Best telescope to view planets

[Shroomy]

What is the best one one to buy to view planets

the refractor, the reflector and the catadioptric.

thanks guys

[Rustmonkey]

No idea about the Cat but I know the Reflectors and Refractors work fine. I have an SW150pl which works really well but could do with a better mount to stabilise it better as its a big unit for an EQ3/2. Barlowed, I can get a very nice view of Jupiter and Saturn and even found the Ring Nebula for the first time the other night. I guess anything from 6" up will do the job nicely in the reflector range.

[John]

They can all work very well on the planets. The most performance per £ spent would come from a newtonian reflector. You can get a 6" or 8" aperture one mounted on a dobsonian type mount (these scopes tend to be known as dobsonians or dobs) for £210 and £290 respectively. I doubt you could buy anything that would perform better on the planets for that price. Here is a like to the Skywatcher dobsonians:

http://www.firstlightoptics.com/dobsonians.html

[DirkSteele]

I am sure that question will generate a number of differing responses.

For any given aperture, a high quality Apo refractor will most likely perform the best as the secondary mirror in the light path of Newtonian and SCT telescopes degrades the image through lost contrast due to diffraction. However, that is for any comparable aperture. There is still no substitute for more aperture to reveal finer details (up to a point of course). A well made 8" (correctly collimated Newtonian) will outperform a high quality 4" Apo refractor. The reason I keep writing Apo refractor, is the false colour seen in Achromatic refractors would be seen by some (including me) as reducing the quality of the image when looking at the planets. This problem does not affect Newtonians as they are completely colour free. This false colour problem can be reduced significantly on much slower (higher F number) Achromatic refractors.

Then that leads us to the next problem. A 4” Apo costs multiple times what a good 8” Newtonian would cost. So on a cost per unit of performance, the Newtonian probably wins out, though if money no object, I would be inclined to go for the refractor.

[E621Keith]

What is your budget and storage requirement?

This Newt will probably beat anything short of the observatory class apo like the Pentax 250 SD or a 8-10" APM-LZOS

http://www.astrobuysell.com/uk/propview.php?view=60229

Mak and SCT are good for planets due to their long focal lengths. You can get a lot of magnification with long focal length eyepieces which are often more comfortable to use.

Newtonians gives you the best performance per £ spent

APO refractors give you the sharpest and best contrast view for a given aperture.

[Capricorn]

Hubble does a good job.

The question is a bit pointless, if you prefer one type over another then that is the one you will use and say is best.

What is "best" in terms of viewing?

What do you consider important?

One person may like the large views there 250mm reflector gives, another the smaller sharper views that their apo gives.

This comes up often, this must be the fourth I have seen, and as yet, no single solution exists, and while there are several types of scopes delivering different results there never will be.

Some people will like one scope because the image is "warm" another will dislike the same scope because the image is "warm" and that is with the same scope.

[John]

It's a perfectly sensible question, it's just the answer that is a bit more complex

[paul schofield]

As others say there is no perfect all round scope for everything. Pound for pound I think a reflector would probably be the way to go for aperture to price ratio. A good reflector will work well on planets as will I'm sure a good refractor. I may be wrong but I think refractor scopes in the budget range would not work as well for deep sky observations. Sorry I know nothing about Cats.

[mart rich]

A friend of mine has a Nexstar 4SE and I have been able to compare this side by side with my Skywatcher 200P reflector when viewing Saturn.

The 4SE was very good, but the 200P was better if not massively so. Without trying something before you spend your money you might be a little disappointed in the difference.

Having said that I think the 200P is a great telescope, but try before you buy, if possible.

HTH

Martin

[Moonshane]

the key word in your question for me is 'view'. this leads me to presume you are considering visual astronomy only.

in my experience, the main thing that affects visual astronomy is aperture but certain objects respond better than others to more contrast rather than more aperture.

the direct answer to your question as far as I am concerned is a large aperture newtonian masked off axis to produce a very long focal length smaller scope. e.g. my own 16" dobsonian allows me to mask off all but a window of 170mm which creates a 170mm f11 unobstructed view which produces views of planets, moon and double stars better than anything else I have looked through. it just beats a 6" f11 dobsonian I also have and assuming you do not want to spend a lot of money for a large APO (and I don't recommend a huge dob at this stage) then I'd agree that either a well collimated and cooled 6" f8 or 8" f6 dobsonian will provide better views of planets than most things and also give options on the fainter stuff.

others will argue that a good 100mm achro will also provide excellent views (and it will) but for me there's nothing like the views in mine.

[sunshine185]

Moonshane, a quick question for you, in a mirror cleaning topic a while back, you mentioned your mirror was not spotless. As a little experiment I put the dust cover on and took the little cover off while I looked at the moon. It was a lot dimmer as to be expected but it also showed up all the fluff and dust on my primary, is this normal?

[E621Keith]

Don't forget the telescope is only half of the equation, eyepieces is the other.

Magnification = Scope FL/ Eyepiece FL

If you have a scope with long FL, you can use longer focal length eyepieces to achieve a given magnification than a scope with shorter FL.

A C8 can achieve 250x (usual seeing limit in UK) with a 8mm eyepiece while a 200p needs a 4mm eyepiece. An 8mm ortho is much more comfortable to use than and 4mm ortho, so you are likely to spend more time at the eyepiece and you will be able to see more details. You will also have the option of using a binoviewer in a SCT.

To be honest, I don't think there is a best scope for planets, or even a best scope design. The best you can get is the optimum scope and that is different for different observer.

[sunshine185]

I don't use anything other than a binoviewer in my dob.

[swamp thing]

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To be honest, I don't think there is a best scope for planets,

^^^^This

I totally agree with this statement. I do a lot of observing in a group with many different types and sizes of scopes, so I am able to compare views a lot between them, TBH one night one scope is best another night a different one seems to have the edge. There is no single one that's best every single time. Seeing never seems consistent enough for there to be the perfect aperture or type for planets.

The only type or scope we're missing from our group is a high end Apo frac but TBH I think these may be a bit better than a 120ED but not a huge amount, and great as the 120ED is, it's not always the best planetary scope there, so I have little doubt that a high end frac wouldn't always give the best views either.

I reckon best to have loads of scopes that way you cover all eventualities

[nightfisher]

Don't forget the telescope is only half of the equation, eyepieces is the other.

Magnification = Scope FL/ Eyepiece FL

If you have a scope with long FL, you can use longer focal length eyepieces to achieve a given magnification than a scope with shorter FL.

A C8 can achieve 250x (usual seeing limit in UK) with a 8mm eyepiece while a 200p needs a 4mm eyepiece. An 8mm ortho is much more comfortable to use than and 4mm ortho, so you are likely to spend more time at the eyepiece and you will be able to see more details. You will also have the option of using a binoviewer in a SCT.

To be honest, I don't think there is a best scope for planets, or even a best scope design. The best you can get is the optimum scope and that is different for different observer.

very good post, as a lunar/planet man, i have my 180 pro, and main ep is a BGO 18mm, this gives me x150, with very good eye relief and i can barlow this to x300, about max but still get good views

[Catweazel]

Well, I have an Evostar 120 frac and it's great for planets; I reckon it to be sharper than my 200P on planets actually. It may be worth trying some scopes out if you can get to a local astro group. It also depends on which price bracket you are looking at, as this will make a lot of difference!

[scarp15]

That's one reason why I will never part with my C8, I have had stunning views of the planets with this.

Check this months Sky at Night Mag, for a write up on my Celestar - under the new section 'Tried and Tested'.

[Moonshane]

Moonshane, a quick question for you, in a mirror cleaning topic a while back, you mentioned your mirror was not spotless. As a little experiment I put the dust cover on and took the little cover off while I looked at the moon. It was a lot dimmer as to be expected but it also showed up all the fluff and dust on my primary, is this normal?

if you use the smaller aperture (50mm?) then you effectively create a scope with a focal ratio of f25 (assuming a focal length of 1250mm). assuming you were using a 10mm eyepiece (giving 125x) then the exit pupil will have been 0.4mm. such small exit pupils often reveal e.g. floaters in your eyes and such and may possibly more easily reveal dust in the optical train. this is more likely to be in the eyepiece(s), filters or binoviewers than optics as dust on the optics will not generally be at the point of focus.

I am not an expert but if you were to put a large 2" blob of black paint on the primary, I doubt you'd even see that at the eyepiece.

[sunshine185]

Thnx, was just something I tried while the moon was out,I won't be doing it again, I'll leave that to you guys with the monster dobs.

[Moonshane]

it's certainly better with a bigger dob as you can get a larger opening.