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emilyy01

Help! How to view planets with a Celestron Newtonian?

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Hi!

I'm a complete beginner to this whole astronomy thing but I've always been interested since primary school. So I bought a second-hand Celestron Firstscope 114 Short 4.5" Newtonian Equatorial Telescope. I understand that this is only a cheaper telescope but I just wanted something to get me started. I followed the instruction manual and did everything as it said. I aligned the finderscope up during the day and could see fine through the telescope. I took it outside last night to view the planets that are visible at the moment, used the finderscope to locate a planet, looked through the eyepiece and I could see lots of light. So I assumed that I was indeed pointing at a planet. However, I could also see what I believe is the secondary mirror holder or spider. So that completely blocked my view. I tried focusing it, trying different eyepieces with and without the 2x Barlow but still I could see the holder/spider. I followed the guide in the manual about collimation and I believe the collimation is correct. What I don't understand is how I could see fine during the day but not at night.

 

 So what is the problem? Is there something that needs adjusting?

 

Please be aware that I am a complete beginner so astronomy is currently a completely different language to me!

 

Thanks if anyone can help!

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In my scope if I can see the mirror my focus if off.  All of my eyepieces will come to focus when fully seated.  it wouldn't amaze me if some combination someday needed tightened when they were high.

What all eyepieces do you have?  I am sure someone on here will know which are the factory provided ones. 

FWIW, My easiest times just to get something in my eyepiece is with my highest numeric eyepiece which gives the least magnification. With no Barlow of course as that doublrs magnification. Typically I find my target that way then start increasing magnification until it gets fuzzy even when focused.

Good luck, this is a decent time for 3 planets for me!

Edited by MarkVIIIMarc
cell phone typos

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Focusing on things during the day means you are by definition looking at targets which are closer than the planets or stars. All that is wrong is that you are well out of focus. Put your longest focal length eyepiece in and run through the whole focus range. You will be in focus when the object or star is at its smallest. You won't see the secondary or the support vanes then, other than as diffraction spikes.

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I have a Celestron eyepiece kit. It has some Plossl eyepieces (4mm, 6mm, 9mm,15mm, 32mm) and some others that don't have Plossl on them so I'm not sure what they are. Celestron 20 and Celestron 10. And then of course the 2x Barlow.

 

Stu I tried that last night. I put every eyepiece in and ran through the whole focus range for each one. The 4mm eyepiece is the one with the longest focal length isn't it? I could only actually see black with that one so I'm not sure why. I'll give what you say another go though tonight.

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5 minutes ago, emilyy01 said:

I have a Celestron eyepiece kit. It has some Plossl eyepieces (4mm, 6mm, 9mm,15mm, 32mm) and some others that don't have Plossl on them so I'm not sure what they are. Celestron 20 and Celestron 10. And then of course the 2x Barlow.

 

Stu I tried that last night. I put every eyepiece in and ran through the whole focus range for each one. The 4mm eyepiece is the one with the longest focal length isn't it? I could only actually see black with that one so I'm not sure why. I'll give what you say another go though tonight.

Hi,

No, the 4mm is the shortest focal length and will give you the highest power and smallest field of view, making it harder to find or see anything. Start off with the 32mm Plossl and see if you can get sorted with that. Don't worry about the Barlow for the moment.

Do try again with that one, and go slowly, it can sometimes be easy to go right through focus and out the other side.

The other thing you could do is post a picture of the eyepiece in the scope just so we can see if something else is wrong. Shouldn't be but worth ruling out any sillies.

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Ok thank you. I'll give that a go with the 32mm tonight and let you know how I get on. If I still have problems I'll take a photo :)

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Yes, the longest FL is what you need to start with - it give lowest power or magnification.  

Adjusting focus over a wide range should give a position of clarity.

One other thing - do align the finder with a very distant object in daylight.  Get something suitable in the eyepiece (EP), then adjust the screws on the finder so the object is centred there too.  Then when you use it on a celestial body, it should put it in the EP for you.

You'll soon be on your way!

Doug.

 

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Hello. If you say collimation is correct from what you are saying it certainly seems like you have a focus issue somewhere in the optical chain. As the other member say on here use a low power eyepiece 32 mm or so. Then from my past if I had focus issues I would find the biggest target, the moon? and then adjust the focuser slowly from the all the way in position to the all the way out position . Hopefully by doing this you should start to get a clear image at some point during your focus movement.  I hope this helps

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Are you able to aim the scope at distant daytime object?  Something like a distant electricity pylon or chimney.  If you can get something a couple of miles away you shouldn't be too far off when it comes to the planets.  As everyone else has said, go with your 32 mm eyepiece first.  From there you should just need minor tweaks to refocus between eyepieces.  Try not to get seduced by the supposed magnifications available.   You can get magnification by dividing the focal length of the telescope by the focal length of the eyepiece.  Example: a 1000mm focal length scope with a 32mm eyepiece = 1000/32 = 31.25 magnification.  If you try going too high a mag then you will end up with a soupy mess.    

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33 minutes ago, gnomus said:

Are you able to aim the scope at distant daytime object?  Something like a distant electricity pylon or chimney.  If you can get something a couple of miles away you shouldn't be too far off when it comes to the planets.  As everyone else has said, go with your 32 mm eyepiece first.  From there you should just need minor tweaks to refocus between eyepieces.  Try not to get seduced by the supposed magnifications available.   You can get magnification by dividing the focal length of the telescope by the focal length of the eyepiece.  Example: a 1000mm focal length scope with a 32mm eyepiece = 1000/32 = 31.25 magnification.  If you try going too high a mag then you will end up with a soupy mess.    

Yeah I can see fine during the day which is why I don't understand why I'm only having the problem at night. But everyone has said the same so I'm hoping for clear skies to have another go tonight with the 32mm. 

 

As Timebandit has said, I'll use the moon as a target when it appears again as it should be easier to get me started.

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If you can get focussed on a faraway daytime object AND you have aligned your finder and scope on a similarly faraway object then you will be fine.  It is likely that the first bright 'star' that will appear tonight will be Jupiter - a bit west of due south, and reasonably high up. You should make that your first target....

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The problem you have experienced is entirely down to the scope not being in focus when you pointed it at the planet. You would get a similar effect if you had pointed it at the moon or a bright star - you will see the shadow of the secondary mirror support and the supporting vanes against the unfocused bright image.

As suggested, find an easy object such as the moon and put your lowest power eyepiece in the scope. As you move towards sharp focus you will see the bright unfocused image get smaller and smaller, the shadow of the secondary and vanes with disappear and when the target is at it's smallest and sharpest in the eyepiece, you have reached correct focus.

 

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Typically it was cloudy last night so couldn't see a single planet but I caught a break in the cloud to look at a star. I had my 32mm in and slowly ran through the focus. Once I couldn't see the spikes of the secondary mirror the star appeared really small in the eyepiece. Is this right?

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19 minutes ago, emilyy01 said:

Typically it was cloudy last night so couldn't see a single planet but I caught a break in the cloud to look at a star. I had my 32mm in and slowly ran through the focus. Once I couldn't see the spikes of the secondary mirror the star appeared really small in the eyepiece. Is this right?

If you reached a position where the star went very small, then started to increase in size again then you have gone through the focus position. Coming back to the star at its smallest will have you in focus. This is far easier to practise on the moon which should be around soon enough if you are still struggling.

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26 minutes ago, emilyy01 said:

Typically it was cloudy last night so couldn't see a single planet but I caught a break in the cloud to look at a star. I had my 32mm in and slowly ran through the focus. Once I couldn't see the spikes of the secondary mirror the star appeared really small in the eyepiece. Is this right?

Yes, stars look really small - just points of light.   Even planets look small in the eyepiece.  The Moon however can fill your field of view, depending on magnification.

As for stars, although tiny, there is much pleasure to be had from viewing groups and clusters of them.

Doug.

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11 minutes ago, cloudsweeper said:

.....

As for stars, although tiny, there is much pleasure to be had from viewing groups and clusters of them.

Doug.

.... And doubles.  Albireo will be one of the prettiest hings you will see.  

If you got small points you had focus.  

Next thing you'll need is a star atlas for finding stuff.  The Sky and Telescope Pocket Star Atlas is very good.  If you have an iPad, then take a gander at Sky Safari - you will be able to set it up with your scope and eyepiece combinations and get a good idea what your field of view should be when looking at objects.

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18 minutes ago, emilyy01 said:

So with a higher powered eyepiece would they appear bigger?

Basically the answer to that is no! You never see any detail on stars, they are just too distant. They tend to look a bit larger and potentially fuzzier at high powers but this is never you seeing detail.

The reason for applying more magnification to stars is generally to get more detail in objects such as open and globular clusters which are groupings of stars; the magnification allows you to resolve, or start to resolve the individual stars.

Splitting tight double stars is another reason for using higher mag. A star might seem like just a single object at low power, but may split into separate components at high power.

Finding the right stars, or the locations of the clusters is the bit that needs practise ?

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