Thursday, April 30, 2009

Rant from "Section Four"

Life and times of the amateur astronomer and all the struggles we face. It happens. We lose. And the flow of information is sometimes never right. Weather is not an exact science.

"What a racket!
Because the web site of your stupid pals at weather stupid canada said that wed night wud be clear; and because their own stupid weather radio said it wud be clear, and because the stupid clear sky clock said it wud be clear ... So because of all this I went to (expletive deleted) wed ... And it clouded over solid at nine ... And the stupid weather radio was still broadcasting six hour old stupid info saying it wud be clear as the stupid clouds were building up all around me.
I'd have been better off hiring a stupid witch doctor Stupid hobby."

Yep, stupid hobby :)

M

Tuesday, April 28, 2009

Seeing Double: Splits with scopes.

You can say astronomy is as difficult as you want it to be. That is true. Many spend the night just looking while other set up elaborate equipment and imaging systems and gather as much light as they can in the short hours we do this.

Double Stars are sort of in between all that. It's observing, fun but also challenging to the eye. Some doubles are easy splits, obvious, and often times beautiful in contrasting colours (Albireo for example). Some require more attention, more power, better optics, sturdy mounts. Castor and Algeiba are more challenging but certainly well within the grasp of today's instruments. Epsilon Bootis is more of an example of a challenge for smaller scopes given the contrast in stellar magnitude (brightness). Some seem almost impossible.

Then there is Porrima or Gamma VirginisWith an orbital period of 168.93 years, it was at it's closest in 2008 at around 0.4 arc seconds the distance is beginning to open up to 0.9 arc seconds in 2010. It will be *observable* in small scopes in 2020 (whatever that means). Here's what I do know. Both my scopes won't spilt it cleanly. This is no surprise. But what can be said is that the Pronto does show this as an elongated single star, meaning it is starting to see the companion. It's tough to tell. I can say that I think I saw what I saw in the Pronto. But that little scope was pushed off the deep end of it's power range, around 300X. If the Pronto could talk, it would probably apologize for "just being a 70mm" which is too bad because the optical quality is more than up to the task. The aging SP-C1o2, a classic achromat that dates back to an era of extremely good quality, shows more of a companion. But the problem with this scope is the mount is just too wobbly and the focuser being a bit too stiff to confirm a sharp image, never mind the atmosphere acting up. This old scope is pushing 25 years old, needs new legs and heftier mount. I'm almost positive I can see the beginning of a companion, but really, I can't totally confirm it.

Did I see it? I don't know. I don't have an answer this time. I'd like to think I did, but that sounds wishful. Maybe I should wait till 2020. But why? Why miss out on pushing the outer limits of the scopes. I mean, how boring it would be to wait.

I just don't know for sure....

M:)

Sunday, April 26, 2009

Saturday, April 25, 2009

How powerful is it?

I hear this question all the time.

Just how powerful is this/a/your/ telescope? It's a misconception of just how a telescope works although the simple answer from today's amateur is somewhat inaccurate. That answer is, "power is meaningless". This is partly true, but does not explain the function of power. By power we mean, "magnification", the actual image scale of what we are looking at. Magnification is required to view just about anything, so saying it is meaningless is essentially wrong. What is meaningless is "advertised power" on today's junk trash scopes found in today's department stores. Advertised magnification claims on such telescopes are trying to dupe you into believing you are buying something with a "tremendous spec". Try using that 500X dinky scope with it's shaky tripod. You'll see what I am talking about.

Astronomers will say that "aperture" is the most important". This is mostly correct. The most correct answer is "the largest aperture you can afford and transport easily". Aperture or diameter of a telescope is the function of light gathering, which in turn, is a function of resolution, or the ability to see detail. After you get the light gathering, you can apply the power...to a point.

Not all objects in the sky need tremendous power (surprise!). In fact, very few do. Most of the "power hungry objects" are the moon or the planets. Deep sky objects benefit from low or high power depending on their size. Try looking at Andromeda Galaxy at high power and you'll see what I mean. Try looking at the Blue Snowball at low power and see what I mean.

There are rules to magnification, but they are rules-of-thumb or guidelines. You can obey them, bend them and break them. The generally accepted rule is 50X per inch or 2X per millimetre of aperture. Simply put, a three inch telescope is generally able to "power up" to 150X, more or less.

The guideline assumes that all things are equal. But they seldom are. The general rule with power assumes that the atmosphere is stable (unlikely on most clear nights), the optics have reached ambient temperature and quality of the optics. This is where it gets a bit muddled. We have pushed high quality, little scope well past the 50X per inch guideline either because it was stable or the optics reached ambient. Well past the breaking point of the guideline. Or we have been restricted on larger instruments to well below the guideline because the reverse is true.

So just how powerful is it? I don't know. Depends on the night, depends on the scope, depends on the object. One thing is certain, it's something that needs no advertising.

M:)

Friday, April 24, 2009

20 years in the Dark

It seems fitting I suppose that the International Year of Astronomy 2009 is also the 2oth year that I have been seeing in the dark. I am self-learned, more or less. I started off wrong, with the wrong telescope, a Blacks Camera 234 Magnicon 60mm Refractor and a pair of humble 7X50 Bushnell Binoculars. But I did manage to see a few things with this junky scope including Jupiter's cloud belts and the craters on the Moon.

Dozens of scope later, I'm still at it. I have a had few years where I wondered why I still do it, but I seem to have almost answered that. Because it's there. No wait, that's cliched. Because I can. Well, that's no better. Because....so there.

So here's to my first blorg. Blog. Seeing in the Dark--a journey, so to speak of one astronomer, or many.

M:)