86 replies to this topic

[badback]

Sadly not a single one of the many 4.5 F.L. red-tubed models that I

own have really good optics. Some may be OK perhaps. Perhaps?.

This includes all the different red-tubed 8",10" and 13.1" models.

Without a doubt my long ago ex 10" red-tubed Coulter was optically

the far worst telescope I've ever owned. Hope yours fares better,

 

But now, the horrid optics torch may actually be passed on, as my

recently acquired 13.1" red-tubed model may be even worse. This

has endured exposure, termites, floods, wood rot, deterioration,etc.

 

And you call yours the Problem Child. So what if it's a "chip off the

old block?" That child has had all the advantages. Things like

being sheltered, well cared for, custom diagonal bits and a 9 point cell.

That child was spoiled sir! Spoiled I say. Sheesh!

 

PROBLEM CHILD indeed? Lucky man.

 

Inspired by your post I shall now christen my recent Coulter abomination:

The BATTERED RED-TUBED STEP-CHILD.

What a blast.

[clamchip]

I have my fingers crossed mine will be okay.

Sadly the mirror probably can't be refigured with its "end cut" mirror blank.

Whenever I go to a restaurant for prime rib I order a "end cut" you

always get a bigger slab.

 

Robert

Edited by clamchip, 12 November 2021 - 05:43 PM.

[clamchip]

Looks like it needs a Telrad. 

I have one and its on there now all aligned to the main scope and everything.

I'm ready to go I'm just dying to try it out

With the rainy weather I'm so tempted to make a oil pan flat and bench test the

scope. At least I'll get to play with it.

 

Robert

Edited by clamchip, 12 November 2021 - 05:51 PM.

[DAVIDG]

I have my fingers crossed mine will be okay.

Sadly the mirror probably can't be refigured with its "end cut" mirror blank.

Whenever I go to a restaurant for prime rib I order a "end cut" you

always get a bigger slab.

 

Robert

"Sadly the mirror probably can't be refigured with its "end cut" mirror blank."

  Sure it can.  It is no different then having a convex surface on a  lens or meniscus. All it takes is pitch and optical polish and some patience. 

 

                  - Dave 

[DAVIDG]

I have one and its on there now all aligned to the main scope and everything.

I'm ready to go I'm just dying to try it out

With the rainy weather I'm so tempted to make a oil pan flat and bench test the

scope. At least I'll get to play with it.

 

Robert

 Since a Foucault test is done at the radius of curvature which is 2x the focal length you can Foucault test the mirror while it is in the scope. The only part you can't  see is the area blocked by the secondary but it will tell  you if the mirror is optically smooth or has zones.

 

                     - Dave 

[clamchip]

Good idea Dave, Foucault test without removing the mirror, I didn't think of that.

I need Foucault practice, I should make that a priority.

The rain let up long enough for me to do more daytime observing. The shortest

focal length ep I had with me outside was a 5mm Celestron Ultima, 231X, and

no image breakdown, very sharp, and of course still bright with 10 inches.

Notice I have waterfront now. Next photo a couple weeks earlier, Tasco 3 inch, you

can see a puddle forming out there.

With the odd 45.5" focal length of this Odyssey I made a new eyepiece card for

out in the field, very handy to have.

Robert

 

Edited by clamchip, 13 November 2021 - 07:03 PM.

[DAVIDG]

It looks like you have buildings across  the new lake and they have lights on them so even if it is cloudy the lights would be far enough away to use them to do a "star test" 

 

                 - Dave 

Edited by DAVIDG, 13 November 2021 - 08:01 PM.

[clamchip]

I do use the outdoor lights over there for star testing with mixed results.

Most of the lights have diffusers and they don't seem to work well for a artificial star.

If I look hard enough sometimes I will find a suitable star, mostly a indoor bulb, or a

automotive light if it sits still for me, I only need a few minutes. 

 

Robert 

[clamchip]

Here's the Problem Child as it's rolled from my shop. 

I chock a wheel with the block of wood, remove the shower caps

pull up a chair and observe.

Even though I haven't had a chance to actually observe, I've rehearsed

the event many times. And I have done some daytime observing.

This must be a record for the most time waited for firstlight. 

I'm beginning to think the optical quality will most likely surpass anything

I've ever experienced in real life or my dreams.

 

 

[DAVIDG]

 I can't stress enough that a simple Foucault test with the mirror left install in the telescope will take less than 15 minutes to setup and it will tell you if the mirror has zones and/or astigmatism. If not then it has a chance of performing well .  If  you then see something weird in a star test then the problem is most likely the secondary. 

 

          - Dave 

[clamchip]

I'll dust off my tester and give it a try.

I've never used it before so it will be new to me. I built it from Sam Brown's plans in

All about Telescopes and the plans include detailed instructions on how to use it.

Robert

 

Edited by clamchip, 14 November 2021 - 07:46 PM.

[clamchip]

Also while I'm waiting for the weather to change I'm going to make a aperture mask.

I've never felt the need to view planets at f/4.5, but I want this Odyssey to be a general

purpose telescope if possible, a do all scope.

These dimensions are from the Coulter Odyssey Operating Guide and will convert the

Odyssey to f/12. These dimensions will probably work with other f/4.5's Like the Meade

DS and Starfinder scopes.   

 

Edited by clamchip, 14 November 2021 - 08:01 PM.

[DouglasPaul]

Also while I'm waiting for the weather to change I'm going to make a aperture mask.

I've never felt the need to view planets at f/4.5, but I want this Odyssey to be a general

purpose telescope if possible, a do all scope.

These dimensions are from the Coulter Odyssey Operating Guide and will convert the

Odyssey to f/12. These dimensions will probably work with other f/4.5's Like the Meade

DS and Starfinder scopes.   

 

manual5.jpg

There was one that did double duty as a cover when I got it but it got lost on one trip I took it on unfortunately. Truthfully I didn't see much difference with it but I didn't have much time at an eyepiece at that point either. Getting a little exasperated at the weather, I look forward to hearing how it performs for you plus I'm going to miss the eclipse on the 18th/19th.

[clamchip]

I set up my Foucault tester upstairs with a aluminized Edmund 6 inch f/5 mirror just to

keep the distance from tester to mirror short.

I can see I need to reduce the amount of light hitting the mirror because it's coated, and

I need more comfort so I can concentrate on the test and not the pain in my body !

Very fun and interesting the Foucault test, I'm going to like this, no, I love it !

I did dim the light somewhat with 4 layers of scotch tape over the port, enough to see

the mirror's surface and every single speck of dust on it. And I could make out what 

looks like a bowl with a slight raised broad rim, I suppose this must be the parabolic figure.

Before I move on to the Coulter mirror I will first and foremost do some reading so I

know what I'm seeing, dim the tester light, and sit in a chair !

 

Robert

Edited by clamchip, 15 November 2021 - 01:13 PM.

[DAVIDG]

 You don't have to use the knife edge only but you can also use your Ronchi screen. You just need to mount it were the knife edge is now and place a LED behind it. The Ronchi pattern maybe easier to understand then a shadows you see and they will easily show if the mirror  has any zones. 

  When it comes to understanding the shadow pattern you see with the knife edge, Sam Brown's 'All About Telescopes" has the best drawings in my opinion that shows all the different defects one can have.

 

                             - Dave 

[clamchip]

I'm going to read Sam Brown's work and watch some utube videos and see if I can

get a crash course on Foucault testing. I find the shadow pattern really interesting and

I'd like to know more.

I was able to dim my light source easy with a dimmer since it's 120 volt. I still don't

quite like it, I think I'll try a milk jug diffuser as well.

 

Robert

[clamchip]

Today I had one of those days here in the valley when seeing is almost

perfect. I don't know why, it may be because the ground and air are nearly 

the same temperature today, I'm not sure.

I do know I love this telescope. It could probably be any 10 inch f/4.5, or it

might need to be a Coulter Odyssey red tube 10 inch f/4.5, all I know is it

suits me very well.

I  was able to come up with some standout eyepieces to use in this scope.

Eyepieces I feel work well and match this seemingly demanding ultra fast

f4.5 telescope.

It didn't take long to weed thru down to these, the coulter is a little fussy.

I only own a few 2" ep's in focal lengths not for the Coulter so these are all

1.25 inch:

Astro Tech Paradigm 18mm

Celestron Ultima 12.5mm

Meade Research Grade Ortho 7mm

Celestron Ultima 5mm

Parks Ultrascopic 3.8mm

 

Robert

Edited by clamchip, 17 November 2021 - 10:41 AM.

[clamchip]

First light finally !

I started right in with Polaris for a star test with a 5mm.

Looks fine and no sign of my 'end of sheet' primary with it's uneven thickness

causing the figure to deform. It looks perfectly fine.

Polaris B was very obvious and piercing bright and not behind a spider vane

as usual ! because of the double circle spider.

I started counting Plato craterlets and was clouded out or more of a high fog

than anything else.

I saw nothing that set off any alarms except at low power bright stars looked

like disco balls !        I thought the double circle spider was responsible, the

diffraction from these curved vanes must go somewhere. But in fact it was the

mirror hadn't equalized, and I think it also has something to do with the curved

vane spider, I've never seen disco balls before, only on the television !

The focuser upgrade is a real plus I wish I knew who made it. I've searched

to exhaustion, no luck. I almost wish it had 2 speeds, depth of focus is measured

in 1000's of a inch at f/4.5 instead of inches at f/15 where I normally observe.

That was a pretty smart move on Coulter's part, lets give the amateur the bare

essentials and let them upgrade as needed if they feel its necessary. This is

how Coulter could keep the cost down so everyone could afford a Odyssey and

enjoy never before experienced huge aperture.

Robert

 

Edited by clamchip, 17 November 2021 - 12:24 AM.

[DouglasPaul]

Looks like I picked the right person to adopt that telescope Robert, it makes me happy to know it's going to be enjoyed, used and well cared for. I simply had no place to put it anymore. That was my first telescope, and I bit off a bit more than I could chew just stumbling along by myself because of the pandemic and never really got more than sporadic use out of it.

[clamchip]

Thanks again Doug I have really enjoyed working on it.

And I've only just begun, I'm planning new paint in the spring.

And maybe a Ebony Star and Teflon azimuth bearing.

The Coulter Odyssey is my kind of telescope.

 

Robert

[Kasmos]

 

The focuser upgrade is a real plus I wish I knew who made it. I've searched

to exhaustion, no luck. 

 

IMG_0536.jpg

The other day I spotted a ATM focuser in a old S&T that was very similar. It was also bare aluminum and the only difference that comes to mind was it had a piece of 90°angle aluminum where the two wheels mount. If I can find it, I'll post it.

[clamchip]

Here's the original 'sink drain' focuser that would have been supplied with these

red tube Odyssey telescopes.

The body is a ABS plumbing part you will usually find under your sink, complete

with it's compression fitting. The aluminum focuser tube is a part made by Coulter

specifically for the purpose. 

It works very well. I use the knurled aluminum focuser tube for course focus and

draw the eyepiece in or out for fine focus. 

Robert

 

[Kasmos]

Robert,

I found the focuser I was talking about. 

It's more different than I thought,

but I can still see why I thought of yours when I saw it.

It's pretty cool so figured you'd like to see it anyway.

It makes me wonder if yours is also a ATM

[clamchip]

Thanks for hunting it down.

Yes similar and very cool. I like the bearingless Teflon strips, I'll bet its really smooth and precise.

A focuser at f/4.5 needs to be precise and the Crayford design is perfect. It's only fault is the Crayford

is not the best for heavy loads, it can slip, in my experience.

Mine could very well be ATM.

 

Robert

[clamchip]

As much as I love a Telrad the Telrad base is stuck on the tube a little lower than

my neck likes. And for that matter the short Odyssey tube is just not a good scope

for a straight through finder of any design.

So the problem child has more to dish out !

I know from experience if you try and remove a Telrad base you will scalp your scope.

The attempted base removal with heat, fishing line, dental floss, etc will remove the

cardboard 'skin' and there's a big repair job in your future.

I recommend leave it be and work with it.

I have a laser base from Scope Stuff and it is basically a platform for anything and it

mounts in the Telrad base just as the Telrad does.

I'm going to mount this fabulous Treckerscope Galaxy right angle 7 X 50mm to the

laser base, and I will have no problem peering into it, even at Zenith.

Robert