Manufacturer of degree circles for my dob.

[Doc]

Does anyone know of a UK based firm that makes engraved degree circles similar to this USA based firm.

Dials

Or would any sign makers be able to make one up. My azimuth encoder keeps playing up so thinking about manual degree circle on my dob base instead.

Needs to be 32" in diameter though.

TIA

[weareborg]

Have you considered making your own using the Setting circle software from StarTrak home page. You can make anysize you like then.

Andy

[kniclander]

Doc, I found a program on Cloudy Nights that would allow you to print your own setting circles for your size scope. problem was I couldn't find anyone who would laminate a circle so i gave up. Good luck if you get anywhere!

[The Warthog]

Thanks for the URL!

[weareborg]

Doc, I found a program on Cloudy Nights that would allow you to print your own setting circles for your size scope. problem was I couldn't find anyone who would laminate a circle so i gave up. Good luck if you get anywhere!

The software prints off 4 parts of a full 360 degree protractor on A4 paper, so you could just print them off and laminate each 1. Then all you would have to do is line them up. That would be teh hardest part I would imagine.

Andy

[Doc]

Staples print up to A0 size which is ideal but they don't laminate that big.

Plus they don't laminate circles. So I would have to cut around the circle after it's laminated and then the end would be undone, so there's no point.

What I thought would be a nice engraved plastic circle maybe 3mm thick. Drill a few holes in it and screw it down.

Would look smart.

[irishbloke]

I tried making one using the above template site. The laminating thing was the issue. I ended up sticky plasticing it to a peice of cardboard. I got heavy duty velcro, which in fact turned out to be heavy duty enough to hang the base from the ceiling!!! Meant removing the circle from the base interesting. Cardboard is not enough. Your plastic idea sounds the way to go.

Brian

ps. what do you use for the alt and az co-ordinates and have you red sheilded this?

[Doc]

I tried making one using the above template site. The laminating thing was the issue. I ended up sticky plasticing it to a peice of cardboard. I got heavy duty velcro, which in fact turned out to be heavy duty enough to hang the base from the ceiling!!! Meant removing the circle from the base interesting. Cardboard is not enough. Your plastic idea sounds the way to go.

Brian

ps. what do you use for the alt and az co-ordinates and have you red sheilded this?

The reason I'm doing this is after quite a few sessions with my azimuth encoder I have found that it is not quite reliable. It has a tendency to work well for a few objects then lose the plot for quite a while. So have decided to make things dead simple and have a manual setting circle.

Lamination does seem to be the problem so my idea is to get the circle printed out on A0 size paper and take this to a sign writer who hopefully can cut and engrave whats on the paper onto 3mm plastic.

As for Alt/Az Co-ords Brian I use my lap top and Cartes du ceil lists bot Alt/Az and RA/Dec and updates every 30 secs . It also has a Red filter in the program and all I do is dim the laptops brightness really low. But soon I'm going to make a red screen to slip over the laptop as well.

[irishbloke]

Doc how are you going to align it? I had thought to use the clips artist used to keep paper on a drawing board and put a nail or pointer through it. My thought was to find an object I know, centre it in eyepeice and find out the az on the pda and place the clip in line with the appropriate point on the setting circle. I think from then on az coordinates should work.

[Doc]

Doc how are you going to align it? I had thought to use the clips artist used to keep paper on a drawing board and put a nail or pointer through it. My thought was to find an object I know, centre it in eyepeice and find out the az on the pda and place the clip in line with the appropriate point on the setting circle. I think from then on az coordinates should work.

Thats about it Brian.

What I plan is to stick the setting circle on the ground board. Then the bearing and plates can sit on top of the plastic.

I'll cut a section out of the base board just big enough to see the setting circle and then secure a length of metal banding or similar to the edge of the cut I have made and get a magnet and a pointer.

So all I have to do is point the base roughly North towards Polaris and then centre polaris in scope and move pointer/magnet along the metal banding until it's above Zero degrees.

Then go to laptop look up co-ords for say Rigel and move scope until it reads the correct co-ords and Rigal should be there.

I'll use the Wixey for Altitude as this is very good and works a treat.

[weareborg]

heres a link for making setting circles for a dob. Sky-Watcher SkyLiner 200 Dobsonian Telescope

found this yesterday. hope it helps.

Andy

[Doc]

Thanks for this....

The problem with having a design like this is that you have to get your ground board exactly North as you only have a little window to view the scale with and no way of adjustment unless the scale can be moved and locked down.

[weareborg]

I made settig circles for my old 4.4" dob some yrs back, and I used a very small, but useful program called DobPC. Program can be downloaded from here Astronomical Software

If I remember correctly, the software take into consideration slight errors such as whether the mount is pointing true north, axis misalignment, and stuff like that. Give it a go. It may be just wot u need. It has a database of various objects, and I think you can add to it too.

Hope its helps, and good luck with which ever route you decide to take. As soon as Ive built another dob base and added setting circles again for my 8" OTA, i'll post some pics up

Andy

[Doc]

Cheers Andy I'll have a look tonight.

[Bracken]

Hi, I want to print a strip around the base of my dob then fit an adjustable pointer to the rocker box bit. Do you know any software that will 'make' this strip if I give it the circumference of my base, so I can print off a 0 to 360 degree strip and glue it on?

Thanks in advance

[Doc]

Here Bracken.

This is what I used.....

http://settingcircles.robertwillett.com:8000/indexcomplex.php

[irishbloke]

heres a link for making setting circles for a dob. Sky-Watcher SkyLiner 200 Dobsonian Telescope

That web page is fantastic. I might make it a summer project. I'm not that keen on drilling through the boards. I can see is value but does it not mean its more likely to get affected by the damp and warp?

The wixey is a great job.

[Doc]

Just had my circle printed out at Staples.

It fits on A0 paper as its got a diameter of 800mm

Not bad at £2.57.

Now the hard part how to waterproof it.

Apparently they don't lamminate shapes.

[insomnia]

Can't you mount it on cardboard and then give it a few coats of some kind of lacquer?

[Doc]

I've ordered some sticky back plastic.

So I'm going to buy some hardboard about 2mm thick. Cut out a 800mm circle and glue the degree circle to it. Then cover this in sticky back plastic to waterproof it.

[insomnia]

How about having the desired setting circle plastic vacuum formed?

[Doc]

How about having the desired setting circle plastic vacuum formed?

Whats that then?

[insomnia]

My understanding is that you have a template of the circle size and shape, its then put in a machine that moulds plastic around the template, the end result is a permanent formed piece of plastic that is the same as the template.

[Doc]

I've just googled it. I don't think it would work with the lines and numbers.

I did pop into a sign writers a few days ago and had to sit down when they gave me a quote.

To cut a circle out of 5mm white acrylic and engrave the degree circle onto it they wanted £85 + VAT.

Ouch!!!!!!

[insomnia]

Possible idea moment...... What about printing the circle design onto T-shirt transfer paper. The design can then be 'ironed' on to whatever you are mounting it on. You may still have to seal the transfer on to the mount in some way.

I printed my own t-shirts a few years ago and they are still going strong

I got the transfer paper from Staples