Merits of 2" eyepieces over 1.25" ?

[Keithaugur]

I'm sure this has been asked here before, but I have been unable to find a definitive answer, if indeed such a thing exists !

I am a new kid on the block and have only been gazing skywards for a couple of months with my newly purchased Bresser Messier AR-102/1000 EXOS-1. As most of you might know, this piece of kit comes

with a chunky 2" diagonal with attached 1.25" converter. All eyepieces I have bought to date have been from the 1.25" stable. Results have been very satisfying,but what advantages would I get if I was to

buy some 2" eyepieces ?

I am aware that they are big and heavy, and more expensive. But why would any manufacturer

including Bresser, supply 2" diagonal if there are no notable advantages in 2" eyepieces ?

I am sure someone out there could enlighten me ?

Regards

[singlespeeder]

To the best of my knowledge with 2" eyepieces you get a larger field of view (which also allows lower magnifications) and also better eye relief.

[John]

The wider field of view is the primary advantage with the 2" eyepiece. The 2" barrel can accomodate a wider field stop so the apparent field of view of a 2" eyepiece can be up to approx 45% wider than that of the same focal length eyepiece in the 1.25" format. You don't tend to find the 2" format used in the shorter focal lengths because there is no point so many folks end up with an eyepiece set comprising 1.25" for the short and medium focal lengths and a 2" or two for lower power, wide field viewing.

The 2" eyepieces tend to cost more than 1.25" ones (more materials used) and weigh more as you might expect. You need to use 2" filter with 2" eyepieces as well so thats something else to consider although 2" filters can serve 1.25" eyepieces too but not the other way around.

[ronin]

I am aware that they are big and heavy, and more expensive. But why would any manufacturer
including Bresser, supply 2" diagonal if there are no notable advantages in 2" eyepieces ?

Simply it is easier, they have to allow a 2" eyepiece to be used and focusers are now not uncommon at 2.5" and 3" - they are stiffer to hang camears off, assume 1Kg for a DSLR.

I have a scope that takes 2" diagonals and I have a 1.25" diagonal, the 1.25" looks stupidly small, and I do mean STUPIDLY.

The other is you have to consider it from a company point of view, if they supply 1.25" and/or 2" they need to purchase 2 diagonals, and fit one or the other depending on the scope model. This way they just purchase 1 diagonal, more of them, likely cheaper therefore. Purchasing in bulk and storage logistics is highly relevant to Bresser/ES/JoC.

The other aspect is - Do you want go and buy a 2" diagonal to use a 2" eyepiece that you have, or would you rather Bresser gave you a diagonal that would do both? Looking at FLO the least costly 2" diagonal there is £91. THe Bresser one may not be as good but it is additional cost to you.

Also there would be an outcry if they only supplied a 1.25" diagonal, so many people would complain.