Telescope for total newbie

[steppenwolf]

Tee hee, we are indeed into Alt/Az versus Eq territory now and there is no definitive answer - it would be great if there were but this is, of course, the joy of a forum like this, you will get a whole load of opinions and you must then sift through the answers to tailor the responses to your actual needs. However, here lies the major dilemma for any new astronomer - what are your actual needs!

I hope that whatever you go for you will enjoy the hobby as much as the rest of us do!

[MartinB]

Tee hee, we are indeed into Alt/Az versus Eq territory now and there is no definitive answer - it would be great if there were but this is, of course, the joy of a forum like this, you will get a whole load of opinions and you must then sift through the answers to tailor the responses to your actual needs. However, here lies the major dilemma for any new astronomer - what are your actual needs!

I hope that whatever you go for you will enjoy the hobby as much as the rest of us do!

Well said that man!

[amigaman]

steppenwolf and martin b your input has been very much appreciated i have looked into both models and both seem very capable telescopes alt/az vs eq teritory sounds like both have their pros and cons with respect to both postitions could you possibly explain some of the advantages and disadvantages of each system you both seem to know what you are on about and respect to martin b after seeing your website you definetly have an impressive array of equiptment without trying to go on the money i will eventually spend won't be available for at least a couple of months so i have time to evaluate what you both consider valuable

thanks in advance phil

[GazOC]

IMHO the big strike against fork mounts is that you are limited to one scope per mount (well 2 if you want piggyback a small refractor) whereas the HEQ5 can be used with any number of different scopes, weight permitting.

[Astro_Baby]

I I could chip in as a relative newbie myself. The problem here is that £1k is a lot of money so in some ways it makes the choice harder because its so much more expensive if you get it wrong.

I had a similar dillemma not so long ago. In theory I could spend up to 2k and not stress out BUT the problem was at that level what do you buy from a position of knowing nothing or nearly nothing.

I looked at some small Meades with GoTo, looked at some BIG Celestrons but wondered if it would end up being a HUGE waste of money. Lots of what ifs in a first telescope purchase like what if I get bored ? What if I cant understand it? What if I get into it and realise I have the wrong type of telescope ? If your going at the £100 end its not a disaster ( well it is I suppose if you only have a £100 ).

In the end I bought tiny one the basis that if I got it wrong and couldnt sell it I could skip it and it wouldnt be a big thing. Not much more than I'd spend on a handbag and in fact some of my bags cost a lot more. It was an agonising type of decision I found because you cant read enough quick enough and in the absence of direct experience you kind of all at sea.

For me I realised within a few days of the scope getting here that what I thought I'd want to do ( astrophotography ) was going to be a) too expensive and too much aggravation and being sat in front of a PC ( I do enough of that as it is ). Soooo my needs changed a lot from what I thought I'd do and what I now realise I do want to do.

Logically for me using a scope primarly for observation a big Dobsonian would be the real choice BUT I kind of like EQ mounts with clock drives - it makes looking at stuff much less hassle when the mount is doing the tracking. So for me it was Sky Watcher 200 as the best compromise and with at least a mount that can be used for other stuff if I have a change of mind later. Yeah I know the setting circles are pants but at least you can hget to sort of the right area whereas with a Dob you either know how to get there or you dont - I'm in the latter group and past experience tells me with a Dob I;d spend most of my time looking at nothing much. At least with an EQ if you can find something that you know you can find other stuff ( weather permitting ).

Ideally I'd have wanted a 10" but as I have to stay portable it wasnt really possible.

Longer term I might well buy something like a small SCT on GoTo just for holidays when I go somewhere sunny - after all an 8" on an HEQ5 os hardly transportable via air very easily.

[steppenwolf]

The advantages of the EQ/Newtonian system are that:-

1. It is very much more versatile because it can handle a very wide range of equipment on it as you can adjust the 'balance' weight to compensate for whatever you load on to it for a particular session whereas an Alt/Az mount is more of a one particular instrument mount

2. The mount only has to track in right ascension (RA) to follow objects across the sky so your chosen object will stay in the right position AND orientation throughout a session. An Alt/Az can only do this with addition of a 'wedge' to make it act like an equatorial fork mount.

3. The 'scope itself is very simple, just two mirrors so a minimum of optical aberrations are introduced (although both Newtonians and SCTs suffer from 'coma')

4. A Newtonian is very unlikely to suffer from dew on the optics - mine never has either inside my observatory or when I used it outside in the elements - wheraas an SCT will most likely require a heater to stop it from dewing up

5. A Newtonian has a better light grasp (typically F5 against the F10 of an SCT - although for planetary and lunar close-ups, the longer focal length of the the SCT is a great advantage)

How's that for starters? Now look what you've started !

A quick look at my website will give you an idea of the sort of results you can achieve with a Newtonian and an EQ mount:- www.skyatnightimages.co.uk

[GazOC]

A "Newt vs SCT" thread......I'll get my popcorn.

[MartinB]

Differences between alt az and equatorial or more properly, a german equatorial mount - GEM

obviously an altitude azimuth mount moves in horizonatal and vertical axes. So does a german equatorial except for the fact that the mechanism is tilted to match the tilt to match the earths axis. A carefully polar aligned german equatorial mount just has to rotate in one direction, the Right Ascension axis to track the stars whereas an alt az mount has to make continual adjustments in RA and Declination.

These are the pros and cons

Equatorial pros - only needs movement in one axis - RA completes a 360 degree turn in 24 hours

The alignment of the scope rotates with the sky - a bit difficult to explain but if you place your elbow on a surface and then rotate your arm in an arc you will see that your hand also rotates. This makes sure stars stay in exactly the same alignment over an extended period of time - makes little odds for observing but important for extended exposures when astroimaging.

German equatorial mounts can be very easily balanced to ensure motors aren't overloaded and tracking is smooth

GEMs have a saddle which will accept a standard dovetail which allows it to accept any sort of scope up to it's weight capacity.

Cons of GEMS - They have to be carefully polar aligned to give best performance especially when imaging otherwise the target slowly drifts out of view necessitating adjustments in declination.

They are rather ungainly and with moderate sized mounts the counterweights necessitate a seperate trip when setting up

They have to be balanced both in RA and DEC to avoid straining motors.

The scope is often placed at an awkward angle resulting in uncomfortable observing.

The mount has to be "flipped" as it passes the meridian - the counterweight arm and the scope have to swap places by turning through 180 degrees to avoid the scope hitting the mount. This isn't too big a deal when observing - a five minute job max but it is a serious pain in the neck when imaging and also results in the new image being upside down unless the camera is also rotated.

Alt az pros

Pretty much the reverse of GEMs

pros - If you are reasonalbly fit the NS8 can be carried outside in one go as a complete unit.

In NS8 GPS guise no polar alignment is required

The scope always has the same orientation so no awkward viewing angles. With the possible exception of viewing right at the zenith viewing is always comfortable which can make a huge difference to the quality of your observing.

Provided you aren't attaching any heavy imaging kit to the scope no balancing is needed so another stage to eliminated in the set up

No problems when crossing the meridian - no need to flip the scope

Cons - The mount is effectively built around the scope and can't be used for other scopes. It is therefore less flexible than a GEM. You can however piggy back a small refractor onto the scope. A small refractor and an SCT make a great combination of scopes for imaging.

The mount stays in a fixed orientation unlike the sky which rotates in relation to us. This means that long exposures result in star trails from field rotation. This occurs surprisingly quickly. Using a 0.33 focal reducer my exposures were limited to around 45 secs. At F3.3 45 seconds is quite a lot - equivalent to 3 minutes at F6.6. For long exposures you have to get a wedge which can be quite expensive.

There is a problem if you are using bulky cameras since there isn't room for them to pass under the forks. This can limit you when imaging in certain parts of the sky.

One thing to remember with SCTs is their incredible flexibility - using focal reducers and barlows they can be transformed from an ace F20-30 planetary imaging monster to an F2 high speed deep sky astrograph.

The job of any set up you get is to get you into the hobby. As you do this you will want a system that allows you to explore different areas - this might be messier hunting, lunar observing, double star splitting, sketching at the eye piece, taking pretty pictures or scientific photometry. You want a system that is flexible enough to allow you to try your hand at these different things. If you do get deeply into things then you may want to go for a change of kit that more specifically meets your needs. If that happens your start up system will have done a great job and set you up for life. On the other hand you may just want to pop out into the garden on the odd starry night when you don't have to be up early in the morning and just have a look around. Both of the systems you are looking at is capable of giving you a great deal of enjoyment. As I've said, the NS8 would not disappoint if you chose that route.

OOOH I've just read Steve's post and I really do have to bite my lip now

Take this with a pinch of salt Phil, we are dancing on the head of a pin -

SCT vs Newt - I use both regularly

Newt - noticeable coma off axis, intrusive with most wide field eye pieces. SCT barely noticeable unless you look very hard.

Newt - bulky, act like a big spinnaker in the wind. SCTs compact, easy on the mount

Newt - star spike artefacts noticeable on bright stars because of the spider veins, none of this nonesense with SCTs

Newts pip SCTs for contrast on bright planets and the moon, but neither as good as a refractor!

SCTs can be used at a wide range of focal ratios using reducers. Fast newts can be cranked up with a barlow but problems with focal reducers because of serious limitations in back focus.

This is tongue in cheek Phil both scopes can be superb for observing and imaging. Newtonians definitely give you the most aperture for your money.

Whilst you are chewing it over Phil, I have a Tal1 110mm refractor. This is a stunning little scope with superb optics on a good solid german equatorial mount (non motorised). You are more than welcome to borrow it whilst you are waiting for your new scope. It was given to me by a previous member of the forum and in many ways I feel it is an SGL scope. I live in Chesterfield so a bit of a drive the offer is there.

[GazOC]

Its worth noting that one of the reasons that a fast Newt shows more coma than SCTs with widefield eyepieces is that its also showing more sky.....

[Astro_Baby]

Well as I have said before buying anything be it a car, a handbag or a telescope is often as much about emotion as it is about logic. For me - well its probably my peasant origin but bigger/heavier is better ergo - a huge Newt on a monster mount does it for me.

I know, I know - its a scientific instrument so a purchase should be made on strict logic. For me though theres something 'sexy' about a newt. Its a kind of 'purity' of design.

[steppenwolf]

I got through a whole bag of popcorn reading Martin's excellent response! But, I do need to take him to task on one point at least. What is this nonsense about "They are rather ungainly and with moderate sized mounts the counterweights necessitate a separate trip when setting up" - make that at LEAST two extra trips with the weights!

Excellent post, Martin, I hope I didn't make you bite that lip too hard!

As you can see, Phil, this is no straightforward choice and to some extent, we all make the best of what we have so we overcome the 'cons' and emphasize the 'pros' in our own equipment choices. I don't have an SCT - but I wish I did have one as well as I NEED one for smaller galaxies, the planets and close-ups of the Moon. One day I'll have one ........

[GazOC]

Newts only "pipping" SCTs on planetary contrast made me chuckle as well.....

[MartinB]

Well I love my 12" dob and can ignore all the artefacts, just glad I don't have to stick it on a mount! "Pips" is the right word, all these differences between scopes are a bit exagerated. I have to admit my ED120 does a bit more than pipping when it comes to contrast but when it comes to my 10" LX200 and 12" newt, the extra contrast is there if you look but not a huge deal. Mind you, one mans "pips" is another mans "blows away"

The LX200 doesn't show coma with a Moonfish 30mm UWA. The NS8 did a little.

Hey Gaz we've not had a chat like this for a few months now. :wave: This is like an old Damo vs O'C thread!!

[GazOC]

Yep, I remember that one mate!!

I think comparing the Newt is a little unfair as its showing coma in parts of the FOV that the SCT isn't even showing, comparing coma for a given FOV would be a much 'fairer' way to do it IMHO, IIRC a f10 SCT is supposed to show similar coma to a f6 Newt (don't quote me on that!!!), but then you have the option of the flattener/ reducer for an SCT.

"Blows away"..thats another for the "First Light" reports thread eh?

[MartinB]

Phil, I don't know if you're familiar with coma but it refers to distortion of the stars at the edge of the field. It is inherent in the design of some scopes esp Newtonians. It bothers some people more than others. I find it a minor irritant only.

Gaz - the design of an SCT results in much less coma than a newt regardless of field of view. The benefit of the design is seen in schmidt newtonians which have much less coma than a conventional newt but equally fast focal ratios. For equal overall magnification there is no comparison between an SCT and a Newt.

As I said though, I don't think it's a big deal. Stick a decent wide field EP in a newt, point it at the double cluster and WOW!

[AllanJ]

Phil - Echoing Saso's point about add-on expenditure being a significant element of your budget, my experience is as a relative newcomer who bought his first telescope for £300+, but have since spent what seems to be adding up to quite lot (I haven't dared do the sums) on eyepieces, barlow, books, red torch, and "stuff"; and that's before I start to get into webcam imaging and things, so try to think about total initial budget as well as 'scope price.

Allan

[Astro_Baby]

Excellent point Alan and one I should know being in the same position.....

With a powered mount your also into a relatively expnsive power tank if like me you need portability.

Expense beyond the telescope has been

1x Compass at £18

1x Planisphere at £10

1x Eyepiece kit at £139

1x Bubble level at £5

1x Red light torch at £9

1x Power tank at £40

1x 2" EP ( cheapie success in flea market ) at £30

1x Flight case to put all the stuff in at £14

1x Set Replacement Attitude Bolts for HEQ5 at £19

1x Light Pollution Map at £9

1x Light Pollution Filter ( cheapie ) at £5

1x Laser Collimator at £55 ( subsequently proved useless and sent back )

1x Chesire Collimator at £24

That adds up to £377 - which is no small amount of cash really.

[steppenwolf]

1x Set Replacement Attitude Bolts for HEQ5 at £19

Hi Mel, I make enough typos to be shot down in flames but this tiny typo of yours was amazingly apt - I have to agree with you, the Altitude bolts on the HEQ5 and EQ6 most certainly have 'attitude' and a bad one at that!

[GazOC]

Gaz - the design of an SCT results in much less coma than a newt regardless of field of view. The benefit of the design is seen in schmidt newtonians which have much less coma than a conventional newt but equally fast focal ratios. For equal overall magnification there is no comparison between an SCT and a Newt.

I know theres less coma in the SCT design the point I was making is still valid, its unfair to plonk in an eyepiece that gives a 2 degree field in a f5 Newt but only a 1 degree field in an f10 SCT and then say that the outer 10% of the view in the Newt is showing more coma!! If you compare the same FOV then a SCT will still show less coma (but more field curvature) but the difference will be less pronounced, more in line with a f6 Newt IIRC.

I've no idea how much better these new 'coma free' designs are though but a f4 Schmitt-Newt will still show the same amount of coma as a ~f5.5 Newt, they arn't as coma free as some people think.

[MartinB]

Gaz, is that what you find with your SCT and dob, that for a given magnification the coma is similar? I've never noticed coma with either SCTs I've used. I can put a 30mm UWA in an SCT and have to look hard for edge of field distortion. Put a 10mm Pentax in my dob and the coma is obvious. If I put a plossl in the newt there's coma. It seems ever present. The F7.5 Tal1 has coma. I've used a 6.3 reducer with SCTs without causing noticeble coma - it's there if you look hard at the edge of the FOV.

Do you get a wider field of view for a given magnification with a newt than with an SCT? I know when you get up to 40mm with an SCT it starts to be looking down a tunnel. Maybe that's why the coma doesn't show on an SCT.

[GazOC]

The largest eyepiece I use in my 10" SCT is a 50mm Plossl and it still shows less distortion at the edges than my 30mm Moonfish 70 deg does in my f4.5 Newt with a similar FOV but it IS there. I seem to remember my 80 deg Moonfish being awful in the Newt but OK nearly to the edge in my SCT but I was seeing a lot less sky.

I'm pretty sure that coma is also worse for a given FOV the lower the magnification, which doesn't help the Newts cause when comparing the same eyepieces in both scopes. Having said that there is a pretty big difference between the amount of coma in a f4.5 Newt than a f6 Newt, its not a linear relationship but its been a while since I owned a f6 Newt to compare in with an my SCT. The coma can't be too bad though as my f6.3 reducer rarely comes out of the box....

[MartinB]

Yes that all makes sense, thanks. The main thing is coma's not worth getting too uptight about. Now as for contrast...

[GazOC]

[Astro_Baby]

Phil - see what you have started by asking 'whats the best telescope ?'

:lol:

[Helen]

Hi Phil,

I thought I'd join in too....

My first scope was a 6inch newtonian on a heavy equatorial mount. It nearly put me off for life! I saw some great views - but by accident as I never really got to grips with setting up the equatorial mount properly, and I found finding anything very difficult as you have to move the scope in arcs to get get to anything! And the mount was so heavy I nearly did myself an injury (I'm not very big!).

I got back into astronomy because I bought a very small scope and put it on a photo tripod, and attached a red dot finder, and all of a sudden I could easily get the scope out, and find things, and it was brilliant! Ok, the views weren't nearly as good as with the 6inch scope, but I knew what I was seeing, and could find things that I was looking for .

That led to wanting to see more, and I bought a Nexstar 8 GPS. Like Martin, I love the NS8GPS. Its heavy for me, but managable just. But once the scope is on the tripod it takes only a couple of minutes to set up. And the goto means you can be looking at amazing objects straightaway. My first view of the moon was awesome - I felt I'd fallen into a crater! The technology is so whizz that your kids will love it - plug in Saturn to the handset and just watch it appear in the eyepiece (and stay there all night if you want!).

I got into astro photography, and have happily used the NS8 in Alt Az mode for a year. I've now bought a wedge to go under it to transfer it to equatorial mode for longer exposures. But its so versatile - planets, deep sky etc. I wouldn't want to sell it.

On a practical point, the NS8 would be easier to store than the SW200 combo.

But as has been said earlier, you'll get great views either way. My vote would be for the NS8 because I think the learning curve is shorter and therefore you're less likely to get frustrated and give up!

HTH

Helen