BYEOS focus

[primordial atom]

Hi all,

I've been using FWHM focussing aid on BYEOS several times, it's easy to use and I think I'm getting the best focus possible.

I'm typically getting about 3.5 to 4 (3.2 best) as a minimum, I'm wondering what number other BYEOS users achieve and what factors effect how low you can get this reading and how can you improve it??

Thanks in advance

David

[gkec]

I also find BYEOS FWHM function useful for focusing.  The minimum FWHM is very dependent on atmospheric conditions.  Atmospheric turbulence will make the star move about on the sensor affecting the FWHM reading.  You just have to find the minimum at any particular time.  The minimum is the point of best focus.  I think the best I have achieved is 4 ish.   

Making sure that the scope is in thermal equilibrium would possibly help. 

Whilst in theory it shouldn't make any difference object brightness has an effect as the refracted photons can be detected to a greater distance from the stellar centre.

Of course getting good focus is dependent on good collimation which there are several resources on here that deal with this. 

[Oily]

You could improve it by using a bahtinov mask too

[primordial atom]

Hi oily thanks

Are you same oily as the Astronomy Shed??

[Oily]

Hi oily thanks

Are you same oily as the Astronomy Shed??

That's me!

[primordial atom]

Ah Ha

I'm galileo from the shed, thought I'd trip across here incognito to see what was going on .

How are you doing?