Telescopes

Archive for the ‘Telescope Eyepiece’ Category

Taking time to invest in a new eyepiece, i was wondering which would be better suited. I am currently interested in getting Saturn a little closer than what i see in my f/5 8" Dob with my 25mm sirius plossl. I was wondering would it be better to view Saturn through a TeleVue 15mm Plossl with/without a 2x barlow, or a 9mm Orion Edge-On Planetary eyepiece.

The TeleVue goes for $75, has 4 elements, an apparent FOV of 50 deg, is fully multi-coated, and has a 10 mm eye relief. This eyepiece boasts a great all around eyepiece that lives up to the TeleVue standard for quality for the money.

The Orion Edge-On Planetary goes for $105, but is on sale for $85 (which makes me sorta lean towards buying this one on opportunity), has 7 elements, fully multi-coated, apparent FOV of 55 deg, has a 20 mm eye relief. This eyepiece boasts that it has a flat-field design that is sharp to the edge, and boasts that barrel distortion and field curvature commonly seen in standard eyepiece designs are gone.

With these details, which do you think is the better buy?

You have done much of your homework and both of these are good choices. If I had to choose, I would go with the Orion because of the excellent edge on reviews and because of the well known customer service reputation provided by Orion. http://www.orionTelescopes.com/

Skip the Barlow no matter what brand you choose. Added pieces of glass just add more distortions to your image, and if you have well trained eyes, you will not like what you see.

What is the magnification of a Telescope with an objective of 4000 mm and an eyepiece of 26 mm?

No idea, some pre-lab question, not in textbook, TA said "use the Internet"

4000/26

i have a dobsonian Telescope with 8 inch aperture and 1200m focal length. i also have a 25mm eyepiece to go along with it. i wanted to buy a new 7.5 mm eyepiece but i have gotten a lot of reccomendations for a barlow lense but i still want the closer magnification and 12.5mm just wont do it for me. so which is the best options out of these?

7.5mm eyepiece
17mm eyepiece with 2x barlow
12.5mm eyepiece with 2x barlow

ignore price, because that is not really an issue at this point. i was told that if i were to use a 7.5 mm eyepiece then i would end up putting my eye forcefully up against the eyepiece, and that a barlow would eliminate this problem. if i were to get a 12.5mm eyepiece with the 2x barlow would that be too much magnification compared to 7.5mm without a barlow? and with a 17mm eyepiece with a barlow would that also be too little compared to a 7.5 mm lens? do i even need a barlow or should i just go straight for the 7.5 mm? also, what type of barlow do you reccomend? i have gotten suggestions to buy from antares. could you post a link if you know an online source?

This is what I and many others consider a well made eyepiece-
http://www.telescope.com/control/product/~category_id=eyepieces/~pcategory=accessories/~product_id=E0014

Kinda pricey but worth every penny
Wally