7003 replies to this topic

[musicengin]

That's great!  she's way, way ahead of me, today I decided to change how I attach my secondary holder to the vane, which means redrawing the vane.  There ARE things I can do fast, such learning and playing contra dance tunes, but not building telescopes.  I'm much too interested in exploring my oddball ideas.

[member010719]

I'm using the ''Reflecting Telescope Baffle Calculator'' :

 

http://www.bbastrode...com/baffle.html

 

I made the calculations for the 8 inch Dobsonian and today was the day to make the focuser baffle.

The secondary mirror and primary mirror baffles are solved with the solid tube , however I checked my choosen values with the calculator.

Having to change the blade for metal and to do epoxy glueing , I made also new field stops for two DIY oculars.

 

 

At left is a WWII ''Busch'' 30mm Erfle , in the middle is a RK 35mm and at left is the focuser baffle for the HC-2.

 

 

For both oculars I modiffied  the baffles for a 60 deg. field.

 

 

For the main  item ,the focuser stop , I started from the 31mm field stop of the LV 30mm ocular to be used on the Dobsonian.

The diameter of the focuser stop is 38mm ,the secondary is 46mm m.a.

 

 

Ziridava

Edited by ziridava, 03 July 2017 - 03:56 PM.

[PETER DREW]

Started work on a driven chair mount for a 150mm F5  achromat binoscope.

[Jeff Dunn]

 

Installed cooling fan controller today. DT switch controls low, high, and off near the eyepiece. Adding a third fan on the bottom, one of the fans I have is bad.

[brave_ulysses]

mr turco,

 

have you considered setting up a webex or similar link to reach potential students?

 

 

 

A lady called me a few weeks back and wanted me to teach her how to make a telescope. 

 

 

SHE FINISHED IT ALL TODAY !!!

 

 

I can hardly believe it but she came every day, 4 to 6 hours per day.   I wonder if there are any more like her, waiting to call.

 

Recently, I realized that my RA has crippled me to the extent that I can now longer make telescopes.  Hell, I can barely walk now.   Or observe.  It was a great 60 year run. 

 

But these new experiences have taught me this new role as a teacher is FUN!

 

 

ed

[DivisionByZero]

I am nearly done with a heated sensor window for my DSLR.  I got the TEC device and controller working and then re-opened the camera to sort out a sensor-window heater.  I had previously pulled out the low-pass filter from in front of the sensor and replaced the sensor glass with AR-coated stuff after removing the CFA.  There's now this plastic window frame that will now hold an additional piece of AR-coated glass.  The AR glass is 1mm whereas the old filter set was about 3mm.  The space left over is now partially filled with nichrome heater wire and kapton tape.  The image is during my "winding" process.  The finished version has about 4 layers of nichrome there for a total resistance of 55 ohms or so.  As long as I put a suitable resistor in line, I can run it off of 12V with everything else and add 0.5W to the camera power load.  Previous investigators found that if you set up two windows like this (the nichrome will be between the top glass and the sensor glass), you'll get a "greenhouse" effect and keep the middle part warm enough to fight condensation when the sensor is cooled down.

 

This first glass got abused a bit much during the winding and it's been replaced with a piece that I've been much more careful in handling.  I have some silicone drying now but I'll snap another picture when it's re-assembled on the sensor.  APS-C sensors are crazy big and i don't have a coma corrector yet, so even if I vignette some of the edges of the frame, it won't impact me too much, I don't think.

Attached Thumbnails

• 

[musicengin]

I still like my secondary holder design, but the details of building it have been in flux.  I think I got all my drawings done this morning. 

 

Sweating details like crazy.  But I'm having fun, and it's going to be a better gadget for all this.  I think!

[Biff]

I neatly packaged the OnStep electronics and 3D printed a custom case for it. It took me a few failed prints to sort out all the design errors, tolerances are pretty tight, it fits like a glove!

 

FullSizeRender (9).jpg

FullSizeRender (10).jpg

Very nice. Do you have some better pictures on how you wired the circuit boards together? Looks like you have the HC-05, my setup on the bench has the sparkfun unit but I don't imagine that would change much over what you have. 

[brave_ulysses]

i decided i'm a button pusher and not a handle turner...

 

part way through a conversion on my mini lathe. the quick change tool post is a welcome addition. wedge > piston for cutter registration

 

http://www.ebay.com/...w-/331712436344

Attached Thumbnails

• 

[DivisionByZero]

I breathed a sigh of relief today as I closed up the camera and took a few shots to make sure the thing still worked.  It does!  

 

I also did the assembly of the TEC system with thermal paste at the appropriate locations and ran the setpoint at 19C (ambient is 25C in my basement).  Works fine there.  I've already identified some design adjustments to improve the cooling performance, but even this should be an improvement over uncontrolled temperatures during imaging sessions.

 

It's not very pretty, I know, but should be effective.  I haven't connectorized the sensor-window dew heater yet, but that went in without a hitch. 

 

A small informational note: 4-pin computer fans are designed to operate at maximum RPM if no signal is detected on the control wire.  I had to look that up for this project.

 

 

Attached Thumbnails

• 

[musicengin]

I think I got all the drawing work done and I can cut it out.  I'll find out this afternoon.

 

 

 

 

 

When I have glued it up I'll post a picture.  Even if I decide to change it again, I'm getting really close to feeling satisfied enough to leave it as is, so I don't think I'll make any more than minor changes.

[jtsenghas]

I made a quick Baader film solar filter for my antique 75 mm refractor. The idea was inspired by those foam insulating holders for canned drinks. 

 

 

I sliced some leftover foam from making my eyepiece case on my wood lathe using a faceplate, some double sided tape and a knife. One piece has an inside diameter that stretches slightly to fit around my objective cell and the other has an inside diameter to match the 75 mm objective. 

 

I attached the film to the latter with two sided tape and then duct-taped the two together while the other piece was on the scope. It worked great. There are some interesting sunspots to see now. 

[jtsenghas]

I didn't even have to make a solar finder! 

 

With the red dot finder removed from within my PVC altitude bearing, the 1" holes that finder usually sits between work great. All I have to do is aim the scope so that I don't see a crescent of light on the inside of the bearing at the rearmost hole. 

 

[musicengin]

I cut out my secondary holder and dry fit it, recut the piece I got backside to, and here it is, front and back view.  The micrometer is set to one inch.

 

 

 

 

 

 

The doodads in the middle are where the vane attaches, fitting in between them and with another bolt running down the middle of it all.  There are two whole little 4-40 captured nuts in the thing, this delights me no end.

 

 

I still really like it, that's a relief. 

 

The vane is cut, but needs bending, which I am procrastingating on.

Edited by musicengin, 08 July 2017 - 05:03 PM.

[jtsenghas]

The micrometer is set to one inch.

Funny, your micrometer looks just like my dial vernier calipers! 

[Bob4BVM]

 

The micrometer is set to one inch.

Funny, your micrometer looks just like my dial vernier calipers! 

 

" dial vernier calipers" ??   Never seen one of those...

OK, if we are being picky we should point out that a Vernier caliper is a distinct tool, it does not have a dial, the user interprets a linear rule scale for measurement.

Cheers

Bob

[roscoe]

being REALLY picky, a micrometer is a c-shaped mechanical measuring device using a fine-thread calibrated barrel and bolt.

 

A digital micrometer, still c-shaped,  still incorporating a fine-thread bolt, reads and displays thickness of a test piece with sensors and a digital display.

 

A vernier caliper uses two sets of graduated marks on a pair of straight bars that align to indicate thickness.

 

A dial caliper uses a mechanical geared pointer riding on a pair of straight bars to indicate thickness.

 

A digital caliper uses electronic sensors and a digital display on a pair of straight bars.

 

It seems to me that any mechanical caliper that incorporates a dial indicator uses that indicator as a vernier, supplementing the mechanical marks on the caliper, so would most accurately be called .... a ..... dial vernier caliper.

 

However..... the person in question here works in a shop that builds and restores musical instruments, and niche occupations and other locales often have different words for the same tool.... an open-end wrench is a spanner in many places, for instance...

 

So let's back off and tell the lady, who is new to astronomy and new to ATM, that it's a very cool secondary holder, instead of getting all OCD and picking her choice of tool-description words apart, even if in humor, which not everyone finds funny.

 

Grumble mode off....

[member010719]

Agree , it is a very cool secondary holder !

Can't wait to see the whole telescope ready for a stellar ride...

 

Ziridava

[musicengin]

Agree , it is a very cool secondary holder !

Can't wait to see the whole telescope ready for a stellar ride...

 

Ziridava

Thank you!

[musicengin]

 

The micrometer is set to one inch.

Funny, your micrometer looks just like my dial vernier calipers! 

 

 

We can't make up our minds at work what it's called either.  There's another post I made about oddly named tools of the trade, if you're interested by creative naming conventions.

 

Sometimes, people wander around looking for, "the um thing that you know does such and such" and someone points it out in its current non-standard location and work flows forward. Names are handles, any name will do if someone knows where it is and its user knows how to use it.

 

And before you complain that a well regulated shop should have all it tools properly put away all the time, well, people forget, people open the wrong drawer and put things in, people here are musicians first, highly able and motivated musical instrument makers and fixers second, and well regulated somewhere a lot further down the list.

[mark cowan]

"That thingamy with the whatsit" usually gets the job done.  

[roscoe]

I mostly work alone, so whatever's misplaced, misfiled, misnamed, or empty when it should be full....well, at least I know who to yell at.....

Edited by roscoe, 09 July 2017 - 06:49 PM.

[Frank]

Worked on the secundairy cage of my 13" bino-scope. Stil a lot of work to be done.
.

[Frank]

Picture of focuser set-up. Eye-distance setting via a double spindle and 3D-printer sliders.

.

 

Attached Thumbnails

• 

[roscoe]

That is truly amazing!