Setting circles for my dob

[geppetto]

Whilst waiting for the clouds to clear for first light with my new 8" DOB, I decided to fit setting circles to it.

The alt is read from an inclinometer stuck to the OTA with its magnetic base.

The azimuth is read from a 19" diameter circle of 2mm ply with degrees printed on, fitted between the

two base boards.

Being a fairly large diameter circle it gives a decent resolution.

Since the pictures below, I have fitted red led's to illuminate both scales.

Tried it last night and after setting up on a known star, I used the data from Starry Night and pushed the

beast to M51 M37 M35 and M67 getting all on the nose in my 26mm 2" eyepiece.

This "poor man's goto" really works well 8)

[GordonCopestake]

Excellent. I've never had any luck with settings circles, most of them dont offer enough resolution as the disks are too small. But if they work for you it opens up a whole new list of objects to see that are not naked eye visible.

[Naz]

Excellent one, That is a simple modification that can improve a Dobs ability.

naz

[geppetto]

I quite enjoy using setting circles, these are on my alt/az pier base that

holds my 70mm mac.

I like to image Iridium flares and this base lets me setup in advance.

Have to agree about the resolution though

[FLO]

All good stuff,

Thanks for sharing Philip

[OXO]

Some great ideas there Phil!

You say you photo Iridium flares any chance of a pic please?

James

[Mick.G.]

What a cracking idea Phill.

I've been looking at these Revelation dobs(getting aperture fever)

I don't think I would have the nerve to cut a piece out of the base!..I would have to put the reading circle protruding from the base.

Also I would have to put the inclinometer a little further down the OTA,for a better look through the finder.(as your getting to your target's

O.K I don't suppose that.s a prob')

I reckon our resident D.I.Y man Mr wartHog will like to see what you have done.

Once again great idea.

Mick.

[geppetto]

any chance of a pic pleas

Here's one James

[OXO]

Ah cool Phil thanks for that, i have seen a few but never captured one yet :shock:. corker that!

James

[MartinB]

That's very impressive Phil, both the set up and the pic. Must have a go at using the setting circles. My super polaris has vernier scales which help get over the problem of the scale being small but I will have to re read how to use them before I go out..

[Kaptain Klevtsov]

What a very clever idea!

Must get something made for a camera mount along those lines, fancy catching me an iridium flare like that. I think it look svery cool.

Captain Chaos

[GazOC]

I don't think I would have the nerve to cut a piece out of the base!..I would have to put the reading circle protruding from the base.

..or put the scale on the top of the base and connect the indicator to the bottom piece.

[The Warthog]

That's brilliant! Especially the idea of the inclinometer, as even if your base isn't dead level, your altitude readings will be correct. Great! My PDA Messier program has the Alt-az readings for all the Messiers. Could keep me busy.

[iancandler]

Thats sweet.. I feel a mod coming on for mine

How did you get the bottom setting circle printed?? thats always been the problem for me when Ive thought aout doing this.

[geppetto]

Ian

I used some white face hardboard (stuff they use for kitchen cupboard backs).

Cut to a circle using whatever tools you have. (mine was 19.5" on my 8" DOB)

Then, using a protractor, mark the angles from the centre spot and draw the lines

from centre to edge with a permanent marker.

Finish of by marking the numbers and then cut the centre hole to match the azimuth pin.

Doesn't take long and is well worth it.

[iancandler]

Thanks Im going to have a go.. I did think of just using a compass attatched to the tube along with the inclinometer but it will be affected by the tube itself and not give me the accuracy you need..

[geppetto]

Its surprisingly accurate for setting azimuth.

Thing I need to upgrade is the inclinometer.

Although it works fine, I think a digital one would give me a better ALT accuracy.

There's plenty of digital ones around but its more spending :nono: as I'm sure you understand

[GazOC]

http://www.startrak.co.uk/MakingSettingCircles.htm

[geppetto]

Thanks for that Gaz

Thats the protractor that I printed out and used but forgot the URL for it :oops:

[iancandler]

Thanks Gaz.. i will get on it

Yes I understand exactly what you mean, I just found an identical one to your for around £12 online, but I will have a better look later..