Skywatcher Explorer 150PL

[starscy]

Is anyone using the Sky-Watcher Explorer-150PL (6" f/8) reflector? How does this compare to the Skywatcher Evostar 100ED DS-Pro (4" f/9) ED refractor?

[michael.h.f.wilkinson]

Sometimes 6" f/8s are called APO-killers, and I can confirm they can be very nice instruments (built one in 1978 (yes, I'm that old), and used it until about 1996, when I got my GP-C8 from Celestron). When well-collimated they are sharp on axis, and do not show severe coma off axis (as faster Newtonians do). Though I do not now the exact scopes in question, there are some general points to make, depending on the objects you want to observe.

The Newtonian gathers more than twice the amount of light captured by the 4" refractor, and it is likely to be almost as sharp for planetary work. For deep sky it is just as good as its faster brethren, although you need some of the larger and more expensive eyepieces to get wide true fields of view. If you want to do deep-sky imaging, faster scopes mean seriously shorter exposure times, wider fields in the camera, and better match of optics diffraction disk to the physical pixel size.

I would say the Newtonian is a great allrounder, whereas the ED refractor is a bit more specialized for planetary work. The latter is also more portable, though my rather heavy old 6" f/8 never stopped me observing with it.

Cheers

Michael

[dweller25]

In terms of planetary detail they will be a close match to each other.

In terms of DSO's the 6" will win.

The Apo will give a "nicer" image than the reflector.

The reflector is excellent value for money.

The lens in the Apo will never degrade.

HTH :-)

[ponte carlo blue]

Hi Dweller 25

What do you mean by the lens will never degrade, does this mean the mirrors in the reflector degrade?

In what way?

Thanks

Rich

[dweller25]

The mirror coatings and reflective surface will need to be renewed every 10 ish years or so for maximum performance.

[michael.h.f.wilkinson]

The mirror coatings and reflective surface will need to be renewed every 10 ish years or so for maximum performance.

That was certainly true for the old silvered mirrors, much less for aluminium coated mirrors, even less for those with dielectric coating on top of the aluminium (Hilux, Starbright, and the like) which prevent oxide building up. These last for 25 years or more. Even "regular" aluminium coatings of many manufacturers have a quartz or silicon monoxide coating on top to prevent oxide build-up and scratches.

[Gina]

Considering the lifetime of "consumer goods" I think you could probably say mirrors last a lifetime!