of course not only visually but via CCD or CMOS camera as well. Especially in combination with live-view cameras, the otherwise painful focusing process becomes a breeze.
If you need to use a dew shield, that’s fine, please use the Bahtinov mask inside the dew shield or at the end.
There is a slightly flexible bracket (see image with a load of 2.4kg) to secure the Bahtinov mask for ideal adaptability to conventional tube diameter.
Our Bahtinov masks can be found in the following diameters:
- 80mm or 100mm lens diameter (dew cap = 116mm, as Synta and Celestron EDs 102/1000)
- 127 mm optic diameter (dew shield = 145 to 157mm, as Synta MAKs or Meade 127 ED APO)
- 150mm lens diameter (dew cap = 181mm, such as Celestron or SkyWatcher Newton)
- 200mm lens diameter (dew cap = 236mm, as SkyWatcher Newton or C8)
- 250mm lens diameter (dew cap = 289mm, such as Celestron or SkyWatcher Newton)
Bathinov telescocus focusing mask