Glasspathcorrector 2" / 1.7x for Newtons – incl. T-2 change ring

Nous recommandons le GPC pour les Newton : s'il ne fonctionne pas, rien ne fonctionne généralement, et il corrige également la coma. 

Avec lui, vous avez besoin d'environ 3 cm d'espace supplémentaire par rapport à sans MaxBright Bino.

(I hope, the translation works - the GPC for Newtonians is the best recommendation, it requires ca. 3 cm of backfocus compared to the position of the eyepiece without MaxBright. As you have 4 cm, it should work.

This an "Glaspath corrector" only for use with binoculars. It corrects the color fringes that occur when light travels through the prisms of an binocular. When you use it photographically with a camera, you will see an "overcorrection" - means, color abberation. Therefore this corrector doesn´t work for photography. If you want to correct coma of your Newton for photography, the MPCC is the right choice https://www.baader-planetarium.com/en/2%22-mpcc-mark-iii-(multi-purpose-coma-corrector-for-newtons).html Here you find the manual: https://www.baader-planetarium.com/en/downloads/dl/file/id/483/product/3004/mpcc_mark_iii_instruction_manual.pdf

Yes, the GPC has got a 2" filter thread on the front, so you can use one 2"-filter for both eyepieces.

When the GPCs were designed f/3.5 Newtonians were not very common. Using a GPC at this f-range will likely cause some vignetting (not to speak of residual uncorrected coma). However we are confident since never ever had we receivded complaints about unpleasing results. We can´t say though if this is due to so very few people using this combo or if those that are utilizing the GPC in this configuration do accept the possible downsides. At any rate - in order to get focus so far out on an f/3.5 the real compromize will be in the position and size of the secondary

We are sorry but we do not have adapters for William Optics bino-viewers and dont know their design good enough. If it has got a 2" filter thread, maybe you can use Baader Expanding Ring T-2f / M48m (T-2 part #29) # 2458110 - but this will bring the glasspath corrector much farther away from the bino than desired, thus increasing the magnification even further.

The length of this Item is 92mm. The diameter ist 2" and must be insertet into a 2" focuser completely down to the flange. The focus gain is 80mm so with most commercial newtonians you´ll reach focus. A list according the different GPC and focus gain you can find here on page 5 and 10 https://www.baader-planetarium.com/en/downloads/dl/file/id/433/product/1264/mark_v_gro_feld_giant_binocular_user_manual_12_pager.pdf