My small frac beat my dob :-/

[John]

When I stop down my 12" F/5.3 dob to a 4" unobstructed aperture it performs very like my 4" ED refractors on double stars and planets. Perhaps slightly less light throughput (my mirror coatings are a few years old now) but pretty good.

 

 

[timwetherell]

That was pretty much my experience with a friend's 24". Stopped down to an unobstructed 9" and after a long cool down, it was very like an 8" apo!

[Victor Boesen]

Do you think a mak would perform like the frac in this case?

[timwetherell]

I once tested a 4" mak against my 5.5" apo stopped down to 4" and the mak performed very favourably. In fact in some ways it was more refractor like than the refractor  Definitely very high contrast and nice crisp details even at very high magnification. A fraction better than the ED apo on colour correction as one might expect but a bit worse on light throughput. I have a very high respect for maks. The Achilles heel(s) are very slow cooldown and small true field of view - well much narrower than a good apo at 30x. But for 1/4 of the cost of a 6" apo one can buy a 7" mak that will be pretty close to its equal on many tasks once it's fully thermalised. 

[John]

The mak that gives the most "refractor like" views that I've used was a mak-newtonian. Intes MN61 to be precise. Does not have the compactness of the mak-cassegrains but, my, the planetary views