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MarkVIIIMarc

Do I have realistic expectations

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Hello, I have been lurking about for a week or so and must say this is a very informative forum.

I am a newb.  My level of experience pretty low.  I can find Jupiter and Betelgeuse like objects quickly and sometimes others using Google Sky and some self awareness.  My primary viewing location is suburban St Louis but we are on large (cheap) lots up hill from the river so my sky does not have the orange city glow many of my friends have. 

For equipment I have a set of  Gemini 435 7 x 35 Binoculars and an ancient toy store telescope which at least does see the moon pretty well.

What I would like to see is some planetary detail like the great red spot, perhaps a ring division on Saturn and a bit of detail in nebula and galaxies.

Here is where I might need corrected.  For this I believe I will need a 6" to 8" scope, some patience and the clear dry skies we have in winter.  Hopefully my skies are dark enough I won't have to make too many trips to the country.

Can I do slightly better than this with a 6" or 8" scope?

post-21324-0-81618100-1380766683.jpg

Is it possible for me to get any more detail of deep space objects than this with that type of equipment?

post-21324-0-33312700-1380858125.png

Thanks for your patience, I am sure I will have plenty of questions in the future as well.

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To make any meaningful observations of the Great Red Spot you'll need at least an 8" scope I would say, and if there are any hints of light pollution you'll struggle to see anything in the DSO category other than maybe a hint of M42 or M31. The drawings you see of DSOs are representative of the smudges you are likely to see through your telescope; the images in books and in the astrophotography fora spoil us really.

James

 

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I have seen the GRS with my APM 80mm triplet, so 6" or 8" is plenty. Emission nebulae can be seen using UHC filters quite well from a moderately light polluted site. From my (mildly light polluted) suburban garden I can see quite a few galaxies, depending on the transparency of the skies. They are little more than smudges, but they are visible. Open clusters and globulars show a bit more. I would advise you to get a scope you can take out to dark skies (like my Celestron C8) so you can make full use of the scope when you want to.

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Hello and welcome to SGL :happy11:

Whilst I'm still quite new to this business myself, I think your thoughts and questions mean your approach is sensible; seems like you've already been reading up on factors that make a difference and are prepared to keep doing so. Good luck, and keep it up!

I'm not the best one to consult on how the various characteristics of equipment influence the ability to see different types of objects in detail, but I'm glad to give you an idea of what I've experienced so far.

I use a refractor with an aperture of 85mm (just under 3.35") and a focal length of 600mm which gives it a focal ratio of 600/85 = f/7. This is regarded as a small telescope, though they do of course come smaller.

I have done all my observing so far from my front yard, except for one session out in the country which, if nothing else, confirmed for me that a dark sky at a location away from "light pollution" makes a huge difference - it's possibly the biggest factor. Our local neighbourhood is very well illuminated at night; we have large street lights both front and back. So possibly the worst circumstances in which to attempt to use a telescope for observing the night sky.

I have yet to see Saturn, so I can't give you any first-hand results regarding seeing a ring division. I have done a lot of observing of Jupiter, always easy to find and very satisfying. Getting to see details of Jupiter has been a challenge, albeit a fun one. I get nice sharp views of the planet and the four visible moons at lower magnifications, but for more detail I need to use higher magnification and the closer I try to get, the fuzzier the view gradually becomes so it's harder to resolve the actual details. I definitely have to work at the actual observing once I've got the view as good as is going to get, and patiently "let the details come to me", so to speak. I have seen the tiny shadows of moons as they pass in front of Jupiter; making out a moon itself as it passes in front of the planet is far more difficult, it tends to get lost in all that light reflected by the planet in the background. I have seen the great red spot (GRS, as it's also called here on the forum) as grapefruit-pink coloured dot which I had to stare at for a few minutes before I was convinced I was actually seeing it.

I have not seen a galaxy yet; I suspect the LP (light pollution) here is just too bad for that. Likewise, the only nebula I've seen is the big one in Orion (Messier 42) but boy is it great! So galaxies and other nebulae might have to wait until I get out into the country more. I have, however, been able to find and enjoy star clusters such as M37, M38, M36 and M35.

More experienced observers have commented that I've done quite well to see what I've seen so far with such a small scope. The scope itself is of good quality, as are the eyepieces I use, so I'm satisfied that the results I'm getting are down to the size of the scope, the viewing conditions and my own abilities. I can't help but think that using a larger scope would make it easier to find stuff and give more detailed views - but using a smaller setup like what I have at the moment is teaching me a lot about what to expect and how to use what you have. Perhaps most importantly, it's mobile and easy to move out and set up for a quick look.

Hope this helps - I'm sure any questions you may have will find excellent answers here.

 

P.S. are you by any chance a baseball fan?

 

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If you can afford 8", get that. If you can push to 10, do it.

I used to have a 12" dobsonian but it did not get used enough but since I changed to a 10" dobsonian thats changed and it is always out when conditions allow, quite a lot of wieght difference and less faffing, the 12" was goto.

With the 10" I can clearly make out shape and structure in many galaxies, Orion nebula takes on a 3D effect with a decent OIII filter and Jupiter the other nght was awesome at x200 magnification.

That said and as Jombouk said you will never get anything like you see in the imaging section of this forum. You will get some decent views with patience and dark enough skies.

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GRS is visible in much smaller scopes if you have experience of viewing it. I've seen it in a 60mm refractor and had wonderful views recently in a 100mm (4") refractor.

That said, a 6 or 8" dobsonian will certainly make it more accessible provided you have the scope well collimated and cooled, and have stable skies. For planetary detail, transparent skies aren't that necessary, you need stable seeing ie as little turbulence in the atmosphere as possible. For deep sky you need the opposite really, nice transparent skies.

The 6 or 8" will also help much more on DSOs, the aperture will allow you to see far more.

To more directly answer your question, under good conditions you will almost certainly see more planetary detail on Saturn, provided it gets to a reasonable altitude from your location. Jupiter is providing lovely detail currently.

In terms of DSOs, this depends more on your Light Pollution situation but I would expect you to see more than the image you attached.

I'm attaching a very poor iPhone image of Jupiter I took through a good 8" scope recently. It shows the basic cloud bands, plus three of the moons and a moon shadow on the planets surface. Bear in mind that visually the view is much better than this. The shadow was jet black and clear, and there is much detail to be seen in the cloud bands and other belts. The planet still appears small but the detail is there.

image.jpeg

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Hello and a warm welcome to the SGL. Lots of good advice already given. I will just confirm that for value for money and for the views given, an 8 or 10 inch Dob would be your best choice.

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An 8" scope, such as a Dobsonian Newtonian-Reflector, really is the 'sweet-spot' in terms of aperture. An 8" should show you Saturn quite nicely, with the Cassini Division and Encke Division visible with good 'seeing' conditions. Jupiter will be quite a sight, too. DSO's will be grey-smudges, but as your eyes adapt to things like 'averted-vision' you will be able to spot more details. This comes with experience.

So I'd be aiming for an 8" instrument.

Clear & dark skies -

Dave

Edited by Dave In Vermont
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Thanks to you all who took the time to reply, post pictures and such.

I will go shopping for 8" Dobsonian Reflectors.  Might even see if I stumble into a 10" but I think the Mustang might complain if I spend that much money on something else lol.

For sure shopping will result in more questions!

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Before you rush off blindly, I'd like to make a suggestion: Try looking at the Zhumell. The reason being it's not far from you for shipping, and it comes with a RACI-Finder-Scope. RACI = Right-Angle Correct-View. This will save you some $$$ from buying one down the road, as bills from the chiropractor are mounting-up! Here you go:

http://www.telescopes.com/pages/search-results?q=dobson&p=1

Hope this helps -

Dave

PS: Seems the 8" is out-of-stock, but you can get on the list. Also note the 2-speed Crayford-Focuser - which are excellent!

Edited by Dave In Vermont

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3 hours ago, MarkVIIIMarc said:

Thanks to you all who took the time to reply, post pictures and such.

I will go shopping for 8" Dobsonian Reflectors.  Might even see if I stumble into a 10" but I think the Mustang might complain if I spend that much money on something else lol.

For sure shopping will result in more questions!

Here's a nice testimonial for the 'sweet spot' occupied by 8" dobs in general, and review of one particular model:

Orion XT8

The rest of that web site is also worth reading.

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FWIW, I'd suggest an 8" or 10" - though for the Great Red Spot, well, I find my 80mm refractor (3 and a smidgen inch) shows it quite well. I think there was a thread on here where we worked out that 6" is the minimum to resolve the Cassini division in Saturn's rings - though you might perceive it with a slightly smaller scope. I've felt like I could see it in my 5".

The reason I'd suggest the 8", though, is for globular clusters. At that kind of size, some of them will start to resolve. When I moved from a 5" to a 10" scope, I didn't expect that - but suddenly globular clusters were so much more exciting. Previously, mostly, they'd been just fuzzy - now they were sometimes great balls of stars. 

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Aside from the scope choice just bear in mind that planetary viewing over the next few years is not at its best. You are much further South than us UK folks but even so Saturn for example is not well positioned for a while and Jupiter's potential is diminishing. Therefore you are right to consider DSOs as an option. This means big aperture and dark skies as described above. Check out the next few years on planetarium software such as Sky Safari or Stellarium..

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23 minutes ago, AndyWB said:

FWIW, I'd suggest an 8" or 10" - though for the Great Red Spot, well, I find my 80mm refractor (3 and a smidgen inch) shows it quite well. I think there was a thread on here where we worked out that 6" is the minimum to resolve the Cassini division in Saturn's rings - though you might perceive it with a slightly smaller scope. I've felt like I could see it in my 5".

The reason I'd suggest the 8", though, is for globular clusters. At that kind of size, some of them will start to resolve. When I moved from a 5" to a 10" scope, I didn't expect that - but suddenly globular clusters were so much more exciting. Previously, mostly, they'd been just fuzzy - now they were sometimes great balls of stars. 

Well when I was 12 back in the Olden Times (1972), I first saw the Cassini Division of Saturn's rings. And I enjoyed it and never forgot. I was using an Edscorp 3" F/15 refractor I'd recently begged out of my parents ($135.00) for Christmas. Not that they didn't owe that much! They were, after all, responsible for taking me to the Planetarium at the Boston Museum of Science when I was 4 years old.

And it stuck!

Dave

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