Y mask

[leemanley]

I've been looking at these Y or Lord masks for a few days online, so, I'm going to make one for my ED80 today.
I have bought some rigid foam filled black card, which is about 6mm thick and a craft knife.
I use a bahtinov on my 200pds, which I swear by. So hopefully this will help in the same way.
As I can see online, the only difference in the diffraction pattern results from the width of the legs of the Y, its actually claimed that these are more effective in that they let more light in, which makes sense !

Does anyone else here use one, and if so, how effective do you find it ?

Thanks Lee

[Alien 13]

I never use my camera linked to a PC so all focusing is done on the live view screen and have found using one and is  better than the Bat mask for small scopes and camera lenses because its so much brighter.

I dont however use it that much prefering to focus by eyeball on a faint star in the live view image.

Alan

[Digz]

If used a Y mask and find it works a treat. Haven't used a bhatinov mask so can't compare to that however.

The Y mask is obviously easier to construct so that's 'y' I plumped for it

[leemanley]

Thanks for the replies, I'm going to make a start on it in a mo.

[frugal]

I have never understood the physics of the y mask. Diffraction only happens at the point where the light diffracts around the edge of the mask. So if you only have a single edge there should be less diffraction. Otherwise why would spectroscopy require very fine gratings. But that does not seem to be the case.

Sent from my GT-N7000 using Tapatalk

[leemanley]

Nor have I, but I guess we'll find out tonight, if the forecasts right !

[ChrisLX200]

I've never tried a Y-mask - but I will. They look to be a lot easier to make that the Bahtinov. I just made a Bahtinov for my 127 refractor but not had chance to use it yet due to the weather, but I do know cutting all those slots out was not a fun task.

ChrisH

[ollypenrice]

I never use my camera linked to a PC so all focusing is done on the live view screen and have found using one and is  better than the Bat mask for small scopes and camera lenses because its so much brighter.

I dont however use it that much prefering to focus by eyeball on a faint star in the live view image.

Alan

I really don't believe the eyeball method has much hope of getting optimal focus. When I focus using Full WIdth Half Max measurement no perceptible change occurs to the stellar images once I'm roughly right. As the FWHM comes down from 3 to 1.5 (quite an improvement!) I can't see the stellar image improve at all. However, the difference between focus using a Bahtinov and focus using FWHM is tiny, so I think the Bahtinov gets you there.

I couldn't get much sense out of a Y mask on the 14 inch, I must say, but find a Bahtinov works well. However plenty of people use Y masks and swear by them so it might just be me.

Olly

[edjrgibbs]

Can't comment on the Y mask but I use bahtinov masks which are great and I've just made some homebrew Hartmann masks for my DSLR lenses which are good. I used a DVD case.