Eye piece suggestions please?

Question

i just bought an 8" dobsonian (meade lightBridge), it came with only a 26mm wide field eye piece.

im planing to get some higher power eye pieces, can anyone make suggestions please.

i specifically interested in observing the moon + planets.

Answer 1

You have not told us the focal length of the telescope so I cannot help you without that info.

Thanks for the additional info.

If you are using a 25 mm now, that means your magnification is about 40 times.

The Lightbridge should be able to give you 400x no problem (maybe more if the seeing is perfect and the optics are really good). To achieve 400x you will need a 2.5mm eyepiece, but it is also wise to get one that gives about 100X which means a 10mm would be useful.

If I were you I would get a couple of Meade Plossls, say a 9 or 10mm and a 6 or 5mm, and a 2 or 3mm this is what most amaters use, they have a reasonable field of view of about 60% and reasonable eye relief (about 10mm) and at a reasonable price.

If budget is a problem, you can get a short 2x barlow tube which will shorten the 25mm to a 12.5mm giving an increase in magnification to 80x and a 9 or 10mm eyepiece from 100x to about 200-220x.

The magnification is obtained by dividing the focal lenth in mm by the eyepiece size in mm.

I would say that a Barlow tube of 2x or even 3x would be a useful addition to give you additional magnification on all your eyepieces if carefully chosen, and if you need a cheaper solution to give you various magnifications for planets and deepsky objects like galaxuies etc..

Do not go higher than about 400x though as seeing and resolution do not often permit much higher on a Meade, but I have not used one of those so I may be wrong it may be slightly less..

I use a Takahashi 4" f8/f6 and have been to 280x quite often with that at a dark site, which shows fantastic planetary views on a 2.8mm eyepiece.

Let me say one thing though, you will probably end up using the 25mm more often than any other.

Answer 2

For high mag eyepieces, one thing to look for is good eye relief.  Of the various designs, the most common and cost effective one is Plossl.  This design gives good eye relief with reasonable cost.  If you have bucks to spend, get a Nagler.  I've got one wide field Nagler that actually requires me to move my eye around to see the whole field.  It's like watching a movie on a theater big screen rather than on a home TV.  One thing to consider here is Plossl designs tend to use fewer elements which means possibly better contrast.

BTW, if you are going to be looking at the moon, invest in a polarizing filter.  This will cut the brightness some and also improve contrast which will make features stand out without blinding (figuratively) you.

Answer 3

what size focuser?

any decent plossl eyepiece will work well in shorter focal lengths on this telesscope. i have several televue radian eyepieces. they're really cool.

Answer 4

Looks like an f/5 to me! The faster the scope is, the better the quality of eyepiece you should obtain. The maximum magnification for an 8 incher should be around 400 power, conditional on seeing conditions. I wouldn't get anything shorter than a 5 or 6mm EP. You will likely find that your best view of the planets will be well less than 400 x. A good quality 6mm is as low an EP focal length as I would go for your scope. Anything more "powerful" will present an image that flies across your FOV. Good luck---you made a good choice in the telescope you acquired!

Answer 5

a  9 ,10 and a 7 will be awesome , i have the same and it works on all things you will see .

Answer 6

I think the bang for the buck champs on high power eyepieces with good eye relief and a reasonably wide afov are the TMB/Burgess Planetaries.  

They sell for $59 each, and have close to a 60 degree afov.

The problem with Plossl eyepieces is as they get shorter, eye relief becomes very tight.  An 8mm Plossl will have eye relief of about 6mm.  They also typically have a field of view of 50 degrees, so you'll need to nudge the scope to keep things in the field of view more often than you would with a wider field eyepiece.

I have dozens of eyepieces including many that sell for four times as much in the same focal lengths, but still use the TMB planetaries frequently.  They're available in a variety of focal lengths between 2.5 and 9mm.  I'd start with a 9, and if you like it and still want more power, I'd get a 7 next.

You may or may not like barlows.  I only use mine for imaging.  But if you got a good quality 2x barlow, it would give you twice as many magnifications from each eyepiece.