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XW range Combined with the VIP Barlow - Lunar Review

Pig

By Pig
in Discussions - Eyepieces

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Pig

Pig

Posted
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My main objectives for tonight are:

  • To determine how versatile the VIP Barlow is when using a combination of fixed focal length eyepieces and two very different types of telescopes.
  • I also wanted get a feeling of how the Pentax XW's compare to other eyepieces I have owned such as the TV Delos, Nagler, Radian & Vixen SLV

Telescope selection:

  • 80mm Esprit Triplet – Max magnification used 130 X
  • 150mm SCT – Max magnification used 300 X

Eyepieces: Pentax XW’s 20,14,7 & 5mm

Barlow Lens: Baader VIP Barlow – Varying magnification between 1.4 and 2 X

I had to wait until about 1am until the clouds and haze finally disappeared before I could start observing, but it was worth the wait as I was treated to the additional fact that it was a “Blue Moon” tonight or the second full Moon in a calendar month, whichever description you prefer   :laugh:

As you all know a full Moon does not have the added benefit of the fragmented termination profile and thus is probably one of the least exciting phases of the Moon to observe. However, there is always an exception, and in the case a full Moon when viewed at low power it still looks beautifully crisp when set in the centre of the eyepiece. The 20mm & 14mm XW gave the perfect example of this and it appeared as if the moon was simply hanging there in 3D like as if it were a bauble on a Christmas tree.

The views through the Esprit.
From the 20mm all the way through to the 5mm eyepiece the views of the Moon were nothing short of fantastic, the crispness of the few available crater edges were spectacular and the combined white and grey surface contrasts are as natural as one could ask for, be it at high power or at low power. Simply stunning

I used as many combinations as I could betwixt the eyepieces and the VIP and I could not detect any differences in the views with or without the VIP in situ. The views were absolutely perfect and these views were emphasized against what seemed a navy blue painted background sky.

Without having other eyepieces alongside to compare with it is very difficult to make any definitive judgement but what I will say is “I haven't seen views this bright before” even through brilliant eyepieces such as the 6mm SLV or the 3-6mm Nagler zoom.

I observed no distortion to the shape of the Lunar disc until I positioned it at the very edges of the field stop when using the 20mm at which point a very tiny amount was apparent.
To me this is not at all important as I would only ever be observing the Moon with the area of interest positioned centrally within the FOV at this power. However, this may be a more important factor when I use the eyepieces to view star clusters etc…

Viewing comfort is a given with these eyepieces and annoyances such as blackouts and kidney beaning kidney beaning can be simply removed from the equation. This is due to the very fine thread adjustment that can be achieved with the eyecup.

One point to note is that I was unable to achieve focus with the 5mm and the VIP set at the 2X configuration due to lack of inward focus travel. However, after some adjustments to the VIP’s configuration this was rectified and I would say I ended up observing at around the power of a 3mm eyepiece.

Views through the SCT
As expected in an F10 scope all four eyepieces gave excellent results, delivering great natural colour with lovely crisp detailed views. I was able to Barlow all the eyepieces with the exception of the 5mm upon which the views became over magnified and blurred.

The range of magnification was between 1.4 and 2 X and once again as with the Esprit no loss of clarity and colour was apparent. In addition I did not notice any distortion to the shape of the disc through the SCT with the 20mm eyepiece.

Tonight's summary:
I genuinely believe I have found a brand of eyepiece that are tailor made for me and I cannot find anything at all that I am not completely pleased with and tonight’s findings have simply reinforced my previous experiences with these eyepieces.

The VIP has also proved to be a great addition to my kit and has enabled a variety of different options available to me. I was able configure at least three changes of magnification to each eyepiece.
Ultimately the most important result tonight for the VIP and me is that it was not noticeable in the light path.

Objectives achieved.

:laugh:

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RikM

RikM

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Interesting report Shaun. I wouldn't have thought the VIP would be needed since the XW's progress at 1.4x and 2x natively.

20 / 1.4 = 14

20 / 2 = 10

14 / 1.4 = 10

14 / 2 = 7

Etc.

The VIP does give you the 10mm and 3.5mm options if you don't yet have those eyepieces but you have all the other possible focal lengths covered. It is very good to hear that the VIP doesn't detract from the wonderful XW views though.

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Pig

Pig

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Rick,

The 1.4 is a complete guess and is clearly wrong based on your examples above :laugh:

There are also at least three different elements that can be changed /combined with the VIP configuration thus I would think there are at least three different mags per eyepiece. However, there is almost certainly going to be some cross overs due to the number of different combinations.

For these reasons I believe the account I have given is pretty accurate in the actual views observed and the combo will result in quite different magnifications :laugh: especially as the common factor was the FOV delivered by the eyepiece and I clearly saw many differences.

My apologies for any confusion caused.

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alan potts

alan potts

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Really good review of your nights observing Shuan and I leanrt a few things about the Moon, The Blue Moon. I thought this came from the USA where some years back there was a massive forest fire and due to the amount of sulphur in the air the Moon did in fact turn blue.

I think the Pentax Xw's do transmit as good as any on the market but for me there is no difference between them and the Delos, the problem is there is only 3.5mm 14mm and 10mm where they are the same, 3.5mm is a bit short most of the time and when I did use them I could see no real difference apart from the XW having a tiny bit of CA at the very edge apart from that it was made be a bit whiter. The other two F/L's I have never matched up.

Great piece of work, I like the way you were going to move that haze and start a session!

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Pig

Pig

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Laudropb, thank you :smiley:

The VIP is very good indeed. However, I forgot to mention something I noticed.

The main body of the barlow is a rather handy 2" in diameter and thus can also be used in a 2" diagonal, this does also mean that the 1.25 cone may foul against the mirror in a 2" diagonal. So a little caution may be needed.

So all in all this gives another dimension to the changes in magnification that can be achieved as the whole unit sits lower in the diagonal :laugh:

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Pig

Pig

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Alan/ Piero... thank you

I believe the term " Blue Moon" derives as it does not happen very often throughout the calendar year. Hence the saying once in a blue moon.

In the good old USA its probably down to The Marcels, Elvis Presley and the legendary Frank Sinatra. I will let Gerry answer this one :grin:

https://www.youtube.com/watch?v=Sbw2dsqpX94

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Stu

Stu

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Laudropb, thank you :smiley:

The VIP is very good indeed. However, I forgot to mention something I noticed.

The main body of the barlow is a rather handy 2" in diameter and thus can also be used in a 2" diagonal, this does also mean that the 1.25 cone may foul against the mirror in a 2" diagonal. So a little caution may be needed.

So all in all this gives another dimension to the changes in magnification that can be achieved as the whole unit sits lower in the diagonal :laugh:

Nice review Shaun, the VIP is a great piece of kit which I use a lot. It works well with the Leica Zoom too, making a very versatile setup.

I bought an extra 1.25" to T2 nosepiece and shortened it down so it just protects the Barlow element. This gives you more safety room to avoid hitting the diagonal mirror, and especially for me when using Zeiss Prisms which obviously have even less space.

Enjoy!

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Stu

Stu

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Thank you Stu,

I will have to try it with my Leica :laugh: I will have to search out the nose cone you mention.

I could do with a shorter nose full stop :grin:

I'll find a link for you later. I think I got mine from TS but am not sure whether 365 Astronomy do them. You just need to make sure they have the internal thread to accept the Barlow element. I just shortened mine myself with a hacksaw and smoothed it off with a file!

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jetstream

jetstream

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Alan/ Piero... thank you

I believe the term " Blue Moon" derives as it does not happen very often throughout the calendar year. Hence the saying once in a blue moon.

In the good old USA its probably down to The Marcels, Elvis Presley and the legendary Frank Sinatra. I will let Gerry answer this one :grin:

https://www.youtube.com/watch?v=Sbw2dsqpX94

I love Elvis  :laugh:  and my VIP. I like Stu's hacksaw solution!

If the barlow element is screwed into the VIP eyepiece holder, with no T2 adapter ring, it pull's the nosepiece in a bit. I did shorten mine a hair though.

I'm off to listen to Bill Monroes " I'm workin on the building " :grin: https://www.youtube.com/watch?v=yBDZ3G4RCHc

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John

John

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Great report Shaun :smiley:

I've not tried a VIP barlow as yet - something to look forward to I think :smiley:

I currently have a 2x Powermate which works brilliantly but is a lot heavier than the VIP and less flexible perhaps ?

The XW's are really top flight eyepieces. Amazing to think that it's take Tele Vue all these years to produce something as good and Pentax were not even trying to make astro eyepieces when they produced the XW's. Goodness knows what they could do if they applied themselves to our hobby :grin:

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Pig

Pig

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Thank you John,

The VIP is pretty versatile and should prove to quite useful, especially so if one has a few different scopes :smiley: I think we should all petition Pentax to up the anti :grin:

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alan potts

alan potts

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Great report Shaun :smiley:

 Pentax were not even trying to make astro eyepieces when they produced the XW's. Goodness knows what they could do if they applied themselves to our hobby :grin:

I think the XO's were aimed at our hobby John, not that I have ever seen one but they run the Z word close by all accounts.

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John

John

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I think the XO's were aimed at our hobby John, not that I have ever seen one but they run the Z word close by all accounts.

Thats possible Alan. Pity they only produced one focal length thats useable in most scopes. The 2.5mm XO can still be found but it's going to overpower all but the shortest focal length scopes. I'd like to try 5.1mm XO if one ever came up at a half decent price. The eye relief is tight with it though. This data shows why people seek them out though:

http://astro-okulare.de/English/pentax/penxo5e.htm

Mind you the 5mm XW does just fine here too:

http://astro-okulare.de/English/pentax/penxw5e.htm

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