Best 8mm eyepiece for planetary.

[Guest]

I have been experimenting with eyepieces whils observing Jupiter and the moon with my Skywatcher Skymax 127mm maksutov.Eyepieces that I have used so far are TMb 8MM,8mm Vixen npl an unbranded 7.5mm plossl.I an wary of the multi element long eye relief eyepieces where yopu may lose some brightness,bearing in mine that my telescope is 127mm.

The 7.5mm unbranded show the best view so far,brightness and contrast.I feel that an 8mm plossl or orthoscopic would be just right.Any views or advice would be welcome.I was thinking of the Pentax 8.5mm for around £119,but not sure haoow many glass elements it contains.I think that multi element eyepieces for planetary and lunar are fine in larger apature telescopes where ligh grasp is bigger.

Thanks,

Martin.

[John]

I use eyepieces with lots of glass in my scopes down to 4" in aperture but they are expensive ones (Ethos + Pentax XW's) so the amount of glass does not seem to detract from the image. I've compared them to orthos and even simpler types.

On a more reasonable budget however you might want to see if you could find a Baader Genuine Ortho in the 9mm (167x) or 7mm (214x) focal lengths. They cost around £50 each used (not available new now) but probably offer the best performance you can get without spending a very considerable amount more. Like all orthos they do have quite tight eye relief although no worse than the plossls.

Alternatively the BST Explorer 8mm seems to compare very favourably with the Pentax XF 8.5mm in the review discussed in this thread:

[alan potts]

Im my opinion Radian are very good for planetry viewing. as are Pentax. The Meade UWA are very good indeed for the money 5.5mm and 8.8mm. The Ethos 13mm with a powermate is sensational and even better when you take the end cap off. However from good quality, S/H Radian of S/H Meade UWA.

Alan.

[michael.h.f.wilkinson]

I found the Pentax XF8.5 a shade better than the Radian 8mm, and both are very, very good indeed. I have not compared either to a Plossl or Ortho as I do not get along with those at such a short focal length (lack of eye relief).

[E621Keith]

I found my 8mm LVW great for planetary.

Unlike older coatings which can loose a few % of light in each glass air interface, many modern anti reflection coating have over 99%+ transmission. As such the degradation associated with multiple element are reduced to a undetectable level.

Then Pentax XO, one of the best planetary eyepiece in recently years, has 6 elements, which is the same as the XF. The former cost a lot more and Pentax probably put a lot more effort into optimising the coating for the XO, but it shows a well designed 6 element eyepiece can rival the premium 3-4 elements such as ZAO and TMB Supermono.

[Mr Moff]

My favourite planetary eyepiece is the 7mm bgo, which is still available new in most shops.

As Alan says the barlowed ethos 13 is stunning but I'm still a bit scared letting mine sit in a Barlow hanging in there.

[alan potts]

My favourite planetary eyepiece is the 7mm bgo, which is still available new in most shops.

As Alan says the barlowed ethos 13 is stunning but I'm still a bit scared letting mine sit in a Barlow hanging in there.

Mr moff,

Know what you mean about the powermate and Ethos, if it were any longer I would be in a different time zone.

Alan.

[michael.h.f.wilkinson]

Mr moff,

Know what you mean about the powermate and Ethos, if it were any longer I would be in a different time zone.

Alan.

Not as bad as a Speers-Waler zoom in a barlow

[John]

.....The Ethos 13mm with a powermate is sensational and even better when you take the end cap off.....

Oh, I'm so glad I'm not the only one who has done this

I thought I'd got the worst case of rapid dewing up that I'd ever experienced ......... until I saw the lens cap still on the 1.25" barrel of the Ethos ......

[NGC 1502]

Unlike older coatings which can loose a few % of light in each glass air interface, many modern anti reflection coating have over 99%+ transmission. As such the degradation associated with multiple element are reduced to a undetectable level.

Yes, I'm sure this is true. I think that the perception of less light throughput with multi -element eyepieces comes from when they first came onto the market, and lens coatings were not as good as much later coatings. Just use what fits your budget and and usage, and forget about any losses with lots of lens elements. The TV Ethos has around 9 elements, and the light throughput, contrast and sharpness is superb. ( I don't own an Ethos but have looked through the 13mm and 8mm)

Regards, Ed.

[Guest]

I am grateful for all of your input.It is a matter of personal perception.I recently tried out a TMB Mk 2 planetary.It was sharp acroos the field and good eyerelief.But I found it too warm or dim for my liking.I guess that the higher priced multi elements may produce a brighter image.Or it could be that the light gathering power of a 127mm is not that of a 200mm telescope.

Martin.

[alan potts]

Oh, I'm so glad I'm not the only one who has done this

I thought I'd got the worst case of rapid dewing up that I'd ever experienced ......... until I saw the lens cap still on the 1.25" barrel of the Ethos ......

John,

I thought the same, dew what that quick, never, checked the scope, nothing. Then took the eyepiece out checked the 2 inch ring and put it back. By this time it was dark and the Moon was not bright enough for me to see how stupid I was. You don't know how pleased I am to know you did this as well.

Alan.

[Moonshane]

I have 10mm and 8mm Radians and 12.5mm, 9mm and 7mm BGOs as well as a Nagler 6-3mm zoom. I really like the Radians as they give a nice wide field are confortable to use and the provide superb sharpness and details. That said, the view through the BGOs is a little 'whiter' and seems a little cleaner to my eyes. The zoom is basically like a set of plossls with infinite range between them and good 10mm eye relief. If you can use and afford one, it's a truly remarkable eyepiece.

The differences between the above are exceptionally minor though and I hope to never part with any of them.

[Guest]

I am looking to build a set of eyepieces to enjoy using and to truly say that I love using them.I am interested in the Pentax 8.5mm xf.

Thanks,

Martin.

[michael.h.f.wilkinson]

I am looking to build a set of eyepieces to enjoy using and to truly say that I love using them.I am interested in the Pentax 8.5mm xf.

Thanks,

Martin.

There is one going on ABS-UK:

http://www.astrobuysell.com/uk/propview.php?view=60828

[Capricorn]

As has been said modern antireflection coatings are very good, the percentages you are considering is too small for the eye to distinguish in terms of transmitted light.

Scatter and internal reflections are of more concern.

You mention a set of eyepieces, I can only see 2 XF's on the Green Witch Site.

TV plossl's should be good in your scope, if the eye relief is acceptable. To be honest if you actively want to avoid multi element eyepieces the the TV Plossl's are probably one of the better options.

From the selection of eyepieces I ahve it tends to be the TV Plossls or the BST Explorers.

Prefer the BST's at the end of the day, planets come out very good on them, and comfortable to use.

[michael.h.f.wilkinson]

The XF "series" consists of just the 12 and the 8.5, no more.

[E621Keith]

Pentax XF was designed as 'budget' eyepiece for their 65mm spotting scope, so it's only available in two focal lengths. I guess it's to encourage people to buy XWs.

It's a bit annoying because there's definitely a market for a good Japanese made 60deg eyepiece for £120. Look at the popularity of the Chinese made X-Cel LX and BST and you would know. Likewise there is also a market for longer focal length Pentax XO, but Pentax is gradually leaving the astro market after being sold first to Hoya and then to Ricoh.

[John]

Pentax XF was designed as 'budget' eyepiece for their 65mm spotting scope, so it's only available in two focal lengths. I guess it's to encourage people to buy XWs.

It's a bit annoying because there's definitely a market for a good Japanese made 60deg eyepiece for £120. Look at the popularity of the Chinese made X-Cel LX and BST and you would know. Likewise there is also a market for longer focal length Pentax XO, but Pentax is gradually leaving the astro market after being sold first to Hoya and then to Ricoh.

It's a pity the Vixen LVW's are not just a little less expensive. The importer was doing them at 50% discount (£99) at the SW Astro Fair last year and I reckon they were real bargains at that price.

[E621Keith]

It's a pity the Vixen LVW's are not just a little less expensive. The importer was doing them at 50% discount (£99) at the SW Astro Fair last year and I reckon they were real bargains at that price.

OMG, I wish I went to SW astro fair last year. They are real bargain at that price.

Actually when you think about what TV charges for the Radian (£190), the price of LVW (£198) doesn't seems so bad. However compared to the Chinese offerings and the XW, I think Vixen can do with a lower price point of around £160. The LVWs are really good eyepieces in scopes slower than f6 (I haven't tested them in anything faster).

PS.

The OP's scope is a 127 mak, so a Baader Mk3 8-24 zoom could be a good alternative to fix focal length eyepieces.