Altitude/azmith graduations for DOBS ?

[richardda1st]

Is there any altitude and azimuth graduations ready made of the shelf to fix to a Dob's base. I'm planing to make some up but thought that I'd better ask this mighty forum as someone might have already sorted this out.

I'm thinking that this would be a useful mod. I have been trying to locate Neptune and this might make it a bit easier, (a cheap go to, sort of).
Mind you a full moon near by does make it very hard, probably impossible, but it's fun trying. :)

Richard

[kinetic]

Richard,

A quick way to graduate a large circle is to use an old tape
measure blade.

Wrap it around your base circle for example and read off degrees
at the appropriate intervals.

Obviously if you have access to a few power tools you can do
an even better job. IE cut an exact circumference disk to
match, say, the tape measure blade with 360mm...gives you
nice 1 degree accuracy.....720mm gives you half degree accuracy etc.

Same for the Alt bearing. You could attach a similar disk to the hub
and read off sub-degree alt measurements...

My first GEM setting circles were made this way.

Steve

[JethroB76]

You most likely wont find an off the shelf option for azimuth but altitude can be done using digital angle finder.

This thread on Cloudynights has the pdf files (for azimuth degree circles) and pictures etc that will answer any questions you will likely have..

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/937949/page/0/view/collapsed/sb/5/o/all/fpart/1

[richardda1st]

Thanks again JethroB76 for the link, will check it out.
Hi steve, I was planing to draw up the graduations on Cad and have someone print them up for me full size on some plastic. Anyway I will check out whats around first, like the link that Jethro B76 has supplied.

Richard

[bobson]

You have it here:

http://www.iceinspace.com.au/63-434-0-0-1-0.html

I made mine for 12" dob. At the end of the page you can download the picture and resize it for your need, print it, cut out pieces, join them together, fun stuff :)

For Alt. I simply bought digital thingy (whats it name)from Bunnings for $20
dollars.

bob

[bojan]

This may also be very helpful:
http://www.startrak.co.uk/MakingSettingCircles.htm

[richardda1st]

Thanks all, I knew I didn't have to reinvent the wheel.
Haven't read everything as yet, got another thread at the moment and family duties which come first. Been to and fro for the last hour.:lol:

Richard

[Spanrz]

This is my rendition.
http://farm4.static.flickr.com/3310/3343638778_abb13e5d6c_o.jpg

http://farm4.static.flickr.com/3384/3343641192_25c5fcd477_b.jpg

It was made or put on a sticker and physically stuck to the lower side of the base/bearing.
Cut a hole/slot in the top part of the base to look.
I am yet to put a laser/LED pointer on it yet.

Care of http://settingcircles.robertwillett.com:80 00/

It is a bit technical, if you are that way inclined, as I had issues of printing it out on A4 (it comes in a huge paper size PDF/TIFF).
But I also had to turn the numbers around 180 degrees (I think by memory), as I wanted to view the numbers from the EP area, not lift head from EP, turn head 90 degrees to right too look at the numbers.

[Screwdriverone]

That would be an inclinometer Bob! :lol:

I bought one from the UK on ebay and it works a treat, magnetic base etc, never leaves the tube...Wixey was the brand.

Cheers

Chris

[bobson]

Thanks Chris,

Yes, thats the one, I couldn't remember the name... I am getting old mate :)
Works very good, much better choice than making the 90 degrees dials on the trunnions.



bob

[richardda1st]

Inclinometer, also known as a wankclinometer when introduced as a must have accessory to some off road vehicles. A useful tool to indicate at what angle the car will tip over. Use it once and throw it away with the car.:lol:

Actually had a quick look at bunnings today but did not find any, I'll ask tomorrow.

Nice rendition, Brett.:thumbsup:

Thanks
Richard

[bobson]

Richard,

When I went to Bunnings and asked for one they didn't know what I want, and yes I knew the name back then :)
They just said no, we don't have anything like that.

Anyway, I was just browsing around tools section and saw it there. I told them, this is what I want, Oh the guy said, why didn't you say you want it for angle cutting with circular saw? 'Cos its magnetic he says and you just attach it to circular saw to make any angle you want to cut.

Looks like not many astronomers work for Bunnings :)

bob

Here is the pic, its called Digital Angle Guage

[SteveCav]

Brett, How did you turn the numbers around 180 degrees?

[richardda1st]

Bob, you must have got the last one from bunnings. :mad2:

[Lumen Miner]

Try "special orders", they will need its brand atleast.

I don't think you will find that line in many stores... I haven't seen it come into my store, i've been there 8 years.

[Lumen Miner]

Hi, I'm Mitchell and I work for Bunnings... Nice to meet you ;) :rofl:

[bobson]

Mitchell,

Nice to meet you too mate!

I found this info about angle gauge on woodwork forum, the guy claims he bought it from Bannings:

Digital Angle Gauge craftright
4711414131292
PROTRACTOR-DIGITAL CRAFTR
ANGLE GAUGE LCD AX-007


Richard,

If you are still looking for one, apparently much better quality (Wixey) you can get it from ebay:

http://shop.ebay.com.au/items/_W0QQ_sopZ12?_nkw=angle%20gauge&_fromfsb=0&_trksid=m270.l1313&rvr_id=&keyword=angle+gauge&crlp=3670480133_55&MT_ID=77&tt_encode=raw

bob

[richardda1st]

Hi Mitchell.:welcome:

Apparently bunnings only had a few and has not continued with them. Bunnings has got an analog dial but these are harder to read, as per Bob's ref. link.

Bob, I also came across the Wixley on ebay. Will consider this, but I'm in no hurry.:whistle:

Richard

[JethroB76]

The wixey works pretty well, I got mine from the UK a couple years ago now. I have found that it will go to sleep after a few hours in very cold conditions, but other than that it works fine

[Harpspitfire]

i made mine similiar to yours, i got the larger print and smaller print #'s ( i used the larger)- i used a shim and larger center bolt, then laid the paper on the lower base and covered it it plexiglass (cut it with a die-grinder)- then notched out the upper base and installed a pointer-- i used a wall clock hour hand arrow for that attached to a magnet, screwed a little metal plate on the base to hold to pointer in place, worked fine, i didnt worry about the ALT to much

[Clarry]

You don't actually turn the numbers around. Look at Spanrz's second image (http://farm4.static.flickr.com/3384/3343641192_25c5fcd477_b.jpg), where he has cut away a section of his dob base so he can see the numbers. If you make that cut-out directly below your EP rack instead you of in the front, then you can view it from where you are sitting instead of peering at the front of the base to get your azimuth reading. You still set up where the scope is looking at the direction you want it to look, but the readout will be side on, however east will still be 90 deg and so on regardless.

[Visionoz]

Clayton

SteveCav is right when asking Spanrz as to how he had the numbers turned around 180 degrees - not so much as in his ability to view the numbers from the EP position only as opposed to looking at it from behind - but rather that the numbers themselves are printed 180 degrees to what Rob Willett's online apps actually prints them out as.

Rob's apps prints the numbers reading from the inside direction of the center of the circle (so to speak) to the outside direction of the circle; however Spanrz has his numbers printed out reading from the outside towards the inside direction of the circle looking from above and hence this is easier to read from any dob's EP position, otherwise the numbers would appear to be upside down!!

Perhaps he modded Rob's Postscript source code methinks

Cheers
Bill

[Clarry]

Ahh, I see, I stand corrected.

[Visionoz]

Hopefully Spanrz would actually give us an answer as to how he did it as it would certainly assist those of us who would benefit from contributions from fellow amateur astronomers - in the same spirit that John Ward contributed to the community with his "gift" of the Crayford focuser invention without earning a single cent from it and Rob Willett for the setting circles apps!

Cheers
Bill