Barlow and erector lens?

[dotty603]

Hello all, I'm about to buy my first scope - thinking of skywatcher explorer 130p - but have a couple of questions:

What's the Barlow lens for??

Can you use a prism erecting lens with a Newtonian reflector? (I'd like to be able to use it for terrestrial viewing as well if possible)

The field of view calculators I've been looking at suggest that any view of eg saturn will be no better that with my 10x50 binoculars, and there appears to be little difference between the view through the 130p and the 150p. Is this correct, or am I not understanding the field of view callculator?

My primary interest is in tracking down DSOs. I have little interest in astrophotography at this stage.

Thanks for any help.

[Cornelius Varley]

Helllo and welcome to SGL.

A barlow lens fits between the focuser and an eyepiece effectively increasing the magnification of the eyepiece. The 2x barlow supplied with your telescope will double the magnification of an eyepiece ie a 25mm eyepiece with a barlow attached will have the same magnification as a 12.5mm eyepiece.

[jason.p]

Hi Dotty and welcome to the Stargazers lounge. As Peter says, the Barlow effectively doubles the magnification. Of course a lot depends on the quality of the Barlow and you may be better off getting a range of eyepieces to cover. I can't help with that scope, but there will be many on here who will be able to advise, just ask.

Good luck and clear skies

Jason

[dotty603]

Thanks for that, I posted in haste last night hoping to pick up some replies before going off to telescope shop today. Reason I'm not that confident about just asking the experts in the shop is that on my first visit the chap focussed so much on "managing my expectations" that I almost decided that there was little point in buying any scope at all.

To be clearer; my choice is between the Skywatcher explorer 130P on EQ2 mount, 150P on EQ3-2 mount, and Dobsonian Skyliner 150p or 200p. I've pretty much decided on the lower end (cheaper and possibly more manageable) scope for now, i.e. the 130P as if this dense cloud cover continues to predominate for yet another year, I may just not get to use it enough.

On the shop website one of the optional extras listed for the 130P is the Ascension 1.25 x 1.8 Prism erector, which I was thinking of getting. On other sites though I've read that you cannot use a prism erector with a Newtonian Reflector. I have no idea why, so was wondering if any members here have experience of this. Any clues? Thanks in advance.

[damnut]

Hi There,

Warm welcome to SGL.

The reason that most folk do not usa a diagonal or prism with a reflector is this. The eyepiece comes straight out of the telescope tube focusser, so if you put a diagonal in there you would be viewing at some awkward angles!. If you compare to a refractor where the eyepiece come again out of the focusser, the addition of the diagonal makes for a much easier viewing position and saves my old back!.

If you are looking for some books try 'turn lef at orion' and 'sky & telescope pocket star atlas' these wil help guide you round the sky. Also download a planetarium program, try stellarium, its great and free, to be found here :--- http://www.stellarium.org/

In terms of scopes, get the best you can afford, the 200p will serve you well for many years and has a great reputation. However no good if its sitting in the garage.

Good luck with your choice.

[Mattscar]

Hi Dotty

The Explorer 130p is a great scope. I bought one myself (also my first scope) at the start of the year and still love it to bits. Its a great intro scope as it does well for observing, you can try your hand at planetary imagining with a webcam and there are some mods you can do to it (flocking for example) to try your hand at improving kit. As for views of saturn, Iv seen it with all the EP's listed in my sig and every one of them gave a different piece of detail and thrilled me in a different way. Sure, bigger scope = better images, but the 130p is a brilliant way into the hobby

Clear Skies!

Matt

[Avocette]

Hi Dotty and welcome to SGL. You're in the right forum but perhaps not quite the right place to get answers to your questions. Try posting your Qs again in 'Getting Started Equipment Help and Advice'. But my view would be to get a Skyliner 200p if you're really after DSOs. DSOs are the opposite extreme from land based objects and there's a whole other set of telescopes for terrestrial use (spotting scopes etc.) By the way Saturn through binoculars is a bright ball with 'ears' whereas in a telescope at 100x or more magnification you see the rings clearly, and you may be lucky to observe the Cassini division and some texture on the planet surface.

[Charon]

Hi from me too.

[dotty603]

Thanks again for your help all, I'm off to go to telescope shop shortly, and hope to find a different person from my earlier visit to answer my questions. I do think that I'm going to end up with the 130P, in part because it's a present! I'd feel a bit greedy (and not able to make that good a case) choosing to spend someone else's money on the 150P with the EQ3-2 mount, I think that comes to twice the price of the 130P.

Thanks damnut, stress on the back is an issue for me certainly. I'll try and get the chap in the shop show me how the erector lense would work. As with all this kit there's no point if it's too difficult, uncomfortable, heavy etc to ever get used.

You're right avocette, a terrestrial scope can be got for not much money, and I can of course use my binoculars for terrestrial stuff!

I'll let you know what I end up with.....

[dotty603]

Mattscar - what the bleep is flocking??? Why would I want to do it?? I'm imagining you are referring to decorating the exterior of the scope with the sort of wallpaper that used to be traditional in Indian restaurants in the 70's. Do let me know if I'm mistaken before I go ahead and do it.

[Mattscar]

Haha, your not a million miles away. Flocking is where you cover the inside of the telescope with something like this http://www.firstlightoptics.com/telescope-flocking-material/black-velour-telescope-flocking-material.html

It increases the contrast and stops light reflecting around the inside of the OTA. I'll admit I havn't done it myself yet, but alot of people have and say its worth doing, although only once you know how to collimate your scope (the equivalent of tuning a guitar, something that looks scary before you do it but is actually quite simple to do with the guides on here).

But this is getting ahead quite abit anyway, get yourself what your happy with and use it for a while first.

Sorry to have confused!

Matt

[michigander]

Welcome to SGL, Dotty!

Flocked wallpaper WOULD look pretty cool on the exterior of your scope

But you are right. Flocking itself is a technique to reduce the reflectivity of surfaces which is used to create the effect on Indian wallpaper, but in this case is used on the inside of the telescope to reduce unwanted stray light.

Here's a couple of links which explain it better than I can. First one is about the technique of flocking in general,

http://en.wikipedia....ocking_(texture

And this one shows you how to flock a telescope.

http://washedoutastr...ontent/flock-it

Dana

Edit - to Matt. Would have got there first buddy, but it took me 45 minutes to compose the post in the face of Marion's insistence that it is the same thing as Indian wallpaper. It's not fair, I just woke up.

D

[HIP3802]

Hi, dotty603, and welcome to SGL!

[Schorhr]

I have the heritage 130p- these small telescopes show a lot for their low price. But I didn't find it too good on an astro3 mount, and that's more stable then an eq2. Using it as Dobsonian again.

A good eq-mount is expensive, the dobsonian mount is much more stable, but at 650mm focal length a bit low on the ground.

The 200mm would show much more on deep sky object- if you can transport it out of light poluted areas. The h130p is probably the only still somewhat back-pack-able telescope in this price-range ;-)

[JamesM]

Hi and welcome to the forum

Clear skies

James

[dotty603]

Thanks for the welcomes everyone. Just got back with my new telescope - the Skywatcher explorer 130P - and I think I'll hold of on the flocking until I've worked out how to see anything through it. At the moment even the reflected light bouncing round the tube would be more exciting than the grey blurry blur I can see at the moment. I think I've got some bits of the mount the wrong way round as well, so I'm planning to take it all apart to start again. There's no rush, the next night of broken cloud isn't forecast until next Monday, but it would be nice to know that it worked.

[ronl]

Hi Dotty603 welcome to the lounge,

congrats on getting your new scope, getting to know it and using it

takes a little time, especially while it's cloudy, it's a nice scope so "Enjoy."

Good Luck and Clear Sky's

[Pig]

Hello & welcome

Shaun

[Bizibilder]

Hello Dotty and welcome to SGL!! Feel free to ask any more questions and I'm sure the answers will be forthcoming.

[Pete Presland]

Hi welcome to SGL from Pete in Bedfordshire

[glowjet]

Hi Dotty and welcome to SGL, congratulations on your new scope, but leave flocking to the sheep for the time being and get used to your new scope, it can be a very steep learning curve, but you will find the membership very informative, should you come across a problem, just ask, enjoy