Which XW ?

[vlebo]

I will be soon be able to buy some astro gear after having sold off my equipment last year. I have decided on a 12" dob ( probably Flextube ) and was looking for advice regarding eyepieces. I have 3 Pentax XW's ( 30mm, 20mm and 10mm ) and was thinking of completing my set by by getting two more. Given the choice and having the three I already have which two of these three would you go for XW 7mm , XW 5mm or XW 3.5mm ?

Thanks in advance

[Damo636]

With my 12" the 7mm (214x) gets used most nights. Although I plan adding the 5mm at some point, I'm in no hurry as 300x would only be useable on the very best of nights. In your case I would add the 7 & 5mm.

[Mike73]

If you just want to stay with the XW range then I'd go for the 7mm, like Damo says x214 is a very handy mag to have.

However the Delos range are also very nice EP's, I prefer the views from my 8mm Delos compared to my 7mm XW. XW's seem to have slightly better contrast but Delos are pin sharp but are a bit more fussy about eye placement. The Delos build quality wins for me as my twist up eye cup on the 7mm XW has lost its smoothness and has got a worrying wobble to it.

[alan potts]

I would not do that I would go for 14mm and 7mm myself as i believe you could use the 7mm most of the time The 5mm would be a bit more limited by seeing. If I am honedt I would get all three. For me the 3.5mm would be only a very rare visiter to the focuser.

Alan

[John]

I've currently got the 5mm and 3.5mm XW's and they are superb but are much more useful with my 663mm and 900mm focal length ED refractors than they will be with my 12" F/5.3 newtonian, when I get it mounted.

In your case the 7mm XW would make sense and maybe the 5mm for the best nights. I've read a lot about field curvature with the 14mm XW which makes me a little nervous about that one but I'm sure there are very satisfied owners of it too. I think it suits certain scope designs better than others, perhaps ?. The 10mm XW is an absolute gem and the best of the series possibly. The XW's don't use a consistent optical layout throughout the range though.

[rwilkey]

I would just go for the XW 7mm, you won't get much use out of the other two I don't think.

[scarp15]

I have recently purchased a 7mm for my 300p flextube, although in my case a second hand nagler T6 (as yet though unused on this scope). Like all the other comments I considered that at 214x it will receive a decent amount of use.

[John]

I have recently purchased a 7mm for my 300p flextube, although in my case a second hand nagler T6 (as yet though unused on this scope). Like all the other comments I considered that at 214x it will receive a decent amount of use.

You will enjoy that one

[vlebo]

If you just want to stay with the XW range then I'd go for the 7mm, like Damo says x214 is a very handy mag to have.

However the Delos range are also very nice EP's, I prefer the views from my 8mm Delos compared to my 7mm XW. XW's seem to have slightly better contrast but Delos are pin sharp but are a bit more fussy about eye placement. The Delos build quality wins for me as my twist up eye cup on the 7mm XW has lost its smoothness and has got a worrying wobble to it.

i think i will stick with the XW range as I am a spectacle wearer and find the 20mm eye relief very comfortable to use.

[vlebo]

I would just go for the XW 7mm, you won't get much use out of the other two I don't think.

That had crossed my mind but the intention is to leave my light polluted Middlesex patch and occassionaly try and find some dark sites where I could possibly get to use the 5mm as well. i think the 3.5mm may be asking too much unless anyone has any experience of one?

[Sarah]

I have never had a sharp view with our 5mm Radian through our 12" flextube. Hubbie has only had one clear sharp view with the 5mm, on one exceptional night at Kelling. We have mainly used the 8mm, although we have sometimes barlowed our 13mm Nagler to get 6.5mm.

[Damo636]

i think i will stick with the XW range as I am a spectacle wearer and find the 20mm eye relief very comfortable to use.

The Delos also have 20mm of eye relief and a height adjustable eyecup. I would agree with Mike, they are amazingly sharp across the fov, and although maybe not quite as comfortable to use as the XW, there's not a lot in it. I plan to reacquire the 6mm whenever I can afford it, they are the perfect range to fill the gaps in the XW's.

[John]

That had crossed my mind but the intention is to leave my light polluted Middlesex patch and occassionaly try and find some dark sites where I could possibly get to use the 5mm as well. i think the 3.5mm may be asking too much unless anyone has any experience of one?

Well I have an XW 3.5mm but it does not get used in my current 10" F/4.8 (342x) and the situation may well be the same in the 12" F/5.3 that I'm setting up (454x).

It's a great eyepiece though and ideal for my faster refractors

Edit: I've just realised that the above repeats my earlier post in this thread. Sorry about that - doh !

[vlebo]

The Delos also have 20mm of eye relief and a height adjustable eyecup. I would agree with Mike, they are amazingly sharp across the fov, and although maybe not quite as comfortable to use as the XW, there's not a lot in it. I plan to reacquire the 6mm whenever I can afford it, they are the perfect range to fill the gaps in the XW's.

Looking at the Delos range they do seem to fill the gap of the XW's and with 20mm eye relief may be a good alternative. I will probably go for the XW 7 and 5mm but will also look at the Delos range. Thanks

[rwilkey]

I bought an SW 3.5mm and have never used it in anger to be honest, waste of time and money I admit.

[John]

I bought an SW 3.5mm and have never used it in anger to be honest, waste of time and money I admit.

I tried one of those in my ED120 at the SGL Star Party earlier this year. It showed Mars rather nicely I thought

Might be too much for your ED100 though, apart from tough binary stars where very high power can sometimes be useful

[alan potts]

I am still wondering about getting something in this neck of the woods. At the moment I have a 4mm Radian as my shorest eyepiece that gives me x200 ish in the APM and x250 in the M/N 190mm, though I can never remember using it. I don't if it will be the 3.5mm Delos or 3mm Radian (or both)

Alan.

[RikM]

The 7mm XW is a peach. I have 7, 10, 14 and 20mm and use them mainly with my 10" Skyliner. I can definitely see a 5mm XW in my future.

[John]

I am still wondering about getting something in this neck of the woods. At the moment I have a 4mm Radian as my shorest eyepiece that gives me x200 ish in the APM and x250 in the M/N 190mm, though I can never remember using it. I don't if it will be the 3.5mm Delos or 3mm Radian (or both)

Alan.

Don't rule out the 3.5mm Pentax XW Alan

I was in two minds when I sold my Nagler T6 3.5mm to move to an XW but I've had no regrets. It's like a 70 degree orthoscopic with 20mm of eye relief

[Naemeth]

I'd say the 7mm would probably be best, if the conditions were right you could always use a 2x Barlow, if you have one of course. Otherwise, it would have to be the 5mm, best balance of both.

[Dunkster]

I'd go for the 7 also. Regardless of where you view from, the seeing is more likely to influence how useful the higher magnifications are than the darkness.

[vlebo]

I'd go for the 7 also. Regardless of where you view from, the seeing is more likely to influence how useful the higher magnifications are than the darkness.

Thanks for the input , looks like the 7mm is a cert and I am thinking 30, 20, 10 and 7 may probably be enough with seeing conditions over here being what they are, but while I am still in this position ( not for long with Christmas round the corner ) I may still go for the 5mm and hope to be able to use it occassionally in the Dob and sometime in the future may get a 120mm ED which it may be more suited to.

[vlebo]

I have just been on TH website and they have the Delos range with a 10% discount so the 8mm and 6mm come in at £533.90 only £25 more than the Pentax 7mm and 5mm. Confusion beginning to set in . I wish there was some way of comparing them side by side before I pull the trigger.

[S.A.M]

I personally would go with the 14 and 5mm eye pieces, getting more mag for your money is not everything, especially if the seeing conditions are not 100%. I have the 14 and use it a lot on my Meade LX90, do not use the 10 much but use the 20 more than the 10 but lest than the 14. hope this is on some help to you.

[Damo636]

A rule of thumb I have followed putting together my eyepiece collection, is to have roughly a 1.4x progression from low to high power. In my case I have a 31, 21, 13, 10 & 7mm lineup and still want to add a 5mm to complete a set, (as a minimum) even though it will only get used nights when seeing permits. (300x)

At a push, I could probably skip the 13mm if I had to though, as the 10mm is a perfect mid-high power workhorse at 150x 2mm exit pupil in a 12" f5 scope. If I were in your shoes and had the option of adding two now, I would definitely add the 7 & 5mm and think about the 14mm at a later time.