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Help with my first telescope

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#1 mman22

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Posted 05 January 2013 - 01:55 PM

First of all, I have read through many posts on here and I am delighted at the friendliness and helpfullness of everyone on the forum! I am considering purchasing a telescope, will be my first (as a kid I utilized binoculars and plotted all the northern constellations, but very litte time with telescopes). After research I am leaning towards a Dob, but need to make sure and determine my aperature. I live in Montana, have great sky viewing with minimal light contamination. I am mostly interested (for now) in solar system viewing, no interest in viewing the Sun. Portability is important, but I have space in my Dodge Durango, so size isn't as important as weight and ease of setup. My potential concerns are that my primary viewing area will be off my balcony (live in a townhouse) which is approx. 4 feet by 12 feet with a 3 ft railing. Would a Dob have a problem with viewing objects near the horizon (over the rail)? Also, I plan on taking it to a nearby mountain pass (about 6500 ft elev.) and wondered that with its base would uneven ground cause problems. I am also going to post some objects below, if someone would be kind to let me know what aperatures are needed to view (I know some won't be in my first scope's ability). If the answers to some of these is "your own planetarium", feel free to say so:). BTW, I am trying to stay under $500 but will go a little higher if it makes a large difference). Thanks in advance for the help!

The bands of Jupiter

The Gallilean Moons of Jupiter (more than specks preferred)

The rings of Saturn

Neptune (shape viewable)

Ceres (just a dim light is fine)

Phobos and Deimos (specks are fine)

Titan

#2 MikeBOKC

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Posted 05 January 2013 - 02:07 PM

A Dob can be used just about anywhere. If you are limited somewhat by the balcony issue, just look at things within your field of view. As far as uneven ground goes, the Dob base footprint is not that large -- there's bound to be a level spot somewhere.

For your listed objects, 8-10 inches would be quite adequate. I note yo don't have any DSOs listed . . . with your darker skies, you are ideally positioned for those as well. The cost difference between an 8 and 10 is not that much. I think if you can afford it, you would look back and be very glad you got the 10.

#3 paul hart

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Posted 05 January 2013 - 02:12 PM

Hi and welcome to CN

Even a 6 inch would show everything except Phobos and Deimos. In fact you would need a very large scope to see them. It's great you live in a dark area because you will be able to see many more faint fuzzies than in a more light polluted area. I never have had a problem putting a dob on an uneven surface. My back yard is a slope off the side of a hill and as long as the slope is gentle, you won't have any difficulty. I'd recommend a 10 inch dobsonian. You shouldn't have problems over the rail mainly because usually we do not observe objects near the horizon due to turbulence in the atmosphere. A 10 inch is fairly easy to transport and set up and will show all the Messier objects. In fact I saw Pluto through my 10.

#4 BarabinoSr

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Posted 05 January 2013 - 02:30 PM

I agree that a Dob is a simple but easy to use mount for the apertures mentioned , and those instruments themselves will certainly show the objects very well. However , a Dob becomes very difficult to use on objects near or in the zenith(overhead),as the scope will spin around in movement. This area is known as the Dobson Hole. A few years ago I bought a 12" f/5 GSO Reflector, and dealing with the Hole was very frustrating. I ended up building a table to carry the scope and mount ,but I built it to allow the scope and mount to be inclined to my latitude of 29 degrees, and that eliminated the Hole. Gary(G:cool:)

#5 Seldom

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Posted 05 January 2013 - 02:44 PM

The Gallilean Moons of Jupiter (more than specks preferred)

Is "more than specks" realistic for any amateur scope? There were 5 specks last night instead of the customary 4, but one was a star, and the moons and star were both the same diameter in my scope.

#6 Jeff2011

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Posted 05 January 2013 - 03:48 PM

+1

Many of us would die to get dark skies like yours. Planetary observing can be done from most urban areas. I think the first time you see M31 (andromeda galaxy) with a wide angle eyepiece you will change your mind.

I bought an 8 inch Dob and have been happy with it. It really shines at dark sites which unfortunately I have not been able to frequent enough. I think most here would recommend a 10 inch. The best scope is the one you use most often. That has become a cliche but it is still true. I believe you are on the right track. You will find much help here on CN.

Jeff

#7 Matt2893

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Posted 05 January 2013 - 04:14 PM

Catching views of Mar's moons, Phobos and Deimos, sounds like a challenge according to this article: http://www.skyandtel...html?page=1&...
But with a big enough scope, the right alignment of our planet to Mars, and a bit of determination, it looks difficult but possible...

#8 MikeBOKC

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Posted 05 January 2013 - 04:54 PM

Yes the Galilean moons will show as distinct discs in decent seeimg in apertures at 10 and up, even in 8 when conditions are right.

#9 Tony Flanders

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Posted 05 January 2013 - 05:29 PM

I'm a big fan of Dobs, but I think they're a poor match for balconies. Your field of view will be very badly restricted, and if there's another balcony above yours, it will be virtually nonexistent.

For that particular application, it's very attractive to have a scope where you view from the back, like a refractor or SCT.

By the way, is your balcony made of wood? Wooden platforms can be very problematic for telescopes; you will discover that they wobble hugely when the wobble is magnified 200X.

Expecting to see the moons of Jupiter as more than simple points of light is asking a lot. It can be done with a scope as small as 6 inches in aperture, but it requires very good seeing (stable air). Balconies tend to be poor because of all the heat that a house emits -- though there are exceptions.

I've never seen Mars's moons -- though admittedly I've never tried. It requires a good scope, very careful planning about when you view, and an occulting bar in your eyepiece to block Mars so that its light doesn't overwhelm the faint moons. In any case, this won't be happening until Mars comes to opposition again in a couple of years.

The two main bands of Jupiter are obvious in any decent telescope, as are Saturn's rings. Obviously, bigger scopes show them in more detail.

At the moment, Ceres is obvious with any optical aid at all, even opera glasses. At its brightest, it's even visible naked-eye.

Neptune is an obvious disk in a good 4-inch scope on a night of good seeing.

If you want a scope that can do all these things for $500, a Dob is pretty much your only choice. Dobs do fine on uneven surfaces -- at least within reason. I wouldn't recommend setting one up in a talus field.

#10 panhard

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Posted 05 January 2013 - 05:46 PM

My potential concerns are that my primary viewing area will be off my balcony (live in a townhouse) which is approx. 4 feet by 12 feet with a 3 ft railing.

I have a 10" dob It can't see over the top of a 30" railing. The centre point of axis is 29" off the ground.
The views of anything that low in the sky wouldn't be that great anyhow. There is too much atmosphere to look through. You are much better off waiting until objects get higher in the sky.
PS I would love to have my scope under your skies. Good luck I hope you make the right choice.

#11 CosmoSat

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Posted 05 January 2013 - 07:57 PM

Zhumell Z8 Deluxe Dobsonian Reflector Telescope

Clear Skies!

#12 orion61

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Posted 05 January 2013 - 08:10 PM

Greetings salutations, and a warm welcome.
One thing I havent seen a lot of detail about is even tho a Dob can be a wonderfull scope, you mentioned a lot of Planetary observing, This requires a lot of magnification!
Remember a Dob must be pushed to keep things centered, Most Dobs are fast FL's F4.5 or so. This means once you get a bit off center the high detail sharpness goes down sharply.
Simply speaking by the time you move the Planet into the field,let it settle down it will be time to move it again!
A Meade 8" F6 made into a dob is a fantastic scope and will
give fantastic views!!
BUT for around $400.00 you can get a good used Celestron C8
SCT or Meade! That scope offers much more flexibility.
Stay away from Dynamax 8" unless you can look through it first. the 6" are good.
Best of luck and feel free to send me a Private message for any questions you may have!!
Cheers
Larry

#13 Achernar

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Posted 05 January 2013 - 08:59 PM

You won't be able to see over the rail very well, if at all when looking near the horizon with a Dob because the view will be blocked. Also the seeing will be usually bad near the horizon, the views will be blurry and even show a prism effect from refraction effects. The Dob will work fine if there is a slight grade, but obviously you will want reasonably flat site for other reasons too. When the seeing is good, and you use the appropriate eyepieces, Jupiter will show a lot of detail in it's atmosphere, including features and changes within it's belts. The moons show up at high power as disks through a good 6-inch of varying sizes and hues, that is more obvious through a 10-inch. I have seen Titan as a very tiny orange disk at very high power through my own 10-inch when the seeing was excellent.
Any good small telescopes shows the rings of Saturn, a 10-inch shows features in the rings. Neptune and Uranus are two tiny disks in any telescope, a 10-inch does however has a shot at revealing the larger moons of these two planets, even through they are 14th magnitude starlike pips of light.
Ceres and the Martian moons will always be starlike pips of light, and Phobos and Deimos are also nearly swamped by the glare from Mars. You would want to use an occulting bar to see them without interference from the planet. They are tough targets for a 15-inch.

Taras

#14 Dennis_S253

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Posted 05 January 2013 - 09:19 PM

"primary viewing area will be off my balcony (live in a townhouse)"
Is there a balcony above you?

#15 mman22

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Posted 05 January 2013 - 09:23 PM

Thanks for all the suggestions! I am learning more about the solar system even, never knew that Ceres was sometimes visible to the naked eye. I should have mentioned that being in Montana, my horizon is at a slightly higher angle than some of you:), the Continental Divide is about 20 miles away. Tony, never thought about the balcony having any wobble. It is wooden (or fake wood in parts), but is on legs to the ground, not just mounted to the building. I don't have anything or anyone above me, so no issues there. I forgot to ask in the original post about recommendations on brands (especially ones to avoid) and best eyepieces for a beginning set-up. I am leaning towards the Dob, still debating an 8 or a 10. Sounds like my views of the larger moons will be much better with a 10, so that may be the deciding factor. I will be viewing DSO, but thought it best to start with the Solar System as I am more familiar and should help me while getting comfortable with my scope. Thanks again for all the help!

#16 TheMadHatter

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Posted 05 January 2013 - 10:39 PM


The Gallilean Moons of Jupiter (more than specks preferred)

Is "more than specks" realistic for any amateur scope? There were 5 specks last night instead of the customary 4, but one was a star, and the moons and star were both the same diameter in my scope.


I saw this too, normally I'm use to seeing only four the fifth was a surprise thought it was from cleaning and collimating my optics!

im not a big fan of dobs myself, ive used an 8inch one before and the viewing was good from it, and was able to see jupiter much better with it then with my 5 inch orion space probe. If i had the choice now through i would have gone with the 10" orion scope. You'd be able to see alot from the 8 in. ive had the 130mm for a little over a year and its only now become a chore to lug the thing around.

from a 5in scope i can see all the planets, the rings of saturn and the cloud bands to go with it, the cloud bands of jupiter and the moons. Ive seen neptune and uranus( they look like stars moving across the fov). As far as DSO im able to see most all nebula that ive set out for and all globular clusters. For spiral galaxies im afraid M31 is the only one i can see or find.

IMO, go with the biggest scope you can get if its a reflector, adding a few eyepieces helps a lot to. In the long run the ten inch will be worth it. The dob that i used had a goto mount thing to give how many degrees away from an object you were to.

Ive also looked through a ten inch Sct-cassi, and viewed saturn. ive been trying to get that view back now since i saw it!

#17 dpwoos

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Posted 05 January 2013 - 10:44 PM

Expecting to see the moons of Jupiter as more than simple points of light is asking a lot. It can be done with a scope as small as 6 inches in aperture, but it requires very good seeing (stable air).


I haven't found Jupiter's moons all that difficult to see as non-stellar discs in my 6" f/8 dob. Using my 10" f/6 dob I regularly challenge the more interested folks at public observing events to estimate the relative sizes of the moons, and I am frequently pleasantly surprised that they get them correct. I find that 200x-250x is plenty of magnification for this, coupled with decent seeing. I last did this in early December, and though the seeing wasn't great it was pretty easy to see the discs steadily through the fluctuations. When the seeing is very good I always try to see some detail, but I can't say that I have.

#18 Maverick199

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Posted 06 January 2013 - 07:50 AM

I would go for the 8". Collimation and cool down will not be much of an issue. Add to this, any eyepiece will work fine though you could get one or two mid priced one's like ES or Meade. Get a Dob which comes with a primary mirror fan like Zhumell or Astrotech.

#19 Tony Flanders

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Posted 06 January 2013 - 09:28 AM

Using my 10" f/6 dob I regularly challenge the more interested folks at public observing events to estimate the relative sizes of the moons, and I am frequently pleasantly surprised that they get them correct.


I suspect that's because their sizes are strongly correlated with their brightnesses. Brighter dots (including stars) always look bigger.

#20 Tony Flanders

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Posted 06 January 2013 - 09:32 AM

Thanks for all the suggestions! I am learning more about the solar system even, never knew that Ceres was sometimes visible to the naked eye.


Take a look at the website that I help maintain; lots of good info there, including answers to all your questions.

Better yet, buy a good book. The internet is OK, but for well organized authoritative information, there's no substitute for books.

The balcony is wooden (or fake wood in parts), but is on legs to the ground, not just mounted to the building.


Ouch! It will probably work, but you're going to have to learn to keep very still.

Anything wrong with observing from ground level?

#21 Billytk

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Posted 06 January 2013 - 10:05 AM

Thanks for all the suggestions! I am learning more about the solar system even, never knew that Ceres was sometimes visible to the naked eye.


Take a look at the website that I help maintain; lots of good info there, including answers to all your questions.

Better yet, buy a good book. The internet is OK, but for well organized authoritative information, there's no substitute for books.

The balcony is wooden (or fake wood in parts), but is on legs to the ground, not just mounted to the building.


Ouch! It will probably work, but you're going to have to learn to keep very still.

Anything wrong with observing from ground level?


Tony, I checked out the link that you posted and went to "A Saturn Almanac" and it's all 2011 information. Are they going to update this?

#22 newtoskies

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Posted 06 January 2013 - 10:21 AM

Welcome to CN. Lots of good info here already so as a newb I can't really add to it. The S&T website and link Tony posted is great. I get the mag every month and check the site almost daily. Lots of good reading there. The yearly SkyWatch is a very good issue that covers each month of 2013 and some god articles from Tony on viewing during the four seasons.
As for a Dob and your situation, the 8" from any of the top three will be best. The 10" is a bit taller so it may work over the hand rail.

#23 mman22

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Posted 08 January 2013 - 11:27 PM

Okay, so I have pretty much narrowed down my options. I have been looking at the Orion Skyquest Dobs, but the XT10 is a little more than I want to pay. So, I am thinking either the XT8 or the Zhumell Z10 Deluxe, which is about $90 less than the XT10. Orions appear to have good reputations, but I haven't read too much about the Zhumells. Anyone care to give their opinions on these two options? Also, I am just starting to research eyepieces to start with, so suggestions would be appreciated. Tony, regarding going to ground level for viewing, it is somewhat of a nuisance. No private yard so my scope would not be secure. Not a big deal, but hopefully balcony viewing will work. Thanks again for the assitance everyone, anxious to get my scope ordered and get started!

#24 Tony Flanders

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Posted 09 January 2013 - 06:38 AM

Tony, I checked out the link that you posted and went to "A Saturn Almanac" and it's all 2011 information. Are they going to update this?


Whoops!

Unfortunately; we've put a moratorium on the Saturn-moon "wigglegrams." They were great when Saturn's rotational plane was edge-on to Earth, but they're much harder to interpret now that the moons are moving around Saturn in ellipses rather than back and forth in a line. In practice, the interactive tool is vastly more useful.

Nonetheless, the website shouldn't advertise things that are out of date. I'll take care of it.






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