Setting circles?

[fountain]

Never used them but wondered if anyone does and what they think.

I know they are bound not to be 100% accurate, but are they still useful?

[barkis]

I always advocate setting circles of at least 8" in Diameter or larger.

Not practical on the modern mount unfortunately.

A shame really, as a set of good quality Circles, accurately divided, plus a Sidereal Observatory Clock, negates the need for a Goto Mount. I used to have 10" ones on my Obs Home Built Equatorial Mount +12" Newtonian, and never failed to find any Deep Sky object. I didn't have a Sidereal Clock either, but once I locked on to a star of known coordinates, and set the RA Circle to the East or West pointer, depending on which side of the mount I was viewing from, and with the drive switched on at sidereal rate, I could then directly index any object, by manually slewing the scope to the objects coords. I also had a N/S Pointer exactly on my local Meridian, so my local sidereal time was indicated by that pointer, as long as the drive remained on throughout the session.

I loved that setup .

Ron.

[brantuk]

With EQ mounts - I can't see them in the dark, and fiddling with spectacles on/off all the time and in a red light, I can barely read them they're so tiny.

Now an AZ setting circle on the base of a dob is a different matter - you'll be surprised at how accurate it is when used with an electronic angle guage for altitude.

[rwilkey]

Hi, I can never read them in the dark either, can't understand why nobody points this out in books etc.

[fountain]

Must admit the reading of them is the thing that has put me off. I was wondering whether anyone gets any value from them at all. The day I bought my scope I asked about them and was told not to bother.

Barkis; that's some set up:D

[AndyH]

My Tal 2 mount has 4" diameter ones that work quite well, when I bother using them. I must admit, I prefer the fun of the 'star hopping' method.

Andy.

[swamp thing]

IMO they are more aggregation than they are worth.

They have to be large to be of any use. Small ones are worse than useless.

As they deceive you into thinking that you'll be able to index stuff with them.

It's always quicker and easier to star hop.

Regards Steve

[dazd798]

I asked about this last week. So I went and made one for my supatrak mount and gave it a test last night. Using stellarium for co ordinates I found it very useful, although not 100% accurate it got me very close to the targets with just some slight adjustments to centre it in the eyepiece.

[barkis]

Must admit the reading of them is the thing that has put me off. I was wondering whether anyone gets any value from them at all. The day I bought my scope I asked about them and was told not to bother.

Barkis; that's some set up:D

HehHeh!. It was, and housed in a domed Obs. too. Ah, happy days.

Almost took an arm off with an angle grinder dismantling it, silly old duffer .

I have run off roof Obs's now, and they are excellent. I've been gearing up for a late life imaging career, and during Obs visits I have been noticing the plethora of flipping security lighting that has sprung up all around me. B&Q must have been having surplus stock sales. Blooming pests they are.

Ron.

[barkis]

If you have a decent Declination Circle that can be read quite easily, that alone can be a big aid to finding a dim object.

With the mount accurately setup on the NCP, your target position on a starmap can be estimated within it's constellation.

Point your scope in the direction of it make sure your dec. pointer is bang on the objects declination degrees & minutes. Loosen your scopes RA clutch, and with a low power eyepiece, gently sweep your scope in RA only. Chances are you will locate the target. Lock the RA clutch, and the drive will take over the tracking, and allow you to centre it, and study it. Do it all in an unhurried way, a dim object can easily be missed, but gentle manual movement of the telescope can often be a help in seeing the dim ones.

Worth a try chaps and ladies.

Ron.

[fountain]

If you have a decent Declination Circle that can be read quite easily, that alone can be a big aid to finding a dim object.

With the mount accurately setup on the NCP, your target position on a starmap can be estimated within it's constellation.

Point your scope in the direction of it make sure your dec. pointer is bang on the objects declination degrees & minutes. Loosen your scopes RA clutch, and with a low power eyepiece, gently sweep your scope in RA only. Chances are you will locate the target. Lock the RA clutch, and the drive will take over the tracking, and allow you to centre it, and study it. Do it all in an unhurried way, a dim object can easily be missed, but gentle manual movement of the telescope can often be a help in seeing the dim ones.

Worth a try chaps and ladies.

Ron.

That, Sir, sounds like good advice and a plan.