657 replies to this topic

[clamchip]

I just love the bare aluminum airplanes. My dad was a mechanic in the Airforce  

and worked on the B-29. He told me changing the 144 sparkplugs on the B-29 

was a major pain and he made his own tools to make the job easier.

I have a mount for the Edmund 5 that will be perfect for it, the Edmund "Extra Heavy Duty".

I hope it turns out to be fabulous because its the perfect size refractor a 5 inch.

I really think the laws of physics are against it though, being a f/14 5 inch achromat. 

 

Robert

Edited by actionhac, 30 December 2015 - 01:10 AM.

[Joe1950]

They are certainly mechanical marvels, with an element of beauty, especially the bare aluminum as you say, Robert.

 

However, I wouldn't want to be in one when they were in action and have a deep respect for those who were.

 

Is the Edmund Heavy Duty Mount the same one used for the 8" Reflector? That is a 'Rock of Gibraltar' mount. Wow! I think Arnold S. had trouble lifting that one. Mounts don't get much more sturdy, Robert.

 

I do understand your concern. I know with my 3" f/15 Towa, the length lends itself to sway when you are focusing, etc. I'm sure a 5" is numerous times more difficult to steady. Just the nature of the beast. I guess that's why someone decided to build a dome and a permanent mount somewhere along the line.  

 

[Terra Nova]

Robert, I am sure that the EHD Edmund GEM is the perfect mount for that 5". Afterall, they coupled the next size down (the one with 1" shafts) with the 4" F15 and the smaller 5/8" shaft GEM with the 3" F15. The thing that these Edmund mounts have going for them is that both axes have solid single piece shafts going all the way through the housings and resting on bronze bearings. They are alot like pillow-block mounts and the way they are constructed make them very stable for their size. I say, "Go for it!" You have all the parts so why not?! Besides, you are worried about the 5" F14.5 having CA? There are a lot of Jaegers and D&G 5" F12s out there! And just look at all the modern 120mm F9 and F10 achromats. Build it and enjoy it. You will have one of the most unique Edmund refractors out there. Shoot, any 5" >f12 achromat is pretty darned unique! And if my 4" F15 Edmund is any indication, they don't get any better. You were the one who convinced me to get it and I have never regretted it. That scope will stay with me as long as I'm topside! "If you build it, they will come!"

[clamchip]

Yes the Edmund "Extra Heavy Duty" came with the 8 inch f/8 reflector and was available in the

catalog by itself. Its a great mount, I use it for everything if I can.

Here is a picture of it at standard reflector pier height, and you can unscrew the head and add as  

many pieces of pipe as you like because its regular old pipe thread. So a coupling and a 2 foot

section of pipe will get you to a nice refractor height.

 

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[clamchip]

I am worried about the chromatic aberration and its damage to the wave front.

I don't know what the wave front is for a 5"f/14.2 achromat but I know its no where

near as good as a 4"f/15. So thats going to leave me with a major handicap at

the eyepiece.

I'm getting the cart in front of the horse, I've got to try it out and

see.

Edmund more than likely got the 5 inch lens from the same source as the

3 and 4 and if thats the case the 5 will be as good as a achromat can be made.

But at f/14.2 it doesn't even meet the Sidgwick standard CA ratio of 3.

(f/ratio divided by objective diameter in inches = CA ratio)

 

Robert

Edited by actionhac, 30 December 2015 - 04:26 PM.

[Bomber Bob]

The CA of my D&G 5" f/10 didn't bother me, or the astronomer who bought it from me - got filters for the brightest objects.  No doubt it would've been better at f/15 or f/20, but it managed to keep up with 6" & 8" reflectors.  I think its well worth your efforts.  I've developed a respect for Carton achromats.

[Joe1950]

2.84 Sidgwick ratio IS just in the green zone - 'little or no CA.' And the quality of the lens can impact the CA to a degree, so 3 is not a hard and fast number.

 

Terra and the Bomber are right! You don't want that 5" in the back seat of a cab saying, "I coulda' had glass. I coulda' been (an APO) contender. I coulda' been somebody ('s go-to scope)."    

Edited by Joe1950, 30 December 2015 - 06:34 PM.

[Terra Nova]

What a great line! What a great film!!

http://youtu.be/AwlqKiCpQ9Y

[clamchip]

I was going to have a clear night so I brought out the Edmund

Super Space Conqueror as a control to compare the Edmund 5

with since its optical quality is known.

The Edmund 5 is a big surprise, it is a beautiful lens.

I didn't have much time before the fog but long enough to observe

some stars in focus and defocused and it will do just fine and DANDY!

I was worried because during daytime tests I could see high amounts of

CA around tree branches and power lines, but when viewing astronomical

objects the telescope transformed into an entirely different personality, like 

a Dr. Jekyll and Mr. Hyde scope.

Heres the Super Space Conqueror. I didn't get a chance to do any comparing,

I didn't really need to the Edmund 5 is going to be a excellent telescope.

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[ScottAstroNut]

Congratulations on a successful first light with the 5 inch Edmund!  I am glad that the optics turned out to be fine. 

 

Nice looking Super Space Conqueror, too.  Just wondering, where did you get the great looking tube rings?  I've occasionally thought about adding some to my SSC.

[Terra Nova]

I thought it would be, I'm glad it is...... "a contender!"

[Joe1950]

"Ladies and Gentlemen."

"In this corner, From Seattle Washington,

Weighing in at One Hundred Twenty Seven millimeters, F-Fourteen Point Two"

"the Lens of Leathality,"

"the APO Annihilator,"

"the Chromatic Crusher"

"And Reigning Undisputed Achromatic Champion of the World"

EDMUUUUUUUND FIVE!!!!!!

 

  

Edited by Joe1950, 31 December 2015 - 11:20 AM.

[clamchip]

Congratulations on a successful first light with the 5 inch Edmund!  I am glad that the optics turned out to be fine. 

 

Nice looking Super Space Conqueror, too.  Just wondering, where did you get the great looking tube rings?  I've occasionally thought about adding some to my SSC.

I have two sets of rings I use with 7" OD tube like the Super Space Conqueror, this 182mm:

http://www.telescope...s?ensembleId=39

these will be to large and I shim them down to size with military style web belt material.

I also have another pair that are unknown and even larger and I use rug padding (goes under floor rugs)

to bring down the size. This pair is the same size as Criterion RV6 rings.

I did have a pair of Parallax rings that were definitely the best but they were sold recently with my D&G 6"

which also uses 7"OD tube.

 

Robert

[clamchip]

Project Edmund 5 has been given the green light and I would

like to start with these items:

1) a light baffle in the center of the tube.

2) assembling the Edmund Extra Heavy Duty mount for it.

3) the focuser needs some help.

I was also thinking about this lens as a possible key to unlock

the source of the Edmund 3,4, and 5 inch telescope objectives.

This uncommon 14.2 focal ratio of the 5 inch lens may help unless

this ratio was made specifically for Edmund.

I'll research Carton Optical Co. and see if they ever made a 5"f/14.2

(127mm x 1803mm).

Edited by actionhac, 31 December 2015 - 06:51 PM.

[ScottAstroNut]

 

Congratulations on a successful first light with the 5 inch Edmund!  I am glad that the optics turned out to be fine. 

 

Nice looking Super Space Conqueror, too.  Just wondering, where did you get the great looking tube rings?  I've occasionally thought about adding some to my SSC.

I have two sets of rings I use with 7" OD tube like the Super Space Conqueror, this 182mm:

http://www.telescope...s?ensembleId=39

these will be to large and I shim them down to size with military style web belt material.

I also have another pair that are unknown and even larger and I use rug padding (goes under floor rugs)

to bring down the size. This pair is the same size as Criterion RV6 rings.

I did have a pair of Parallax rings that were definitely the best but they were sold recently with my D&G 6"

which also uses 7"OD tube.

 

Robert

 

Thanks, Robert .   Much appreciated .  I'll   check out those rings.  I agree that Parallax  rings are great, but a bit pricey.  Did you  have  to  shim the  Parallax  rings, though?

[ScottAstroNut]

Project Edmund 5 has been given the green light and will now enter into a more intensive

testing and evaluation program which will begin with:

1) a light baffle in the center of the tube.

2) assembling the Edmund Extra Heavy Duty mount for it.

I have another nose art in my files I kinda like:

Oh!   (The nose art, that is...)

[clamchip]

I thought I'd better remove that nose art once I saw it in my post, I can describe it though,

 

"a green eyed red head in a red rather short Federation uniform holding a Phaser riding on the

back of the starship Enterprise".

 

The parallax rings were a perfect fit without shims. The D&G 6 uses the same irrigation tubing

as Edmund.

Edited by actionhac, 31 December 2015 - 07:04 PM.

[Terra Nova]

I have a retro serving tray with this picture on it. I always thouht it would make great 'noseart' for the right telescope. Maybe for the retro homage long blacktube 6" Newt I am building.

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[clamchip]

It sure is a mystery, why f/14.2? another 4 inches and it would be f/15.

127mm x 1803mm, 5" x 71", it is less than 6 feet which is the limit for some shipping carriers.

The tube doesn't need to be 6 feet long if and when the Edmund 5 was to go to production.

It seems to be a high quality lens like the Edmund 3 and 4 inch, which are obviously

astronomical grade.

There were superb Japanese battleship binoculars made in the 127mm size, but even if the prism

assemblies ate up 6 inches of the focal length that would make the binocular 5 feet long which seems too

long.

 

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[Joe1950]

I have a retro serving tray with this picture on it. I always thouht it would make great 'noseart' for the right telescope. Maybe for the retro homage long blacktube 6" Newt I am building.

 

Terra!!!

 

Got any more?

[Rich (RLTYS)]

Folks, please stay on subject. Discuss noseart on a separate thread. Thanks.

 

Rich (RLTYS)

[clamchip]

Here is a picture of the Edmund Extra Heavy Duty at refractor height by adding

a section of pipe and a coupler.

The telescope is my R.E.Brandt 6 inch.

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[clamchip]

I love the Edmund "Extra Heavy Duty" here are a few more pictures.

Allenscope 6"f/13

 

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[clamchip]

D&G 6

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[clamchip]

Edmund Scientific 4

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