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Is a goto scope nescessary

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#1 keyth

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Posted 11 June 2013 - 11:15 AM

I am considering purchasing a 10 " Dob Is a goto scope necessary . The prices are quit extreme for computerized scopes . How fast would planets etc go out of view I would like to hear from anyone that has either 10 ' dobs Thanks again Keyth near Toronto

#2 Thomas Karpf

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Posted 11 June 2013 - 11:28 AM

That depends entirely on the field of view of the eyepiece.

The Earth rotates at one degree per four minutes. Assuming your target is at the celestial equator, that means that with an un-driven scope (i.e. no clock drive) it will take four minutes for the target to cross an eyepiece with a 1 degree field of view.

The typical 10" dobsonian has a focal ratio of 4.7. Maximum field of view with a 2" eyepiece (like the 41mm Panoptic) is about 2.3 degrees. So, with that 41mm Panoptic, a target will take ten minutes to cross that field of view.

Higher powers yield faster motion. If you were using a 4mm eyepiece, that target on the celestial equator would take a minute to cross the field of view.

Aim closer to the poles (say at declination +60), and stars move more slowly. At declination 60, stars move at half the rate they do at the equator.

#3 radial195

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Posted 11 June 2013 - 11:30 AM

No, a goto scope (or push to) is definately not necessary. With a telrad (or similar), a small finder scope, and the main scope you can find anything visible in the scope. Depending on your magnification planets should be in the eyepiece for about 2 minutes or longer at low mag, less as you increase magnification. It's not hard to learn which direction to move the scope to keep things in view.

I find my 14.25" dob to be much easier to use than my ETX125 goto scope! Not that the ETX is that difficult. The dob is just much more fun.

Berry, berry eezy!

Chris in sunny (or dark) Arizona.

#4 MitchAlsup

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Posted 11 June 2013 - 11:38 AM

I have not found it needed after 1.5 decades with my push-to 20" DOB (after a decade with a goto.)

What you need are good star maps of the night, a Telrad (or equivalent), and a good widest field EP (31NT5 for example).

If you can point within 1 degree, and stand to pan around for 30 seconds, you can find just about anything.

#5 RAKing

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Posted 11 June 2013 - 12:07 PM

I agree with the others. I was worried about it at first, but came to realize that things didn't move as fast as I thought they would.

I have learned that I have plenty of time to locate the object, adjust my chair, take notes, do a rough sketch, and even change eyepieces while the object drifts across the FOV. Rushing is not necessary and I even find it kind of relaxing to be the "master" of my scope's movement. :cool:

Cheers,

Ron

#6 Jeff Morgan

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Posted 11 June 2013 - 12:07 PM

Planets are very easy to find, so GOTO would be a waste of money if you are predominantly a planetary observer.

Tracking however takes observing (especially planetary observing) to the next level and is very worthwhile. Dobs move easily and all kinds of folks will chime in how they track planets at high magnifications. And that is true - it can be done. But with a tracking solution you absolutely positively will see more detail vs. manual tracking.

If planets are your thing, an equatorial platform would be an excellent accessory to get, and reasonably affordable - in some cases less than a premium wide field eyepiece. And it will be far more effective than trying to defeat the problem with wider field of view.

OTOH if you do lots of deep sky also, the GOTO solutions like ServoCAT become viable. Much more money, so you need to figure out the value proposition for yourself. In my case, the productivity potential makes it a good value.

#7 Jarad

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Posted 11 June 2013 - 12:09 PM

With a 10", you could also consider using an equatorial platform to get tracking.

It's not absolutely necessary, but I find tracking to be valuable. Makes observing more pleasant - you can focus on looking and not worry about nudging.

Jarad

#8 DavidNealMinnick

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Posted 11 June 2013 - 04:06 PM

I never had GOTO on my 10" dob, and enjoyed using it for more than ten years. I ordered GOTO with my 18" but haven't used the drive for several years, now.

#9 David Pavlich

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Posted 11 June 2013 - 04:24 PM

If you get involved in outreach and decide to show your viewers Jupiter or Saturn or the Moon, you'll wish that you had tracking. Also, if you prefer hunting to viewing, then you don't need goto. I prefer viewing over hunting, especially in my typical light polluted backyard. If my gotos are good, then I can put a dim object in the eyepiece and know it's there. It's then up to me to see it.

David

#10 Achernar

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Posted 11 June 2013 - 06:23 PM

Not really if you just want to look at the Moon and planets. However, both GOTO and PUSH-TO telescopes are really nice to have when you are observing in light polluted areas where star hopping is difficult or even impossible. They allow you to spend more time actually observing and less time hunting them, though for many the hunt is just as much fun as finding things. I prefer to use digital setting circles and spend more time studying what does appear in the eyepieces, many of the galaxies I search out are faint. A PUSH-TO has the advanatage of allowing you to choose to starhop manually or to use it, aand it does not require power hungry motors either. If you plan to do a lot of high power planetary and lunar observing, it might be worth your while to consider a GOTO telescope because it tracks while a PUSH-TO doesn't unless that telescope has an equatorial platform.

Taras

#11 GeneT

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Posted 11 June 2013 - 06:33 PM

You don't need a GoTo. They are great, and a lot of people swear by them. I own a 12.5 inch Portaball and there is no GoTo for Portaballs. I do have a Tom O Platform. About half of the time, I don't use the Platform. It is not that hard to find, view, nudge. My life is less complicated without GoTo.

#12 jrbarnett

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Posted 11 June 2013 - 06:34 PM

Exactly!

- Jim

#13 SeattleScott

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Posted 11 June 2013 - 06:56 PM

If you view solo, tracking is not that critical unless you specialize in the moon and planets. If you stargaze with buddies or family, then tracking is really nice.

#14 DavidC

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Posted 11 June 2013 - 07:07 PM

You don't absolutely need a Go-To. I have never used Go-To in my 8 + years of observing, I've tried to learn the night sky and remember where stuff is. I find the hunt for dso's a rewarding challenge, and like said B-4, most of the stuff you can see in a finder scope. I don't use my finders all the time, after a while you tend to know where to align the telrad when you star hop. But I do use my telrad on ngc and caldwell objects, some of those are really faint, and harder to locate.
David

#15 coopman

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Posted 11 June 2013 - 07:17 PM

Absolutely not!!!

#16 Jon Isaacs

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Posted 11 June 2013 - 07:18 PM

Also, if you prefer hunting to viewing, then you don't need goto. I prefer viewing over hunting, especially in my typical light polluted backyard



If one is thinking outside the box:

Looking for an object is "viewing" there is plenty to see, plenty to observe, plenty to learn...

Yogi Berra said it, "You can observe a lot just by watching."

Many of my favorite objects, I discovered (for myself) just by looking around.

Jon Isaacs

#17 gaz-in

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Posted 11 June 2013 - 07:42 PM

IMHO,

GOTO - Definitively not a necessity. In fact some find it a pain (batteries, etc...)..
Push-To- Not a necessity but very very nice...
Tracking - Not a necessity but IMHO convenient

IMHO I would spring for a 10 inch Push To Dob and, if inclined, add an eq platform for tracking later.

#18 MikeBOKC

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Posted 11 June 2013 - 09:29 PM

The answer depends on your wants, desires and needs. If you are a fairy patient person, willing to invest some months (at a minimum) in learning the sky and how to use star charts and finder devices like the Telrad or a finderscope, then go to is certainly not necessary. If you are eager and a bit anxious to get out and see some galaxies and planetary nebulae and other fairly faint objects, then go to is probably very desirable, if not strictly necessary. If you are going to be viewing under heavily light polluted skies ("near Toronto" would probably qualify) then go to is extremely handy, but again not strictly necessary. Really, no piece of astronomy equipment is truly necessary in the sense of not being able to function without it; you can view the constellations with the naked eye and pick out and identify many individual objects. I would say that go to is not necessary for anyone, but it and the tracking that comes with it is pretty darn useful for many under most observing conditions.

#19 Jon Isaacs

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Posted 11 June 2013 - 10:33 PM

I am considering purchasing a 10 " Dob Is a goto scope necessary . The prices are quit extreme for computerized scopes . How fast would planets etc go out of view I would like to hear from anyone that has either 10 ' dobs Thanks again Keyth near Toronto


Keyth:

Here's a question for you: Will this be your first scope?

My thinking:

- Some observers enjoy the star hopping experience, that means that the process of identifying stars, star fields, remembering locations and just looking is a part of the fun.. If that's you, then GOTO or PUSHTO (Intelliscope) will just get in the way.

- Some observers find hunting down objects frustrating, "wasted time", they prefer to just go from one object to the next with the minimum of effort. If that's you, then PUSHTO or GOTO is definitively worthwhile.

In reality, these represent the two extremes, most will be somewhere in the middle. Dobs are well suited for star hopping, most who star hop with larger scope probably use Dobsonians...

Tracking Platforms have been mentioned, another alternative to Pushto/GOTO are manual setting circles or "Degree Circles". There is along thread in the equipment forum discussing how to make your own.

The way it works is you have what amounts to a large protractor on the base (Azimuth Axis) which is aligned with the north pole. For the altitude axis, circles can be made but a $25 digital compass is handier, they will read the altitude with an accuracy of 0.2 degrees. Combined with a planetarium program on a cell phone, tablet or laptop, this serves as a manual way to accurately point the scope.

A final thought.. Tracking.. at this stage, tracking adds a lot to the cost. Tracking can be nice, they say it adds a couple inches of effective aperture, probably now is not the time to invest in tracking, if you find out you really want it, you can think about that later.

Jon

#20 donnie3

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Posted 12 June 2013 - 12:47 AM

goto isn't a must and a lot of button pushing. push to is a more simple system and if your looking for some of the more difficult objects the digital setting circles are real handy. orions intelliscopes are very nice and easy the use. if you live in a light polluted area, star hopping can be a real pain. just my 2 cents here. donnie

#21 Jarrod

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Posted 12 June 2013 - 01:12 AM

Tracking is very desirable. Goto is a bonus. Tracking turns what for me is the "annoyance" of chasing an object across the sky into a serene observing experience.

Could I live without it if I had to? Yes, but I don't have to and I'm glad for that.

#22 Jon Isaacs

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Posted 12 June 2013 - 07:41 AM

Just a comment on GOTO. Just because an object is in the field of view, it still may be necessary to use a star chart to actually locate it...

The other night I was looking for NGC5634 from my light polluted backyard. It's a magnitude 9.4 Globular that's spread out over about 5 arcminues so the surface brightness was about 21.7 MPSAS, only the core would be detectable. I was using my 4 inch refractor.

I had the target well centered in the field of view but I couldn't see it because I did not know exactly where to look.

So, using Sky Safari, I saw that it was 1.5 arc-minutes west of a magnitude 8 star I had identified, I knew exactly where to look and sure enough, there it was...

Jon

#23 Jeff Morgan

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Posted 12 June 2013 - 03:25 PM

goto isn't a must and a lot of button pushing.


You should see SkySafari on the iPad driving ServoCAT. It truly changes everything.

#24 jgraham

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Posted 12 June 2013 - 06:10 PM

Necessary?

No.

Really nice?

Absolutely.

I am not sure that I would want it on a Dob though. For me, the attraction of a Dob is its simplicity. I use a separate point-to system for my non-GoTo scopes.

#25 Sarkikos

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Posted 12 June 2013 - 09:26 PM

I am considering purchasing a 10 " Dob Is a goto scope necessary . The prices are quit extreme for computerized scopes . How fast would planets etc go out of view I would like to hear from anyone that has either 10 ' dobs Thanks again Keyth near Toronto


Nope, not necessary. I've located and observed over 1000 different deep sky objects (not counting double stars) with my 10" Dob and never had goto or DSCs. No doubt many have observed many more than that without the help of these gizmos.

I've also observed - and drawn - planets at high power without tracking. Now, I admit tracking would be nice. But it's not necessary. Goto and DSCs are even less necessary - much less.

Mike






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