40 replies to this topic

[Jeff B]

More to follow later:

 

https://www.youtube....h?v=9q4oGqGm748

 

Some good stuff here.

 

Jeff

[denis0007dl]

Awsome Jeff!

[RichA]

More to follow later:

 

https://www.youtube....h?v=9q4oGqGm748

 

Some good stuff here.

 

Jeff

AHHHHHHHH!!!!

 

[kgb]

Thanks Jeff. Nice scope. For that optical flat that you purchased on eBay, did the seller make any representations regarding the accuracy?

[weis14]

Great video Jeff (and team)!  I can't wait to see the full results.  I didn't think it was possible to get even more excited for my SD-120, but somehow it did!

[Joe G]

AHHHHHHHH!!!!

 

dpac.jpg

Looks like my Springer Spaniel.

[EricCCD]

Looks like my Springer Spaniel.

The opening theme of classic Doctor Who started playing in my head.

[RichA]

Looks like my Springer Spaniel.

It's like an ink blot.  I see a monkey's face in the middle.

[PKDfan]

It's like an ink blot. I see a monkey's face in the middle.

It reminded me of a startrek villian from one of their spin offs. Wish i could recall the exact series- STNG I think.

Looks exactly like the alien races ambassador !


CSS
Lance

[Jeff B]

Teaser.

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[EricCCD]

It reminded me of a startrek villian from one of their spin offs. Wish i could recall the exact series- STNG I think.

Looks exactly like the alien races ambassador !


CSS
Lance

This?

[BRCoz]

AHHHHHHHH!!!!

 

dpac.jpg

When I first saw that photo I thought of an ELP album.

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[davidc135]

Teaser.

Doesn't look so good, and why the difference between top and bottom?   David

[Kent10]

Doesn't look so good, and why the difference between top and bottom?   David

This was before the scope was thermally stabilized.  Wait to see what it looks like after another 2 hours pass to stabilize the scope.  Straight bars!

[Jeff B]

Looks like my Springer Spaniel.

It really is a Springer Spaniel peeking through the vertical window blinds.

[Jeff B]

This was before the scope was thermally stabilized.  Wait to see what it looks like after another 2 hours pass to stabilize the scope.  Straight bars!

Yup.   As described in the video, we quickly set up Larry's SD 150 and I took a "before" shot in green, inside of focus.  The scope was noticeably cooler than ambient in the room so I figured this would be a great chance to again demonstrate why its absolutely necessary to let a scope stabilize thermally before testing, and in this case, warm up.  As the scope was warming, over correction is added with the flip of that, under correction, being added when cooling down.

 

Larry, Tony, Little Moose and I then went to lunch and had a great time chatting.  About 2.5 hours later we returned and I redid the DPAC image.  I had to slightly refocus too.

 

You see the results below.  The temperature delta we were experiencing was a lot less than what you might experience in the winter time between your house/car and the outdoors so the figure distortion from the thermal ballistics of the system would be much worse than what you see here.

 

The small residual area of mild over correction at the top of the "after/later" image improved a little with time but there was still a small and mild residual left.

 

Jeff

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[PKDfan]

This?
Fish.jpg

Good try but no.

It was definitely a Picard episode. I think.

Thanks for attempting to bring some clarity !

CSS
Lance

Edit
The character was seen in this weird distorted frame out of focus just like a small monkey in a small fuzzy window on the bridge deck of the enterprise- Picards ship i'm sure. I think.
Edit2 lol now this has been haunting me now i concede the possibility of the scene was on Janeways ship Voyager. They were of the super superiour race simian looking who disliked the entrance into their territory- to the best of my recollection. Very blurry looking aliens lemur face like.

Edited by PKDfan, 04 March 2025 - 02:35 AM.

[Wildetelescope]

When I first saw that photo I thought of an ELP album.

Welcome back my friends to the show that never ends…….:-)

 

JMD

[Wildetelescope]

Yup.   As described in the video, we quickly set up Larry's SD 150 and I took a "before" shot in green, inside of focus.  The scope was noticeably cooler than ambient in the room so I figured this would be a great chance to again demonstrate why its absolutely necessary to let a scope stabilize thermally before testing, and in this case, warm up.  As the scope was warming, over correction is added with the flip of that, under correction, being added when cooling down.

 

Larry, Tony, Little Moose and I then went to lunch and had a great time chatting.  About 2.5 hours later we returned and I redid the DPAC image.  I had to slightly refocus too.

 

You see the results below.  The temperature delta we were experiencing was a lot less than what you might experience in the winter time between your house/car and the outdoors so the figure distortion from the thermal ballistics of the system would be much worse than what you see here.

 

The small residual area of mild over correction at the top of the "after/later" image improved a little with time but there was still a small and mild residual left.

 

Jeff

THAT is educational!  Very interesting to see how the temperature delta distorts the lens figure.

 

JMD

[Jeff B]

Here are my usual white light shots, inside/outside of focus with the 133 LPI screen as well as the green, at focus image.

 

The white light images show me that both secondary spectrum and spherochromatism from blue to red are very well controlled as the central ronchi line shadows show almost no color fringing.  Only at the very tips of the lines on each side of the center line, do I see some small amounts of red/blue fringing, indicating mild spherochromatism.

 

The green at focus image (hyped in contrast to bring out detail) shows random, small scale textures with smooth transitions and no real zones/conic/radius errors.  However, if I look carefully at the top edge, I see a subtle "frown"  in the figure which may correspond to the area of mild over correction there.  I'm also going to speculate that the textures are associated with the hand figuring needed to apply the aspheric to the figure for these designs.  I have seen similar textures with some CFF objectives, which also have an aspheric applied by hand and a copy of the CFF 160 F6.5 is shown for comparison.

 

Jeff

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[Jeff B]

Here are my usual color "montages" derived from the inside/outside of focus white light images.

 

They reinforce to me what I saw before:  Essentially neutral correction in green and well controlled/subdued secondary spectrum and spherochromatism.  This is a well balanced objective.

 

I also noticed no sign of astigmatism.  That would show as a rotation or "clocking" of the center line shadow while racking the focuser smoothly from one side of focus to the other.  I did not see that.

 

The overall look, feel, fit and finish were just superb.  

 

I measured 176mm of available back focus (distance from back of collet to focal plane with focuser racked all the way in).

 

Jeff

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[RichA]

Well,  that's a "kind" ronchi, it includes more than three lines.  Despite that, it seems to show that at least one of the elements has a turned edge.  Ever rotate  the ronchi, to see if it changes its appearance?

[manolis]

a lot of good stuff in that vid , very informative , thanks !

[Tyson M]

Looks like an incredible lens for its size. No zones! 

[R Botero]

Great scope and video!

 

Roberto