Pentax 10mm XW (Second light)

[25585]

8 hours ago, Alan White said:

I am working on fund raising for the 7 and 5 now John,

Christmas is so over rated, it’s the thought rather than size of present that counts.......

or Christmas Beans on Toast, these big meals are so over rated too.....

Turn off the heating for January......hmmmmm not so sure on this one?

I would say 7mm if you have to choose Alan. A barlow with the 10 will get you a 5mm equivalent. The 7mm with a barlow gets 3.5 fl. 

 

 

[Alan White]

14 minutes ago, 25585 said:

I would say 7mm if you have to choose Alan. A barlow with the 10 will get you a 5mm equivalent. The 7mm with a barlow gets 3.5 fl. 

 

 

My thoughts exactly.

 

[F15Rules]

1 hour ago, Alan White said:

I would say 7mm if you have to choose Alan. A barlow with the 10 will get you a 5mm equivalent. The 7mm with a barlow gets 3.5 fl

+1 for that logic.

I can barlow my Pentax XL 10.5mm to c 5mm (Baader x2.25 Barlow) and I've just bought a 7mm XL which I can Barlow to c3.1mm ?.

Dave

[John]

Personally I prefer not to barlow now. If I did, with the XW's I think I'd be using a Powermate to maintain very fine optical quality in the optical train and to avoid lengthening the already generous eye relief beyond the reach of the adjustable eyecup.

 

[Alan White]

54 minutes ago, F15Rules said:

+1 for that logic.

I can barlow my Pentax XL 10.5mm to c 5mm (Baader x2.25 Barlow) and I've just bought a 7mm XL which I can Barlow to c3.1mm ?.

Dave

Sound logic indeed.

So that was you who pulled the trigger on the 7xl Dave, I was about to go for it, when it was posted sold.

I have barlowed the 10mm with my TV 2x Barlow and was able to use it ok, I don’t like Barlow but needs must sometimes.

[Timebandit]

 

Well worth the effort of going without a few luxuries to get a mini set of Pentax XW IMO. It took me best part of two years to complete my mini set of XW 3.5 , 5 , 7, and 10. But what a great set of eyepieces I now have. I Have never thought of ever parting with any of these ,so that tells you what my opinion of the XW mini set are?

IMO I would not Barlow them , not only will you start to get a reasonable high stack effect. But to pay the optics justice you will need something top of the range like a powermate, and these are not cheap, and the stack will be on the tall side IMO

Well worth just going for single eyepieces in the XW range and get yourself a mini set of some of the best optical performance on the market, combined with 20mm eye relief and 70d fov , these eyepieces will last you a life time so well worth the effort? 

 

 

[Ricochet]

I use a Meade 2x TeleXtender with mine and after flocking the section between the two lens groups to get rid of reflections I don't think it degrades the image. The stack height isn't too bad either. The TeleXtender adds ~60mm but the shorter XW's are taller so it works out at ~40mm additional height. Besides, £50-£75 on a TeleXtender vs £300-£500 on a pair of shorter eyepieces is a considerable saving.

 

[25585]

13 hours ago, Timebandit said:

 

Well worth the effort of going without a few luxuries to get a mini set of Pentax XW IMO. It took me best part of two years to complete my mini set of XW 3.5 , 5 , 7, and 10. But what a great set of eyepieces I now have. I Have never thought of ever parting with any of these ,so that tells you what my opinion of the XW mini set are?

IMO I would not Barlow them , not only will you start to get a reasonable high stack effect. But to pay the optics justice you will need something top of the range like a powermate, and these are not cheap, and the stack will be on the tall side IMO

Well worth just going for single eyepieces in the XW range and get yourself a mini set of some of the best optical performance on the market, combined with 20mm eye relief and 70d fov , these eyepieces will last you a life time so well worth the effort? 

 

 

For shorter FL eps, the extra eye relief from a Barlow is small compared to longer ones. 

That aside, price for top end Barlows & Powermate's etc can be more than an extra ep sometimes, but the former are good when extra eye relief is needed. 

 

[John]

The effect on the eye relief depends on the focal length of the barlow lens as well as that of the eyepiece. The "shorty" types of barlows increase eye relief more than longer designs. So a short barlow used with a longer focal length eyepiece gives the maximum eye relief change.

I wish I had a neat "sliding scale" type diagram to illustrate this, but I don't

[YKSE]

2 hours ago, John said:

The effect on the eye relief depends on the focal length of the barlow lens as well as that of the eyepiece. The "shorty" types of barlows increase eye relief more than longer designs. So a short barlow used with a longer focal length eyepiece gives the maximum eye relief change.

I wish I had a neat "sliding scale" type diagram to illustrate this, but I don't

Is this graph sort of you're thinking about?

Edited December 19, 2017 by YKSE
PS: The graph is based on 2x barlows, therefore the barlow focal length equal the phisical length

[25585]

2 hours ago, John said:

The effect on the eye relief depends on the focal length of the barlow lens as well as that of the eyepiece. The "shorty" types of barlows increase eye relief more than longer designs. So a short barlow used with a longer focal length eyepiece gives the maximum eye relief change.

I wish I had a neat "sliding scale" type diagram to illustrate this, but I don't

Lengthening must effectively be what a Powermate does with its extra optics I guess. 

[Louis D]

1 hour ago, 25585 said:

Lengthening must effectively be what a Powermate does with its extra optics I guess. 

Telecentric magnifiers work by returning the light bundle to the same cone angle it was before the diverging element by adding a converging element.  The effective focal length on that chart would be very, very long indeed.  The effect is such that there is little to no extension of the exit pupil or vignetting of the outer regions of the FOV.

[YKSE]

8 minutes ago, Louis D said:

Telecentric magnifiers work by returning the light bundle to the same cone angle it was before the diverging element by adding a converging element.  The effective focal length on that chart would be very, very long indeed.  The effect is such that there is little to no extension of the exit pupil or vignetting of the outer regions of the FOV.

That's assuming it's a true telecentric, which is not always the case. There're report that ES 3x tele-extender has decreased ER. I would not be surprised there're powermates which have increased/decreased ER too, though milder than a barlow does.

[25585]

Not with Tele Vue, but in respect to Pentax XW, one argument in favour of "gotta buy 'em all" is how long the eps will be made. 

Already the 30 & 40 have gone, & all XL seemingly. 

Vixen discontinued their LVW range. 

If enough equivalent cheaper Chinese eps affect sales, the remaining XW range may go. 

[Louis D]

The word is that the Pentax XW 3.5 mm and 5 mm were discontinued last year and dealers will be selling out their stock.

[25585]

12 minutes ago, Louis D said:

The word is that the Pentax XW 3.5 mm and 5 mm were discontinued last year and dealers will be selling out their stock.

I have the LVW 3.5 & doubt it will be used much. But am glad I bought the 5mm XW now. 

Checking Ricoh though 3.5 to 20 are all listed. 

 

Edited December 20, 2017 by 25585

[mikeDnight]

On 23/11/2017 at 17:49, Alan White said:

Second light with my XW as it got dark this afternoon and before the cloud rolled in from the east.
I used my ED 80 and did some lunar observing, having worked from home today I was ready to roll at 4.15.

What a comfortable eyepiece it is, at native 10mm a nice 60x and what a sharp and enjoyable view.

Mare Crisium, Mare Fecunditatis  very defined with some very fine detail visible.
Mare Crisium gave up its four small craters well and the raised peaks.

Decided to do something I do not normally do and Barlow it with my 2x Televue Barlow, wow. 

120x with the Barlow and as good as at 10mm 60x just bigger, probably at edge of the seeing for me today though, or so I thought: 
then I did something wild and set the barlowed ep into my tal 2x barlow, wow again, still held together but getting rough at something like 200x?

Rolled it back to just the 10mm and brighter and crisper due to the magnification and fine eyepiece.

This are the best lunar views I have had, ever, the XW is that good.

I have been using TV plossl and also Tak LE So was very surprised by the view.

The eyepiece is so comfortable, eye placement is simple and just so nice to use.
Makes me a very relaxed observer and that makes for good observation when conditions allow.  
Clearly this may vary from person to person.

I never believed eyepieces could be so different until the last 12 months when I have moved through a number and getting more expensive.
Now at Pentax XW and Vixen LVW and can see a lot of selling going on and a little buying with the resulting funds.

Did I saw WOW?   

Alan, you NEED them all!

When I wanted XW's I contacted FLO, some years ago now, but the 5mm wasn't in stock. Steve assured me I'd love the 3.5mm, so desperate to buy something I bought it. In my mind I thought it would be a bit over the top power wise, but I was SO wrong. Later I bought the 5mm, then the 7mm, then 10mm, 14 and 20. If I were to omit one it would be the 14mm purely because its too close to the 10mm, which is an amazing eyepiece. The 10mm XW was my favourite fuzzy finding eyepiece when contrast was needed to really dissect an object. The e & f stars were easily visible almost every time when using the 10mm in my Tak FC100DC. The 20mm, which you also NEED, is stunning on objects such as M42. My heart rate has increased noticeably since you got me thinking about the XW's! 

It's only money!!

[25585]

Glad the XW 20mm is good for you after varying reports. My LVW 22mm rocks!

Yet to be tested the 20mm 2 inch 80 deg from Orion, also Lanthanum - a possible rival for 22mm Nagler T4. 

 

[Alan White]

2 hours ago, mikeDnight said:

Alan, you NEED them all!

When I wanted XW's I contacted FLO, some years ago now, but the 5mm wasn't in stock. Steve assured me I'd love the 3.5mm, so desperate to buy something I bought it. In my mind I thought it would be a bit over the top power wise, but I was SO wrong. Later I bought the 5mm, then the 7mm, then 10mm, 14 and 20. If I were to omit one it would be the 14mm purely because its too close to the 10mm, which is an amazing eyepiece. The 10mm XW was my favourite fuzzy finding eyepiece when contrast was needed to really dissect an object. The e & f stars were easily visible almost every time when using the 10mm in my Tak FC100DC. The 20mm, which you also NEED, is stunning on objects such as M42. My heart rate has increased noticeably since you got me thinking about the XW's! 

It's only money!!

Mike glad the XW thoughts have got you pulse rate up, the 10mm does with me.

I am getting closer to the next one, hope Christmas monies will be the final push.

I have since used the 10 in my 150p.newtonian, which is. f5 an it was great with this too, so much so I want the 7 and 5 in 2018.

For longer the 22 LVW is not going, it’s far too good.

Are you still an XW owner, could not see in the eyepiece case pictures?

[mikeDnight]

1 hour ago, Alan White said:

Mike glad the XW thoughts have got you pulse rate up, the 10mm does with me.

I am getting closer to the next one, hope Christmas monies will be the final push.

I have since used the 10 in my 150p.newtonian, which is. f5 an it was great with this too, so much so I want the 7 and 5 in 2018.

For longer the 22 LVW is not going, it’s far too good.

Are you still an XW owner, could not see in the eyepiece case pictures?

Sadly ive no XW's in my possession currently. Im really enjoying some of the simpler, smaller gems that are floating about. When i bought my Tak i sold all my Televue eyepieces. The XW's were my most used eyepieces, so i kept hold of them as they were purer than any of the Televues, and more comfortable to use. One evening i was visiting a friend with my Tak in hand, but id only taken my binoviewer, as we were suposed to be observing the moon and planets. As it happened, we had opportunity to do some shallow sky observing, but as I had no low power eyepieces with me, my friend loaned me a Meade plossl ( I think it was 26mm but can't be certain). I was appalled that he'd even offered the Meade eyepiece to me and complained loudly at the insult. He laught as he knew my views about Meade in general. However, the eyepiece was a real gem, showing a clarity and peppered stardust quality I hadn't seen for a very long time. It was only a 52° apparent field but its real field was still large enough to frame the double cluster with plenty of room to spare. I hate to admit it, but that cheap little Meade plossl thrilled me so much that I decided to go retro and use simpler eyepieces (not Meade) to see if they meet my needs. So far so good! ?

[Alan White]

52 minutes ago, mikeDnight said:

Sadly ive no XW's in my possession currently. Im really enjoying some of the simpler, smaller gems that are floating about. When i bought my Tak i sold all my Televue eyepieces. The XW's were my most used eyepieces, so i kept hold of them as they were purer than any of the Televues, and more comfortable to use. One evening i was visiting a friend with my Tak in hand, but id only taken my binoviewer, as we were suposed to be observing the moon and planets. As it happened, we had opportunity to do some shallow sky observing, but as I had no low power eyepieces with me, my friend loaned me a Meade plossl ( I think it was 26mm but can't be certain). I was appalled that he'd even offered the Meade eyepiece to me and complained loudly at the insult. He laught as he knew my views about Meade in general. However, the eyepiece was a real gem, showing a clarity and peppered stardust quality I hadn't seen for a very long time. It was only a 52° apparent field but its real field was still large enough to frame the double cluster with plenty of room to spare. I hate to admit it, but that cheap little Meade plossl thrilled me so much that I decided to go retro and use simpler eyepieces (not Meade) to see if they meet my needs. So far so good! ?

Interesting and I fully understand your rationale.

I did similar but used Tele Vue Plossls and still do, but I like the longer eye relief at shorter fl and the wider five as I use a manual mount, so nudge and curse.

The XW give that same clarity but with the desired eyerelief and wider fov.

 

[Ricochet]

1 hour ago, mikeDnight said:

Sadly ive no XW's in my possession currently. Im really enjoying some of the simpler, smaller gems that are floating about. When i bought my Tak i sold all my Televue eyepieces. The XW's were my most used eyepieces, so i kept hold of them as they were purer than any of the Televues, and more comfortable to use. One evening i was visiting a friend with my Tak in hand, but id only taken my binoviewer, as we were suposed to be observing the moon and planets. As it happened, we had opportunity to do some shallow sky observing, but as I had no low power eyepieces with me, my friend loaned me a Meade plossl ( I think it was 26mm but can't be certain). I was appalled that he'd even offered the Meade eyepiece to me and complained loudly at the insult. He laught as he knew my views about Meade in general. However, the eyepiece was a real gem, showing a clarity and peppered stardust quality I hadn't seen for a very long time. It was only a 52° apparent field but its real field was still large enough to frame the double cluster with plenty of room to spare. I hate to admit it, but that cheap little Meade plossl thrilled me so much that I decided to go retro and use simpler eyepieces (not Meade) to see if they meet my needs. So far so good! ?

I've never been so grateful to a Plossl . 

[F15Rules]

6 hours ago, 25585 said:

Glad the XW 20mm is good for you after varying reports. My LVW 22mm rocks!

Yet to be tested the 20mm 2 inch 80 deg from Orion, also Lanthanum - a possible rival for 22mm Nagler T4. 

 

Yep, I moved on my XW20 due partly due to its  field curvature (though not as bad as the XW14), but mainly after extensive side by side comparisons with my then newly acquired LVW 22mm on M42. To my eyes the LVW definitely and absolutely is the better eyepiece.

The Pentax short FL versions are superb though (both XW and XL versions). I have today received a 7mm XL and already have a 10.5mm, which is a wonderful eyepiece ?. With a 12mm XF and my Pentax SMC zoom, almost half my EPs are now Pentax..but the LVW22 is a keeper!

Dave

[Highburymark]

2 hours ago, mikeDnight said:

Sadly ive no XW's in my possession currently. Im really enjoying some of the simpler, smaller gems that are floating about. When i bought my Tak i sold all my Televue eyepieces. The XW's were my most used eyepieces, so i kept hold of them as they were purer than any of the Televues, and more comfortable to use. One evening i was visiting a friend with my Tak in hand, but id only taken my binoviewer, as we were suposed to be observing the moon and planets. As it happened, we had opportunity to do some shallow sky observing, but as I had no low power eyepieces with me, my friend loaned me a Meade plossl ( I think it was 26mm but can't be certain). I was appalled that he'd even offered the Meade eyepiece to me and complained loudly at the insult. He laught as he knew my views about Meade in general. However, the eyepiece was a real gem, showing a clarity and peppered stardust quality I hadn't seen for a very long time. It was only a 52° apparent field but its real field was still large enough to frame the double cluster with plenty of room to spare. I hate to admit it, but that cheap little Meade plossl thrilled me so much that I decided to go retro and use simpler eyepieces (not Meade) to see if they meet my needs. So far so good! ?

Until 2013 my eyepiece case consisted only of Meade plossls. Used with a much loved 4" Mak, they were superb. It was only when I bought a solar ha telescope that TeleVue plossls showed a distinct improvement. Sadly I lost that collection of Meade plossls - still miss them. Sorry for derailing thread - but Mike's words struck a chord

[25585]

13 hours ago, F15Rules said:

Yep, I moved on my XW20 due partly due to its  field curvature (though not as bad as the XW14), but mainly after extensive side by side comparisons with my then newly acquired LVW 22mm on M42. To my eyes the LVW definitely and absolutely is the better eyepiece.

The Pentax short FL versions are superb though (both XW and XL versions). I have today received a 7mm XL and already have a 10.5mm, which is a wonderful eyepiece ?. With a 12mm XF and my Pentax SMC zoom, almost half my EPs are now Pentax..but the LVW22 is a keeper!

Dave

How is the zoom performance optically for 10 to 20mm focal lengths compared to the XW 14 & 20? Is eye relief less?