120ED and Baader genuine ortho

[moriniboy]

Been looking at the 7mm version for planetary work based upon the NAA Telescope Math Calculator findings.

Has anyone had any experience using the 5 and 6mm with this scope, does it push it too far?

I have a set of Hyperions, the smallest being 10mm so the DSO's are covered by them.

Thanks Nigel

[MjrTom]

No experience of the ED120 but I do use the 9mm, 7mm and 5mm BGO with my 102mm f/10 refractor (1000mm focal length)

They are perfect for me giving 111x, 143x and 200x respectively and form the basis of my planetary eyepiece collection.

[newman]

Both 5 and 6mm should be usable - I assume it's the 120/900 ED. Of course, the worse seeing gets, the less magnification you will be able to use effectively. The only problem is the ortho's tight eye relief at those focal lengths. If you're not bothered by it, go for it. Otherwise, barlow something to get the same magnification

[John]

I have an ED120 and I've been using a "low glass" selection of 6mm and 5mm and occasionally even 4mm eyepieces extensively on Jupiter over the past couple of months. The Baader Genuine Orthoscopics work very well indeed with the scope although they have the normal orthoscopic traits of tight eye relief, small eye lenses and relatively narrow fields of view. I have a TMB Supermonocentric in the 5mm focal length which is a highly specialised planetary eyepiece but with a miniscule 30 degree field of view. Wonderful sharpness, contrast and light scatter control though. In the 4mm focal length I have been using a Circle-T orthoscopic and a 4mm Skywatcher Nirvana so two real extremes there but both pretty compentant though not quite rivaling the Baader GO's or the TMB Supermono for contrast and light scatter control.

Generally I find 180x (5mm) the optimum for teasing detail from Jupiter with this scope although the 4mm's have done well on Mars as it's starting to rise earlier. I'm expecting Saturn to respond positively to a little more magnification than Jupiter, from previous experiences.