What is your favourite f ratio ?

[IB20]

17 minutes ago, John said:

Currently all my scopes are refractors ranging from F/6 to F/9.2. 

As long as the optics are close to apochromatic I guess F/8 would be pretty optimal (I am a visual astronomer only) but I don't actually currently own a refractor of that exact focal ratio.

When I've had newtonians I have found F/5.3 - F/6 a good focal ratio range for visual use.

 

 

Have you parted with the 12” dob @John?

[John]

8 minutes ago, IB20 said:

Have you parted with the 12” dob @John?

Yes. It was a tough decision but it took up a lot of room and we have grandchildren now so needed to de-clutter a bit. Refractors can be stored away safely but a 12 inch F/5.3 solid tube dob is difficult to hide away from lively, enquiring small folks.

I may re-acquire a larger aperture scope again at some point but for now I am managing without. 

[IB20]

Understandable. I have two little ones who love to drive vehicles into the 8” dob that sits in the kitchen. Not used it for a while so expect I’ve a fairly lengthy collimation job on it at next light. The lovely fracs get hidden away from sticky fingers and tantrums! 

[Bivanus]

My ideal scope , with the knowledge level I have now , would be a 5" APO , f/5.8 - f/6 , FPL53 glass.

I would not mind it being fluorite , but I think the price would already be way above what I can pay 😅 

[niallk]

Well I've one dob, so I guess my fav f-ratio must be 4.43 😉

My little Lunt is f7 I think for daytime wonderment.

Both do their jobs well!