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24" f/2.75

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#126 BinTian

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Posted 30 December 2018 - 12:06 AM

wow! nick telescope!



#127 Bob4BVM

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Posted 30 December 2018 - 12:21 AM

Thanks to everyone supporting this thread.  With the eclipse fast approaching & another star party immediately afterwards I won't be able to post on a daily basis. However I would at least like to answer Chris's question regarding collimation and will provide more detailed information at a later date.  Thanks for the lunch offer Chris.

 

Building a robust & reliable remote collimation system was easy compared to mating it with the "human" interface.  When done right it can be downright fun to collimate & "nail" the setting every time...if it's off it can be very frustrating.  Much time was devoted to getting this little part "just right". 

 

Since everyone's interpretation of "just right" is different here is the method I used:  Staring at Howie's TuBlug, a version of a barlowed target, it takes about 4 to 5 seconds for me (and several others who have seen it) to just make out with certainty, which way the return laser is moving on the target. Much faster, say 1 or 2 seconds and overshoot starts to become a problem.  Much slower, 8-10 seconds or so, makes it hard {for me} to retain a stare plus I get bored. And at least for me the same timing parameters were noticed at the eyepiece under high magnification star testing.

 

The method I used to determine this was to shoot high using a temporary gearbox/motor and a PWM control to "dial down" to find the ideal speed at the collimation tool.   That became the design point for the maximum primary mirror movement speed. From there the lowest required speed was determined by high-magnification star tests.  For me this proved to be about 1/8th to 1/10th of the barlowed target speed.  I found this difference a bit surprising but it clearly indicated that a single fixed-speed solution would not work well.

 

With the min and max speed of mirror movement determined the rest was easy:  2 RPM of gearhead output driving a stainless 1/2"-20 thread bolt moving a heim joint of a 3 point cell mounting system (one point pivoting but fixed) gives an edge movement of about 0.10" per minute.   This translates to about 0.048" of vertical primary centermark movement per minute at maximum speed and roughly 0.005" per minute at minimum speed (well before motor stall).   For Chris's scope, I would probably use these numbers as his primary f-ratio of 2.89 is close.

 

So with Elvira, the maximum output speed of the gearbox/motors is 2 RPM at 12VDC at 0.060 amps (60 milliamps each) which can be adjusted down to 0.2 RPM.  Even though the gearbox/motor units are smaller than a pack of cigarettes they can lift the 55 lb. mirror even when sitting level (scope pointed at zenith).  Due to the lack of motor mounts in this design, the motors are virtually silent with only the click of the direction buttons and corresponding movement of target as indicators of operation.  That's just the way I wanted it.

 

Ed

What can I say. WOW !

What a scope !

 

And maybe a coincidence too, since I also settled on 2 RPM@12V gearmotors for the collimation bolts in my binoscope project. My bolts are similar - 3/8-24 tpi s.s.  I tested in my Old Dob and found that operating at a fixed 2rpm seemed satisfactory so I am going that route for now, easy enough to add pwm later if necessary

 

Thanks for sharing your amazing creation with us !

If you are ever out this way , the burgers n beers are on me  :)

 

CS

Bob


Edited by Bob4BVM, 30 December 2018 - 12:43 AM.


#128 opticsguy

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Posted 30 December 2018 - 12:49 AM

My apology for using the word "competition" in a previous posting.  Was intended as a little fun, not to be taken seriously.  Both scopes are incredible, inspirational, and amazing.  

 

Elvira, the scope we are talking about in this forum, is probably the most comfortable scope I have ever used in many ways.  My personal scope, the one most used by me is an 8" f/13 refractor, almost completely the opposite from this 24" scope.  I have greatly enjoyed my 8" scope, very easy to use and comfortable.  Elvira was even easier and I was able to vies some objects in the sky I had been chasing for awhile that I could not find in any other scope.  

 

Excited to get my hands and eyes on Mel's scope if he allows . . . . . . . . . .

 

No competition here, just fun!!!!!



#129 phonehome

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Posted 02 January 2019 - 10:22 PM

Thanks everyone for the comments!  If there's no opposition, I'll continue in the "no competition/keep it fun" spirit suggested by Pierre Lemay and opticsguy. 

 

And on that lighter note, here is a pic of something you don't see everyday...a license plate/frame on the back of a scope transporter:

 

 

Elvira's License Plate.jpg

 

 

Note: the camera doesn't do the red paint job any justice.  It's a metallic deep candy apple red with clear-coat.


Edited by phonehome, 03 January 2019 - 08:20 AM.

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#130 phonehome

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Posted 02 January 2019 - 10:32 PM

For clarification and full disclosure:  the pictures in posts #110 & #111 show the scope tilted while on the transporter.  In actuality, the scope is kept vertical with the mirror horizontal while being driven around.  This keeps the mirror's weight on the cell's 18 pads and not the whiffle-tree rollers.

 

When compacted down for trailer hauling as shown in post #119, the mirror is of course horizontal.

 

Ed


Edited by phonehome, 02 January 2019 - 10:33 PM.


#131 phonehome

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Posted 09 January 2019 - 08:31 PM

This post regards a recent update to the cage handle that controls the electronic clutch system.  As Mr. Lockwood mentioned in his post #123 below he thought he would prefer an optional button for activating/deactivating the clutches for finer pointing/release accuracy:

 

 

Anyway, I wanted to mention Ed's clutch/drive system, since he and I have been discussing it a bit lately, and because I have used it quite a bit.  It makes moving the telescope around quite effortless and fast.  You simply grab the handle, the clutches unlock, and you can move the scope in any direction that you wish to.  My only personal request would be that the clutch unlocking could be done optionally with a button mounted on the handle.  That way I could more precisely determine when the clutches lock back up, which would allow me to more easily center objects.

 

 

We have discussed this human-interface detail on and off for about a year now.  Although adding a button is certainly easy enough, after further review I believe the root cause has been determined.   It consisted primarily of two timing delay components.  First, the original IR beam was located parallel to and at a distance of 0.55” out from the handle's surface.  When closing/wrapping a hand around there is a delay from the time a hand makes contact with the outer-part of the handle and the fingers wrapping around and breaking the beam (in itself not an issue).  However the ensuing release of the handle is an issue for a few since one's fingers have to completely clear the beam to deactivate.  The second timing component was a programmable digital circuit that was used as a IR de-bounce plus DOR (delay on release) for dampening.  Adding these two together plus the response time of the IR detector circuit itself resulted in an average release time of approximately 300 milliseconds. 

 

As Tom Masterson mention way back in post #10, capacitance-based sensing circuits were experimented with early-on but dropped due to issues with stability/compatibility which is why IR was eventually adopted.  However, for this time around the topic included a “crash course” on the finer design points of touch-capacitance sensors and overlay interfaces with different IC chips.  Below is the best version:

 

 

 

Sensor Handle Components -Redux.jpg

 

 

This is a disassembled picture of the revised handle.   As before, the handle itself is made from glass-filled, non-conductive plastic taken from a side-handle of a hammer-drill (E-bay part).  An unmodified, common, 4-point touch sensor circuit board based on a TonTouch TTP224N-BSB chip, available from Amazon, E-bay and a thousand+ other places for a couple of bucks is shown at the bottom.  The same board in the middle of the picture has been modified to allow for insertion inside the hollow handle (about 24mm ID).  The board was simply cut at the pads, folded 90o & soldered into an “L” shape.  Plastic brackets were added, the insulating PC overcoat removed to bare the copper pads and conductive foam attached with conductive adhesive to extend and connect the electrostatic field to the inside of the handle.  The conductive foam fills the air-gap and electrically couples the flat pads to the round handle interior.  The four touch-point outputs are matrixed together so detection at any one or more results in clutching.  The circuit assembly slips into the hollow handle, held in place with non-conductive foam plug inserts.  As before, the bottom end plug on the right is soft-red LED illuminated with both handle ends sealed with O-rings.

 

The chip is strapped into “fast mode” so detection and release are each about 60 milliseconds.  The debounce circuit is set to match and the DOR function is zeroed out.  The total electronic release delay is now about 1/5th the original.

 

 

 

Sensor Handle Touch Area Redux.jpg

 

 

 

The projected exterior sensing region is outlined in this second picture.  It actually consists of four in-line and overlapping areas which form a long rectangular area. The sensing distance from the handle to the hand is around a few hundredth's on an inch and it works equally well with a bare hand, a light glove, a rubber glove or an insulated winter glove. 

 

The chip is self-calibrating, meaning that each time the scope is powered up or a handle release is performed, the circuit quickly re-calibrates for it's environment.  In-between activations it slow-calibrates.  This makes the handle sensor moisture proof (both dew and frost) and temperature change proof.  The chip is strapped for no time-limit on how long the handle can be activated.  Power consumption in standby for the sensing circuit is 10 micro-amps @ 3.3VDC.  So far it has been completely immune to a barrage of RF signals.  All these aspects have been tested and confirmed.

 

A lesser but related determination was the location of the IR beam.  It was not quite optimal as before it was in a fixed position directly between the handle and cage.  Having the entire sensing circuit inside the handle makes rotation possible, placing the sensing area into the best position for hand-wrapping before finger-pad contact.

 

On a side note, in strong direct sunlight the IR system was sometimes inoperative.  The capacitance-based sensor is of course immune to this. 

 

This post probably has more detail than needed but if anyone wants a touch-sensor controlled device inside a weather-proof overlay or housing then maybe this information will prove useful.

 

Ed


Edited by phonehome, 09 January 2019 - 11:39 PM.


#132 Mike Lockwood

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Posted 11 January 2019 - 11:20 AM

Another fine update/upgrade.  I look forward to trying it out at Okie-Tex.



#133 darthwyll

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Posted 18 January 2019 - 06:22 PM

I was able to get lots of footage of Elvira this year at Okie Tex. It's been fun seeing the upgrades as time goes by. :)

 

Link to video:
https://youtu.be/PXBmwN2auLY


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#134 Chucky

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Posted 19 January 2019 - 11:13 AM

<<  I was able to get lots of footage of Elvira this year at Okie Tex.  >>

 

Nice.  Eddie is a true gentleman and more than willing to demo and explain every working of his very, very cool scope.  I saw it in action at Okie-Tex in 2017.


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#135 a__l

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Posted 19 January 2019 - 05:01 PM

The author on his videos in youtube showed a photo of the moon through the eyepiece. If he shows StarTest in the future for the telescopes , it will be really interesting information smile.gif


Edited by a__l, 19 January 2019 - 05:41 PM.


#136 phonehome

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Posted 26 February 2019 - 07:03 PM

Since there are a few more areas left to be outlined/shown this post will detail the Alt drive and clutch mechanism.  Attached are two photos, one with the cover on and the other with the cover off.  

 

In the middle is a typical Pittman servo-motor with it's 10-1 reduction box (silver).  A 40-1 ULB worm gearbox by OnDrives is just above (in red).  Together these are mounted on a sliding plate (silver-vein gray) with the two star knobs in slots used for adjusting timing belt tension.  The belt couples upwards to one of the two Alt trunnion weight bearing shafts.  For scale the shaft is 1.0" O.D.   

 

The belt is coupled to the top-hub which is both free-wheeling and shuttles back and forth about 2/100ths of an inch.  This hub transfers drive force to the clutch which is immediately to the left of the hub.  There are some unseen & adjustable components inside the clutch which ensure clean separation of the plates.  To the right of the top-hub is the clutch yoke (black).  To the right of the yoke is an adjustable spring for adjusting/adding latent resistance as needed.  Below the yoke and behind the aluminum "triangle" is a linear actuator inside a rubber cover.  As in the Az mechanism, there is a 4-1 ratio of actuator-movement-to-clutch-movement.  The pivot can be seen at the top of the aluminum triangle plate.

 

The Alt trunnion weight bearing shafts are 0.065" wall (hollow) stainless tubing that's been TGP'ed.  Note on the end of the shaft between the black hook (rocker is hanging from an overhead winch) and the gray pillow block in the upper right is a stainless collar.  These collars are what the red aluminum trunnions of the mirror box ride on.  This not only reinforces the tubing at the contact point but it also decreases the ratio between the shaft and trunnion from 40-1 down to 30-1.  This kinetically low-mass approach to these shafts and their ratios are important for the scope's unique very fine-feel when aiming manually (both axis). 

 

The collars also offer the opportunity to securely hold (sandwich) large poly washers (gray) that keep the trunnions tracking and in-place between the pillow blocks.  I've found this works much better than rollers or guide pads at the bottom of the rocker box to hold the trunnions/mirror box in place laterally.  With one collar+washer in each of the four corners they also function as convenient guides when using an overhead winch to raise/lower the trunnion/mirror box assembly on the rocker.

 

 

Alt Drive & Clutch Cover On 1.jpg

 

 

Alt Drive & Clutch Cover Off 1.jpg

 

 

BTW, the large black rectangular plate to the left of the Pittman is a pivoting cover which allows inspection and access to adjustments for everything located in the groundboard below.


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#137 clivemilne

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Posted 06 April 2019 - 08:54 PM

Some excellent stuff there Ed... thanks for the heads up..

Looks like these guys do complete track assemblies with motors... not sure if that is the cheapest way to go, however.

 

 

https://puyitracks.e...-for-300kg.html


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#138 jeff.bottman

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Posted 02 May 2019 - 03:20 PM

Today at Texas Star Party Ed presented Elvira to us and demonstrated its many amazing capabilities.  I can't conceive how he created this masterpiece in only 8 months, and would love to hear a bit about Ed's career and background some time.  The project required so much advanced knowledge and skills in so many disciplines ... optics, air flow, robotics, electronic control systems, power systems, etc, etc.  I guess in each generation are born a few Einsteins or Mozarts!


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#139 Mike Lockwood

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Posted 06 May 2019 - 06:36 PM

Ed is an electrical engineer, like I was, but he actually got to build things.  (I ended up in DSP, and then started making mirrors.)

 

So, he took the opportunity to design and build exactly what he wanted.  I will let Ed fill in what he wants about his experience, but I will point out that what Ed did was take the best-suited technologies off the shelf and integrated them into Elvira.  Simply knowing what is available and appropriate for what you want to do is half the battle these days.


Edited by Mike Lockwood, 07 May 2019 - 10:24 AM.

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#140 skyward_eyes

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Posted 07 May 2019 - 07:37 AM

Had a chance to see and work with Ed’s scope last week at TSP. This scope is nothing short of phenomenal, it is one of the most well thought out and executed telescopes I’ve ever seen. Every last detail is just impriessively done.

The operation of the scope is excellent and as someone who does tons of outreach I would say this is the ultimate scope. The Lockwood optics are beautifully crafted to provide solid images, I would expect nothing less.

All I can say to Ed is thanks for being so generous with your scope and allowing my friends and I to work with it.

Edited by skyward_eyes, 07 May 2019 - 07:39 AM.

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#141 phonehome

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Posted 14 May 2019 - 10:42 PM

Thanks guys for the support and encouragement!  The Texas Star Party was a blast with multiple good nights of good seeing and tons of comradery...attendance is highly recommended for those who can!

 

Mike is correct, I was an EE and over a long career was fortunate enough to be tasked with a variety of projects for a wide range of clients.  And yes off-the-shelf IS the first place to go for most things...sometimes the wheel doesn't need to be reinvented...just turned!

 

One of my personal idiosyncrasies for project development was an examination of the human-machine interface.   That's how the "Elvira Project" originally started out: by observing amateur astronomers at star parties and how they interacted with their scopes...probably more so than my observing through them.

 

Here is the crawler-transporter timeline as there are probably few better examples of "working-from-the-shelf":  

 

In the beginning - life as a wheelchair:

 

In the beginning.jpg

 

Then re-purposed into a Scope Transporter:

 

Original Transporter Sideview.jpg

 

And finally a Transporter-Crawler:

 

Transporter Revised Side View.jpg

 

At least it kept its colors!


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#142 starzonesteve

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Posted 15 May 2019 - 12:00 AM

One of my personal idiosyncrasies for project development was an examination of the human-machine interface.   That's how the "Elvira Project" originally started out: by observing amateur astronomers at star parties and how they interacted with their scopes...probably more so than my observing through them.

That is wild. I would have never thought to take that approach - but then again, it's not my area of training. Good on you!



#143 starman876

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Posted 18 May 2019 - 05:42 PM

This is amazing.  Wish I had the time to build something like this. I am impressed beyond words.

 

bow.gif bow.gif bow.gif



#144 Bob4BVM

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Posted 18 May 2019 - 06:27 PM

She just keeps getting better Ed !

 

When will we see the ride-aboard observer's seat ?  ;-)

 

I hope to make it to Long Creek at months end, thx for the heads-up.

 

CS

Bob



#145 phonehome

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Posted 24 May 2019 - 07:39 PM

When will we see the ride-aboard observer's seat ?  ;-)

 

That would be just after Mr. Lockwood's automation request is implemented:    Alexa - drive the scope out and acquire the first target smirk.gif

 

My guess is after that the amatuer astronomer becomes...optional.



#146 Mike Lockwood

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Posted 24 May 2019 - 09:01 PM

Then comes the next great advance in technology - the self-contained, lithium battery-powered, all-terrain mobile beer fridge.  "Alexa, adjust temperature to 38 F and bring me a craft beer."

 

We live in a wonderful time.


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#147 Bob4BVM

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Posted 25 May 2019 - 01:09 PM

Then comes the next great advance in technology - the self-contained, lithium battery-powered, all-terrain mobile beer fridge.  "Alexa, adjust temperature to 38 F and bring me a craft beer."

 

We live in a wonderful time.

Ha, we're closer than you think !

Ed already has it 90% done. The cooler is in the crawler base, all he has to do is install the plumbing for the tap, up next to the focuser.

And that is why I asked about the seat...

CS

Bob



#148 WoodyEnd

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Posted 27 May 2019 - 03:41 PM

This scope is truly beyond my imagination. If I see a telescope driving itself down the road I will know who built it. All I need to do is follow it to its destination! 

 

I really need to check the reflector forum more often.



#149 phonehome

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Posted 10 June 2019 - 09:17 AM

Way back in post #105 I mentioned attending Star Parties and not always knowing what to expect [for terrain].  Thought I'd share this pic of one of those obstacles located between the campground at Logan Valley SP and the observing field:

 

 

Cattle Guard Crossing.jpg

 

 

The grates are spaced about 10" on-center but thanks to the tracks it was easy to traverse, just went a little slower.  


Edited by phonehome, 10 June 2019 - 09:21 AM.

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