If Earth Had Rings

This is a fascinating concept. I have to wonder how my life would be different if I had a vagina. I probably still wouldn't get out very often.

ROFLMAO!!

Had to look it up

ROFLMAO

Acronym Finder: ROFLMAO stands for Rolling On Floor Laughing My Ass Off.
www.acronymfinder.com/Rolling-On-Floor-Laughing-My-Ass-Off-(ROFLMAO).html

Thanks, I thought he was mad at me.

Hi Masu

Just the man I want to see. I was told that on Aug.27 we should expect Mars to show off real big. Something like near full moon size? Hoax or exaggeration or what? And another thing; my grandson turns 5 on Aug.24. would it be to early to present him with a telescope? He is fascinated by the Planets and knows them all by heart. I don't see him on a daily basis so I can't really evaluate his maturity. Did you start early?

Happy gazing, Ky.

We'll never see Mars as big as the Moon or we're in big trouble. Hoax, or clearly an exaggeration.

Thanks. I will get on to the originator of the Power point presentation. I thought it was a bit over the top. It's a shame I can't post it here, or can one? I know about as much about the stars as I know about operating websites and the functions they provide. Not unwilling to learn though, Ky.

Masu has not yet responded, thus let me.

It IS a Hoax. It started from (if I remember correctly) from 2003 when Mars was at the closest over the many centuries. Thus the Mars was quite big as compared to its size over many earlier centuries and over the centuries to come. It was as big as, when "seen through telescope of some 50 to 60X" would look as big as "moon when seen without optical instruments". It was 27th August of that year.

From that year, every year this hoax mail is floating on net / email, without fail around early August.

Regarding gift to your grandson, in my I opinion that telescope will be not a good gift. This may create hate about sky because Telescope is always difficult to handle, neck straining.

Better, you start with binocular with stand + some introductory sky map books. The views through binocular are spectacular because of two reasons. Firstly its wide field and secondly, eyes are not strained as we are using both the eyes together.

This will create liking about sky. Let him start recognizing the stars and star groups through binocular. Then around age of 10, you may gift some small telescope of say 4" to him. Entering in the subject gradually will be fruitful.

Besides, do attend the local star parties, with your grandson, where you can show him objects through bigger telescope.

I advise same thing to adults also.

That was very kind of you, thanks. We live quiet a distance apart so I can only observe his fascination once in a while. I've got some binoculars and will give it a go to the end of August.

Enjoy, Ky.

G'day gals, guys & gurus,

"I was told that on Aug.27 we should expect Mars to show off real big. Something like near full moon size?"

As gsuhas stated the story of Mars being as big as the moon is total crap. Mars takes about 687 days to orbit the Sun while the earth takes 365 days and that means Mars is in opposition (lined up on the same side of the Sun and at the closest point during an orbit) every 780 days. The last time Mars was in opposition was on 28^th January 2010 and the next opposition will be on 3^rd March 2012. So at the moment Mars and Earth are were no where even close to being in opposition. We are also moving further apart every day and on 27^th August will be even further apart.

"Regarding gift to your grandson, in my I opinion that telescope will be not a good gift. This may create hate about sky because Telescope is always difficult to handle, neck straining."

I disagree with this totally. Binoculars are good to start with but you will very quickly hit the limits of what they can observe and become boring. As for the neck strain part this can be very easily overcome but more on that later.

Before going further you need to understand some things about telescopes:

• Aperture: This is the diameter of the telescope and for astronomical use the larger the better. The reason for this is that the larger the area collecting the light the brighter the light you have to play with and the brighter the final image. It also allows you to have higher powers of magnification so the bigger the better.
• Refracting Telescopes: Terrestrial telescopes and most binocular utilize glass lenses to collect and focus the image. However, different colours of light diffract differently as they go through a lens and this causes the edges of objects to have a coloured halo. This can be overcome to a certain extent by utilizing different types of glass with different refractive indexes but this can be expensive and difficult to achieve.
• Reflecting Telescopes: Most astronomical telescopes are reflectors rather than refractors. This type of telescope utilizes a concave mirror as the primary optical element. Because the light is being reflected it doesn't matter what colour the light is and hence doesn't have the coloured distortions around the edge that refractors do. You can also make much larger diameter telescopes and all of the major astronomical telescopes around the world are reflectors.
• Focal Length: Focal length has a lot to do with how much magnification you get. In general the longer the focal length the better.

Ok, for a first off astronomer I would recommend getting what is called a Cassegrain telescope. This is a compound type of telescope that utilizes both refractive and reflective elements. The image at the right (courtesy Wikipedia) shows a cross section of a typical Maksutov-Cassegrain telescope.

This type of telescope utilizes a concave primary reflector in combination with a correcting plate that also has a mirrored surface towards the centre that acts as the secondary mirror. These type of telescopes have several advantages over straight reflectors.

1. Firs off they are generally completely sealed or close to it. This makes them more robust and less prone to damage and dust that can severely damage the performance of the telescope.

2. The complex optical path also means that they have much longer focal lengths than a straight reflecting telescope. For example the one I have is approximately 450 mm long yet has a focal length of 1,900 mm. So instead of having something that is around 2 metres long I have a telescope that all up is under 500 mm long.

Another thing worth discussing is the mounting system. Once you move above the sort of magnification you get with a pair of binoculars the Earth's rotation is going to become a problem as an object will move outside the field of view very quickly. However, you can now get relatively cheap computer controlled mounts that can position your telescope within a few minutes of arc and track objects as they move across the sky.

Next off, lets discuss the neck problem. Trying to look along the barrel of a telescope does require you to be a contortionist, but you can easily add an erecting prism (image on right) that refracts the final image through anywhere between 30° and 90°. As a result you can set up your telescope so that you can view it by looking downwards rather than having to hang by your feet from the ceiling. In fact many off the shelf Cassegrain type telescopes come with an erecting prism or equivalent built in.

Finally there is the topic of astrophotography. It doesn't take many nights of fine viewing before you want to show others what you have seen so adding an imaging system is definitely worth thinking about. The limitations of eyesight are also something that restricts what you can see, but by taking long term time exposures the sky can light up and reveal itself in its mind blowing magnificence

However, you can't just stick on a camera and snap away but for a hundred dollars you can get a usable imaging system. Astrophotography is a complex subject, but you can get imaging units that come with all the software and hardware you need for anywhere between a couple of hundred dollars to tens of thousands of dollars. Even so, you can get some impressive images with a relatively cheap low end imaging system.

Ok, so what would I recommend?

For a first time astronomer I would recommend getting a telescope along the lines of a Maksutov‑Cassegrain telescope that has a computerized mount. While this type of telescope isn't the cheapest they are relatively affordable, more robust than most, are relatively portable and most important easy to set up. They can also be expanded upon by purchasing add on extras like different eyepieces, imaging systems, etcetera, etcetera, etcwtera and that give you a never ending list of potential Christmas/birthday presents.

If you would like to discuss telescopes further drop me a personal message and I will help as much as I can.

Regards, masu

Thanks for taking the time Masu.

It looks like I'm gonna follow up on this if not for young Kyran but for myself. I always wanted to have a closer look for myself and around here there is not much light pollution except for Townsville (Australia) in the west.

I'll PM you over the next days. Thanks again, Ky.

lined up on the same side of the Sun and at the closest point during an orbit

Not on the same side of the Sun. In that case Mars will be on very far distance and will not be visible due to nearness to the Sun. Opposition is when the Mars will be exactly on opposite side of the Sun, when it will be near to earth. Every opposition the distance between Earth and Mars is not the same. It varies due to eccentricity of orbits of both.. Earth and Mars. On 27th August 2003, it was the least over last so many centuries and over future so many centuries.

Regarding telescope gift to 5 year old:

All the explanation about type of telescopes is Good.

Ok, regarding directly going for telescope, those are you opinions. I have experience of running amateur astronomer's association for last 20 years. It is always better to go in Sky observations is following sequence:

Visual observations,

Binocular and then telescope

Then bigger telescope.

(I never said, never go for telescope in my earlier post)

If a totally new person takes up with telescope, a person will not find the objects in the sky so easily. Even if you purchase GOTO, alignment of telescope is not a cake of 5 years old boy. Besides, the beauty as seen through binocular catches your interest. Though telescope you will see single object at a time, which will not be so attractive.

but by taking long term time exposures

So you are going in the area of photography. Visual observation time exposure is not possible. Thus the object we see through telescope are never so attractive as we see in the magazine.

Again I repeat, you are advising for 5 years old child. You view may be OK for adult.

I have chance to meet many great figures in astronomy like, (one I told.. David Malin), Prof Hoyle, Prof Chandrasekhar, Paul Vita, Prof Vikramsinghe. and many others (due to my astroclub). As I understand, their view also concur with what I said.

All the best.

It would e interesting to know how Ky's grand son progresses, if ky gifts a telescope to him.

G'day gals, guys & gurus,

"Opposition is when the Mars will be exactly on opposite side of the Sun"

When we say in opposition it means that from the point of the observer the two objects being referred to appear to be 180° apart while when in conjunction they are lined up together and in some cases with one obscuring the other. (See image on right courtesy of Wikipedia)

For Earth and Mars to be as close to each other as they will get to each other in a given orbit they need to be on the same side of the Sun as shown in the lower instance in the image. This will mean that Mars will be almost directly overhead and midnight and 180° away from the sun hence the term Opposition. The lower instance on the right shows how thing line up.

On the other hand when Mars and the Sun are aligned and in Conjunction Earth and Mars are on opposite sides of the Sun as shown in the top instance of the image.

At least that's the way I was taught and the Wikipedia articles on Opposition and Conjunction seem to back that up.

Regards, masu

At least that's the way I was taught and the Wikipedia articles on Opposition and Conjunction seem to back that up.

You are absolutely right Masu in all the explanation you have given in your above post. There is no mistake at all in this post.

But in your earlier post, it was surely confusing. Your sentence was:

Mars is in opposition (lined up on the same side of the Sun and at the closest point during an orbit)

It was meaning that Mars lined up on the same side of Sun. Don't you agree?

"But in your earlier post, it was surely confusing."

After rereading my original post I was thinking exactly the same thing and it's a classic example of how relational directions or positions can be so easily misinterpreted.

Whenever possible I try and use absolute rather than relational directions, positions or dimensions but it's not always possible especially when you are talking about something as relationally dependant as orbits.

Then again, I think that last paragraph manages to make things even more confusing so it's probably worth ignoring.

All the best for your star gazing.

I get hint for good optics. I need one personal telescope. I may think of Meade. Thanks for tips.

BTW, do you know David Malin (as you are from Australia). Few years back, I had a chance to be with David for couple of days, great to learn manythings about sky photography