Jump to content

SkySurveyBanner.jpg.21855908fce40597655603b6c9af720d.jpg

Advice on eyepieces for 5" newton telescope


pluton

Recommended Posts

I have a similar set-up with a 3" scope, and it doesn't like Barlows at all.

It struggles to get enough light into the tube, and a Barlow seems to make things worse.

Your 5" will suffer to a lesser extent.

Even so, you should benefit from a sharper / brighter view without the Barlow if you can.

I was trying different eyepiece combinations today using expensive EP's borrowed from my bag of bits.

The 82 degree Explore Scientific was wasted due to the small secondary mirror on the scope.

The 66 and 68o eypieces were the widest I would want to go.

So the 60-degree BST's are good shout.

Link to comment
Share on other sites

The theoretical maximum of the scope is mirror diameter x 0.5 = 260x magnification.

The practical maximum will be nearer 130mm diameter x 0.7 = 180x magnification.

The atmosphere normally limits the viewing to 200x anyway.

A good quality 2x Barlow with a 9mm and 7mm Celestron X-cel will give you 72x / 93x / 144x / and 186x.

http://www.firstlightoptics.com/celestron-eyepieces/celestron-x-cel-lx-eyepiece.html

If you wanted to stick to one brand, the 25mm Xcel will fit in nicely with those two.

I have never used the X-cels, so there maybe better eyepieces out there.

But you will need 3.5mm (or equivalent) for 180x magnification, and the BST range don't do a 7mm.

If it were my money, and I had enough inward focus on the scope, I would get the £32 Revelation 2.5x Barlow (at an actual 2.2 or 2.3x)

And take up RWilkeys suggestion of BST's, but get the 25mm and 8mm. 

= 26x / 57x / 81x / 179x

The best option is for you to try someones 7mm and a barlow.

If you feel ambitious later on, £140 will get you a brand new 3mm TeleVue Radian at 217x (which will be far too much magnification)

http://www.telescopehouse.com/acatalog/TeleVue_Radians.html

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.