Bahtinov masks

[SteveA]

I was just looking at the Bahtinov masks on FLO's site...

Does anyone know how critical it is to get the correct optimised version? I've got a 250mm f4.7 newtonian but the closest one I can see on FLO is for 250mm f5. Is that going to work OK ?

Cheers

Steve

[FLO]

Yes, definitely, we have rounded-up f4.7 to f5 for convenience. It is designed specifically for the Synta (Skywatcher, Celestron and some Orion-US) 10-inch f4.7 Newtonians.

(I have changed the listing to show f4.7)

http://www.firstlightoptics.com/bahtinov-focus-masks/starsharp-bahtinov-focus-masks.html

HTH,

Steve

[Stephen]

If you mail them I'm sure they can get Keith to make you the correct one (if it's not already!) (he offers that service through his eBay sales.)

I had an f6 8" and moved to an f5. I tried using the same mask and it was very close, but there was a slight difference and lifes too short for fiddling so I bought the f5 version.

Just my opinion though

[Komet]

It will work fine.

Also get Bahtinov Grabber - its almost essential and makes focusing a breeze.

[callisto]

Yup, Its fine, I got the f5 from FLO for my Orion f4.8

[SteveA]

Thanks chaps......

I'll be ordering one of those today..

What does the Bahtinov Grabber application do for you ?

Steve

[Stephen]

Thanks chaps......

I'll be ordering one of those today..

What does the Bahtinov Grabber application do for you ?

Steve

IIRC it can analyse the image on the screen and tell you how far out focus is rather than doing it by eye

[Komet]

IIRC it can analyse the image on the screen and tell you how far out focus is rather than doing it by eye

.... and its blumming good at it!