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Posts Made By: dan hilts

April 5, 2010 11:47 AM Forum: Deep Sky Observing

Marking up a star atlas

Posted By dan hilts
I use Taki's Mag 8.5 star maps for stuff I want to mark up. The maps are free on line and are to a scale that makes them easy to read at the scope. I can't use Peterson's without a magnifier, especially under low light conditions.

I simply print out a index from Taki's and then when I'm planning an evening, print whatever pages I need and mark them up at will. There's no expense, nothing lost, and the pages can be kept in a log book if you wish.

http://www.asahi-net.or.jp/~zs3t-tk/atlas_85/atlas_85.htm

Taki is better known for his contribution to PLOP but I use his maps much more often than I design mirror cells.

have fun,
dan

April 14, 2010 05:31 PM Forum: Equipment Talk

correct view?

Posted By dan hilts
<>

Probably.

A regular "astro" diagonal, either a prism or a mirror will put things right side up but leave them reversed left to right. It is easy enough to get accustomed to this view.

A 1.25" erecting prism has somewhat less path length than a 2" mirror diagonal. If you use a 2" diagonal for star gazing, the erecting prism won't cause in travel problems. Also note that for most terrestial viewing, targets are closer than astro targets so typically you need to focus further out.

dan

April 15, 2010 05:53 PM Forum: Pictures of Me and My Telescope and........

First time with med-large aperture.

Posted By dan hilts
Congratulations on your acquisition. It sounds like you got a good one!

enjoy!
dan

April 16, 2010 01:03 PM Forum: Eyepieces

Trading Up

Posted By dan hilts
<>

That's a foolish and expensive way of doing things. There are lots and lots of inexpensive eyepieces but not all are worth anything. It also seems that the cheaper eyepieces follow trends that are often more fashion than science. The fashion that comes and goes reduces value and often you won't get 40% of the original price.

A good example of this is the 30mm 80 degree 2pound eyepiece that was all the rage about 6-7 years ago. There were a number of sources. You will have trouble getting rid of one today at half of the new price. Likewise with the Expanse eyepieces and some of the other widefield offerings.

Choose wisely and buy only what you need, not what you want and not just to try 'em out. If you do buy to try them out,(and there's nothing wrong with that), you can't hang onto them very long or you may end up with a boxfull of eyepieces that nobody wants.

Decent eyepieces don't have to cost an arm and a leg. Chasing the latest offering in the cheapy lineup will simply erode your resources faster than you can accumulate them.

Research - Buy - Use. Tradeup when you are ready.

my $.02 worth

dan

April 20, 2010 12:57 PM Forum: Reflectors

odd optics

Posted By dan hilts
There have been threads before regarding double images in Newts. It was agreed that the most likely cause was due to different path lengths in the scope caused by thermal layers in the tube. That is pretty much the only thing that can cause multiple images. A poorly finished mirror will smear the image but not create distinctive multiple images.

I have seen double images in more than one Newt but I have no experience with SCTs.

good luck,
dan

April 21, 2010 01:10 PM Forum: Equipment Talk

2x Barlow (not a shorty) question

Posted By dan hilts
It may not be light from the sides of the Barlow. I've experienced ghost reflections with Barlow use because light is reflected off the surface of the field lens and back to the Barlow. It all has to do with the curves of the specific lenses and the distance they are separated. You can't change the curve on the camera lens but changing the spacing by using a longer Barlow may very well put reflections far enough out of focus that they can't be detected.

dan

June 17, 2010 03:38 PM Forum: Eyepieces

field stop measurement for eyepiece fov-works?

Posted By dan hilts
<>

What numbers are required? Why do any math at all?

The only things you are going to see with either eyepiece are those that are inside the FOV defined by the field stop. The field stop defines the largest possible FOV for the eyepiece. The eyepiece with the largest field stop wins.

Whether or not that FOV is distortion free doesn't really matter. You won't see anything more than the field stop allows. If it is a poorly designed eyepiece, you may see less.

dan

June 23, 2010 05:37 PM Forum: Off Topic Discussions

8" Celestron NexStar chucked off the roof in L.A.

Posted By dan hilts
I never cease to be amazed at what some folks will find entertaining. Too bad about the scope though.

dan

June 26, 2010 02:58 PM Forum: AstroMart FAQ

make an offer

Posted By dan hilts
How much do you want for that scope?

I dunno, make me an offer.

Ok, how about ten bucks?

I don't think so. That's not enough.

How do you know? You said you didn't know what you wanted. I think you wanted ten bucks.

Be reasonable. The scope is worth more than that.

Not if nobody wants to buy it.

This is a waste of my time. Do you want to buy it or not?

Yeah, how much are you asking?

Make me an offer.

Look, I'm the buyer. You are the seller. If you want me to do your job you will have to accept the way I do it. I'd sell the scope for ten bucks. Do we have a deal?

No.

Why not?

I don't like your price.

What price do you like?

I dunno..............

July 3, 2010 10:53 PM Forum: Refractors

Short tube vs. Long focal length refractors

Posted By dan hilts
<>

A refractor in your price range is likely to be an achromat and if a short tube, will show some color error which will hamper good planetary views and photography. A camera has no tolerance for chromatic abberations in a telescope. You can get a 120mm at F8 that is a reasonable compromise and with a minus violet filter the CA can be somewhat controlled. If you can put up a little more cash you might be happier with a 100mm ED for photography but it is unlikely you would find one within your budget.

dan

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