1. Eyepiece for a Scope

Hi my name is Ray and i am new to this ... i jumped in with both feet and no life jacket .. i purchased a 60mm lense and frankensteined a telescope out of it .. worked pretty good i might say considering i don't know what i was doing ... i started with a piece of pvc pipe about 36 inches long .. no focus point .. so i cut some off until i was able to focus in the moon .. i saw craters and it was awesome ... don't know what i have but it was cool to be able to do it myself ....

I recently purchased a Meade 4.5 inch F4 telescope spherical mirror kit with secondary and holders 4.5" it states that The mirror cell and spider are made to attach to a 5.25" outside diameter tube. so i am thinking that if i get a pvc pipe that is 5 1/4 inches . i can attach that to it .. now the question is what kind of eyepiece can i get or should i get to be able to use this .. i have no problem stepping my self down to get the focus down.

BTW is there another way to determine how to figure out the focal length with just the primary and secondary mirrors?

Thanks in advance for you help

Ray

2. Re: Eyepiece for a Scope

Here is a handy calculator if you don't feel up to doing the math.
Telescope Optics Formulas with Calculators

3. The Following 2 Users Say Thank You to Alpha Tauri For This Useful Post:

EyeLostMyMind (12-04-2012),j.gardavsky (12-04-2012)

4. Re: Eyepiece for a Scope

The thing that makes the eyepiece go up and down to get it into focus ... where might i find one and what kind should i get for this particular set up ?????

Thanks for you prompt response ....

Ray

5. Re: Eyepiece for a Scope

Originally Posted by EyeLostMyMind
I recently purchased a Meade 4.5 inch F4 telescope

...

BTW is there another way to determine how to figure out the focal length with just the primary and secondary mirrors?
Focal length is aperture x focal ratio. 4.5" x 4 = 18"

6. Re: Eyepiece for a Scope

You might also want to check this out for calculating the dimensions of your scope: Newt for the Web

As for focusers, for a 4" f/4 I'd suggest a crayford style like this one: GSO Crayford Focuser for Reflectors - Single Speed Really a 1.25" focuser would be sufficient, but if you go ahead and get a 2" focuser, you can use it on a larger scope if you decide to build one later. It also allows you to use 2" widefield eyepieces.

Finally, for eyepieces, you probably would get some good mileage out of a kit like this one: Meade Series 4000 Eyepiece & Filter Set Telescope accessory kit

Since you clearly like to experiment, this would give you a wide range of eyepieces to try. Note that your f/4 will likely exhibit a fair amount of spherical aberration and coma at the edges of the field. You can mitigate the effects of this to some degree with high-end eyepieces, but it sounds to me like you're more interested in tinkering with some stuff that isn't too expensive for the time being.

If \$200 for a full eyepiece kit is a bit to spendy for the moment, I suggest you pick up a few GSO Plossls at the following focal lengths:

• 4mm: maximum magnification (1mm exit pupil) (note the eye relief on this will be really uncomfortable)
• 9mm: optimum magnification for DSO observation (~2mm exit pupil)
• 15mm: midrange magnifcation (3.75mm exit pupil)
• 25mm: low magnification (6.25mm exit pupil)

All four of these eyepieces are available for under \$40 each here: 1.25" Eyepieces - Eyepieces

As you can see, the kit (which contains these eyepieces, and more) is about the same price as buying all four of the GSO eyepieces individually.

7. The Following User Says Thank You to skaven For This Useful Post:

EyeLostMyMind (12-05-2012)

8. Re: Eyepiece for a Scope

Thank you for that info ... the website only had a focuser for a 6" 8/10" ... would i be able to use a 6" for a 4.5 inch mirror ????

Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•