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Well that escalated quickly- intense Fever + addiction.

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#1 AposkiiLola

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Posted 26 February 2020 - 01:41 AM

My aperture fever has caused a bit of crazyness.   I bought a 444mm x 2000mm mirror in december and im not one to quit a challenge!   Telescope building is crazy addictive, and i must say that Hubble must of been a great friend!

 

Trying to decide if i want to add a tertiary folding mirror to this next or just mount up the  secondary and call it a build..   IF i fold this , I am going to mount a 100mm x 540mm apo fluorite to its output to function as a relay system; which will be feeding a hungary  80mm x 540mm apo fluorite. 

 

Oh woe is me. IS there a cure, or am I now doomed.   Is 17 inches enough? Are projects even worth time and effort when one could just sleep the fever away and ignore the calls to go back working for the sky?  :)

 

49586597626_2f4793e0b2_o.gif49586843252_a7c38b3123_o.jpg

 

 

I will update this as I progress;   I could mount up the primary to this base plate as is-  but i think the crazy doctor wants to slice out a few sections; freeing up some precious ounces.

Eventually some spring prosthetic support and the inevitable cooling fan.

 

Oh Heck my fever is causing vivid hallucinations of a bluetooth linear actuator instead of a focuser.  Doh......


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#2 scngc7317

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Posted 26 February 2020 - 01:51 AM

So whats the problem ???

 

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#3 Jon Isaacs

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Posted 26 February 2020 - 02:15 AM

A few thoughts:

 

-A 17.5 inch F/4.5 only needs a short ladder. 

 

- 4 inch F5.4 Fluorite sounds like a Genesis. The Fluorite is in the rear , not the objective. Not an apo.

 

- What scopes do you currently use? How long have you been observing with them? Why a larger scope? 

 

Jon


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#4 AposkiiLola

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Posted 26 February 2020 - 09:18 AM

A few thoughts:

 

-A 17.5 inch F/4.5 only needs a short ladder. 

 

- 4 inch F5.4 Fluorite sounds like a Genesis. The Fluorite is in the rear , not the objective. Not an apo.

 

- What scopes do you currently use? How long have you been observing with them? Why a larger scope? 

 

Jon

Well the boxes say apo soi guessi just naturally trustedcelestron.

 

one is a celestron regal 100F-ED

two is a celestron regal 80F-ED

 

they are advertised as fluorite apo spotting scopes,  so i unthreaded the prism and focuser assembly.

 

 

i have many scopes thati seldom use anymore and like the large collection above quite a few just sit around now due to kids and work.     The main reason is i find a deal which i consider to good to resist to i end up gobbling the  up

 

my pride and joy is a 150mm x 2250mm ,  and a 160mm x 1600mm h-alpha solar scope.

 

my first telescope as a kid was a meade 4500 mirror, and its what got me addicted to telescopes over the years just tinkering and fidgeting with parts cannabalized from other things like cars and microscopes. 
 

i just have the wierd urge to do something unconventional and massive for onlooker shock factor, using a more complicated approach.  Thats where the folding mirror and fluorite optics go into play with the 17” mirror.

 

if i add the therelay system, no mirror would be required and the eyepiece section would be attached to the 80mm end.

 

 

i have a bit of experience making complicated laser assemblies with dozens of beam turning mirrors and kinematics , so i thought to my self  “what would the moon look like projected though one of these optical benches”.   Then it hit me like a brick thats what all scientific grade observations do.   
 

pump light from the universe through dozens  of beam turns and splitters applied to exotic filtration systems and spectrophotometers

 

also building something that resembles the hubble space telescope a bit does seems kinda interesting.

 

construction.jpg
 



#5 Jon Isaacs

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Posted 26 February 2020 - 09:54 AM

The Regal spotting scopes are not Fluorite but rather some Fluorite based ED glass, probably FPL-51.

 

I had a similar scope, an 80 mm ED spotting scope and I decided to use the objective for an Astro scope so I built up a test platform using the objective a tube and a focuser.  The result was most disappointing. As a spotting scope, the color correction was quite good but in the test platform, the chromatic aberration was quite significant and provided a turquoise CA. I could only think that the lens itself was designed with the prisms and lenses in mind and that without them, it changed the color correction.  I also have corresponded with folks who've tried to use the Regal 100 mm objective with disappointing results.

 

I can't help you if you goal is onlooker shock, I just don't think that way. I think in terms of a practical scope easy to use scope that provides the best possible images. Any onlooker shock hopefully comes from looking through the eyepiece...  There can be some from the mere size of the scope but it's best if that can be avoided.. 

 

4391326-Obsession and Jon at Jewel Valley.jpg

 

Lasers and complicated beam paths are quite different than a telescope where every optical surface degrades the image and near perfect optics are possible. 

 

My two cents

 

Jon



#6 Mike Spooner

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Posted 26 February 2020 - 10:08 AM

 

 

Oh woe is me. IS there a cure, or am I now doomed.   Is 17 inches enough? Are projects even worth time and effort when one could just sleep the fever away and ignore the calls to go back working for the sky?  smile.gif

 

 

 

 

 

17.5 inches?? Sure the cure for this fever is 18"!! Be aware that a mutated fever circumvents this particular cure.lol.gif



#7 macdonjh

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Posted 26 February 2020 - 12:21 PM

17.5 inches?? Sure the cure for this fever is 18"!! Be aware that a mutated fever circumvents this particular cure.lol.gif

Careful, AposkiiLola, Mr. Spooner sells vaccines.  I smell conflict of interest.  smile.gif

 

I like Jon Isaac's comments.  Something unreasonably complicated makes for a good project.  If you want to really go all the way, make it Steam Punk.  That will get your on-looker awe.  Lots of brackets and polished brass.

 

However, for actually seeing the stars, simpler is better.  Better views, less time setting up and taking down, more time viewing.


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#8 AposkiiLola

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Posted 26 February 2020 - 03:19 PM

All good stuff to think about, and yes the spotting scopes certainly use the prism to alter the refractive index and remove chromatic aberration via advanced corrective coatings.   Probably similar to the semi apo filter by baader planetarium.  I mounted one up using the internal 66mm threads directly to an sct focuser. I found the optics acceptable for gamble, and a cost of only $120 was irresistible for what they are advertised at.  But again i agree this is nothing worth bragging about. Just another mass produced chinese optical gimmick spoiling the real market of high class instruments.

 

however; i am not a perfectionist and this is merely a form of entertainment to me at this time;  the mirror is an odyssey 17.5” and likely nothing spectacular worth bragging about.  I am interested in the structural challenge and the mount up procedure.  I live near chicago so my local seeing conditions do not provide the appropriate sky other than planetary.  No chance in me lugging this scope around ever.  I could also picked a more practical to build it, but i am also trying to use up stuff i have collected over the years that currently is laying around the garage and shed taking up space.  Including the regal scopes, this just makes things a bit more interesting.  

 

agreed about the optical surfaces as well, my folding mirrors and secondaries are 20lambda so no troubles there.

i must admit i may end-up never pointing this at the sky, and will likely just keep it as a conversation piece in the window.  I cant live with the thought of keeping the mirror trapped in a shipping crate :)  

 

it is similar to a puzzle, if i can get away using that analogy.

 

thank you for the comments!



#9 gregj888

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Posted 26 February 2020 - 05:30 PM

AposkiiLola,

 

Please take solace in the fact you will be cured.    For me it was at 20", though I do enjoy a dram from something larger when I can get it.



#10 Steve Dodds

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Posted 26 February 2020 - 05:42 PM

This is the cure for aperture fever.  Although if a 100" came on the market it might start him thinking.

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#11 gregj888

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Posted 26 February 2020 - 06:08 PM

This is the cure for aperture fever.  Although if a 100" came on the market it might start him thinking.

In all fairness, some are more easily cured than others...  but I'd have a dram of that... jump.gifjump.gifjump.gif



#12 Benach

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Posted 27 February 2020 - 01:59 AM

Well guys, I beat y'all when it comes to aperture fever. See my undersign. I have worked a tiny tiny bit on the ELT design.

#13 AposkiiLola

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Posted 27 February 2020 - 04:37 PM

This is the cure for aperture fever.  Although if a 100" came on the market it might start him thinking.

oh my gosh you just gave me a reason to visit utah!  



#14 Steve Dodds

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Posted 27 February 2020 - 05:01 PM

It's up and running every clear weekend, spring through fall

 

http://www.slas.us/spoc2.asp



#15 hamishbarker

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Posted 02 March 2020 - 03:37 AM

So whats the problem ???

 

nice forked newtonian!




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