Heritage 130p Setting Circle

[happy-kat]

I had a project in mind after seeing numerous other posts on adding a setting circle to a dobsonian mount, so I thought why not...

The Heritage 130p does present a change because the bottom mount is an irregular shape and does not lend to the approach I read about and found great examples of on here.

So I thought I would treat the setting circle as a relative solution and not absolute like the other project threads I had read.

So I have a degree circle on the top base board.

On the underside of the bottom board I have fitted magnetic tape.

I used a jam jar lid and a bit of coat hanger to fashion a moveable degree marker.

For the altitude I bought a Wixey.

When using, of which I am still testing, I find an object that is easy then move the angle marker to a convenient spot and then using Stellarium decide on a nearby target and then I move the top board relative to where the marker to the new object by the distance between the two objects. So if the current object is 97 degrees and the new one 85 I would move the top board 13 degrees in the relevant direction. This in my theory means I don't need to align the mount.

I then use the wixey to change the angle by the relative difference between the two objects.

I didn't need to print any numbers on my setting circle but I wont reprint just for that so I just ignore them.

Each fat marker is 5 degrees apart with a 32mm I get 2 degree FOV.

What I should do next is fashion a level board for the Heritage to sit on as my paving slab base is very off and I think this is not helping my testing.

Also included an image of the attachment bought that means I can use a camera or say my short ST80 refractor on the same mount, makes it very veratile.

First print outs and dummy runs

Printed out and loose aligned. due to the design of the heritage base I had to further trim a few areas to have enough clearance and retain a laminated edge.

Laminated 2 sets on A4. Broke the design into three so I could print it out with what I had access too using paper space views.

Trimmed up and loose fit. I used just selotape to stick the laminates together and then onto the top board.

Magnetic tape.

Magnetic tape fitted and test run of jam jar lid.

Jam jar did and angle pointer. The tip is painted red.

I will be fixing a red LED to this marker but the mini battery holder with switch has not arrived yet. My partner soldered the coat hanger on to the lid.

Finished base and showing the skywatcher attachment I bought from FLO and I have a 2 way level (not shown) that I can use to check the base.

Many thanks for the setting circle support to SGL member abberation.

[xtreemchaos]

what a cool mod ,looks perfect, are you going to varnish it when finnshed to weatherprooth it?.thanks for sharing...charl.

[Ju Piter]

Mate that looks awesome im defo going to try that after my lazy susan.do you have one on both axis and are they quite accurate ?

[Ju Piter]

what a cool mod ,looks perfect, are you going to varnish it when finnshed to weatherprooth it?.thanks for sharing...charl.

you just gave me the perfect finnish for my light shield tube to weather proof the outside as the inside is flocked so that will absorb most of the moisture.thak you charl

[happy-kat]

The laminating made the paper waterproof.

I have a Wixey for the Altitude measurement.

It has been used roughly but not in anger as I need to make a levelling platform for the base to sit on or change the three feet for adjustable height feet.

I have stuck a two way mini spirit level on top was about £2 from Amazon.

I would use it using relative settings so no need to polar align but if used in the same spot all the time polar aligning once and marking where the feet would go and fixing the circles based on that would make it quicker to use I think.

My 32mm eye piece gives 2 degree fov so I hope that takes care of any accuracy but I have found you absolutely dio need a level base otherwise the altitude is way off as you swing the scope around.

[Ju Piter]

Another thing i found was the bolt through the base has alot of slop when you dont have it tight enough but when you tighten to much you find it stiff to push so i took it apart and wrapped ptfe round the bolt so its a snug fit in the big black spacer that the bolt goes through and ptfe wrapped round the big black spacer which is a snug fit in the base hole and the top hole.now i have no play with the bolt and can loosen it more so it moves smoother.

Sent from my LG-D855 using Tapatalk

[happy-kat]

I will try that, my bolt is loose but the move is sticky, perhaps the Teflon pads are sticking on mine

[Ju Piter]

Make sure the staples are below the teflon mine had worn grooves in the top plate

Sent from my LG-D855 using Tapatalk

[happy-kat]

Should add a note re relative use. 

Centre telescope on known star near/neighbourhood where want to find something, move degree marker to correct degree reference for reference star. Then you can move the az to where the sought object is and adjust altitude using wixey. 

I still need to fit/make base with adjustable feet as none of my outside space is level enough.

[sockgoblin]

On 04/04/2016 at 16:57, happy-kat said:

Should add a note re relative use. 

Centre telescope on known star near/neighbourhood where want to find something, move degree marker to correct degree reference for reference star. Then you can move the az to where the sought object is and adjust altitude using wixey. 

I still need to fit/make base with adjustable feet as none of my outside space is level enough.

sounds great , may I have a copy of your print files please?

[brantuk]

Superb solution - looks neat and professional and does the business! Excellent!

[happy-kat]

I should add that since I did this I saw a member last week so a much better solution of a full 360 degrees around the outer edge of the top board.

[leo82]

Hey happy-kat,

I know this is an old post, I came across it looking for setting circles for the heritage 130.

May I ask where you got these plans as I have searched all over the internet and cant find any that will fit the 130.

Thank you.

[happy-kat]

Hi

If I did it again I think it would be easier to do what Geoff Lister did with his much easier and didn't need a wixey. I'll see if I can find the post.

Found it

https://stargazerslounge.com/topic/324515-setting-circles-on-a-dob/?tab=comments#comment-3538017

Otherwise drop me a PM.

Edited August 22, 2019 by happy-kat

[leo82]

Thanks for the speedy reply happy-kat.

I've had a read through the thread in your link, I like the alt setting and the bonus holders for the eyepieces!

I like the idea of the compass, but as Geoff states the ota deflects the compass pointer.

I would like to do the setting circles with the red light, did you complete yours?

 

 

 

[happy-kat]

The led that I painted red using nail polish I've pinched and use on the barn door tracker.

The key is having a level base I think when using. I like that the mod is not permanent though the magnet tape was sticky.