Some more personal stuff.

As some of you know from posts in our clan forum and in "Off Topic", my great nephew Zachary (3 years old, I have found out, not 4) had to have brain surgery for Chiari Malformation (http://www.2old2play.com/modules.php?name=Forums&file=viewtopic&t=47627&highlight=chiari). Well, he had the surgery on Monday, September 29th and I'm extremely happy to say that it appears to be successful. After a few days of concern since he wouldn't eat and was suffering from vomiting (a common side effect), we got a call today from his dad to let us know that they have released him from the hospital in San Antonio, Texas. They will start the long drive back to Rockford, IL soon. WIth the after effects of the surgery, they didn't want to take him on the plane. Thanks to all who prayed and kept him in their thoughts. Our families appreciate the concern and support of everyone here.

Astronomical Observing 101 (or before) Part 3

OK, so I lied! I had ended the last blog with "Next time I'll look at the 3 types of reflectors and give some examples of the prices of some popular models (two of which I have plus one that is on loan to my brother)."

Instead, I find I need to cover just a little bit more on terminology and on the types of telescopes.

Refractors have an Objective lens (the big one) and an eyepiece (or ocular). Reflectors have a primary mirror (the big one) and either a secondary mirror or a diagonal, and the eyepiece. The size of the objective lens or the primary mirror is known as the aperture. The focus point of lens/mirror is based on the amount of curvature of the lens/mirror(s). The distance from the lens/mirror/eyepiece that the image comes to a focal point is known as the focal length. This is important when calculating the magnification achieved with certain telescope/eyepiece combinations. The focal length divided by the aperture is known as the focal ratio and for a 150mm telescope with a focal length of 1200 would be shown as having a focal ratio of f/8. If you are into photography, this will seem familiar as camera lenses have a focal ratio assigned to them in the same way and it defines how "fast" the lens is. The lower the number, the faster the lens and thus requires a faster shutter speed to properly expose the picture. It has similar ramifications in doing astrophotography!

When you look at the design of reflector telescopes, you will see that the effective aperture usually is not the same as the diameter of the primary mirror. Following is a chart from "Norton's Star Atlas and Reference Handbook" that I referenced in my first Astronomy blog.

This diagram shows the focal point and not the eyepiece. It must be understood that eyepiece is located just beyond the focal point and in case you can't read the fine print, here is the explanation:

Different types of telescopes. For telescopes of similar apertures, the path of light ray from a celestial object to the focus F is shown through (a) a refractor, (b) a Newtonian, (c) a Cassegrain, (d) a Cassegrain-coude', (e) a Schmidt-Cassegrain, and (f) a Maksutov-Cassegrain.

Note that I did not mention the Cassegrain and Cassagrain-coude' earlier because they are rarely found. There is actually a rare 7th type which tilts the primary mirror of the Newtonian, reflects the image off a mirror which is outside the the path of the incoming light, and passes it through lenses that correct the astigmatism caused by the tilt of the primary. Although more difficult make, it offers brighter images than possible through the other reflectors for the same size primary mirror. This is known as a tilted-component telescope. With the exception of the this last type, you will notice that the incoming light has part of its path blocked by a diagonal or mirror, and in the case of several of them, a hole in the primary mirror. This is what reduces the physical aperture to an effective aperture that may be as little as 60-70% of the actual one.

One last term that you may come across is the catadioptric telescope which is a generic term for the telescopes like the Schmidt-Cassegrain and Maksutov-Cassegrain.

The last item to cover in this blog is magnification. Eyepieces have their own focal length and when used in conjunction with a telescope with its own focal length, defines the magnification achieved. Magnification is determined by dividing the focal length of the telescope by the focal length of the eyepiece. Here is a table of the magnifications from my eyepieces and telescopes. There is an additional lens that can be used called a Barlow which doubles the effective magnification, hence the nnnn.x2 columns.

Next time I'll REALLY look at the 3 types of reflectors and give some examples of the prices of some popular models (two of which I have plus one that is on loan to my brother).
 

Astronomical Observing 101 (or before) Part 2

Some info on telescopes. The purpose of a telescope is to really to do two things, not just one.The first is to magnify the image which is the obvious one. The other is to increase the amountof light which reaches your eye. The magnification is a result of the focal length of the lenses involved. THe amount of light that reaches your eye is based on the size of the primary lens OR mirror.

Most people are familiar with binoculars and the designations listed. 7x35 are common field glasses or binoculars. They are 7 power (7x) which means that things look 7 times bigger when looking through them. They also have 35mm diameter lenses in the front (objective lens). They gather in more light than your eyes do normally. When using them at dusk for example, you can see more detail through them not just because the image is larger, but it is also brighter. For astronomical purposes, a 50mm objective lens will gather much more light than a 35 mm lens. Now a 10x power will enable you to see more (especially of planets and the moon) than the 7x binoculars. Obviously 20x would allow even more to be seen, but they are MUCH harder to keep steady if you are holding them in your hands. There are some devices that can be made or purchased that will allow one to use binoculars of high power with little or no movement. (A subject for the future?)

Now most refractors and binoculars have the objective lenses measured in millimeters and reflectors are usually measured in inches. Here is a table of approximate conversion. The area of the lense is a good indication of the light gathering effect of the lens/mirror. For example, going from a 4" to a 6" telescope increases the light gathering by over 2.3 times. Going from a 4" to an 8" increases it by 4.1 times.

35mm = 1.4" = 962 sq mm
50mm = 2" = 1963 sq mm
80mm = 3.1" = 5027 sq mm
90mm = 3.5" = 6362 sq mm
100mm = 4" = 7854 sq mm
125mm = 5" = 12272 sq mm
152mm = 6" = 18146 sq mm
203mm = 8" = 32365 sq mm
244mm = 10" = 46760 sq mm

There are basically two major types of (amateur) telescopes. The refractor and the reflector.

Both have benefits and drawbacks. There are a bunch of variations though. Some have to do with with the optics themselves and others have to do with the mount.

The refractor is like the old fashion spy glass type. At one end of a tube is a larger lens and the other end has a smaller lens which is what you look through. These are relatively expensive for the size of the objective and can be very expensive depending on the quality and type of lenses. In these there are two types, achromatic which can have a color halo on bright objects, more so on larger objectives which is why they are limited to a max of about 100mm but are relatively inexpensive (Orion has a 70mm with two objective lenses, mount and finder for only $150). An apochromatic has different glass and construction and can be found in larger sizes with less false coloration, but you will pay for it! (for example, Orion offers a 72mm apo with no lenses, mount or finder known as a tube only for $500, a 120mm version of tube only goes for $2,000!, a Takahashi 130mm tube only goes for over $6000!).

The reflector type scopes fall into (about) 3 categories.

The newtonian is what most folks think of as a reflector. These have a mirror at the bottom of a tube, a reflective mirror close to the open end in the middle of the tube that reflects the light out to the side where there is a mount for a lens (eyepiece) to look through.

The Schmidt-Cassegrains with a mirror at the back end of the tube, a lens combined with mirror at the front end that adjusts the lights, seals the end of the tube, and reflects the light back down through a hole in main mirror to a mount for the eyepiece.

The third type is the Maksutov-Cassegrain which is similar to the Schmidt-Cassegrain but has a slightly different type of front lens and reflective mirror.

Next time I'll look at the 3 types of reflectors and give some examples of the prices of some popular models (two of which I have plus one that is on loan to my brother).

More to come (?)

Astronomical Observing 101 (or before)

One of our clan members sent me a PM a month ago about wanting to get into astronomy and wanted some tips. Here I present the original question and answer. Rather than doing this through PM's, I felt that others might also want to know more about this. Plus, if I screw up in something that I tell them, there will probably be folks, more knowledgeable than I am, to correct me or add stuff that I forgot!

***********************************************************

I am seriously considering the purchase of a telescope, and I know you are a big astronomy buff, so I thought you would be a prime candidate to ask some questions to.

First off, I am a SUPER beginner. I don't know where to start as far as what I would need on a qualtiy scope, what lense, computerized/not computerized, prices vs quality...

I have soo many questions and am having a hard time finding some good quality, down-to-earth (no pun intended) answers.

Can you just tell me a little bit about beginning star-gazing and possibly a bit about telescopes in general. I would really like to be able to see Saturn and Nebulas, along with constellations.

***********************************************************

To which my answer was:

First, this will be a multi-phased information process. Second, I am not an expert, so don't be afraid to question my suggestions.

Here are my first suggestions.

1. Get a GOOD pair of 10x50 binoculars. They are great, easy to use and you can see some of the nebulas and star clusters that are fun to view.
2. Get some books. I like the following and they are not outrageously expensive:
3. Collin Pocket Guide - Stars and Planets by Ian Ridpath and Wil Tirion
4. 365 Starry Nights by Chet Raymo
5. More Expensive and more technical is Norton's Star Atlas and Reference Handbook edited by Ian Ridpath (mine is a 19th edition).
6. The Cambridge Star Atlas by Wil Tirion. Very detailed but not super easy to use.

Start with this. Use the binoculars to find stuff and learn the constellations.

More to come!!!!!

***********************************************************

To the above, I would also suggest picking up a copy of Sky and Telescope magazine (my preference) or Astronomy magazine. The star charts in there are for the current month and will help identify a lot of the current stuff (like Jupiter being in the southern sky right now).

The use of binoculars will even let you see the moons of Jupiter, if you are steady enough. One of the charts in magazine will show which moons are to the right and which to the left of Jupiter or are transitting (crossing the face of the planet) or being eclipsed (passing the far side of the planet). This changes daily!

Hopefully this a good start and if others want to ask questions, feel free, just don't expect me to be an expert, just another fan of the heavens.

Even more rambling!

Ok, a time for reflection. As I've stated several times in my blogs, I don't do them often enough to really count as a blog (in my opinion). It seems that true blogs are a continuing state of being type thing on close to a daily basis. Usually I have trouble finding things to write about, so this time I'm going to reflect on what I've said here before. If you are still interested, keep reading. Otherwise wait for my next blog, it might be fresher.

I joined this site in September, 2005 which means I've been here for just over three years. I was an I.T. mainframe computer specialist. I was a manager, a systems analyst, a programming analyst, and a (primarily) COBOL programmer. Which doesn't mean diddily squat to a gaming community nor should it!

I wrote my first blog in May, 2006 eight full months after joining this great community. Typically, I wrote about how I got into this and outlined my gaming setup. Real exciting stuff!

The next one explained some of my feelings for why I was still here and some general ramblings on the community.

The three blogs that followed "Where am I, how did I get here, why am I here?" parts 1, 2 and 3 were an attempt by me to reflect on the amazing chain of events that led ALL of us to this time and place. The technological changes that most of you take for granted, not having lived through them, that I have found to be incredible. Some of you added your own memories to mine to add depth to my scant knowledge and writing ability. Thank you!

All those were written in May, 2006. After that I had a dry spell (to be repeated later) and didn't write for 5 months. No one noticed, nor should they have. I was just one silent voice among a large number of highly active voices that are part of what 2o2p such a great place.

When I wrote again, in October of 2006, it was an admission of failure on my part to be all that I want to be. Not that I think I'm a failure, just not as successful as I could wish. As stated in that blog, I read a LOT (just ask my wife!). I see how some people in all kinds of genres paint pictures with words and get a grip on your imagination that makes you want to keep reading 'til the end. I have found that I can't do that and it pains me deeply.

Then in November, 2006, I once again wrote about this place and how great it is that such a diverse group of people has created a virtual community that often exceeds the physical communities in which we live for compassion, caring, and a will to help each other.

Eight months would go by without another word from me (July, 2007) and then it was only, in a way, to cry out against the age that I had become (64) with a quote of the great Beatle song, "When I'm 64". A weak blog, but a heartfelt one.

Later that same month, was one of my first really introspective blogs. To me, a "Meaningful" one. My thoughts about how time has flown by and now that I'm what I consider "old", what is truly important to me. As I ended that blog, "Yeah, life goes on and it's good." And you know what? It is!

My next blog was also in July of 2007. Mostly it was a report on the "red ring of death" that I had once again experienced. But I also remarked on going to Niagra Falls and Boston and how no one would care to read about a couple of old folks taking a trip. Surprisingly, several people did want to hear about it, but I never followed up on it. Maybe one of these days I'll go back through my pictures to remind me of the details and bore you all with the account. (You've been warned!)

In August of 2007, I posted (can't really say I wrote it) an article about "Global Warming" with references to a former (great blogger), TheDastard who had to leave our confines due to conflict with his real life position. I sorely miss his blogs and the thinking that he made me (and others) do.

Then a short blog later in August to announce my acceptance into the COD4 Beta! Just a boast to make others feel bad (so petty on my part!).

At the end of that month, I wrote a blog about my marriage of 39 years. I think that this blog was more open and feeling that I am accustomed to be.

It then took almost a year to blog again and then it was to show pictures of my youngest grandchild (at the time). He is a joyous child and easy to be in love with, at least for me. In the words of a song, "he makes my heart sing!".

And my last blog expressed some of my feelings about being retired, another grandson, and 40 years of marriage.

All in all, as I reflect on my ramblings and the changes in my life, the community that we call 2old2play, who we are, what we do with our time, and where we are headed, I find that I still appreciate this community and the ability to express myself without expecting dire consequences. I truly feel a part of a diverse and dynamic community that helps fill my needs and hope that most of you feel the same way.

What I say here will not have far reaching or important impact on the world as whole nor even on our large, but limited community. But I have a place to do it, and that feels good.