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#1 leonard

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Posted 03 July 2009 - 10:16 AM

Hello Group ,

I like setting circles , but have not used them in years . The scope and mount that I used the setting circles on is long gone . After getting into the dob squad I have not even thought about using circles . Here of late I have been thinking about using a 4 inch refractor on an equatorial mount with circles, usefull circles . Some of the new equatorial mounts these days seem to have circles to small to use well . My question would be : Does anyone use a small refractor mount that has accurate and easy to use circles ? If so what make is it ?

Thanks , Leonard

#2 Quintessence

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Posted 03 July 2009 - 12:28 PM

Leonard,

I'm just curious: Why would you not consider digital setting circles? They're accurate and very simple to use. They have object catalogs built into them -- and they're not expensive given their general high quality and great utility. And they work on alt-az or equatorial mounts. (Buy one DSC unit and use it for both your Dob and your refractor.)

In my opinion, digital setting circles represent the most significant advancement in equipment for amateur astronomy over the past 50 years.

Charles

#3 gnowellsct

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Posted 03 July 2009 - 06:16 PM

Try this other thread, let me know if it helps.

Greg N

beginner's forum thread on setting circles

#4 leonard

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Posted 03 July 2009 - 09:53 PM

Hello Charles ,

No need to be curious , I just have no interest in digital circles .

Leonard

#5 Eddgie

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Posted 04 July 2009 - 08:13 AM

If on a budget, the Vixen Super Polaris has about the best setting circles in that class mount.. NOT the Great Polaris, but the older Super Polaris. It is a excellent mount, and the circles are far more useful than the later GP mounts. At least that is my own opinion.

Another benefit of the Super Polaris is that some models had a RA drive that ran off a single 9 Volt battery.. WOW!

Next up on the ladder is the GM8. A bit more mount than migh tbe required for a 4" refractor, however they are of course heavier, and much more expensive.

Good luck.

#6 Eddgie

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Posted 04 July 2009 - 08:17 AM

Oh, and the Super Polaris could also be used in Alt-az mode without modification. Just a little extra.

The Super Polaris is in fact a beautiful mount. This is especially true if you can find one with wooden legs. They have a far higher quality feel than most mounts in this class.

#7 rmollise

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Posted 04 July 2009 - 09:14 AM

Oh, and the Super Polaris could also be used in Alt-az mode without modification. Just a little extra.

The Super Polaris is in fact a beautiful mount. This is especially true if you can find one with wooden legs. They have a far higher quality feel than most mounts in this class.


It is, but IMHO, the setting circles are still way too small. You need to get up to something about 6 - 8-inches in diameter before you get to the "useful," I'm afraid. I've always been able to get by with SCT setting circles, since I know the error is likely to be in the too small declination circles. Bigger is better. :lol:

#8 Eddgie

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Posted 04 July 2009 - 10:29 AM

Ah, well, I would totally disagree. For a 4" refractor these setting circles are MORE than sufficient. I worked for a decade with this setup and found it to be far more than satisfactory. When I was using them a lot, I could literally nail any target. To to this though, you need to be able to use the vernier scale. With the scale, it is possible to get EXTREMELY accurate pointing.

One of the reasons I like the Super Polaris over the GP is that the GP did in fact go to a ring that is rather small. The DEC ring is mounted near the top of the counterweight shaft, and the RA circle is mounted at the tail end of the RA housing. Neither of these rings is very big, and the graduations are rather fat.

The Super Polaris on the other hand has a DEC ring that is quite large and sits just below the mounting head.

The RA ring is above the RA housing and is also quite large.

I could easily and reliably hit within a degree or two of my target just about every time. More than close enough with a 4" scope, especially with todays super-widefield eyepieces.

I also was very successful with the GM8 manual circles.

The main reason I went to Digital circles so long ago was because for ANY setting circles to work well, accurate polar alignment is far more critical.

Still, if you are willing to do polar alignment, the circles on the Super Polaris are of excellent quality and if the OP has used setting circles previously, I think he will be very happy with the GM8 or Super Polaris.

But that is just my opinion. Having done it successfully myself though, I am very confident that either of these mounts will serve his well.

NOT so with a standard CG5 or a GP type mount. On these, the circles are smaller and not as finely indexted.

Super Polaris is a class act. In many ways, the GP and CG5 was a step backward. If your comments are based on exposure to these mounts, then I agree. I totally disagree as far as the SP and GM8 are concerned though.

Regards.

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#9 Eddgie

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Posted 04 July 2009 - 10:49 AM

And by the way, in this picture, the mount is pointing to 4 Hours, 7 Minutes RA.

And it is pretty easy to get within a half of a degree in declination. The Dec scale is easily big enough to get this kind of accuracty even without the vernier scale.

#10 Guest_**DONOTDELETE**_*

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Posted 04 July 2009 - 11:35 AM

So how about the Orion SVP? The pictures on Orion's website shows it built like the Vixen SP, unless they've redesigned it like the GP. Seems like it would be a good mount with decent manual setting circles for smaller-medium loads.

#11 rmollise

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Posted 04 July 2009 - 01:04 PM

Ah, well, I would totally disagree. For a 4" refractor these setting circles are MORE than sufficient. I worked for a decade with this setup and found it to be far more than satisfactory.


To each his own, I reckon. I find the circles on this mount less than desirable, especially, for a longer focal length telescope. In fact, I'm not a huge fan of the SP at all, having owned a couple and got rid of both back in the 1980s. But that is just me. ;)

#12 hudson_yak

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Posted 04 July 2009 - 03:55 PM

Orion SVP


The circles on the SVP are about 3.25" diameter and quite functional, looking similar in scale to the picture Ed posted above. You don't get any vernier scales though.

They aren't perfect, as the printing isn't real accurate, on mine anyway. There's about an extra degree of spacing between adjacent hash marks near one of the 0 Dec marks and also at the 12 RA mark. Not enough to make too much of a difference, practically-speaking, as long as you aren't expecting too much.

Mike

#13 Eddgie

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Posted 04 July 2009 - 05:28 PM

I can't speak for the mount itself, but in pictues, the circles look to be a decent size.

Now just becase I think the circles on the SP and GM8 are more than big and accurate enough for a 4" scope doesn't mean I personally would own one these days.

The problem is that for them to work, you have to not only accuratly polar align, but you also have to ensure that you have adjusted your OTA to your mount to eliminate cone error. If you fail to do this, pointing may not be accurate on both sides of the mount.

And there is also the issue of precession. You may also have to plan your observing in advance using a chart or astronomy program that is updated for precession. While this seems to be minor, things up there do move around.

And by the time you accuratly polar align, you could have a go-to mount up and running and have already done a few targets.

So, while I like the GM8 and SP mounts (and I would think the Orion mount would be similar) in terms of their fairly sized setting circles, the truth is that today, when you can get a used LXD55 for $250, and it comes with electronic drive in both axises, and has a computer that automatically adjusts for precession, and can be up and running in 3 minutes, and give you motor driven sweeping, and fairly precise pointing, and allows the swapping of OTAs witout having to worry about Cone error, and can get you a catalog description of an object you stumble on while just slewing around (Identify function), then I simply don't know why someone would WANT to manual circles today.

And to be fair, while I prefer the circles on the SP to those on the GP, even those on the GP and CG5 are good enough for most 4" refractors being sold today. Most 4" refractors being sold today can generate a 2 to 5 degree field, and when you relize that centering the pointer on a CG5 even in the middle of two fat index 10 minute marks is giving you .75 degree pointing then if you are BOUND and DETERMINED to keep it simple with a manual setting circles, then all of these mounts should deliver the goods.

But they are SUCH a pain in the rear!

I was only giving the OP what he asked for though.

Me? I went to DSCs when they first came out, and have never looked back. They were the single biggest revolutaion in mounts in 300 years. Using a mount without DSCs to me is an exercise in tedium.

But that is NOT because the circles are too small. It is because dealing with all of the adjustments and fiddling simply consume too much time. And you HAVE to do it to get accuracy. It is not optinal. And when people tell me that that manual circles don't work well, I know that it is because they didn't take the time and considerable effort needed to make them work correctly.

If the mount were on a permanant pier, that would be another story. There, even CG5 style manual circles can give outstanding results in a modern 4" refractor. But if you have to move it? Like wearing a "Kick Me" sign.



#14 Guest_**DONOTDELETE**_*

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Posted 04 July 2009 - 06:05 PM

Thanks Ed, and nice summary on the pluses and minuses of both. I'm like Leonard, I prefer the manual EQ's being a visual observer only. If I had any desire for AP, then definitely a Go-To w/ autoguide capability would be the answer. I've been looking for a good manual EQ to supplement my Voyager for some time but had overlooked the SVP until your earlier post.

Leonard, you have plenty of choices in different price ranges. The EQ-6 mounts like the Atlas have decent setting circles for manual use, if you're looking for a heavier load mount. If money were no object, then my dream choice would be either Losmandy mount without Gemini.

#15 gnowellsct

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Posted 04 July 2009 - 07:51 PM

The Super Polaris is an excellent choice for refractors to about four inches and SCTs to 8 inches. The setting circles work very well.

The Losmandy line also has setting circles, g8, G11, but not the Titan. The AP900s and AP1200s still have setting circles; the Mach 1 does not.

For cost effectiveness it's hard to beat teh Super Polaris.

regards
Greg N

#16 Eddgie

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Posted 05 July 2009 - 11:22 AM

I totally "Get" why people like to keep it simple. It is one of the reasons I keep my Vixen Polaris (not Super Polaris, but the older Polaris). I like that it runs from a 9 Vdc battery and even using my C5, if I take the time to polar align, I can get within a degree of my target.

But HONESTLY? I haven't used it in a year.

That being said, there is a graceful elegance to using a mount with manual setting circles. It is like a pilot using dead reconing rather than Nav aids like VOR or GPS. There is kind of a zen quality to it, and when you align and get it all set up, you don't have to worry about tripping over power cords, or running down your battery, or random stupid stuff that computerized mounts sometimes do (My LXD 750 HATES to point anyfreakingwhere CLOSE to zenight and gives me warning messages whenever I try).

So, I "Get" it.

But then again, I am a 21st century kind of guy. LED backlighted TV, Windows Vista, Complicated mobile phone with bluetooth radio in the car so I can do hands free. Royal pain to get it all wired togeteher, but when you do, life is GOOD!

Still MIGHTY Miffed about the space station though.. :mad: Should be a BIG FREAKING WHEEL! Idiots. Don't know ANYTHING about marketing at NASA. If it were a BIG STINKING WHEEL, people would smile... I sure would.

Ciao, fellow cosmic babies.

#17 tcat

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Posted 05 July 2009 - 12:18 PM

.... there is a graceful elegance to using a mount with manual setting circles. It is like a pilot using dead reconing rather than Nav aids like VOR or GPS. There is kind of a zen quality to it...


As a recent student of using setting circles I quite agree about those "zen" moments when you locate something without electronic assistance. Sailors enjoy similar moments figuring out where they are using sextants instead of GPS. But I fear both of these skills are on the wane losing out to the convenience factor. Pity.

Tom

#18 roscoe

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Posted 06 July 2009 - 07:03 AM

My smaller scope sits on an older Vixen Polaris mount, which is far above my CG-5 both in overall quality and accuracy of the setting circles. being an old guy, I learned to use circles back when radios still had tubes in them and digital meant using your fingers......... ;-)
I'm building an observatory mount that will feature a pair of 8" circles, that will be a joy to use...no magnifying glass required.

#19 gnowellsct

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Posted 06 July 2009 - 11:31 AM

Let me be clear to folks about why digital setting circles are so much nicer than analog. I like analog and know several different methods for using them. But they don't hold a candle to dscs.

First, DSCs compensate (well, Argo Navis does) for certain intrinsic errors in pointing including polar alignment and other forms of flexure.

Second, and this is the main thing, you don't have to fidget wtih keeping long series of numbers in your head that you have to read and then take over to the scope and then adjust and then say, well now that I've done that four digit sequence what's the dec? You just punch in say M57 and you get two numeric values and you move the scope till each value is at zero. Very simple and no chart-to-scope transfer.

Analog setting circles are like an abacus, they are an analog computational system for finding coordinates on a spherical grid. That's about it.

For a real "pure" experience you can star hop on your German equatorial. I find this easier than star hopping in alt az because you can move exactly east and exactly north, as the charts indicate.

But dscs are really better.

Greg N

#20 Eddgie

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Posted 06 July 2009 - 12:14 PM

Yes, I agree 100% regarding GEM vs Alt-Az. THIS is the MAIN reason I keep the Polaris around. I wrote a review of the Polaris and commented on its ability to be used in Alt-Az mode but I NEVER use it that way.

I LIKE having true RA and DEC motions when using a GEM.

And for star hopping, often you don't even need to be but ROUGHTLY polar aligned.

I used to use my charts and just go to a brigh star in the vacinity of the target, then just use the setting circles to "Offset" from the bright star (ok, this is 7 degreess south in dec and 40 minutes east from my current location.. Ok there it is!)

Manual circles DO have a lot of utility. And again, I totally get the simplicity.

But yes, DSCs to me are the minimum I could settle for today unless my mount were permanant. In that case, I could be quite happy with High Speed Push To using manual circles.

Would still run some some wires and use some of those new-fangled red LED thigamabobbies to the pointer scale though. I hate messing with flashlights in the dark.

#21 leonard

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Posted 07 July 2009 - 07:01 AM

Hello Group ,

Thanks to everyone for your input . Uncle Rod , I'm with you , larger circles are better circles . Mike and Roscoe , thanks for giving me insight into the equipment being sent from China today , this is about what I was fishing for . Eddgie and Greg , thanks for the great info on the Super Polaris mount , I have never seen one(in person) but have for years felt(after looking at pic's and reading) it was "the" one small mount to have . As usual from C.N.'s a cascade of usefull information . :jump:

All the best , Leonard

#22 jrcrilly

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Posted 07 July 2009 - 11:22 AM

(My LXD 750 HATES to point anyfreakingwhere CLOSE to zenight and gives me warning messages whenever I try).


You can turn that off by telling the mount it's on a pier. Of course, if you do that and the telescope then hits the tripod I'll deny any responsibility! :lol:

#23 Eddgie

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Posted 07 July 2009 - 12:58 PM

As best as I can see, this is not a setting on my LXD 750 hand controller.

Perhaps it was something added in a later version.

Either that or I just don't know where to look.

I had a conversation with someone else about whether or not the LX200 used the same handset as the LXD 750, and based on that converstion, the answer was no. However it is possible (Maybe??) that Meade did what does now with the Autorstar handsets and just allows them to program for either Alt-Az or Polar mode, but like I say, either it was not on my version of hand control, or it is not something I can find.

If you can tell me where to look, I will confirm.

Thanks!

#24 Eddgie

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Posted 07 July 2009 - 01:05 PM

Belay that last, mate. Based on your prompting, I just started scrolling the Telescope option and there it was! I guess I just never looked that far before!

Thanks.. Had you not mentioned it, I may have never known!

Regards.

#25 Eddgie

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Posted 07 July 2009 - 01:26 PM

And by the way. I replaced the factory spreaders with aluminum bar stock (.25" x .5") that was about 3 inches shorter than the stock spreader bars. The result is that it reduced the angle of the legs keeping them in a much smaller footprint. I don't understand why Meade used such a big angle on the legs to begin with.

Also, because I have an adapter to use the Losmandy saddle, the scope sits about an inch higher than with Meade Cradle.

And my scope is shorter than the Meade 6" f/9.

Net result is that I can point 25 minutes PAST East or West of zenith and still not hit the tripod with the focuser housing.

And this used to drive me CRAZY, that the circle of sky denied by the mount was so HUGE.. But now that I think about it, with the standard hugh tripod spread, longer Meade telescope, and lower cradle, it HAD to be a fairly big circle of sky.

Great news for me though is that I am pretty sure that I can leave it in "Pier" setting and never really have to worry about a collision with a leg.

Thanks again!

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