Total newbie in need of guidance

[ian-d]

Hi all, stubbled across this forum whilst searching for a decent community to help with my new found hobby for astronomy. There seems to be a good level of advise on here so joined up

My o/h purchased a Celestron Astromaster 114 for me for Christmas as I have a big passion for the universe above.

I'm really struggling to get to grips with the telescope and haven't had much success at all yet, which is starting to frustrate me.

I've not been able to try it out with the moon yet, as every possible day I've had has unfortunately had cloud cover, but I'm guessing using the moon as the first object might be the best introduction.

What I have managed to do is test the telescope in day light by pointing at objects not far away, such as buildings, to make sure I can pick up close detail, which seems fine.

However, when it comes to the night sky, I run in to problem after problem. For example, if I try to focus in on Jupitar, I find all I can see is the black end piece of the telescope which is the large black central circle with the fixing brackets of 4 sides (if that makes sense). It covers almost all of the planet so I only see the outer edge!

I also seem to find the eyepiece gets covered over by a blackness which I can only describe as if it was filling with water. I don't understand if this is my eye, or something else.

The detail of Jupitar is poor (as I only see the edges) but can just about make out bands of lines in it, but everything is pretty much white and blurry despite all the adjustments I know how to do. Trying any star just doesn't offer any detail at all. I'm confused.

I've tried both a 20mm and 10mm eyepiece, with a I presume the 10mm offering a larger zoom.

Any tips would be greatly appreciated.

[BobTheSaxon]

Hi Ia-d,

Welcome to SGL. I have a refractor so cannot help much with your scope. I wonder if you have a problem of the eyepiece fogging when you bring your warm eye a bit to close to it, this may not happen in the day when the etepiece is warmer.

I'm sure others here will sort out your problems.

Best wishes,

Bob

[Astro_Baby]

It sounds as if focus is your problem as evades the big central thingy.

Use the lowest power eyepiece 25mm and very slowly move the focus backwards and forwards.

Try it in daylight and make uses it's coming to focus.

Stars will only ever show as tiny White points of light. Mostly White but some have distinct colors towards the red, blue or gold.

[NGC 1502]

Welcome to SGL. I think that if possible, it would be a good idea to contact

or join a local astronomical society. Most are friendly and willing to help.

Best regards, Ed.

[umadog]

First welcome!

From your description of Jupiter I think you are seeing the dark shadow of the secondary mirror and its four supports. You will see this if the object you are looking at isn't in focus. When you correctly focus on Jupiter you will see a small disk with no hole and the edge should be fairly sharp. How sharp will depend upon atmospheric turbulence.

It ought to look somewhat like this:

Go back and try again!

You will see no details at all in a star. A star will appear as a point of light at any magnification you use. The more point-like the better the optics are. Bad optics or misaligned optics will cause the star to look less point-like or even asymmetric. You don't want those things.

Your telescope has eyepiece of 20 mm and 10 mm focal length. The mirror is 114 mm across and has a focal ratio of 8.7. That means that the focal length is 114x8.7=992mm. You use this to determine eyepiece magnification (we don't generally use the term "zoom"). Your eyepieces will magnify by: 992/20=49.6x and 992/10=99.2x

The moon will look wonderful and you'll be able to see Saturn's rings.

You will want to learn about aligning your optics. They may be OK now but you still want to know how to check alignment and how to correct it. You can find introductory information here:

SkyandTelescope.com - Do It Yourself - How To Collimate Your Newtonian Reflector

[ian-d]

Thanks all for your comments and welcome, I suspect I will become quite a regular on here and hope also to find a local astronomy club for help and guidance.

Presumably then because I'm seeing the black circular end of the telescope through the view finder, that I'm trying to zoom a specific object in too far, as I don't experience the same problem during daylight.

Maybe I was just expecting too much in terms of detail and quality from Jupiter etc, so will hope for a decent day/night where I'm able to look at the moon, as I suspect I should get a much better image of that.

What would work best for the moon, the 10mm or 20mm (I would have thought 10mm but I am a novice!)? I do have a moon filter.

[LukeSkywatcher]

Presumably then because I'm seeing the black circular end of the telescope through the view finder, that I'm trying to zoom a specific object in too far, as I don't experience the same problem during daylight.

It sounds like you are over focusing and seeing the secondary mirror. Also i am not too sure but when you mention the word "zoom" (relating to zooming in on an object), it sounds to me like you are confusing "focus" and "magnification". I may be wrong. The focuser on the scope will not "zoom" in on objects. It will just make the image sharper. A higher powered EP will "zoom" increase the magnification of an object.

But in general it sounds as if you are just over focusing the scope on Jupiter.

Which works best with the moon?

It depends how you like the moon to look. A 10mm EP will give a closer look then a 20mm EP.

[umadog]

Presumably then because I'm seeing the black circular end of the telescope through the view finder, that I'm trying to zoom a specific object in too far, as I don't experience the same problem during daylight.

Ah... I think I may know what's going on now. There is no zoom knob and no zooming. Forget this term. Each eyepiece has a fixed power. You have a focuser knob and you use it to place the image in focus (to make it sharp). When Jupiter is getting bigger as you turn that knob you aren't zooming in, you're defocusing the image. That's bad and the opposite of what you want to be doing. You want to turn the focuser knob until Jupiter looks as small as possible.

[ian-d]

Thanks guys, I really need to get the word "zoom" out of my head...maybe from using cameras all the time!

I can get Jupitar down to a very small size which looks clear, so I guess that is the right setting, but maybe I just expected to be able to see more detail; it seems at this size I cannot see much, nor the moons around it. Maybe my telescope is just not as capable as most (but I am a beginner).

I really need to get practising with the moon, but once again, cloud cover is going to spoil the day. The only time I've had an opportunity was when it was over the houses to the back and from what I've read, this isn't a great option because of the thermal heat from the houses which causes a wave affect on the lens.

[LukeSkywatcher]

With your 10mm EP you should be able to see the bands going around the planet and the 4 main moons.

[ian-d]

Can I ask, why is it when using the 10mm EP the image appears upside down (inverted)? This isn't the case with the 20mm.

[LukeSkywatcher]

Can I ask, why is it when using the 10mm EP the image appears upside down (inverted)? This isn't the case with the 20mm.

Not sure about that. I'd assume both EP's are the same type so they should orientate objects in the same way.

[NGC 1502]

It is normal to get an inverted view. Are you certain that the 20mm EP

does not give this view ? However, it's just possible that the 20mm is

a "terrestrial" eyepiece for birdwatching or similar.

Regards, Ed.

[pvaz]

Generally for astronomy the image is inverted. There's no up and down in space, it's a matter of view point so the inverted image is not a problem. To correct it a lens needs a new piece of glass in between which dims the already faint astronomy objects making you see less. Ideally you always want it upside down for better light throughput.

As been said, each EP gives you a different magnification, so you need a few to get a range of magnifications available. There are zoom EPs but they always loose in quality compared with the fixed one, the exception being some very expensive zooms.

To figure out the magnification you get with any given EP/scope combination, divide the scope's focal length by the EP focal length. Your scope haves a 1000mm focal length so that makes it 50x while using the 20mm EP and 100x with the 10mm EP. For planets you should always use the 10mm and maybe add a 5mm (200x) to you collection for a better look.

[valleyman]

The problem with the EP looking as if it is filling with water, is that you might be getting your eye to close to it. you need to be about 1" AWAY from the EP with a 25mm lens. moving closer as you use small EP's. I am sure it will all come natural after a bit of practise

[umadog]

I find it difficult to believe that one eyepiece inverts and one does not. I've never seen such a thing. Are you certain?

If you can see Jupiter's disk then you can see the moons. Probably they're not looking the way you expect them to. It will look vaguely like this:

http://blog.nj.com/southjersey_impact/2008/09/JupiterMoons.jpg

I think you want to buy yourself a nice introductory book such as "Turn Left A Orion" or "Nightwatch". That will explain most things. Also you can play with this to learn the sky: Stellarium

[Davidv]

I agree with everyone that you just haven't managed to get it in focus and I would expect both eyepieces to give an inverted image. As for the moon, when you get these problems sorted out you will probably find that with the 20mm eyepiece giving a magnification of approx 50 times, the moon will easily fit in the field of view and with the 10mm at a magnification of 99 times, obviously lunar features will look bigger but the moon will nearly fill the field of view or even not quite fit. I'm sure you'll get the hang of it. Dave

[umadog]

I have seen on another thread that there is such a thing as an inverting eyepiece, so your 20 mm may be an example of such a one. I have never seen one myself and wasn't able to get any info on them from a quick Google search.

[ian-d]

I can absolutely 100% confirm that the 20mm eyepiece is inverted (i.e. upside down) and the 10mm eyepiece is the correct way around. This is based on focusing on a building approx. 20 metres away. Could it be that over a significantly longer distance the image would flip?

[themos]

Just about. An object 20 metres away would be focused at a distance of 1044mm from the mirror whereas an object at infinity will be focused at 992mm (as the focal length says). The difference is 52mm, about 2 inches. So, the building's image is formed 2 inches further out the focusing tube than the image of the moon.

Now, my understanding is that the eyepiece intercepts a diverging beam of light after it's passed through the focus and turns it into a parallel beam suitable for the eye. But if the image of the closer object is pushed out then maybe what enters the eyepiece is a converging beam but the eyepiece still manages to produce a parallel beam that they can see, only it's not inverted.

One way to test this: Take the 10mm eyepiece off the focuser and hold it in the air over the focuser hole moving it further away from the focuser and towards your eye. What happens?

[Astro_Baby]

I think its very likley the scope has a corrected eyepiece with it. These were common with lower cost scopes years ago.

Celestron dont mention it on their site. But i would bet the eyepiece has an extra lens so its corrected.

[LukeSkywatcher]

Its not a bad idea for companies to sell one of each with scopes. Many people like to use their scopes during the daytime also for wildlife observing etc. My latest scope (70mm) came with an erecting prism, so its great for sitting in the back room looking out the window at all the birds during the day.

[ian-d]

Well I got an opportunity to try my first telescope on the moon for the very first time a few minutes ago; it is going dark but a good chance to take a look before is disappears out of sight.

Must say I was impressed; I've obviously seem images on the net but nothing like seeing it for yourself. Obviously the 20mm EP was a little distant, but the 10mm was impressive, with I'd guess a eyepiece's worth of full moon (should it have been one).

Just to confirm what I said though, the 10mm was the same way up as how I see it to the naked eye, yet the 20mm was inverted, so very confusing!

On my telescope (Celestron Astromaster 114) what EP would get me the closest view of the moon, a 1mm or similar? Would that mean a 1000x view or is that not how it works?

[LukeSkywatcher]

The 10mm will give you great views. If you want to see craters a bit closer (a lot closer) you could always use a 2X Barlow with the 10mm.

You could even use a 6mm EP with/without barlow.

1mm EP or less?

Absolutely NO WAY. Not sure they even make them that small.

[ian-d]

Would a 2X Barlow offer a better (clearer/closer) image than just getting a 6mm EP as the Barlow appears to be cheaper.

How does it fit with the existing 10mm EP?

(not managed to work out how to fit the moon filter yet; think I might have been supplied the wrong one!).

Went out onto the fields just now before the cloud came in; some amazing views and we get very little light disturbance; managed to see Jupitar and its 4 moons, amazing.