Really struggling to decide

[smeech]

Stoke newington. Near Tottenham. Any idea if anything near?

[andrew63]

The suggestion of the omni 127 sct was a good one, nice compact scope for the flat, an aperture large enough to begin to see some details and a good solid mount. The image showed by SPACEBOY was brilliant - a lot of beginners think that things look huge! a picture at least give a fair impression. If you can find a astro group nearby you can look yourself before you by, which may better help you to decide.

regards, andrew

[spaceboy]

The suggestion of the omni 127 sct was a good one, nice compact scope for the flat, an aperture large enough to begin to see some details and a good solid mount. The image showed by SPACEBOY was brilliant - a lot of beginners think that things look huge! a picture at least give a fair impression. If you can find a astro group nearby you can look yourself before you by, which may better help you to decide.

regards, andrew

As andrew says the OMNI 127 should also be a very good scope given your location but I feel 5" and F/10 might be a little tight???? The FOV will be real narrow and maybe a little dark for a 5". I have not used one so I cannot push my comment too far, maybe if you put up a thread asking about the OMNI people may be better to advise . I would have thought again the optimal F ratio for 4-5" is maybe 6.5-8.5

I have a 127 (5") MAK and IMO the views of planets were equal to my old TAL 200k (8"). but because of the slow F/ 11.5 length of the MAK other than M57 and the like it falls short as regards DSO

[smeech]

Think trying one out seems like a good idea. Will have a look around for some local groups and then decide on which one is for me.

Thanks all

[Dazraz]

Hi Smeech

In a light polluted area I recommend you avoid at all cost fast telescopes as they suck in light. Even if to the naked eye the sky is dark the moment you look through the EP it will look like someones turned the moon on. Try as best you can to get the happy medium between aperture and focal length. I know the best I had was 8" F/10 but this combo costs lots of £££ new so if possible look for similar second hand. If you are looking to buy new? I would say in an ideal world a 120 frac around F/6-8 would be a good investment but like all telescopes they will only excel at either planets or DSO's not both. I'm sure you have seen that most peoples signatures include more than one scope and this is why.

I read some where if you live in light polluted skies it's pointless buying anything over 5" but I have had some good views of DSO's from an 8" F/10 scope. My advice is when you consider buying a telescope the numbers matter "A LOT"!!!

This CCD image is roughly what I see in my 10mm EP. I have a 200mm F/5 reflector and due to light pollution the most I can see by eye are 3.0 magnitude stars. You can tweak CCD images but the eye has it's limits. What looks OK in a CCD image can be a washed out image to my eye.

This is only from my experience other people may agree or disagree but I hope it help you either way.

Hi thats the way i see jupiter and saturn is just stunning i have a 8 inch dob hope this helps

[sixela]

Hi Smeech

In a light polluted area I recommend you avoid at all cost fast telescopes as they suck in light.

Another selection of eyepiece on a "fast" and "slow" scope that delivers the same exit pupil (i.e. magnification) will yield the exact same background brightness. A fast scope becomes a slow scope by just adding a barlow...

Of course there are other differences (the slower scope will --if the designs are the same-- have less image aberrations for off-axis objects, will not require very short focal length eyepieces, focusing will be easier, the scope will be less practical unless it's a folded design, etc.) but differences in "sucking light in" is not one of them.

It may be your "opinion", but in the face of physics...

[spaceboy]

Another selection of eyepiece on a "fast" and "slow" scope that delivers the same exit pupil (i.e. magnification) will yield the exact same background brightness. A fast scope becomes a slow scope by just adding a barlow...

Of course there are other differences (the slower scope will --if the designs are the same-- have less image aberrations for off-axis objects, will not require very short focal length eyepieces, focusing will be easier, the scope will be less practical unless it's a folded design, etc.) but differences in "sucking light in" is not one of them.

It may be your "opinion", but in the face of physics...

I tried the barlow argument in a previous thread and no one stood by it as a viable solution. Effects to exit pupil and not to mention how far a barlow and 40mm EP would hang out from a focuser were good statements. The fact is and not many can deny it, if you have a fast scope your going to need the best eyepieces you can afford to counteract for several issues known to fast scopes. I'm sure most fast scope owners would agree that more money has been spent on EP's than the scope itself.

I agree totally with what you say about slower scopes and I have no debate regards this? My point is finding the happy medium between aperture and speed. Too slow a small aperture will give duller tunnel vision views. To fast a large aperture the wider the field and brighter the background ( or washed out with cheap EP's) If someone lives near London I'm guessing the sky might be a little bright anyway??

It would be poor judgment to say to a beginner that this issue dose not exist. But we are all entitled to our "opinion"

[sixela]

I tried the barlow argument in a previous thread and no one stood by it as a viable solution. Effects to exit pupil and not to mention how far a barlow and 40mm EP would hang out from a focuser were good statements.

The point is that the "fast" scope will show you the exact same field (and magnification) without the need for a 40mm eyepiece - and you'll use the 40mm eyepiece (probably a 2" version) to get more field of view.

You'll barlow your *small* focal length eyepieces to avoid having to take small focal length eyepieces with little eye relief or to buy long eye relief eyepieces. And if "no one stood by it as a viable solution", well, that says more about the public than about the solution.

It is viable, even though obviously it's a lot more clumsy than not having to use a barlow (that's what you pay for more true field of view with a given focuser standard).

If you find it clumsy, you'll find yourself either liking simple designs like orthos with small eye relief (I have no issues with those) or buying long eye relief eyepieces (like the TMB planetary). You have plenty of choices - including picking a slow scope and living with the restricted field of view and/or practical issues that follow from that choice.

The fact is and not many can deny it, if you have a fast scope your [sic] going to need the best eyepieces you can afford

If you use wide field eyepieces. Plössls do just fine in an f/5 scope, and I doubt many people can't afford them (if they can afford a scope. On another forum, someone bought one for €12).

Below f/4.5, well, you do have a point (if you have an f/4 114mm Starblast you *will* be using a barlow or more complex eyepiece designs than a Plössl for high magnification work, at least if you're a critical observer.)

It would be poor judgment to say to a beginner that this issue dose [sic] not exist.

Nobody denies it. When faced with untenable statements about fast scopes "sucking more light" in light pollution environments, a rebuttal is in order. Nothing more, nothing less. I'm not the one trying to "advocate" or "evangelise".

[spaceboy]

Sorry for hijacking the thread Smeech

Forgive me sixela, your obviously a wealth of knowledge and feel strongly about it but I'm a little confused. Are you saying that fast scopes don't lack contrast? If this is the case I have go to be doing something wrong. I had an 8" F/10 the stars were bright and the sky was black. My 5" F/11.8 is the same (all be it the stars are not so bright) but my 8" F/5 the stars are bright but the sky is no longer black. This is also the case with my 10" F/4.8 granted this is not so much an issue when taken to dark skies.

I was hoping my advice would help Smeech choose a good beginner telescope and not one he would regret but it would appear I haven't a clue what I'm talking about. Sorry Smeech

Can anyone tell me why the term light bucket used when referring to large often fast dobsonians? as it appears I miss understood.

sixela what would your recommendation be for eye pieces in a 10" F/4.8? and please no more thesaurus I'm from the hood not Harvard

[AWR]

I live just down the road from Heathrow, so when viewing from home, it is light pollution rather than telescope choice which limits my viewing of DSOs. 'Small', bright objects are ok but 'larger', diffuse ones are invisible against my washed out sky.

I find that my Skywatcher 127 Mak gives great planetary views in a very compact package. The field of view is a tighter than a faster scope but this is less relevant (to me) as I often can't see larger objects anyway.

Simple planetary imaging can be undertaken with the addition of a modified webcam. There are some great images in the planetary section taken with this set-up.

Andrew

[smeech]

No problem Spaceboy - not entirely sure what either of you were talking about anyway? Care to explain the basics to me?

AWR - Yes, back to the Mak again! Every time I investigate it always comes back to that as the obvious choice. Just don't want to make the wrong decision so am going to leave the final decision till around Christmas (ideal present) that way can do a lot more research.

[ollypenrice]

West of London Astronomical Society is a good one but where are you?

The FAS (Federation of Astronomical Societies) has a list of affiliated clubs. You could Google them.

Olly

[smeech]

Thanks Olly. Will take a look.

[Nick P]

Hi Smeech,

I have a similar issue to you, observing from an apartment balcony under light polluted skies. I use a fast (f4.5) 8" newtonian on a goto mount, the advantage this gives me is that:

a) Because the scope is fast it has a short focal length (f4.5 x 200mm = 900mm) which makes the tube short (about 3 feet long) and therefore easily portable (very light) and storable - easily fits on the floor of a wardrobe.

The goto mount and tripod are excellent for elevating the scope so I can easily view over the balcony rail - sadly dob mounts are out because they are too low! the mount and tripod live on the balcony

c) Having a small 'window' of sky to view forces me to explore the constellations available rather than zip around the sky taking everything in - this means a good all round scope is very useful, for example I can rarely view planets at a reasonable time because I face due West! but I can regularly view doubles, globulars, nebulae etc etc, even through the polution.

d) I find that with increased magnification contrast is improved thereby negating the light pollution although the overall view will dim, with 8" of aperture this is not a problem.

Issues of fast or slow scopes is only really of interest to imagers, for visual use the only issue is aperture v focal length (except fast scopes need quality eyepieces as they tend to suffer more with astigmatism and 'seagull' effects with cheaper optics).

I have looked at upgrading my scope several times including considering a 127 mak, but i keep coming back to the same point where it would be better on some things and worse on others than the newt, but not an overall improvement (and a lot less aperture).

Hope this helps a little in giving you an idea of which choice to make, light pollution is a pain but it needn't limit you too much as long as you know what to expect.

Good luck in whatever you choose!

Nick

[smeech]

Thanks for input Nick.

What kind of planetary viewing do you get with your reflector? I think for me this is my main requirement. Whatever way I look at it I always come back to wanting to see the planets. From what I have read the Mak is best for this. I just need to factor in the light polluted skies and this is where I am stuck as I have no knowledge of telescopes!

[spaceboy]

No problem Spaceboy - not entirely sure what either of you were talking about anyway? Care to explain the basics to me?

QUOTE]

Hi Smeech

It's times like these why I'm so happy I joined this forum. There is so much a wealth of knowledge to be gained from other members.

Have a look at this thread http://stargazerslounge.com/beginners-help-advice/119275-contrast-problems-reflector.html so that you can avoid the same assumption I made. Stands a good chance you can make an ideal eyepiece selection from this info also.

The MAK 127 is outstanding on Planetary viewing and will allow some duller views of DSO's but I will still stand by my original statement of small aperture fast scopes giving some what claustrophobic views (this can be over come I think by reducers) and I hope that I stand corrected if I am wrong on this

Waiting till Xmas would be a good plan as you can clear up any doubts you have, get all the info you need from the forum and have a Xmas present from the wife you will cherish for years to come.

SPACEBOY

[Nick P]

Hi Smeech,

I find the Newt to be pretty good on planets (superb on the moon too BTW), although not as crisp as my refractor, which in turn is not quite as good on DSO's as the Newt! As much fun as planetary viewing is, for the limited opportunities I get, its not worth sacrificing resolution and light gathering ability, by getting rid of the Newt.

Without doubt the MaK will make a great planetary scope but remember for detailed viewing you are probably limited to 4 objects - Jupiter, Saturn, Mars, and the moon (plus the phases of Venus).

I agree with Spaceboy above about the limited field of view of the MAK, one of the first problems I encountered when I started using a telescope was being able to find anything (everything upside down the wrong way round, and so many bright dots!), it became clear very quickly that a large field of view was a good thing just to help find my way around. To get a FOV of 1.5 degrees the MAK would need a plossl of around 42mm or a very expensive wide angle eyepiece (for comparison 1.5degrees would cover most of the pleiades in the view) in the Newt the equivalent would be a 25mm plossl, so if needed I can get wider eyepieces to expand the FOV upto 2.5degrees before exit pupil problems, the MAK would only be expandable to about 1.7degrees (31 Nagler), until wider lenses are developed!

As for the light pollution, I tend to find above 30 degrees altitude views are quite acceptable (although I wont see any galaxy details!) but I can easily resolve detail in the ring nebula, M13 globular etc etc, without any filtering, and with magnifications around 80x+ contrast is fine (not black/white but details are easily discernible).

What I particularly like about the Newt set up is I get good views of all objects, rather than excellent views of some and poor views of others, and when I can get to a dark site (already identified) the views should be mind boggling!

Clearly a lot of this is just my opinion, but hopefully help in your making an informed decision, and getting a scope that will meet your needs for years to come.

Best

Nick