Eyepiece advice

[Padtwo]

I have a flextube 130p and am looking for a couple more eye pieces. Those I have are the 32mm and 15mm celestron omnis and a 9mm circle T. I also have the Baader Q turret barlow.

From my calculations that would give me approximately 20x, 43x, 72x and 46x, 98x and 163x with the barlow (without taking it apart to get the 1.3 mag).

I would like something in the 130x range and also something to get me in the 200x range. 

Eye relief although not necessarily a problem would be nice to have and my interest is initially planets, then moving onto dsos.

My dilemma is if I go for a 5mm which would give me 130x, with the barlow it would be too much, so a 7mm would barlow up to 209x but would give me 93x which I've pretty much for covered already, which would leave me with a 6?

Alternatively a 12mm would fill a couple of holes and then a higher power piece to be used in its own. (probably a wide angle one as I'm finding these things move quite quickly at higher mags!)

I've been looking at the star guiders, xcel lx, nirvana and slvs so far. 

Any help or ideas would be much appreciated

[Louis D]

Let's say you want to stop at 0.5mm exit pupil, that would be 130mm/260x or a 650mm/260x=2.5mm eyepiece.  This power would mostly be useful on the moon and for double star splitting.  For planets, I would back off to no smaller than a 1mm exit pupil with a 5mm eyepiece to maintain decent, though not exceptional, contrast.  This equates to 130x.

The 5mm BST Starguider is a very good performer for not a not of money.  I'd start with it and see how you like it.

[KP82]

Based on the usual seeing condition we have in the country, we don't have many opportunities to use super high power. So if I were you, I wouldn't worry about the 5mm + barlow being too much. Just get the 5mm for 130x.

For high power planet viewing, I'd strongly recommend you get a tracking mount rather than an ultra wide angle eyepiece. The 5mm BST suggested by another member is a very good option although some purists would probably suggest an ortho. If you do end up getting a high power ortho, a tracking mount will be even more crucial because narrower fov from the eyepiece means you will need to move the mount a lot to follow the target and that means a lot of vibrations from your hands.

Edited November 21, 2020 by KP82

[Padtwo]

Thank you for the replies. Exit pupil is something to think about and I'm tentative about a higher power ortho as although I don't need glasses at the minute, it might not be long. Plus I enjoy showing others what you can see and they need glasses. So I think a 5mm bst with a bit of eye relief may be the way to go, thank you.