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Posts Made By: Steve Lathrop

March 10, 2003 03:38 PM Forum: Equipment Talk

13mm Nagler or 14mm Pentax with XT8

Posted By Steve Lathrop

One post above noted the weight of the Nagler 13 T6 as 10 oz. Just checked the Televue website where they list it as .4 lbs., (or 6.4 ozs). It's really small.

Steve

March 17, 2003 04:28 PM Forum: Equipment Talk

Televue 102.

Posted By Steve Lathrop

My TV-102 has given me more pleasure than anything else I have been able to get by buying it, and at age 56 I have bought a lot of stuff. It has shown me some of the most beautiful images I have seen.

Does exactly what it is supposed to do, a joy to use, and still new-looking after 2 years of intensive use.

Focuser is superb. Contrast is superb. Color correction is superb, but maybe not perfect, perfect, perfect.

There are some things a TV-102 does not do as well as other scopes, like dim deep sky, or the kind of maxed-out planetary performance you could get from a bigger APO, and that could be a real problem. If you own a TV-102 and would like to expand your horizons, you are not going to want to sell the TV-102 to do it. That's the bind I'm in now.

But I'm not selling the TV-102. Ever.

Steve

March 25, 2003 01:04 PM Forum: Equipment Talk

To bino-vue or not. Is it just my eyes?

Posted By Steve Lathrop

I would like to make use of your experience.

What can you say about your eyes?

I have been thinking about binoviewers but am inclined to be cautious because my eyes are quite different. One corrects to about 20/15, the other to about 20/40. Without glasses, the bad one can't see the top letter on the eyechart, can't even see it's there. BUT, I do get pretty good use out of binoculars if they have extreme +6/-6 diopter adjustments. The bad eye does not quite come to focus, but it contributes enough to add a 3-D effect to the moon.

When I observe with one eye, I favor the better one, but because I can easily reach focus with either, sometimes I alternate. I do notice that there is a not-subtle difference in image perception which does not seem to be optical. With study I can see all the same details with either eye. But I see them quicker and easier with the good eye than with the bad one. I think it is a difference in image processing on one side of the brain vs the other.

I've neglected the bad eye for a long time, which when it deteriorated at about age 13, after a bad bout of measles, had previously been my dominant eye. At that time the easy image perception was through the eye I now disfavor. I remember vividly the hard work of trying to switch to the other. Now I am trying to retrain my brain to make use of the bad eye, at least at the telescope.

I also wonder whether practice might make your own binoview experience better. When you hold my glasses at arm's length, you see the image scale in one lens is about 3 times larger than in the other. It's amazing to me that my brain can merge the images, but it does. When I first started wearing the glasses, no way. Now, I can go back and forth between glasses or no glasses, and not notice any change.

I've never looked through a binoviewer. Would like to give it a try. Question: are your eyes the source of your binoview problem, your eyes, your brain, or what?

Steve



March 26, 2003 04:53 PM Forum: Equipment Talk

Software showing stars down to mag 14 or deeper

Posted By Steve Lathrop

My copy of Starry Night Deluxe, which is about 4 years old, shows stars to at least magnitude 15, using the Hubble Guide Star Catalogue.

Steve

March 28, 2003 07:34 PM Forum: Equipment Talk

How much light is twice as much?

Posted By Steve Lathrop

For me, this discussion will be more directly applicable to the questions I'm trying to answer if we express answers in terms of aperture, not magnitudes, and maybe more in terms of direct experience at the eyepiece, which is the standard I hope to apply, instead of in terms of mathematics.

Thanks

Steve

March 28, 2003 07:51 PM Forum: Equipment Talk

New Scope Curse, the movie

Posted By Steve Lathrop

Last October somebody with really bad juju bought a scope in the Boston area. Nobody in eastern New England has seen anything since.

Steve

March 30, 2003 12:48 PM Forum: Equipment Talk

Beginner looking for a telescope

Posted By Steve Lathrop

Here's a high-risk suggestion.

Beginners approaching the hobby for the first time often think in terms of spending money, not investing it. They figure that whatever they spend, they stand to lose—which, with good equipment, is only partly (small partly) the case. With good equipment, it may barely be the case at all.

Compare the prices of new premium brands, such as Starmaster or Tele Vue, with what sellers ask for them used on Astromart. In many cases good used scopes don't lose much value. And if the scope is third-hand instead of second-hand, what's the discount for that. Maybe about zero.

Price aside. What do you want as a beginner. Minimum hassle. Maximum intuitive-to-use-it-ness. Genuinely exciting views. And an instrument which will make it easy to find things, not frustrating, while you learn the sky. That last part seems to me to have been under-emphasized in other posts on this thread.

Where does all that point? If you don't have much cash to speak of, then the 8-inch f6 dobs that others have mentioned may be the way to go. Probably a better choice than an introductory achromat, which is likely a long-term source of expense, because if you end up liking the hobby you will replace it with something better.

And starting with the achromat, you have less chance of liking the hobby. It compromises on both view quality, and ability to see dim objects, which is a big compromise. But most refractors do offer focal lengths short enough to maximize the ability to learn the sky--a big plus.

And the dob has compromises too, (everything has compromises). Collimation scares some people. Cool-down can be an issue. And an 8-inch f6 dob shows only half the sky or less compared to most refractors, so it's harder to find things and learn.

Here's the high-risk strategy. Buy a used premium APO refractor, a Tele Vue or Takahashi, on an alt-azimuth mount. You compromise on only one thing: dim deep sky. Everything else is maximized, low hassle, ease of use, retained value, stunning, amazing views of moon, planets, star clusters, double stars, many nebulae, and one galaxy (M31, you can also see some detail on maybe a few dozen other galaxies). And most important, learning the hobby and the sky is maximized.

Where's the high risk? It's only a low-cost strategy if you don't like the hobby and sell the instrument. And if you start this way, you are not going to do that.

Steve









April 16, 2003 05:41 PM Forum: Equipment Talk

Question about min. aperture needed for DSO

Posted By Steve Lathrop

What do you mean by "see" structure?

I would be astonished (and disappointed) if my 4-inch TV-102 would not outperform an ETX 125 for seeing structure on M51, but I am guessing that not too many people would think the views the TV-102 provides would qualify as good-quality deep-sky views. From a dark site you can see at a glance that M51 has structure. You have to look a long time, use averted vision, relax your gaze, rest, do it all again, etc. before you become confident you know what you are seeing. I think that rules out scopes smaller than 6 inches for what you are trying to do, but I have no idea where the limit ought to be.

I really want to see what others say about your cool laser pointer suggestion. Isn't parralax going to be a problem?

Steve


April 21, 2003 05:19 PM Forum: Equipment Talk

4-inch to 8-inch: Not Enough?

Posted By Steve Lathrop

Bill,

Something about "...the average two scope household..." gives me a chuckle.

Steve

April 22, 2003 07:39 PM Forum: Equipment Talk

What mirror material is this ?

Posted By Steve Lathrop

Looks like its made out of Jupiter. See the GRS in the upper left?

Steve