Super-beginner questions

Hello, all!

First of all, thanks for these forums and this site. They are a wealth of information.

We received a telescope for Christmas; it's a Skywatcher 6" Dob. After returning from out of town last night, we set it up and had our very first experience ever using a telescope (after aligning the finderscope earlier in the day). I also tried to collimate it, but it didn't seem to need any collimating. Is this possible, or would this just be as a result of my inexperience at collimating a telescope?

At any rate, it was rather cloudy last night, so of the three constellations I can currently spot (Big Dipper, Orion and Cassieopia), I could only see the queen. And the moon was full and very bright, which was a bit hard on the eyes (yes, I have a lunar filter; we just didn't use it last night...don't ask my why not).

At any rate, by some fluke, I accidentally found Saturn (or something that looked suspiciously like Saturn). I was using the 10mm eyepiece that came with the telescope, and in the words of my 10 year old son, "It's so small." Thus my question is, is there anything we can do/use to make it bigger? Or is this as good as it gets with the telescope we have?

I'm working my way through Dickinson's Nightwatch, but there doesn't seem to be a much in the way of "Use this eyepiece to do this" - is this where we just start experimenting with what we have (10 mm, 12 mm, 25 mm and 32 mm 1.25" eyepieces, 2x Barlow, lunar filter and three other filters), or is there someplace/book I can go to for more concrete info (besides here, of course! ).

I apologize for the rambling novel. We are very much looking forward to getting out again either tonight or tomorrow night.

Thanks for any advice/info/help anyone might be able to offer.

Kay

A 10mm eyepiece with the 6 inch dob as described should give you 120x magnification which is more than ample for Saturn. Check your manual to make sure you are using your scope properly. More than one new observor has mistakenly looked into the finder scope instead of the eyepiece and believed this to be the best image their scope was capable of. Also it is possible you finder is not proplerly aligned as you might think.

As far as Saturn is concerned, the rings should be evident even at low to medium power. At 120x you should see a fair amount of detail with a 6 inch dob. My guess is that you were not actually looking at Saturn as this is one of those "Wow" objects that new astronomers really get excited about. Other posters may have more ideas for you.

By the way please use the moon filter when looking at the moon, especially now since it is full and so bright. You will see much more detail and be able to view it much longer. Alternatively you can use sunglasses or look at it before it gets too dark outside to save your eyes. I think with experience you will gain more appreciation for what you see with your new scope and proportionately more enjoyment. Clear Skies, Mike

Kay:

Hello and Welcome to Astromart. You have asked some good questions.

>>> I also tried to collimate it, but it didn't seem to need any collimating. Is this possible, or would this just be as a result of my inexperience at collimating a telescope?
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One of the reasons 6 inch F/8 Dobs make good first telescopes is that they are easy to collimate. Even if they are not right on, they still perform very well. My guess is that it didn't need collimation.

>>2&3. At any rate, by some fluke, I accidentally found Saturn (or something that looked suspiciously like Saturn). I was using the 10mm eyepiece that came with the telescope, and in the words of my 10 year old son, "It's so small." Thus my question is, is there anything we can do/use to make it bigger? Or is this as good as it gets with the telescope we have?
----

Yes it is small. But with some practice and good conditions, there is a lot to see...

Your scope has a focal length of 1200mm. To compute the magnification, you divide the focal length of the scope by the focal length of the eyepiece.

With the 10mm you have: 1200/10 = 120x

This is lower range of where one would view the planets in a 6 inch scope. This would be what is refered to as 20x/in of aperture.

If you use the 2x barlow with the 10mm eyepiece, you will increase the magnification to 240x which will make Saturn much larger.

Other magnifications:

32mm = 37.5x with a 1.3 degree Field of View A barlow doubles that to 75x and reduces the TRoV (TRue Field of View) to 0.65 degrees.

25mm = 48x with a 1 deg TFoV. Barlows to 96x, 0.5 deg TFoV

12mm = 100x with a 0.5 deg TFOV, Barlows to 200x with a 0.25 degree AFoV.

10mm = 120x with a 0.4 deg TFoV Barlows to 240x with a 0.2 degree TFoV.

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For finding things you want a wide field of view so you start with that 32mm.

As you increase the magnification, the field of view becomes smaller, the image is less bright, contrast is reduced...

And you have to remember that you are not looking through a vacuum but the atmosphere, the stability of the atmosphere is very critical. High magnifications (200x) require stable atmosphere.

Atmospheric Stability is called "Seeing." If Saturn is low on the horizon, you are looking through more air, the image is less stable...

You also have to pay attention to the telescope itself. If the telescope is warmer than the outside air, it is like looking through a mirage, the image is unstable... The scope needs time to cool to reach optimal performance...

So where is all this leading: It is just to say that you need to play around with the magnification to get the best views. Some nights Saturn will look like a picture, some nights Saturn will look like the picture is at the bottom of a stream....

There is more to know but that is probably too much already...

So, if you want it bigger, use the barlow but remember that making it bigger may actually make it look worse.

jon

Hello Kay,Welcome to astromart.I think you chimed in during nap time for a lot of Amarters,up all night viewing.I think you have the perfect size scope for the beginner on up to accomplished.It will take a few nights to get to know your scope and follow it's prompt's to view different ogjects and just have fun.Try experimenting with different eyepieces along with the 2X barlow and without.You will notice that the image may get a little softer with higher magnification so back off a little.Saturn will not be huge but you can make the image larger with higher powered eyepieces.Try some of the open clusters with a low powered eyepiece ,such as M41,M37,38,36.Use your 25mm and 32mm with this type of cluster .Having object locator on your scope is a big help so if it has a tonights best mode try it.I don't have this type scope,I have the Meade autostar with mine so I'm not sure if yours has this mode on it.Someone with object locator will help you when they check their emails.I think you'll like the folks here and find them very helpful.I think that you have found a very worthwhile hobby and the folks in this hobby are like none I've never met.Everyone wants you to continue with it and will try to make sure that you get any help needed.Clear skies and have fun,Darrell

Kay
Check out this link http://cleardarksky.com/c/Edmontonkey.html?1
and also the included links that will lead you to local sources of information and viewers like you (PBS Takeoff). The good news is that you have some excellent sky prospects 30 k or so north of Edmonton. Your viewing pleasure will go up exponentially as you go north. It will be worth the trip. But check with the locals for better information.

Kay, you already have gotten good advice.....

You asked something to the effect of "which eyepiece do I use for what object."

There is no answer to this, since it depends a lot on what you want to see of an object. For some people a big open cluster looks good up close, and for others, they want to see such a cluster with a dark background and other stars in the picture. Some people want the detail in a galaxy, others want to see it floating in space!

One good method is to start looking for an object with a properly lined up Telrad (or equivalent) if you have it, then shift to a well-aligned finder scope. At this point the object of your search may be very small. THen Center the object and move to your widest field eyepiece. If you have all the same construction of your eyepieces, they are probably all plossls. And this means your widest has the highest number (32 mm is wider than 10). Find and center the object, then try your next smallest, and your next. When you get to the shortest eyepiece (a 10 probably) You are at your highest magnification. Whichever eyepiece gave you the most pleasing image is the one you should be using.

Other thoughts:
As you go down in eyepiece length, the object will get brighter, but the field of view narrower--so you may lose the field (background). Some things are not as pretty without that background.
As you go down in eyepiece length, you start magnifying movement, air disturbance (bad seeing), and other imperfections. So, you may wish to stop before you get to the highest magnification.
You can use a Barlow to improve magnification. Try it with all your eyepieces.
With more magnification, you will notice the skies getting darker. The object also gets darker, but not as quickly (apparently) as the background. As a result, you will get more contrast with shorter eyepieces.

Generally--You are looking for resolution, not size. A smaller, but more detailed view of Saturn or any other object, will be more rewarding.

In other words--try them all!!!

Alex

Hi Kay:

Congratulations on your telescope.

A couple of thoughts.

I agree with what others have said that 120x is the low range of magnification needed for planetary views. I recommend using a Barlow with another eyepiece to get to a 150x or so. However, keep in mind that the amount of sky that you can see through the eyepieces that you have available gets rather small at high magnification, and it gets hard to keep the object centered in the eyepiece. Therefore, one has to be prepared to nudge the telescope along.

The other thought is that Saturn will get bigger over the next few weeks as the distance between the Earth and the planet decreases. I took a look at the planet 6 weeks ago and was taken aback at how small it looked. I can already see a difference in apparent size, and it should only get bigger.

Good luck and keep posting.

Rey