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Pentax XW versus Delos, an informal comparison

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#101 kkokkolis

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Posted 23 August 2013 - 01:16 AM

For some reason, life expectancy plummeted with the fall of the Roman Empire, and it did, indeed, reach very low levels and didn't really climb back to "normal" until the industrial revolution. Was it hygiene? The foods eaten?
Warfare? The Plagues? Probably all of the above.


Add lead chronic intoxication for Romans (lead was used excessively in their aquaducts) and lots of criminality in the dark ages (sea piracy and land armed thieves) later in the Middle ages. And underdeveloped obstetrics. Also, civilian life. Too many people living in crowded conditions, drinking from the same public taps etc.
This is among the first things taught in the medical school here. Hygiene (and prevention in general) is much better and cheaper for the community and the individual.
Sorry for off topic, but a comment about prevention can't hurt.

#102 Sarkikos

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Posted 23 August 2013 - 06:57 AM

For some reason, life expectancy plummeted with the fall of the Roman Empire, and it did, indeed, reach very low levels and didn't really climb back to "normal" until the industrial revolution. Was it hygiene? The foods eaten?
Warfare? The Plagues? Probably all of the above.


Add lead chronic intoxication for Romans (lead was used excessively in their aquaducts) and lots of criminality in the dark ages (sea piracy and land armed thieves) later in the Middle ages. And underdeveloped obstetrics. Also, civilian life. Too many people living in crowded conditions, drinking from the same public taps etc.
This is among the first things taught in the medical school here. Hygiene (and prevention in general) is much better and cheaper for the community and the individual.
Sorry for off topic, but a comment about prevention can't hurt.


Drastic and relatively sudden changes in climate certainly have had effects on life expectation. During just the last millenium, mankind has experienced the Medieval Warming Period and the Little Ice Age. There must have been many other periods of climate change during the last 30,000 years.

Mike

#103 Sarkikos

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Posted 23 August 2013 - 07:18 AM

I had a similar impression of the Horsehead with a Sterling 25 and H-Beta filter. An obviously brighter and more contrasty view.

Mike


I think getting one of these is in order! I remember reading about your experience with the Horsehead Nebula Mike, and at the time I just couldn't believe it because it was a cheaper eyepiece, then I tried it on the Helix and I was dumbfounded!

You were right all along and I retract whatever it was I said about your experience. I was WRONG.

Cheers!


You never really know how good or bad an eyepiece is until you look through one yourself. You should know that better than anyone!

:grin:
Mike

#104 t.r.

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Posted 23 August 2013 - 08:13 AM

Sorry for the segue. Oh, to have seen the dark skies back then


I have had the opportunity to experience this...I deployed for Operation Restore Hope in '93 to the middle of Somalia, Africa where there was NO electricity or lights anywhere. Not even light domes on the horion. Look at the horn of Africa. I vividly recall looking out of my tent the first night we touched down at Baledogle airport at midnight, looked straight up and gazed upon the milky way...It was obvious that I was in the arm of a spiral galaxy that was all around me!!! :bigshock: I have never encountered as dark a sky since. My trusty C80SS got a workout that deployment. :grin: You can still experience it Don...Travel to it! ;)

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#105 csrlice12

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Posted 23 August 2013 - 08:24 AM

Never been to Somalia (not sure I'd want too right now either), but the darkest skies I've seen were when I was stationed at Thule, Greenland.....no light domes, and for a few months, no light...period. Of course in summer, no darkness either!

#106 JustaBoy

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Posted 23 August 2013 - 09:03 AM

Hi Guys,

If the Sterling 25mm is really something as special as some say, then that does not bode well for the rest of us:-(

They have been out of stock for quite some time (along with the 2" 40mm), and you know how it goes - If something is really good 'they' will quit making em:-)

Happens to me all the time... :(

Have a great day!
-Chuck

#107 Starman1

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Posted 23 August 2013 - 09:52 AM

Sorry for the segue. Oh, to have seen the dark skies back then


I have had the opportunity to experience this...I deployed for Operation Restore Hope in '93 to the middle of Somalia, Africa where there was NO electricity or lights anywhere. Not even light domes on the horion. I vividly recall looking out of my tent the first night we touched down at Baledogle airport at midnight, looked straight up and gazed upon the milky way...It was obvious that I was in the arm of a spiral galaxy that was all around me!!! :bigshock: I have never encountered as dark a sky since. My trusty C80SS got a workout that deployment. :grin: You can still experience it Don...Travel to it! ;)

Yup.
I'm going to Coonabarabran in Australia next March for a week under the stars. It's reputed to be quite dark.

#108 Jeff Morgan

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Posted 23 August 2013 - 11:35 PM

In the time of stone knives and bear skins....they had dark skies...........


And a 30 year life expectancy. :p

If they survived childhood, they lived generally longer than that.
Though there are fossil hominids that died younger, there are significant numbers of Neanderthal and early moderns that died in the 55-75 range.

Even after the cultivation of plants and the start of the Iron Age it was thought that "3 score and ten" (as written) was a reasonable expectation of life IF you didn't die of an accident, or warfare, or disease, etc. Though a lot of people died from disease when we started living in cities, this eased a lot after multiple generations because those prone to death from contagious diseases died. Though Smallpox was a horrible disease, at most 1/3 died from it and the rest survived.
For some reason, life expectancy plummeted with the fall of the Roman Empire, and it did, indeed, reach very low levels and didn't really climb back to "normal" until the industrial revolution. Was it hygiene? The foods eaten?
Warfare? The Plagues? Probably all of the above.

Sorry for the segue. Oh, to have seen the dark skies back then.


To be honest I was don't know if the number was 25, 30, 45, or something else. Aside from the romanticized Hollywood view of aboriginals living in harmony with Nature, the reality of life was "nasty, brutish, and short" for the bulk of humanity before the availability of electricity and the modern hygiene it provides. Of course injury, warfare, and substenance living all pulled the average down quite a bit.

Not that we are free of those ills today, but at least Dobsonian owners have easy access to tracking solutions. Perhaps those that use them will be freed from the risk of Tracking Injuries, and live longer. Or we will become soft from our ease of life, less fit, and be more vulnerable to disease?

But enough of my segue. Yes the skies must have been great even until the time of say, Charles Messier.

#109 Mike B

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Posted 24 August 2013 - 12:36 AM

...but at least Dobsonian owners have easy access to tracking solutions.

Yes, all i've gotta do is kill a bear with my stone-knife, and the tracking drive is mine! :grin:

I absolutely love the looks of the "SlipStream" drive on the SpicaEyes Dobs, but the pricing is a bit large & hairy. The ability to move the scope by hand, at will, and then let go to automatic tracking... schweet! Would certainly make EP comparos, like the Pentax vs. Delos, far easier to bear. ;)

But given the budget i had to work with, i opted for (in descending order) aperture, premium optics, premium build, and DSCs... and then the dough ran out. :shrug: Maybe someday, an upgrade?

#110 Doc Willie

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Posted 24 August 2013 - 06:00 AM

Topic?

#111 MRNUTTY

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Posted 24 August 2013 - 06:44 AM

I absolutely love the looks of the "SlipStream" drive on the SpicaEyes Dobs, but the pricing is a bit large & hairy.


"Eek!", to say the least! But lovely builds to be sure - envy...

On topic, I love my XW's and Delos, hard to let either go if needed someday.

#112 A6Q6

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Posted 24 August 2013 - 11:43 AM

"Not that we are free of those ills today, but at least Dobsonian owners have easy access to tracking solutions. Perhaps those that use them will be freed from the risk of Tracking Injuries, and live longer. Or we will become soft from our ease of life, less fit, and be more vulnerable to disease?" Thanks I like that!!!

#113 Scott in NC

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Posted 28 August 2013 - 05:54 PM

Okay, everyone--how about we get back to the topic of Pentax XW vs. Delos eyepieces? :thanx:

#114 dvb

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Posted 28 August 2013 - 06:50 PM

A link to my daylight comparison of 6mm Delos, 7mm Pentax, and 5mm Nagler. (I liked the Delos best.)

http://tinyurl.com/pw6ormw

#115 coutleef

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Posted 29 August 2013 - 02:58 PM

thanks for the link

i have not tried them during the day yet.

#116 George9

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Posted 30 August 2013 - 09:39 PM

Yes, the 17T4 was a very visceral eyepiece as very few others are. At one time I said if I could only have one eyepiece, just weld the 17T4 into my focuser.

Then I tried the 13 Ethos. Optically, it was better and after careful comparison between myself and a neutral observer there was just no doubt about it. So I reluctantly sold off the 17T4 (and the 12T4).

But the 13 Ethos just wasn't an enjoyable eyepiece to use once the AFOV novelty wore off. What you said rings absolutely true. To see the field requires lots of (for lack of a better term) work. The longer the observing session is, the more you notice it.

But what to do at that point? I knew that I could not go back to the 17T4 since I had found a sharper eyepiece, any thought of doing so was merely nostalgia working against experience and better judgment.

Then Delos came along. After trying the 10 mm I knew this was the line I was waiting for. As many others have reported, I found it even better optically than Ethos. So it was merely a waiting game for the Tele Vue to release all of the focal lengths.

No, Delos is still not the visceral experience of the T4. But in the end the sharpness and contrast wins the day and I didn't have to bob my head like a pigeon to see everything. The slightly smaller size is easier on both of my scopes and greater eye relief was nice. And best yet, it did it about half the price. What's not to like?

And I still might go back for that 17T4 :question:


Wow. What a great thread. Thanks for all the information. I've been away from the forum for a while.

I am living this now. My favorite eyepiece of all time, 17T4. My recent purchase, 13 Ethos, mainly to reduce eyepiece swapping in an 18" Dob. I am finding the exact same clinical improvement but not emotional impact.

My second favorite eyepiece of all time, 5.2 Pentax XL. (I love finding Mars's moons by using the field stop as an occulting bar with the moon just in and Mars just out.)

So you're telling me I will end up with a line of Delos or XWs. You guys are killing me.

But I'm not selling the 17T4.

#117 MRNUTTY

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Posted 31 August 2013 - 08:29 PM

So you're telling me I will end up with a line of Delos or XWs. You guys are killing me.

But I'm not selling the 17T4.


it's OK! you can live with both the 17T4, XW's and Delos too! :D

#118 Starman81

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Posted 01 November 2013 - 12:24 AM

Well there's the problem.

Non-tracking is like going back to stone knives and bear skins.


Tracking is nice, as I always tell my friends who have it....but w/o tracking one can really get personal with the sky and learn everything you possibly can about it. My tracking buddies are always asking me which star is which and where they are in the sky. IMO, it's good to know the sky, and what you are aiming at w/o the tracking....but at the same time, I'd love to just love to punch in a few buttons on the keypad and take a look!

Sorry for going off topic !!!


Markus, I think you assumed in your statement that tracking necessarily goes hand-in-hand with go-to. You can have a tracking platform (for a dob of course) that requires you to find objects and learn the sky by yourself.

BTW, this was a great thread and I hope to compare the Delos with my current XWs, starting with the 14mm focal length.. A good number of them are hitting the used market with regularity, so you can snag a deal with some diligence.

#119 Scanning4Comets

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Posted 01 November 2013 - 12:32 AM

I said the above almost three months ago, LOL!

Yes, I did mean Go-to, however, I have a few friends who have tracking & Go-To and still ask where a lot of things are.

#120 Starman81

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Posted 01 November 2013 - 12:55 AM

Yes, it was a little while back but that doesn't mean I can let you off the hook! ;)

There have been too many ortho threads in this forum recently so I needed to bring back a thread heavy on the wide-fields.

#121 csrlice12

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Posted 01 November 2013 - 07:24 AM

Ordered a 6mm Delos to fit between my Pentax 7 & 5mm...I believe they will play well together...No reason not to have both. For the hairs difference either way (depending on whose writing) they both perform brilliantly. I think its great they both come mostly in different f/ls, especially at the short f/ls, so we all benefit...

#122 kkokkolis

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Posted 01 November 2013 - 08:59 AM

Perhaps mr Delechie could combine some Ethos and T4 properties to provide a new eyepiece not even XWs could compare with. I'll propose a name. The closest island to Delos is called Myconos (but has not much to do with ethos I'm afraid).

#123 csrlice12

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Posted 01 November 2013 - 09:04 AM

I'd kinda like to see a Moe, Larry, and Curly Joe lines of eyepieces. :lol:

A 120*, 20mm eye relief, and the XW immersiveness would be hard to beat....or afford. But I'd love to look thru one.

#124 JustaBoy

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Posted 01 November 2013 - 09:25 AM

How *BIG* do you think it would be? :-)

-Chuck

#125 csrlice12

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Posted 01 November 2013 - 09:46 AM

Ok, and the size of a Meade RGO....






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