Typical noob - first telescope advice!

[bubbabr]

Hi everyone,

I realise this is the kind of post that is written ad infinitum, but while I read the other similar posts with interest there's nothing quite like getting your own personal reply! So thanks for your patience and any advice would be greatly appreciated.

I'm wanting to buy my first telescope and am all at sea as to which would be best - I have a budget of £200-250 (perhaps the tiniest bit more if it really is worth it) and the only thing I can say for sure is that I've ruled out Dobsonians on the grounds of lack of portability. From what I've been reading, at this entry stage including GO-TO detracts from the quality of the rest of the scope and I am not fussed about excluding that either.

If anyone could therefore advise and/or link to some cracking telescopes, or offer any kind of advice at all, that would be great. Thank you very much.

[pvaz]

I can't really understand how lack of portability can be applied to dobs, unless you buy a 12" or bigger.

With your budget, you'll have to choose between a reflector or a small refractor. The refractor would only be good for planetary and the very brightest DSOs, so the most logical option is a reflector.

That said, then you need to choose the mount (dobsodians are reflectors on a cheap, light dobson mount). So you have eq and dobson to choose from. Each have pros and cons.

Eq: tracks objects, may allow some photography (if it's good enough) but on the other hand are heavier and need to align (if there are clouds hiding polaris you can't align).

Dobson: can't track, but no setup is needed and they're pretty easy to use, just point and "shoot".

In my opinion the only real alternative for portability without loss of aperture is a 8" Catadioptric, but price goes up a lot to about 1000 and they are still heavy, but smaller.

I think most people will agree this scopes are a good choice:

http://firstlightoptics.com/proddetail.php?prod=SW150PL (eq)

http://firstlightoptics.com/proddetail.php?prod=dobsky200 (dob)

[TheThing]

Refractors can be used, quite sucessfully on all sorts of targets, not just planets and DSOs, so don't rule them out for that purpose alone.

If you can, have a look at November's issue of Sky at Night magazine (which should still be in the shops until 24th November). They do a review of entry level GOTO scopes. From memory the Celestron Nexstar 102 SLT came out as the top scoring scope in that review.

Although it would be nice to have a dob, sometimes even the small ones can be difficult to transport, especially if you don't have access to, for example, your own car or you have limited storage space (i.e. a flat)

[bubbabr]

thanks for the advice so far guys.

re pvaz - i'll have a look at the Skywatcher Explorer 150PL EQ3-2, so thanks. maybe i'm missing something, but the dobsonians i've seen all seem to be at least 6 foot high and very chunky. is this not correct?

re the thing - i'll def go and buy that copy anyway, but i should have been a little clearer - what I should have said was that i think i would prefer to spend my money on the telescope rather than the computer at this point, so if you have any suggestions for non GO-TO scopes that would be great.

thanks alot.

[TheThing]

Just throwing the GOTO option into the hat to add further confusion!

If it's non-goto you're after then pvaz has hit the nail firmly and squarely on the head!

[bubbabr]

great - thanks for the advice the thing.

anybody else disagree/agree or have any other suggestions (just in the interest of getting as wide a picture as poss - no disrespect to pvaz or the thing!)

thanks.

[stev74]

Eq: tracks objects, may allow some photography (if it's good enough) but on the other hand are heavier and need to align (if there are clouds hiding polaris you can't align).

Pvaz - Some good advice, I just wanted to point out you can polar align even if you can't see Polaris. If your only doing visual work it doesn't have to be 100% accurate, you can align the mount using a compass. Or failing that if you usually put your scope roughly in the same spot look for a guide on a clear night. For me if I look over my fence at 2 of my neighbours houses' Polaris sits in the middle of the gap between them if I extend the line of the edge of each house up in to the sky. So on a night where there's cloud to the North I just aim the tripod leg in the centre of the gap between the houses.

bubbabr - Just thought I'd add if you check the secondhand market you'd get more aperture for your money, the 'for sale' section on here is good and also U.K. Astronomy Buy & Sell. Downsides would be the stuff isn't shiny and new, there's no warranty or as much choice but there are a good few bargians.

Cheers

[bubbabr]

Thanks for the tips Steve. Can you (or anyone else) shed any light on the Celestron Omni XLT 150mm f/5. There's one for sale in that section and was wondering whether, if he accprts an offer in my range, it would make a good purchase? Thanks

[pvaz]

On the size of dobs, it's true they are big. But most of the size comes from the tube, not the base. The base is bulky but low. In other words, if you buy the same OTA, the dob version will probably be more compact then the EQ version, provided that we are talking about the same tube.

I like observing everything but I have a preference for nebulas, galaxies and globular clusters, so I'm a bit biased when it comes to aperture.

I just bought an 8" and will probably upgrade in a year or less, though I'll loose some portability.

I didn't mean to undermine refrators, they can be great too, specially for planets, double/variable stars and clusters. That said, a 6"+ refractor costs a small fortune, so I didn't even consider one as an option when I bought my scope. As an example, I just downloaded a list on the Herschel 400, and they recommend a 10" minimum to see all objects.

[pvaz]

I forgot to say, I just been to the local astronomy club. Only haves 4 members, well 5 now.

One of the members is a women that has been in the hobby for 15 years+, and currently ownes a Meade LXD75 8" Schimidt-Cassegrain and an Orion XT8 dob. She's more of a goto user, so she uses the LDX the most, except when she goes to remote sites. Even though the lxd is more compact it weights a lot more then the xt8, too much for her back. She bought the dob cause it offered the most portability/"light" weight for the aperture.

Cheers,

Paulo

[Capricorn]

How relevant is the transport aspect? It makes a difference. If you don't have a car or use public transport then I suspect that a Dob is out of it.

Dobs have the advantage of mirror size, so gather more light and allow you to see more DSO's. They have disadvantages also, cool down and collimation are two.

A reflector of smaller size say about 6inches, actually same as a dob as a dob is the mount not the scope, on an EQ mount is a mid range starting scope. However for transport you now have a scope and an EQ mount to transport.

A refractor of say 80-100mm dia is another mid range scope, smaller aperture but generally easy to transport, normally smaller in length as well. Will need a mount as well. Keep reading of people that regret selling their 80mm refractors, so there is something about them that fills a niche.

A goto of small size, and big as well, has the advantage that it all comes in one lump. Get box, unpack assemble, power up, use. Problems are they can give up (have 2 and both going well) and that usually means a dead scope, but a lot of problems are the user. Amazing what some do, don't do or expect.

My suggestion is a smallish scope and find out what you want to do in this hobby then make the next scope the one to suit that decision.

[pvaz]

I have to agree on that 100%. I can't see me taking my scope on public transports.

Though there are 4,5" dobs that have a handle and can be carried by a child (such as this one). In the end it always comes down to what you want. There isn't "one" right choice that meets everyone's taste/expectations.

Paulo

[robneath]

well im a newt fan, so next upgrade ( if it happens) will be a larger newt on eq mount. Eq mount suits me, getting good views once the clouds go and it gets used.

[stev74]

The Celestron Omni XLT 150mm f/5 is a good scope but if it's the advert i'm thinking of it's says OTA at the end - http://stargazerslounge.com/sale/90314-celestron-omni-xlt-150mm-f-5-newtonian-ota.html. OTA stands for Optical Tube Assembly which means it's only the scope for sale so you'd need to buy the mount separate.

You can buy the Omni XLT Series - Celestron Omni XLT 150 on a CG-4 mount new for £339 which is outside your price range. It's a 6inch reflector on an equatorial mount and so is this scope Reflectors - Skywatcher Explorer 150P EQ3-2 but it's only £219 new and in your price range.

You should be able to get something bigger than 6inch aperture with your budget secondhand or get 6inch secondhand and have more to spend accessories. Saying that the Skywatcher 150p new is a great deal and now comes with a better focuser than before this thread gives more info - http://stargazerslounge.com/sponsor-announcements-offers/90287-skywatcher-explorer-150p-eq3-2-a.html .

Cheers

[vegas]

I'd just like to add a point about the varying learning with each telescope as well.

EQ mounts do take a while to learn, and though polar alignment doesn't need to be exact, it can take some 'playing' around to learn the nack of operating the EQ.

Dobs appear to be easier to get used to, but require more onhand (literally) adjusting to track targets, where the EQ can be controlled by the Dec and RA controllers.

I have a 5" reflector and though I do not regret the purchase I have come to realise that for me personally a refractor would have been a better first purchase.

With the reflector the sky is essentially presented through the eyepiece upside down and back to front, and as I was/am learning the sky as I go, I've found it increasingly difficult to operate the scope and mount when searching for first time targets. The refractor presents a rightside up image which for myself I think would help me learn the sky (operate the scope) easier.

I no way am I trying to make it sound like reflectors and EQ mounts are too tricky, I just thought I'd add my 2 cents to explain my experience of the scope.

Having said all that, I've found the quality of the Skywatcher very good as a beginner scope and would highly recommend it as an affordable option. With the 150p which is an inch wider than my own, I'm sure you will get astounding views.

[bubbabr]

thanks for all the post guys, learning all the time!

am i right in thinking that the way an equatorial mount works is that you lock its vertical axis when you're fixed on your object, allowing you to track the object by moving the scope horizontally?

is that at all close, or am i way off?!

[RichieP]

thanks for all the post guys, learning all the time!

am i right in thinking that the way an equatorial mount works is that you lock its vertical axis when you're fixed on your object, allowing you to track the object by moving the scope horizontally?

is that at all close, or am i way off?!

You are sort of along the right lines, but instead of horizontal and vertical axes you have Right Acension and Declination (RA and DEC) axes. The RA axis is, through polar alignment, aligned with the earth's rotation. Once you have located your object, if you lock your DEC axis then you can track the object by just adjusting the RA axis alone - or letting a motor do it.

[pvaz]

thanks for all the post guys, learning all the time!

am i right in thinking that the way an equatorial mount works is that you lock its vertical axis when you're fixed on your object, allowing you to track the object by moving the scope horizontally?

is that at all close, or am i way off?!

The equatorial mount haves an axis. That axis is aligned with the earth axis. You do that by fixing the latitude of your position (on earth) and aligning with the North star (Polaris). Polaris is used cause it's the star that sits almost directly above the earths axis, if you ware to draw a line from it.

Then, the axis of the mount is parallel to the Earth's axis. So, as the earth rotates one way, the mount rotates the other way at the same speed to keep objects in view.

The telescope can then be moved both vertically (declination, witch goes up and down the axis) and horizontally (right ascension, that goes "around" the axis) to point at any object.

As objects don't change declination (witch is their "hight" in relation to the earths and mount axis) so once you locked it, you just move in right ascension (around the axis) either manually or by motor to keep the object in view.

In Stellarium you can change the mode to EQ mount, and it simulates these types of movements. Maybe you can get a better idea of what it's like by trying out. (Press the scope icon on the taskbar for EQ mode.)

I just recently learned how to use one, and didn't find it too complicated, but I had help from the scope's owner.

[bubbabr]

ok great.

so whereas altazimuth goes up and down and straight left and straight right, equatorial goes up and down and 'around' left and 'around' right? because object don't move across the sky in a straight line? thank you, yet again.

[johninderby]

ok great.

so whereas altazimuth goes up and down and straight left and straight right, equatorial goes up and down and 'around' left and 'around' right? because object don't move across the sky in a straight line? thank you, yet again.

It's not correct to say that Alt-AZ mounts just go up and down and left to right. They also move at angles. For visual use an Alt-Az GOTO mount tracks as well as an EQ mount. The Alt-Az mount is easier and quicker to set than an EQ mount. For imaging however the EQ mount is preferred as it more accurately follows the path of celestial objects and doesn't suffer from field rotation.

So if it's mainly for visual use an Alt-Az mount has it's advantages and can do some lunar / planetary imaging as that only requires short exposures. But if you think that you will want to do more imaging then the EQ is probably best for you.

John

[AWR]

I went for an EQ mount with my scope (small flat + stairs = no dob) and I've found it helps me find my way around. I don't bother to accurately polar align it - I just point it north and level it by eye. What I've found helpful is that when following star-hopping instructions (in Turn Left for example) one dial moves me N-S and the other E-W, making it very easy to find what I go looking for.

Andrew

[pvaz]

Yeah, it's that. But up-down, on an EQ, is not the same as you looking up over your head.

Once an EQ is align, as you move all the way up in declination, you'll always be pointing at Polaris witch sits right on top of earth. As a figure of speach, Polaris is over the earth's "head".

Unless your exactly on the north pole, your "up" (what's directly above your head) is not the same as the mounts "up".

In reality objects, don't move in a way you'd notice in one night. It's the Earth that's moving and, as you're on it, objects appear to move around the earth's axis. That's a good reason for the ancients to think Earth was the center of the universe and that everything rotated around us, because, when you look up, that's what it looks like.

(I hope I didn't just make it more confusing... :s)

[bubbabr]

thanks pvaz i think i'm getting there! but why does a roughly aligned equatorial mount still make the grade - is it because it will only lose track of an object over a longer length of time than one is typically watching the sky (e.g. a few hours at a time)?

[Astro_Baby]

In a nutshell yes. A roughly aligned EQ will still track but just not as accurately. For any but the fastest moving objects the target will stay in the eyepiece file of view for minutes.

If you've not seen planets under powerful magnification its hard to put over how fast this stuff moves. With a non tracking mount and a medium magnification the moon will cross the eyepiece field of view in under a minute.

Its less critical with Deep Sky Objects (DSOs).

For your money if you want an EQ mount I'd suggest the Explorer 150 on the EQ3-2 mount. Bear in mind though that almost any scope over 6" is a handful of weight.