Mak 127 or 100 ed

[smeech]

I am still in the age old quandry of which telescope to buy. I have been a member of this site for about six months and have asked many questions - I am still yet to make a decision.

I was settled on the skywatcher mak 127 as I like the idea of planetary viewing. I was just waiting on selling a surround sound system (space issues at home - no pun intended) and then I could happily store the scope.

However I recently noticed the Celestron 100ED scope for sale in the FLO section and was immediately drawn to how gorgeous it looked. I asked a couple of questions and it seems that this scope could also be one that would suit my planetary needs. Do any of you have any opinions on how well this scope deals with the planets? I don't even know if they appear in colour - I have never used a scope before.

Anyway, I then happened across a skywatcher equinox 100. This looks to all intents and purposes as the same scope as the 100ed - but a little smaller (good for me as I live in the big smoke). Do any of you know what the differences between the two are? Is it just manufacturing quality and a nicer focuser?

I am at a loss as to what to do (i'm not very good at making decisions). Any help whatsoever will be greatly appreciated.

Thanks

Steve

[John]

I believe that the 100ED and the Equinox 100 share the same optics. It's the mechanicals that are more "polished" with the Equinox.

It would be a tough call between the 100ED and a 127mm maksutov-cassegrain (the Skymax) I reckon - both excellent performers. I guess the mak is a bit easier to mount as it has a short tube although you will need some dew prevention gear (dew shield and / or heated anti-dew tape) which will add a few £'s. With a 1200mm focal length you won't need such short focal length eyepieces to achieve high powers with the mak so that might swing it. On the plus side for the refractor, the cool down time will be much quicker - almost usable right out of the house wheras the mak will need 30 - 60 mins to properly cool.

[Andrew*]

The Mak would provide better views as it has a larger aperture. It's also much more compact than the 100ED. However, the 100ED is a more all-round telescope, with a wider possible FOV.

Andrew

[smeech]

The "all rounder" element really appeals. I think after a few months of owning it I may want to start adding bits particularly for photography. I have no comprehension of what the difference would be from one to the other of say, viewing Jupiter? Or imaging Jupiter also.

What do you mean by "better" views? Do you mean it will be clearer or be better magnified.

[russ]

That's a really tough call. I don't believe there is a lot in it between the views they will provide. My son Harry has the 127 and the views through it have been nothing short of fantastic. Including some nice DSO views as well. But the ED100's i have owned have also given lots of viewing pleasure.

Including Harry's one, i have owned 3 127 Maks and they were all consistently very good. Well built, superb optics, hold collimation incredibly well and the primary mirror focus shows no signs of image shift. Plus it's compact and travel friendly.

But any talk of DSO imaging and it has to be the ED100.

[smeech]

Thanks all for help so far.

As far as I can tell my best option is to get both! Not possible at the moment!

Visually do any of you have any idea what the view of Jupiter would look like through both?

Ie would it be like a pea at arms length through the ED100 and a water melon in the face (slight exageration I know) through the mak?

[John]

Ie would it be like a pea at arms length through the ED100 and a water melon in the face (slight exageration I know) through the mak?

The angular size of Jupiter will depend on the eyepiece you use, not the scope. It's still in the "pea" category even at 250x to be honest which is about the max you can do with any scope in our average seeing conditions. The "pea" will have some nice detail on it and the more you study it, the more you will see, but planets always look relativly small, until you get used to it

They are, after all, a long, long, long way away .......

[smeech]

The angular size of Jupiter will depend on the eyepiece you use, not the scope. It's still in the "pea" category even at 250x to be honest which is about the max you can do with any scope in our average seeing conditions. The "pea" will have some nice detail on it and the more you study it, the more you will see, but planets always look relativly small, until you get used to it

They are, after all, a long, long, long way away .......

Oh ok. I think that makes sense.

So what you are saying is that if I used a 4mm eyepiece the size of the object will be pretty much the same for both. Will the resolution/clarity be the same?

I like the frac. I think it is just the fact it's a "proper" telescope. However it is significantly more expensive, heavier, requires a bigger mount and if it isn't going to offer a better view than the mak then I think I am back to my original position.

Is it possible to photograph with a mak - a long way off buy i'm all for future proofing?

Thanks again for all your help.

[John]

With a 4mm eyepiece in the refractor you would get 225x and in the mak it would give you 375x so Jupiter would appear larger in the mak. Having said that, 375x is far too much magnification to be any use - 250x is a more normal limit or 180x for the refractor.

My general point was that planets just don't look "water melon" sized !. There is a general obsession with magnification when starting out but the real goal should be a sharp, contrasty image - even if it is less magnified.

I'd be a bit carefull about trying cover all your possible future options with one purchase - you could end up going round and round in circles as what's good for one thing is not optimum for another, etc ,etc.

If there really was a scope that would do everything well, we would all have one. In reality we all have a wide variety of scopes for different purposes.

[smeech]

Ah! So do you know which of the two would provide the sharper image with a 4, 5, 6,...mm? I like the idea of being able to see the red spot and the belts of Saturn.

I was really trying to identify the differences between the two scopes. So if 250x and 180x were the limits of both which would provide the better viewing / image? Would the ed100's Jupiter be half the size of the mak or 100th of the size? Do you see what I am saying? Not sure i'm wording any of this correctly!

[Andrew*]

I think some eyepiece theory would benefit you here: http://stargazerslounge.com/primers-tutorials/63184-primer-understanding-choosing-eyepieces.html

For the calculations, the Mak has 1500mm focal length and the ED100 has 900mm.

Basically, you will achieve the same size of disc at the same magnification. The quality of the view will be very similar for both scopes, but the extra aperture of the 127mm will help you in good seeing conditions.

Andrew

[smeech]

I think some eyepiece theory would benefit you here: http://stargazerslounge.com/primers-tutorials/63184-primer-understanding-choosing-eyepieces.html

For the calculations, the Mak has 1500mm focal length and the ED100 has 900mm.

Basically, you will achieve the same size of disc at the same magnification. The quality of the view will be very similar for both scopes, but the extra aperture of the 127mm will help you in good seeing conditions.

Andrew

Ok, I think I am starting to understand this now - thanks for the link.

So essentially they will both give good views at the same magnification. The Mak however can get slightly higher mag and the ED slighlty wider field of view.

I'm still not sure what i'm missing if say I can have 250x on the mak and 180 on the ED. How different would those viewing images be. Is the 70x difference significant? Ie how much of the eyepiece will the jupiter fill and 250 and 180? Difficult to explain without pictures!

I think what I want to here is that the difference would be like a ten pence peice (mak) and a pound coin (ED) rather than a two pound coin (mak) versus smaller than a five pence piece (ED)!

Hope that makes sense! Honestly, one day I will repay the patience you are all showing! Maybe beers at SGL7!

[Andrew*]

The scopes will both be limited by the seeing conditions. This will be around 200-250x. The Mak may possibly achieve a sharp image at higher mag than the 100ED, but not much.

The magnification determines the size of the planet in the eyepiece. You will achieve the same magnifications in both scopes, but with different eyepieces. 250x (a 6mm eyepiece with the mak, or 3.5 with ED100) would give an image about 40% larger than at 180x (8mm in mak, 5mm in ED100).

As John (jahmanson) said, planets are pretty tiny, even in this range of magnifications. Perhaps Jupiter would be about the size of a 10p coin held at arms length. I've no idea, I'm just guessing as it's really difficult to compare eyepiece views with the daytime world. But try not to get too bogged down by what you might see - just wait until you see it for the first time - it will be worth it

Andrew

[John]

Your size comparisons don't really work in reality I'm afraid - do you mean coins held at arms length or close up - you see the problem ?.

At 250x with my largest scope Saturn looks a bit like this:

http://www.rocketroberts.com/astro/images/sat_c.jpg

[catburglar]

I've not tried either scope, but I suspect the views will be very similar, as has been said before.

However, I would expect the Mak to be a bit easier on the mount due to it's shorter tube. In one of your earlier posts, you do imply that space is at a premium.

Remember, the mount will occupy more space, and be heavier than either scope!

[smeech]

Thanks all. You've all been very helpful.

I've seen an Equinox 100 for £450 which I think is a pretty good deal so might go with that.

I'm guessing that will need an EQ5. Is that a big one?

Thanks once again for all of your help. I'm still a little confused but it's sinking in slowly!

[neilmack]

Not knowing how long your arms are means that comparing coins is not too instructive!

Much better perhaps to think of angular sizes and apply magnification factors.

The moon appears in the sky 30 arc minutes across. Viewed in an 8x30 binocular it will appear about 4 degrees across. It will look a splendid sight, with bags of detail. Jupiter, when conveniently located, is about 40 arc seconds. You would need a power of 360x to get it to the same apparent size as the moon in the binocular. And as John has correctly noted, you couldn't achieve such a high magnification with these scopes (and on many nights you couldn't use such a power even with a much more powerful instrument, because of atmospheric instability).

There won't be much advantage in observing with the 127Mak on planets over the 100ED. The Mak's longer focal length means you can use somewhat longer (more comfortable) eyepieces, and the image will be slightly brighter. But it has a large central obstruction, which will markedly reduce contrast, and the complex diffraction effects of that obstruction will impose practical limits on its resolution.

There is no 'all-purpose' telescope, but the 100mm refractor will probably offer a greater degree of flexibility

[smeech]

Thanks Neil.

That last point is kind of what I have come to think. I just now have to convince myself that paying double the amount for the refractor is worth it! Worse still I now think I want the Equinox rather than the normal 100ED as it is slightly shorter and shorter means less space for swmbo to notice! Although does mean getting at least an Eq5!

[neilmack]

Although does mean getting at least an Eq5!

I have used a 4" f/8 refractor on an SW EQ3-2 mount. For visual use, and provided that there's no appreciable breeze, it was perfectly ok - it vibrated more when tapped than a burlier mount would, but not for terribly long. But with mounts bigger is always better, provided that it's not too heavy to use!

A scope on the back of a generously specified mount is a pleasure to use. An 'undermounted' scope is not only ergonomically irritating, but it never gives of its best.

Pay attention to the tripod. Not all tripods were created equal. The big tubular model that comes with the EQ5 that I used was impressively stable. The flat section aluminium one I saw on an EQ3-2 is evidently modeled on the old Vixen SP one, and shares its weakness. Nicest to use are heavy wooden tripods, but they tend to be harder and more expensive to come by.

best of luck

Neil