Posts Made By: Alex McConahay

Really nice.

The first three days and nights were clear, cold at night, and pretty much spectacular. Then we lost a whole night to clouds. The rest of the week, we lost about half the night to scuttling clouds. You had to go for the sucker holes.

The food was really remarkable (for me--people who go there regularly were used to it.) Facilities were very nice.

About 450 showed up, I understand. Event was well managed.

Alex

Most towns have an electronics store that carries almost anything. (In Riverside, CA it is on Main Street, just below the 60....anybody around here knows about it!!!) Take the telescope in there and show it to them. They can either find the connector in a drawer or order it for you, I'll bet a dollar!

Alex

All AFOV's are inherent to the eyepiece, by definition. However actual FOV's will depend on telescope focal length, and other things.

Another question is whether you will get vignetting (darkness around the edges, relative brightness in the middle). I simply have no experience with the Ethos/Powermate to tell you.

And I also would not buy the idea that you can add a Powermate or Barlow and expect to get the performance of a native shorter focal length eyepiece--too much added glass.

Alex

There is no clear definition of what 1 power means. And it is even more confusing when applied to astroimaging.

I think the clearest definition, although it has its own problems, is that one power means it takes up the same actual field of view as it does with the unaided eye. To express this another way, if the moon looks like it is half a degree across in the sky, any device which makes it appear to take up half a degree in the eye would be ONE power. Examples of these are Tel-Rads, red-dot finders, and welding glass to observe the sun.

When you start to apply these things to astro images, you have to factor in how the images are going to be viewed. This includes projected, printed, or displayed size versus distance from the screen to the viewer.

Alex

It's a person who makes a posting on a forum like this just to stir controversy.
They are very unwelcome in Astromart land.

Alex

That sound highly illogical.

Alex

I'm sorry Dave.......

Alex
(actually, I know I was being a goofball.....and was relieved when you got a serious response. It is not good when all of us are goofballs. Of course, then it all went goofbally again!!!)

Alvaro,

You are asking us to make some determinations and we do not have the information.

A 12 inch SCT is a lot of stuff to lug around no matter what.

How big are you? How much can you carry? How big is the storage space for this thing? How far do you have to go to use the scope?

If you are otherwise young and healthy, there is no reason you should not keep the 12 for those times you want to really use a scope with that capability.

Add a high quality 80 mm refractor on a quality portable tripod. That can be your "grab and go" scope for when you just want a little looksee. And it is particularly useful from the city.

Alex

I've never had to wait more than about ten days.

Alex

Bob,

Do I understand your question correctly:

You have a Newt.
You want to mount a camera to it.
When you do, you move the focuser in, and as you are moving in it starts to come to focus, but before it gets sharp, you run out of travel.

If I have that situation right,you need to reduce the distance between your primary and the focal plane. May I suggest:

....RE-collimate such that your collimation bolts are out (or in, depending on your colliimation setup) as far as they can go and still collimate your mirror. Collimation bolts have as much as half an inch of leeway.

....use as short a connector as possible with the t-ring to mate to your camera. (Of course, these things tend to be very short already)

....replace your focuser with a lower profile focuser. (You may want to do this anyway, because the focuser for a typical newt may not have been designed to handle the more critical fine focusing and weight requirements of imaging.)

....Move the mirror forward. This is usually a lot easier than you might think. It could be as simple as drilling three holes further up the sonotube. Or, however your mirror cell is mounted, inserting some shims/blocks and longer bolts to push the mirror forward. Remember that this will almost surely change your balance point. THis may or may not be a big deal. And it may be inevitable if you are thinking about mounting a camera anyway.

After that, there are some things you can change optically (like the Barlow, and afocal imaging) but these things change the nature of your imaging---and I would not suggest they are good first solutions.

Alex