Jump to content

Banner.jpg.b83b14cd4142fe10848741bb2a14c66b.jpg

1.25" versus 2" eyepieces

jammin63

Recommended Posts

jammin63

jammin63

Posted
Posted

Alright, I might change my icon to a dunce cap for all the dumb questions I'm gonna post, but there doesn't seem to be any sets of 2" eyepieces for sale anywhere, they are all 1.25"? My brand new Meade LXD-75 152/762 Newtonian reflector with Autostar has asked Santa for a set of eyepieces, reminding him that he has an adapter for 2" eyepieces. Seems the larger diameter is preferable from a purely technical standpoint, but where can I get them? And do I need/want them, are they worth it, or are the 1.25" good enough? I'm zeroing in on a good set (Plossls, thanks to those who chimed in with my other question), courtesy of Steve. So, how do I change my name? Thanks all.

Link to comment
Share on other sites
  • Replies 45
  • Created
  • Last Reply
FLO

FLO

Posted
Posted

In truth, there is a lot to be said for having all your eyepieces the same 1.25" fitting: It is quicker to move up and down thru the set without a 2-1.25" adapter.

Having said that, it is not really practical (possible?) to make a 1.25" low magnification eyepiece with a wide-field (the 1.25" hole at the front restricts the view) and there is something truly wondrous about sweeping the Milky Way with a 30-40mm wide-field eyepiece 8)

Link to comment
Share on other sites
FLO

FLO

Posted
Posted

The eyepiece barrel will have an inner diameter of 50.8mm.

Look for a 2" eyepiece with a focal-length of around 30mm and a field of view around 60-70 degrees.

Good eyepieces are available for about £50 (PM me for details).

If your budget permits, consider also:

http://www.firstlightoptics.com/proddetail.php?prod=ms500032sp

Or even:

http://www.firstlightoptics.com/proddetail.php?prod=ms500028swa

Link to comment
Share on other sites
FLO

FLO

Posted
Posted

Had a few 2" eyepieces and only one was truly great but that wasn't even a widefield eyepiece. All have suffered from the same problem. Work well in an f10 SCT or MCT but are shockingly awful in an f5 newtonian or refractor.

Quality is reflected in the price.

Can't comment on those Meade 5000's but my guess, looking at the price, they are pretty good.

Top drawer 8)

The Norman Lockyer Observatory (above Sidmouth) bought a set of SWA eyepieces recently so I have the pleasure of using them most Friday evenings - weather permitting.

(If anyone would like to meet me there, PM me for directions).

Link to comment
Share on other sites
Stardust

Stardust

Posted
Posted

I've also been wondering what the advantages are of the 2" jobs. I'm using some Pentax eyepieces with 65 & 70 degree field that I really like. I'm tempted by the likes of revelation for a low power eyepiece, but just how good are they?

What's the contrast like and are they fairly sharp accross the field, they seem incredibly cheap.

thanks

DAve

Link to comment
Share on other sites
FLO

FLO

Posted
Posted

They won't stand up to your Pentax eyepieces (being 5x the price, you probably guessed that).

If you have a scope with that is f6 or slower, you will be surprised at just how good they are and how much you are getting for your money. Otherwise, save your pennies and buy a Meade/Pentax/Televue.

Link to comment
Share on other sites
Andrew*

Andrew*

Posted
Posted

If I get the SkyWatcher 200, I'll probably straight afterwards go for a nice low powered eyepiece to go with it. It's got a 2" focuser I believe, and it's f/5, so what's your recommendation for a nice sharp EP? I don't so much need a huge FOV, just so long as it's fairly sharp edge to edge. I don't really want to spend more than £50 on one, adn I'm looking for something above 30mm.

Andrew

Link to comment
Share on other sites
jammin63

jammin63

Posted
  • Author
Posted

Hi all, thanks for all of the input, it sounds like the 1.25 sets are the way to go, at least for a newbie like me, for now.

Amazon.com in the US is offering a Celestron eyepiece kit (Five superior grade Plossl eyepieces, all fully multi-coated for maximum contrast and resolution; 2x, 1.25-inch Barlow; Six colored eyepiece (planetary) filters, 1.25-inch Moon filter) for $130, it was $99 earlier today!!!

Are these decent enough to start with? OK it's in the US, but I'm traveling there early next year, not sure if its worth purchasing there to save the money, since I'm nearly tapped out for this year? Are there any service issues with eyepieces where I would need to send one back for servicing, meaning a warranty claim? Maybe I'll take Steve's kit, once he tells me how much to send it to France :sunny:, then I don't have to worry about support.....

Link to comment
Share on other sites
FLO

FLO

Posted
Posted

I don't really want to spend more than £50 on one, and I'm looking for something above 30mm.

The revelations are excellent value but be aware that the FOV drops from 70 degrees on the 26 and 30mm to 65 degrees on the 42mm and 55 degrees on the 50mm. So, in terms of FOV (actual visible sky) the 42 and 50mm are practically the same.

post-12699-133877325362_thumb.jpg

Link to comment
Share on other sites
John

John

Posted
Posted

Steve

Yep you are very probably right. The TV85 is an F7 scope so I've got to find someone with one of these 2 inchers and pop it in for a look at the very least.

thanks

DAve

I've just had 1st light on my Orion Optiluxe 40mm 62 degree FoV 2inch EP with my WO Megrez 90 APO (f6.9 - similar spec to your TV85) and the results were stunning - I was expecting some compromise on the pinpoint stars towards the final 20% of the field and there was some - but much less than I expected. The views of Orion's sword and the Pleiades were fantastic - you could have fitted the whole Pleiades cluster in about 2.5 times across the width of the field and the background sky was black - a great sight. With the Megrez 90 this eyepiece gives 15.5x and a 4 degree true field of view. I also had a quick look at M31 / M32 and they looked great too - I could make out M110 even though this part of the sky was sliding towards the fog that clouds the horizons here tonight.

The downsides to this eyepiece are - it needs about 30mm more outward focusser travel than my 1.25 eyepieces (fortunately the Megrez has this) and you could really do with a rubber eyecup to help position your eye and keep out stray light. I'm going to sort out the outward travel issue with a extension tube (on order from Aunty Flo). It's not as heavy as many 2 inch EP's - it weighs about half as much again as my Tele Vue Plossl.

Overall - I'm really impressed - I'll add a pic of the eyepiece shortly.

John

Link to comment
Share on other sites
Macavity

Macavity

Posted
Posted

Then there are these "hybrid" eyepieces - like the Baader Hyperions, which fit neatly into either a 1.25" or 2" formats. Personally, I decided to "standardise" on 2" diagonals to SHARE these eyepieces between a MAK and a ST refractor. (I'm on a tight budget!) But having a 2" capability opens up the POSSIBILITIES (without much loss?) should you decide to explore these at some stage... Once you've "balanced" everything for your heaviest 2" eyepiece, just slip in an (almost weight-equivalent) 2" -> 1.25" adaptor + 1.25" eyepiece etc. :lol:

For so-called "fixed" 1.25" setups, there are other ideas: http://stargazerslounge.co.uk/index.php?topic=8788.0 :)

Link to comment
Share on other sites

Archived

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

Go to topic listing

  • 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.