Posts Made By: Alex McConahay

Look over to the left margin. In the top box ("Forums") you will see a menu choice "Display Preferences." Click it and go the the bottom of the window, and experiment with your choices on Forum Display.

Alex

I like the moodiness.

Alex

As you are focusing, does the image almost come to focus and then you run out of focuser travel, or does it get close to focus and then out of focus without ever really coming to focus?

Alex

Canon seems to be more popular in the astrophotography market.

Both Nikon and Canon offer high quality products, but Nikon appears to be a little more difficult (not difficult, just a little more complicated) to interface with the astro-software.

(My friends who own both use the Canon stuff more.)

However, other factors may have a bigger influence. The best cameras for astrophotography are modified to admit more reds. This makes them limited (and more complicated) to use during the day.

If you already have a set of lenses, and plan to use your new camera with them, then you may want to invest in a new body that is compatible with them.

Are you looking for entry-level or top of the line?

At any rate, you won't go wrong with the latest version of the entry-level Canon DSLR, in my opinion.

ALex

I've never heard of such a problem caused by a t-ring on a Canon.

Alex

From the way you tell the story, you had a good deal and it should have gone through. Why did you wait more than a day or so to contact him and ask the status?

Alex

Some things are extremely easy to find, others are more difficult.

Even with the magic digital setting circles, or goto, it can be difficult to find things if you are not properly aligned either because you have not been careful or because you do not understand what is happening.

The difficulty of finding things without setting circles/goto gets easier with practice, and if you are willing to learn and be patient, then it can certainly be done. (I know a fellow who has completed 109 objects of a Messier Marathon without setting circles, charts, or any goto, using only his memory.) However, you will probably need a chart to find things, and lots of patience.

Another problem--sometimes you can be looking directly at something, and still not see it. It is either too small, or too dim, or whatever.

Either of these scopes is a good starter. The eight inch has lots more light grab. The six inch will, however, get you to "see" (although perhaps not "study") most objects. Whether the six finds them easier depends on how well you have it set up and such.

Alex

Cindy,

I cannot remember whether anybody has given out the standard advice in this case-----

Get to a star party and try it yourself.

In your case, this means finding somebody who is star hopping and watch him or her do it to find an object. Then try it yourself with just a star chart and a telrad or finder scope.

Then watch somebody using digital setting circles---but in that case make sure you start with the initial setup, and try that yourself. As I said, it is relatively easy to find thing once the scope is set up, but getting it ready in the first place can be a challenge.

Alex

>>Good starter camera:

Many people start with the DSI. There are lots of other choices, however. I'll let more knowledgeable people talk about them. As for needing a guidescope--same answer.

>>Is there an Astrophotography for dummies
See

http://www.astropix.com/HTML/K_MISC/TOC_SITE.HTM

for an internet starter. And see Lodriguss' CD for another intro. See Ireland's Photoshop book for processing hints.

Alex

The term "cooled down" is really short hand for something to the effect of "All the parts of the telescope are at the same temperature as the outside air." Since outside air is usually cooler than the telescope that has been riding in a car or sitting in a house, it is usually the scope that needs to "cool down" to match the air.

Before we go further, imagine looking across the desert or a hot pavement on a hot day......Notice the "heat waves" making a distant object shimmer. (They are not actually "heat waves" but different pockets of air at different temperatures--which cause the light passing through them to refract differently, and thus shimmer.) This is "bad seeing." It happens in between the top of the atmosphere and your eyeball, and makes stars twinkle. This is called "atmospheric seeing." It also happens with local sources of heat, like a warm rooftop, or a chimney, or hot car. This is called "local seeing." (It also makes the stars twinkle.)

It can also happen between the mirror and the tube. What is happening is that some part of your scope (usually the mirror since it has the most mass and retains the heat the longest (i.e., cools the slowest) is warmer than the air. It heats the air around it and makes it move, and makes the same "Pockets" that exist in the atmosphere. To see it, defocus a star and watch how the image moves. If it moves back and forth, comes in and out, you have seeing problems.

If there is differential heating of one part of the mirror, you could also get a warped "figure" or shape to the mirror, which would make the focus less than ideal, but this is a relatively rare effect of a heated mirror.

One of the other things the heated mirror does is to heat the air, which then rises up the tube. As it moves up the tube, it disturbs the view.

Any kind off bad seeing makes it so that the object does not stay in one given focus, and also (usually) makes for a little shimmer in the object.

Probably more than you needed to know, but every once in a while it is fun to spout off.

Alex