Pentax X0 2.5mm

[jetstream]

14 minutes ago, Highburymark said:

Highest power I generally use with my TSA-120 is 360x with the TOE 2.5mm.  The 5mm XO (although some say it’s 5.1mm) will give me 180x - perfect for average evenings. But I bought it for better than average evenings! So I have the 1.5x Tak extender which will bump things up to 270x. Yes, it’s more glass, but then it turns the TSA into an F/11.25 planet killer.

I dont note any negatives using the VIP , only positives- do you note the same thing with regard to the Tak extender? Have you tried the Tak extender with the Delite or Delos?

[Highburymark]

2 hours ago, jetstream said:

I dont note any negatives using the VIP , only positives- do you note the same thing with regard to the Tak extender? Have you tried the Tak extender with the Delite or Delos?

I do Gerry - I have a VIP too and my feeling has always been that exceptional eyepieces don’t stop being exceptional with the best barlows and extenders. I think I remember Bill P saying the same thing once with barlowed orthoscopics. I stopped believing in the minimum glass rule when I first looked through a six element TOE.

[jetstream]

36 minutes ago, Highburymark said:

I do Gerry - I have a VIP too and my feeling has always been that exceptional eyepieces don’t stop being exceptional with the best barlows and extenders. I think I remember Bill P saying the same thing once with barlowed orthoscopics. I stopped believing in the minimum glass rule when I first looked through a six element TOE.

I think (know) we are on the same page-  is there any difference between the Tak extender and the VIP view wise? I would think not actually. I might go off the rails here and get a light 82 deg something and try barlowing to see if it sharpens up.

My 16T5 sharpens up with the VIP a good bit. We have a ridiculously sharp ES 82 6.7mm, still boggles me- not in the XO/HR league but vg and the wide field is a nice option for easy viewing.

 

[nicholasastro]

18 hours ago, jetstream said:

Thank you for the excellent reply and now I'm really excited to try the XO... and really want the 5mm too!

I bought the 5mm after having had the 2.5mm XO for a while. Have not been able to use the latter all that often though.

[jetstream]

XO has landed and I love the look and build of it, I now need the 5mm.

[markse68]

I’d be afraid to use that- it’s a proper collectors piece! Brand new! Lovely. All Pentax eps have a really nice build quality to them I think. What’s the weird thing behind- is that a canister for it?

4 hours ago, jetstream said:

I now need the 5mm

if you find 2 let me know 😁

Mark

[jetstream]

@markse68 Thank you. I'll be using it as much as the other eyepieces I have eventhough it is kind of rare. My stuff doesnt just sit on the shelf. The thing behind it is a DPAC eyepiece, to set a Ronchi screen in and an LED to backlight it. Once I have a suitable flat I'll test my fracs for the fun of it.

@Sunshine made these DPAC EP's happen.

I look forward to comparing the 2.4 HR and the 2.5 XO, hopefully Monday.

[Sunshine]

That’s a nice eyepiece! Looks like it wasn’t touched, like new.

Edited March 10, 2023 by Sunshine

[jetstream]

6 minutes ago, Sunshine said:

That’s a nice eyepiece! Looks like it wasn’t touched, like new.

Thanks, Brian said he found it in an old stock display case or something. If you ever here of a 5mm out there let me know will you?

[Sunshine]

56 minutes ago, jetstream said:

Thanks, Brian said he found it in an old stock display case or something. If you ever here of a 5mm out there let me know will you?

In an old stock display case, that’s one of those lucky finds, I’m going to call him to see if he can look around the shop for a TSA-120 tucked under a table or something.

[jetstream]

39 minutes ago, Sunshine said:

In an old stock display case, that’s one of those lucky finds, I’m going to call him to see if he can look around the shop for a TSA-120 tucked under a table or something.

You leave my Zeiss orthos alone!!!

[Highburymark]

On 06/03/2023 at 18:30, jetstream said:

I think (know) we are on the same page-  is there any difference between the Tak extender and the VIP view wise? I would think not actually. I might go off the rails here and get a light 82 deg something and try barlowing to see if it sharpens up.

My 16T5 sharpens up with the VIP a good bit. We have a ridiculously sharp ES 82 6.7mm, still boggles me- not in the XO/HR league but vg and the wide field is a nice option for easy viewing.

 

I haven’t compared them tbh Gerry - I tend to use them for different functions, and physically changing from an extender to a barlow during a session is a bit of a kerfuffle. I’ve heard good things about the ES 82 degree range at shorter focal lengths - at least as sharp as Nagler T6s.

[Highburymark]

21 hours ago, jetstream said:

XO has landed and I love the look and build of it, I now need the 5mm.

Fantastic - I’ll be interested to hear how you get on with the eye relief. I’m hovering above at the moment with the 5mm to avoid any contact with the lens, so not quite seeing the field stop - but am finding it’s relatively easy to hold the view.

[Highburymark]

Well I finally had a chance to test the XO 5mm properly on the Moon this evening. I was studying craters around Mare Humorum - Gassendi, Vitello and Doppelmayer in particular.
Scope was TSA-120 - XO gave 180x.
Very simply, it was outstanding. Sharpness and detail clearly a level above my two other excellent 5mm eyepieces - Pentax XW, and Kasai ortho. But how did the XO match up to the TOEs? It’s very difficult to compare a 5mm eyepiece with a 4mm, but I’d say the difference between the XO and XW 5 was at least comparable to that between the Tak TOE 4 and Delite 4 (much as I love XWs and Delites, no complex widefield EP can compete with these specialist planetaries under good conditions), so moving from XO 5 to TOE 4 and 3.3 felt like a natural progression - the TOEs certainly are not outclassed by the XO. But I would not be surprised if the XO shows just a bit more detail when I experiment with the Tak extender 1.5x and other barlows - so can match magnifications better. 
Of course there is a price to pay - the XO is not the most comfortable EP with a manual mount (I have the Skytee 2). The minuscule eye relief wasn’t an issue though - I just hover above, even if I can’t see the field stop. Just means lots of slo-mo adjustments. But it was worth it….

[Highburymark]

Think it’s worth repeating here that you have to pick features with small details - intricate structures within craters for example, or the definition of minute craterlets, and study them - swapping between eyepieces, to see the differences I saw last night. It’s the final 5% that the specialist eyepieces provide - clear, but at the margins. 

[Highburymark]

On 05/03/2023 at 13:35, Louis D said:

Agreed on all but the 3.5mm.  Did you see chromatic aberration at the edge in your 3.5mm XW?  My 5.2mm XL is also free of color to the edge.  After seeing the chroma at the edge of the 7mm, I decided to keep the 5.2mm rather than "upgrade".

Didn’t see your post originally Louis. No - I’ve never had the pleasure of trying a 3.5 XW. Tbh edge colour is not an issue with the XW5 at all - I’ve only seen it testing the eyepiece indoors with an F/6 60mm ED, not outside observing. I’m fairly sure the Delos 6 I once owned also displayed a touch of colour at the margins. I never really warmed to the Delos 6 for some reason - certainly I find the XW5 more comfortable. But I loved the Delos 10 and 17.3 - comfort wasn’t an issue there. Can’t explain why.

[jetstream]

10 hours ago, Highburymark said:

Think it’s worth repeating here that you have to pick features with small details - intricate structures within craters for example, or the definition of minute craterlets, and study them - swapping between eyepieces, to see the differences I saw last night. It’s the final 5% that the specialist eyepieces provide - clear, but at the margins. 

Just saw this-great report! The TOE sure sounds excellent. I 100% agree with the above ^^  and was doing this very same thing recently.

 

21 hours ago, Highburymark said:

no complex widefield EP can compete with these specialist planetaries under good conditions)

100% agree again with the exception of the Zeiss zoom/barlow viewing in the center of the field, very close- but the 2.5XO squeaked ahead and is ahead in transmission as seen by my eyes.

So glad you are getting a chance to use the XO Mark! and I still want to buy it and I have zero chance now that youve got a good look through it.

Great observing and I hope you get more chance to do it!

Gerry

[jetstream]

@Highburymark forgot to say that Gassendi is a treasure trove of detail and is a favourite of mine. That craterlet in the "V" shaped rilles was very sharp and a great sight the other night.

[Deadlake]

I had the fortune to have a TOE 3.3 mm and HR 3.4 mm using with an LZOS 130 mm on a night of exceptional seeing when viewing the Moon.
Not much chance of looking at anything else this year due to the cloud cover. 😀

The one data point that the HR really showed it pulling away from the TOE was the level of shadow contrast visible within craters.
At one point I had to pinch myself at the detail. 
Also the dynamic range as well, noticeable more than the Vixen SD103S scope I used to have which I feel was still very good.

I also used a 2 and 2.4 mm HR, the scope just opened up with the level of detail on the moon, the limiting factor being I needed a guided mount to minimise vibrations.

Note: using a Baader moon filter took off the extra brightness the TOE adds.

Hoping for another good night, I'll try a BRAVDA and 10 mm UFF and see where that gets me.

Edited April 3, 2023 by Deadlake

[jetstream]

38 minutes ago, Deadlake said:

The one data point that the HR really showed it pulling away from the TOE was the level go shadow contrast visible within craters.
At one point I had to pinch myself at the detail. 

Excellent and I believe this is a reflection of the MTF contrast idea that we're discussing, it seems to show up the best in certain places.

[Highburymark]

1 hour ago, Deadlake said:

I had the fortune to have a TOE 3.3 mm and HR 3.4 mm using with an LZOS 130 mm on a night of exceptional seeing when viewing the Moon.
Not much chance of looking at anything else this year due to the cloud cover. 😀

The one data point that the HR really showed it pulling away from the TOE was the level go shadow contrast visible within craters.
At one point I had to pinch myself at the detail. 
Also the dynamic range as well, noticeable more than the Vixen SD103S scope I used to have which I feel was still very good.

I also used a 2 and 2.4 mm HR, the scope just opened up with the level of detail on the moon, the limiting factor being I needed a guided mount to minimise vibrations.

Note: using a Baader moon filter took off the extra brightness the TOE adds.

Hoping for another good night, I'll try a BRAVDA and 10 mm UFF and see where that gets me.

I remember you reporting this Martin - very interesting, particularly as the 3.3 TOE is my favourite of the line. I’d love to try a 3.4 HR. It’s probably a good sign that opinion seems to be split about the capabilities of the HRs and TOEs - but both have raised the bar in recent years for planetary eyepieces. 

[Deadlake]

24 minutes ago, Highburymark said:

I remember you reporting this Martin - very interesting, particularly as the 3.3 TOE is my favourite of the line. I’d love to try a 3.4 HR. It’s probably a good sign that opinion seems to be split about the capabilities of the HRs and TOEs - but both have raised the bar in recent years for planetary eyepieces. 

I prefer the TOE 4 mm. Having said that the seeing was so good tonight I spent most of the time using the HR 2 mm that the 4 mm didn't get a chance. 
4 mm is usually most used when seeing is average on planets.

Edited April 3, 2023 by Deadlake

[John]

Interesting reading about these top tier planetary type eyepieces 🙂

As @Deadlake says, with the seeing excellent tonight it is a good opportunity to press on the power. 

I don't have eyepieces in the league of the Vixen HR's or TOE's but I have taken the opportunity to compare my Nagler 2-4mm zoom with a Fujiyama HD 4mm ortho that I have had knocking around for quite a while. I was pleased to see that the Nagler zoom produced entirely comparable lunar and double star views both in terms of sharpness and contrast. Given the eye relief 10 degrees additional AFoV and zoom ability, that is quite a fine achievement from the Tele Vue folks. IMHO.

The scope was my LZOS 130 F/9.2.

It seems crazy that most of my observing tonight has been done at 300x plus but it's been that sort of night 🙂 

And, yes, I used 2mm as well at times 😄

Edited April 3, 2023 by John

[Deadlake]

24 minutes ago, John said:

It seems crazy that most of my observing tonight has been done at 300x plus but it's been that sort of night 🙂

Yep, helps with high Strehl scopes around 0.98 to 0.99 to pile on the magnification.

I have used a BRAVDA and 10 mm UFF on other nights, but comparison of performance is as ever seeing limited…

If I had done my research based on CN feedback a high quality Barlow mounted ahead of the diagonal and a good 10 mm EP might give more contrastly views then some high end EP’s.

Edited April 3, 2023 by Deadlake

[Don Pensack]

1 hour ago, Deadlake said:

Yep, helps with high Strehl scopes around 0.98 to 0.99 to pile on the magnification.

I have used a BRAVDA and 10 mm UFF on other nights, but comparison of performance is as ever seeing limited…

If I had done my research based on CN feedback a high quality Barlow mounted ahead of the diagonal and a good 10 mm EP might give more contrasty views than some high end EP’s.

For those not familiar, he is referring to an AstroPhysics BARADV Barlow, one of those high-end Barlows highly touted.