Correct Lens to veiw Saturn

[Karen Thompson]

Hi All, I am really new and feel stupid asking these questions. I have had a Meade 1000mm telescope for years. I can find the moon and see it great. But when I look at Saturn and Jupiter they are small dots. I am wondering if anyone can guide me on what lens I should use? I have currently a 5mm coated, a MA25mm, MA9mm  and a 2X Tele negative multicoated lens. But when I try, I just see dots. What am I doing wrong? Do any of the lens I have work to see Saturn and its rings? Or do I need to buy another lens? Your help would be greatly appreciated. I would really like to use this as it was a gift  to me. Many thanks! Karen

 

[Ricochet]

What is the aperture of your telescope? This will partly determine which eyepieces are usable with your telescope. If you use a 5mm eyepiece with a telescope with 1000mm focal length telescope you will have a magnification of 200x. At this magnification you should see Jupiter as a small disk with up to four moons around it, and Saturn as a small disk with rings. If you do not see this, the first thing I would do is to check the alignment of your finder scope with your telescope as the difference between a planet and a star should be obvious. 

[Karen Thompson]

HI, Thank you!  A real person to talk to. Ok, I am so new and dumb. My telescope says D= 114mm F= 1000mm f/8.8 what does this mean to you? If I use the 5 mm with the 2x barlow lens will that help?

 

[dweller25]

Hello Karen

your telescope had a mirror 114mm wide and its focal length is 1000mm

iy you divide the scope focal length by the focal length of the eyepiece you get the magnification.

So thats 1000/ 5 for the 5mm eyepiece = x200

X200 is plenty to view the planets no need for the barlow.

Have you aligned the finder to the eyepiece view ?
You need to do this to find objects....

1. during the day observe a distant object - ideally a mile away using the 25mm eyepiece.

2. Centralize a feature in the eyepiece, then look through the finder

3. Without moving the scope, centralize the same feature in the finder using the adjustment screws.

Now you are set up to use the low power finder to find the object you wish to view.

Mars is due south  in the mid evening sky at the moment, but very small - give it a go at x200

Good luck 

Edited January 11, 2021 by dweller25

[Karen Thompson]

Hi David from the

UK! One of the paper mills I work for is in Burneside. I got to visit 2 years ago. Loved it for the short time I was there! I appreciate very much your info. I thought I aligned the telescope. I will try again tonight and then see. We have some clouds coming so not sure what I will get tonight. I am just excited to try it! 

[Louis D]

That means it has a focal length of 1000mm and an aperture of 114mm.  The focal ratio between these two is 1000/114 = 8.77 ~= 8.8.

If you take the focal length of the scope and divide it by the focal length of the eyepiece, you'll get the working magnification.  So 1000/25 = 40x, 1000/9 = 111x, and 1000/5 = 200x.  Adding the 2x unit ahead of the eyepiece doubles the magnification of each combination.

I would start with the 25mm and try and get Saturn or Jupiter first.  Remember, they're very low in the sky, so you'll have to work quickly after sunset to catch them at all.  Also, you'll need a clear sight line to the southwestern horizon.  At 40x, Jupiter's moons and Saturn's rings should be obvious.  By the sound of it, you might just be looking at stars in the vicinity instead and need to get the finder scope adjusted to make sure the main scope is on target as mentioned above.

Once you've got one of them for certain at 40x, try moving up in power to the 9mm and then 5mm eyepieces.  You could also try the 25mm or 9mm with the 2x element for 12.5mm and 4.5mm equivalents.  The 5mm plus 2x isn't going to work well in your scope, so just avoid that combination.

[Space Hopper]

Hi

This is a Meade reflector 4.5" by the sounds of it.

The 114mm (4.5") is the diameter of the primary reflecting mirror (at the bottom of the tube.)

The 1000mm is its focal length (from the primary to the eyepiece focus, via the secondary mirror)

The f 8.8 is your focal ration  : the focal length divided by the 114 primary

Even using your 25mm lens this will give you 40x magnification (The focal length of the scope divided by the eyepiece size so 1000 / 25 = 40x)

So your Ma 9mm wil give you 111x

This will be plenty and like David says will show you Saturns rings and Jupiters 4 moon, maybe the red spot and some banding as well.

 

The problem is both Jupiter and Saturn are almost gone now, on the other side of the sun in their orbits and won't be visible till spring, then as early morning objects. 

[JOC]

It is worth a look at the pictures on the first page here:

As written above there is a theorectical maximum magnification for a telescope.  In the UK under our often poor viewing conditions I tend to find with my telescope that the practical viewing maximum is about half that of the theoretical maximum.  Thus, for my 1200mm reflectors I find that anything above about x200 is pushing it.  Saturn and Jupiter might also be sharper at lower magnification and sometimes sharper and smaller is better at seeing things than less sharp and larger.   As written above a 9mm or 10mm Eye piece is probably sufficient for you to see what we all want to see - those rather smart rings around Saturn.  Just because telescopes are sold with all these fancy attachments, ridiculously small eyepieces, x some amount converters and massive spiels about what this might allow you to see, the reality is probably not anywhere close!  Lower your expectations and leave half the kit in the box and you might get somewhere.