The vernier will have to be fixed to the top board otherwise you won't be able to make your setting, I can't see the need for any adjustment.
The main azimuth scale will rotate freely on the bottom base (as previously mentioned) until you align your scope to a chosen target. Same as my setup, but replacing my pointer with the vernier. Actually simpler than I originally thought. You will have to fit the vernier by locating the 12mm hole to your M12 pivot bolt, simple.
As I mentioned earlier I will make a set with the vernier located on the inside of the main azimuth scale. The main thing will be to make the main azimuth scale with enough thickness to rub up against the lazy susan without sliding underneath. Also you will need to make your circular cutout around the lazy susan as close as possible and of course concentric with the calibrations and the M12 pivot. I will include a 12mm circle at the centre of the azimuth scale to locate it on the pivot. With the lazy susan fitted on top of the azimuth, use a new sharp blade (surgical blade) you should be able to stab the azimuth scale right up tight against the lazy susan. With the blade held at a slight angle secured into the bottom board and by rotating the free azimuth scale achieve a very accurate fit, this is how I did mine.
A lot of this depends on what type of lazy susan you are using. The one on the lightbridge has two identical round plates located simply with a centre hole. I have seen some lazy susan bearings which are rings not plates, not to sure how easy this type are to fit accurately.
A new azimuth scale with internal vernier, let me know what you think. An old fashioned phone call will be better.
Cheers
Richard
ps As we discussed, added 60' vernier.
Will post pics ASAP
Thanks Richard, I will print out the 60min internal vernier and let you know if any of the measurements need adjusting, but otherwise looks perfect.
I understand why 60 mins can't be accommodated in a 30deg arc without increasing the main scale gradations, so will just stick to the 60min vernier.
should be able to fix it to my dob in a few days. will post pics once done.
thanks
My name is Dan and I have a odd request about the azimuth ring (circle) template you create (your talents are desired by more than the amateur astronomy groups).
Is it possible to make a azimuth template like the ones you have in this forum, but have it fit a 60-inch radius?
I have been searching for a program or anyone who could make a 120-inch round azimuth ring (template) and found your posts here. I have tried; Word, PowerPoint, Google SketchUp, GcmWin316BeGreat_Circle_Map.exe, RACIRC.EXE, SETCIRC.EXE, and Shadows.exe. None of which I could figure out or have it correctly create azimuth scale with a 60-inch radius (they may do it, I just couldn't).
What is the purpose of the 60-inch azimuth ring? During WWII the seacoast artillery battery's used a plotting board to track the location of targets (ships) to fire at. The actual board is listed in the WWII manual as having a 58-1/3 plotting radius (there are several different board sizes).
I am attempting to reconstruct a seacoast artillery plotting board for Battery 519 (Fort Miles) located in Lewis, Delaware (USA) with a diameter of around 120-inches (60-in plotting radius). It's a little larger due to the construction materials used (wood). The board will be used for student educational purposes and to show the basic operation of a seacoast artillery plotting board.
The outer most ring in the picture is the azimuth ring/circle.
What type of azimuth circle template is needed?
* Fits a radius of 60-inches (120-inch dia)
* "0" as true south (180 north) ** The centerline (directrix) for this battery was: 278.86, East
* scale width of 1-1/2 inch (sections length as fits on standard paper)
* regular font (no italics for the numbers)
And if possible could it be made as "reverse printing" also? This would allow printing the sheets on plastic so they wouldn't be rubbed off.
If making a full circle template is not feasible then could one or two scales be made which when copied/printed they would fit a 60-inch radius (I could edit in the numbers)?
General text from the seacoast artillery manual:
"The circle is engrayed and numbered at 1 deg intervals, and the mean azimuth of the gun is indicated by the graduation on the center line of the board."
"The verniers on fixed gun azimuth circles were installed to read azimuths from true south."
I don't fully understand why they used true south as their base (0/360 orientation).
FYI: the astronomy websites are the only places I have found who deal with making their own azimuth rings/circles (and great pictures also)! So I thank you all for looking to the stars; what a lovely gaze you have!
I will need some more details regarding your project before we can proceed.
As this project is not related to astronomy I think it's best to use Private Messaging or emails. I suspect that there will be a fair bit of corresponding.
Maybe if it all works out okay we can add some details here later, just in case there is any interest from other members.
Dan, I will send you a PM shortly (a day or 2)
I have just perused your Home Page http://www.fortmiles.org/ which has caused me to re-write all of the above, I had some unpleasant thoughts
Hi Richard,
As discussed, I have a Skywatcher 10" Flex Dob.
The diameter of the base board is only 516mm.
If possible, i don't want the Az scale to protrude, so I will cut a notch as you previously advised.
I like the clear bold style of readings and general features you used in the file:
10 inch GSO azimuth scale..pdf
But that appears to be slightly bigger than I can use.
I thought of trying to resize it, but I am not sure this would be successful.
Check out this pdf file, let me know if you would like to change anything.
Cheers
Richard
Thanks Richard,
It worked a treat.
Printed on A1 ($5 at the Copy Shop)
Laminated ($15 same place)
Very Happy Thanks again
One possible improvement, for future users, would be to try to make the scale a little narrower, so that the notch to be cut in the top board of the base does not interfere with the azimuth friction pads.
Maybe limit it to 2cm rather than just over 3cm.
Mine actually runs on the Bunnings lazy suzanne modification (from IIS projects) so it was not a big issue for me.
I'm not sure if you are still providing for this. I have a 12" GSO Dobsonian and would like to attach the setting circles and altitude components to enable a push to scenario. Is this something you can assist with? I believe the GSO mount may be the same as the Light Bridge but I'm honestly not sure on that. Any help or direction on this would be most appreciated. Regards, John.
hi richard,
you did a 16" lightbridge one for me and mate yes i use it all the time..it is a bloody fantastic job you done for me... easy readable and extremely accurate.. i have it on my desktop in pdf so if anybody needs one it's there....
one thing i did do different was not use a paper then laminate but used a drafting film which will last longer and more durable then laminate-recommended from the place where printed and laminated..
i also reduced it to i think 99-98 percent of what you did just to come in on the base 2-3 mm and avoid any damage to the setting circle...
mate once again thank you..
All I need is the overall diameter of the base, and if you have a preference for text type as per my previous versions. As Allan pointed out (post 69), maybe an inner diameter limit so the scale doesn't interfere with anything.
As for altitude, you can't do any better than using a http://www.wixey.com/anglegauge/index.html or similar.
If you still want altitude scale just give me the radius for the 90 degree arc.
Layout and design is really up to you, so if you would like to design your own feel free to do so.
John, I just noticed, have a look at post 31, it's for a 10" gso, you can just print that at a different scale if you like or I will do that for you, just a thought.
------------------------------------------------------------------------------
Hi Peter
Glad to hear that you are using the azimuth scale. Printing on drafting film is a good idea. How's the contrast between the text and the film?
Thanks kindly Richard. I've decided to go for a digital inclinometer for altitude and am working from the 12 Light Bridge template for the setting circle. The bases look to be the same dimensions. I'll let you know how I go. Regards, John.
Quote:
Originally Posted by richardda1st
Hi John
All I need is the overall diameter of the base, and if you have a preference for text type as per my previous versions. As Allan pointed out (post 69), maybe an inner diameter limit so the scale doesn't interfere with anything.
As for altitude, you can't do any better than using a http://www.wixey.com/anglegauge/index.html or similar.
If you still want altitude scale just give me the radius for the 90 degree arc.
Layout and design is really up to you, so if you would like to design your own feel free to do so.
John, I just noticed, have a look at post 31, it's for a 10" gso, you can just print that at a different scale if you like or I will do that for you, just a thought.
------------------------------------------------------------------------------
Hi Peter
Glad to hear that you are using the azimuth scale. Printing on drafting film is a good idea. How's the contrast between the text and the film?
These look great. I have a 10" SAXON, I am not sure if the base is the same size as the 10" Sky watcher template you posted earlier? I would love to get a set of these if I can.
These look great. I have a 10" SAXON, I am not sure if the base is the same size as the 10" Sky watcher template you posted earlier? I would love to get a set of these if I can.
Thanks.
Hi Russ
Open the 10" Skywatcher pdf (or any of the others) and compare the outside diameter to your 10" Saxon. You can get the print shop to just print these setting circles to any scale to fit your base. If you like just post the size you need on this thread.
I too have a GS 12" Dob and was following John's search for a circle for his, and now he's gone in another direction it seems. I'll will be staying manual Pushto.
Is the GS10 the same base? My GS 12 base measures 25" in diametre. Which of the pdfs that you have done would best suit mine? I don't want it to protrude outside the trim on the base, so I'd be cutting a window I guess.
Any advice apreciated as I'm new to all of this Dob stuff.
Cheers Glen
I too have a GS 12" Dob and was following John's search for a circle for his, and now he's gone in another direction it seems. I'll will be staying manual Pushto.
Is the GS10 the same base? My GS 12 base measures 25" in diametre. Which of the pdfs that you have done would best suit mine? I don't want it to protrude outside the trim on the base, so I'd be cutting a window I guess.
Any advice apreciated as I'm new to all of this Dob stuff.
Cheers Glen
Hi Glen, if your GS 12" base measures 25" exactly, that's obviously 635mm. Have a look at post 37, the 12" Lightbridge I made for Wren measures 630mm, that looks just right for your needs. If it's not suitable just let me know.
I too have a GS 12" Dob and was following John's search for a circle for his, and now he's gone in another direction it seems. I'll will be staying manual Pushto.
Is the GS10 the same base? My GS 12 base measures 25" in diametre. Which of the pdfs that you have done would best suit mine? I don't want it to protrude outside the trim on the base, so I'd be cutting a window I guess.
Any advice apreciated as I'm new to all of this Dob stuff.
Cheers Glen
Hi Glen,
Welcome to IIS
Richard's Azimuth scales are great. I have one for my 10" SW Flex Dob.
It really makes finding faint stuff easy (if you have a ALt/Az co-ord for what you want to see).
I use the free web site Tonights sky for a selection of Alt Az co-ords for selected items based on your input.
I use a Bunnings inclinometer for the Alt.
If you want to bring your dob to a dark site, check out the "Star Parties" forum and the thread for Mangrove Mountain Pony Club this weekend.
See the pictures and find attached the PDFs.
I have a 47cm diameter circle inside the rocker box with an arrow pointing to the current value. Only with friction one can rotate the disk relative to the bottom of the box. The disk does not move when rotating the rocker box.
Calibration is rather simple: set the rocker box level (a wedge under 2 of the 3 pods until it is level in two directions using 2 bubble levels perpendicular to each other), point to a star of known azimuth and rotate the disk to that value. The altitude on the scale should match the calculated one. An extra check can be putting the scope vertical and checking with the bubble level and the altitude should show 90 degrees.
Now one can search objects within 1 degree accuracy. Most planetarium apps like Skysafari (Android / iOS), Starmap HD (iOS), Mobile Observatory Pro (Android) show live altazimuth coordinates of the selected object.
Works much better than the Orion Intelliscope XT-10i which I have sold now.
