Best options for lunar/planetary observing

[arctica]

Hello all

Just a quick one. If my prime interest is lunar and planetary observation, and keeping to a budget of say less than £500, what instruments would people recommend. In the past I have always lent towards refractors (had a cheap 60mm one long time ago), but have seen some good reviews for Maksutov-Cassegrains, although I did read something about reduced contrast with the latter.

For just hopping around the sky, do you really need to have an equatorial mount if you already know the night sky?

Sorry for the very general query: bit like asking which is better a refractor or reflector (or cat variants)!

Thanks

Lester

[arad85]

For planetary/lunar, most people prefer Schmitt-Cassegrains or Mak-Cassegrains. Ability to gather light isn't important as the planets/moons are fairly bright, but magnification is. A typical SCT has a focal ratio of 10 whilst a Mak can be up to 15 which means for a given eyepiece the magnification is much greater than an equivalent sized newt.

For hopping around the sky - no you don't need an equatorial - the time it becomes important is for deep space photography as you'll get image rotation on long exposure photos.

For £500 if I were primarily interested in planets/moon, I'd be looking at something like the Skywatcher Skymax 127, Celestron 4SE or if you can push the boat out to £600 you have the choice of Celestron NexStar 5SE or if you want non-goto and want a GEM, take a look at the Skywatcher Skymax 150 PRO with mount. The Nexstars are computer controlled and the Skymax can be bought with various mount combinations. Alternatively, have a look on here for something second hand...

Alternatively choose a refractor or reflector

[brianb]

Ability to gather light isn't important as the planets/moons are fairly bright, but magnification is. A typical SCT has a focal ratio of 10 whilst a Mak can be up to 15 which means for a given eyepiece the magnification is much greater than an equivalent sized newt.

But resolution is important - to the point of being critical - and larger apertures get more resolution.... The focal ratio is largely immaterial (except that short focal ratios are better avoided because of collimation issues & eyepiece matching) but anything from f/8 up is fine, f/6 is acceptable with larger apertures.

The best "bank per buck" is undoubtedly a long focus Newtonian. Skywatcher's 6" f/8 Newtonian is pretty well ideal apart from slightly being on the small side & needing motor drives on the axes ... which can easily be fixed & still leave loads of change from £500. Planetary observers need a quality barlow for imaging anyway so the "short" focal ratio is no problem.

The small Maks are good but, convenience aside, a 6" f/8 Newtonian will blow away a 5" anything. Yet a 6" f/8 Newt on a GEM is still reasonable for most people to handle.

But remember that the "best" scope is the one that gets used, what suits me doesn't necessarily suit you. I'm now an SCT man because SCTs give the best solution to portability & aperture ... there's no way I could handle an 11" f/10 Newtonian, but, with an observatory, I'd prefer one to my 11" f/10 SCT.

[arad85]

Sound advice there The f/8 newt is the Skywatcher Explorer 150PL (the L for the long tube length).