Advice on first scope.

[GazFromBrum]

Hello All

I have only recently gained an interest in the moon, stars and planets around us, I have a limited budget of around £250 to purchase a scope that is going to increase my interest. Is this a realistic budget to purchase a scope that will give me decent enough images of the plants to increase my interest or will a scope in this price range blunt my interest due to poor image size, quality.

I have started to look around and like the look of the

EXPLORER-150PDS 150mm (6") f/750 Parabolic Newtonian Reflector

Would I be better going for either a GOTO or motorised scope as apposed to the above scope ??

Thanks in advance for any advice that will be gratefully accepted.

Gary

[eid]

I think finding your way around the sky is half the fun, especially at the start. This is just personal preference of course.

An RA motor is always a good thing, but not essential immediately.

On a budget, you're better off concentrating on good optics in my opinion.

I cant comment on that particular scope, but a well made 6" reflector wont disappoint.

eid

[nightfisher]

if you stretched your budget a little you could get a 200mm dobsonian, great for learning your way round the night sky, and very good optics

[derekm]

if you stretched your budget a little you could get a 200mm dobsonian, great for learning your way round the night sky, and very good optics

Seconded

[ismangil]

6" is a good size to start with.

Could you tell us a bit more on your situation, where are you going to do most of observing?

For example if you have to take several flights of stairs a largish scope wouldn't be appropriate as you need to sometime to do two trips from storage, one for the mount one for the scope.

Also some people find equatorial mounts hard to setup properly, although easier to upgrade to motorized tracking than a Dobsonian.

Goto can beneficial if you have really poor skies, although setting them up does take time and learning as well unless you have the expensive version.

£250 is a good budget, remember you may need other accessories like planisphere and Sky Atlas, red torch, and usually upgrading or adding the eyepieces.

I started back in March by buying a 10x50 binocular and a few books and accessories, totaling about £150 or so.

By doing that I have found out my observing style.

[GazFromBrum]

ismangil - thanks for the reply

I will be doing most observing from my back garden, so no hassles with stairs or distance. Where I live I am lucky with the lack of light polution as I am on the outer edge of a small village so skies are good. With total darkness only a small drive away if needed.

What size eye pieces am I going to be looking to get, why a red torch ??.

What sort of images of the planets can I expect from a 150mm scope.

Ive seen the explorer 150mm comes in two focal lengths, what are the benefits or drawbacks of either option.

Gary

[Capricorn]

A red torch is to lessen the effect the light has on your eye. If you use a brightish white light then the pupil will shrink and you lose for a while the detail that you can see. Basically you get dazzled.

The 150 comes in P and PL form. If you are only intending to do visual the PL is easier to get along with.

The PL is more tolerant of being a little out of collimation, so you do not have to recollimate the scope as often.

If you expect the put a camera on the system then a P may be better. The focal plane image is a little brighter, the image is a little smaller.

General view is that eyepieces for something like the PL are not as critical as for the P.

Scope will come with a 10mm and 25mm eyepiece, well that seems the normal. The 25mm will be good to locate things. The 10mm seems to get poor reviews as a rule.

Assuming the PL then at some time you may consider something around 8mm and 12mm. TV plossl's, BST Explorers and TMB Planetary's come in these - more or less, some do 12mm some do 11mm.

You will want to try for greater magnification, everyone does, that will mean a 5mm eyepiece. BST Explorers and TMB's. TV plossl's stop at 8mm.

The "standard" plossl may well work fine on the PL, just you lose eye relief as they get smaller, problem if you wear glasses and also means on the 5mm you have to get your eye very close.

The scope should give 150x-200x without trouble. After that it is diminishing returns, image gets bigger, quality generally gets worse.

80x magnification will show Jupiter very well, 120x will show Saturn well. Neither will be big. For Mars you need more and a degree of good luck. If you get 150x-200x out of the scope it may be enough for some Martian detail.

[GazFromBrum]

Thank you Capricorn for an excellent reply.

Stats on the scope give x300 potential, is that rather optomistic ???

Sherwoods do a 7-21mm eyepeice, which I presume gives a range from 7 - 21 mm are these eyepeices any good ??

Sherwoods also do 2mm and 5mm long eye relief pieces are these going to be any good with the Explorer 150 ??

Thanks again for your informative reply.

regards

Gary

[perrin6]

I like to recommend an 8 inch dob to a beginner as it's a fab all-round seriously capable scope although some prefer smaller automated scopes with drives and all sorts of gadgety whatnots.

[GazFromBrum]

Perrin6, thanks, are there reasons you'd recommend the 8" Dob ??

[Capricorn]

Cannot think of any use in any scope for a 2mm eyepiece.

My view is that almost all maximum magnifications are optimistic. If one lot claims 100x, then someone else will claim 120x, then another claims 150x. If Scope A said they couldn't match Scope B then you wouldn't buy Scope A. Even if Scope B were lying through their teeth.

300x is "unrealistic" because of the general atmosphere, just not stable enough here to make anything over 200x realistic except on odd occasions.

Stick to 150x as a max at first, go up later, that will show just about everything you will need just about all the time.

Planetary views of Mars may need more but Mars is a real pain to see

[perrin6]

I havn't had that particular model, I just remember that an 8 inch dob was what really started showing me a lot. It's good for detail on the planets, moon as well as nebulae, galaxies, loads of clusters & double stars plus the brighter globular clusters begin to show as a lot of tiny faint stars instead of misty patches. An 8 inch dobsonian is easy to set up, not particularly heavy and cools down to air temperature within an hour.

I know some people are refractor people, some are catadioptric (cassagrain, maksutov etc) people. I'm a newtonian dob bloke because it's all I could afford really, refractors & catadioptrics are expensive for their size and I always wanted to get as much for my money as possible so I've always made my own dobsonians (except the optics).

Some people really don't like having to look for objects so prefer to spend money on GOTO. I think looking for things kind of makes you learn more and enriches your knowledge so you can eventually look up at any portion of sky and know whats there.

[Moonshane]

ismangil - thanks for the reply

I will be doing most observing from my back garden, so no hassles with stairs or distance. Where I live I am lucky with the lack of light polution as I am on the outer edge of a small village so skies are good. With total darkness only a small drive away if needed.

What size eye pieces am I going to be looking to get, why a red torch ??.

What sort of images of the planets can I expect from a 150mm scope.

Ive seen the explorer 150mm comes in two focal lengths, what are the benefits or drawbacks of either option.

Gary

when you say images, are you talking about visual images or photos/imaging? most people use a webcam for planets and moon which can be cost effective.

assuming the usual seeing limited magnification range of 150x-200x (4-5mm eyepiece) then the visual image of e.g. Jupiter will be about the same as a 2p at arms' length - it will be small but detailed. I'd just use the eyepieces that come with the scope for now and decide what to get in due course.

a red dot finder would be a better initial buy as this would allow you to place the scope more accurately.

a (dim) red torch allows you to look at star maps etc without ruining your night vision.

the longer version of the 150mm newtonian has a slower focal ratio which means more magnification per any one eyepiece and also that you can potentially use slightly cheaper eyepieces to get a decent view.

all newtonians need to be collimated (or at least the collimation checked by the user - it's easy) before each session, especially if imaging.

in short you'd have a great set-up with some advantages if you get into imaging but personally, if visual only, I'd also recommend an 8" dob.

[GazFromBrum]

I'd like to thank you all for your interesting and helpful replies.

I'm not rushing into a purchase as I want to get crimbo out the way and will be making the purchase in the new year.

I will look at a dob, before making my choice and will report back with my decision.

thanks again to those that have taken the time to respond.

Gary

[Omar]

if you stretched your budget a little you could get a 200mm dobsonian, great for learning your way round the night sky, and very good optics

Can I use Dobsonian for Astrophotography? I read somewhere that reflectors are better or maybe easier than refractors in terms of Astrophotography.

Thank you!

[Telrad]

Dobs are OK for AP, mainly planetary and lunar shots, not so good for DSOs. It's best to get an EQ mount if you are going to take DSO images.

[Telrad]

I read somewhere that reflectors are better or maybe easier than refractors in terms of Astrophotography.

Thank you!

It depends on what you're photographing and how dim and/or large it is. The extreme case would be a shot of the whole sky, in which case you'd want a wide-angle lens. For "constellation shots" (piggybacked or tripod-mounted) you'd want something like a good 135mm or 200mm ED camera lens (refractor). For lunar and planetary work, you want something with focal length and the best all-round for this would be a Schmidt-Cassegrain telescope of something like 8" to 10" in aperture. For higher-resolution (storm clouds in Jupiter's belts, smaller craters on the Moon, etc.) then a 12" is where you want to start. You could also use a newtonian reflector or a refractor and add a barlow (or two!) to get the focal length you need. But a 12" newtonian is going to require a very large mount. For extended objects like emission or reflection nebulae, you're going to want a wide field of view rather than magnification (which comes from focal length) and small apochromatic or ED refractors really shine for this type of target.

[Omar]

It depends on what you're photographing and how dim and/or large it is. The extreme case would be a shot of the whole sky, in which case you'd want a wide-angle lens. For "constellation shots" (piggybacked or tripod-mounted) you'd want something like a good 135mm or 200mm ED camera lens (refractor). For lunar and planetary work, you want something with focal length and the best all-round for this would be a Schmidt-Cassegrain telescope of something like 8" to 10" in aperture. For higher-resolution (storm clouds in Jupiter's belts, smaller craters on the Moon, etc.) then a 12" is where you want to start. You could also use a newtonian reflector or a refractor and add a barlow (or two!) to get the focal length you need. But a 12" newtonian is going to require a very large mount. For extended objects like emission or reflection nebulae, you're going to want a wide field of view rather than magnification (which comes from focal length) and small apochromatic or ED refractors really shine for this type of target.

I just want to narrow down my research to which type of telescope I should buy. If I can't afford it now, I will save money and buy it later on. Thank you Telrad

[Telrad]

I just want to narrow down my research to which type of telescope I should buy. If I can't afford it now, I will save money and buy it later on. Thank you Telrad

You're most welcome Omar. I hope you find the right scope. ATB Good luck!