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Posts Made By: Milton Wilcox

December 21, 2004 01:15 AM Forum: Astro-Physics

Horsehead by Chris Hetlage

Posted By Milton Wilcox

Absolutely breathtaking - Kudos to Chris.
Milt

January 3, 2005 02:07 AM Forum: Refractors

How to detect over or under correction?

Posted By Milton Wilcox

Bill,

H.R. Suiter addresses this question in both chapter 1 and Appendix 'A' of his excellent book 'Star Testing Astronomical Telescopes.' Star testing is the most sensitive test an amateur has for measuring aberrations - and the most fun, because we are under the stars!

Clear and steady skies (for testing),
Milt

January 4, 2005 07:21 PM Forum: Deep Sky Observing

Splitting Sirius?

Posted By Milton Wilcox

Quoting S & T,

At its current separation of 7", it is visible in an optically excellent 5 or 6 inch scope. Indeed, Sue French reported glimpsing it in her 4.1" apo refractor [A-P Traveler] in 2001, at a separation of 5.5"

I have never split it myself, but I'm sure many others have.

Good luck,
Milt

January 6, 2005 10:26 PM Forum: Takahashi

Shoul I get Mewlon 180?...if I have a 80mm spottin

Posted By Milton Wilcox

Sure, you will need one [eq mount] for imaging, but as you say you won't be imaging all the time.

Hi Nils,

Since you haven't lived with an eq mount, here's a counterpoint from a fellow 5 year visual observer who started with one. Even when you don't hook up a drive or do an exact polar alignment (eyeballing Polaris is good enough for visual), knowing N-S and E-W is extemely helpful for finding DSO's.

Star charts always show N up, S down, E to the left and W to the right. With my alt-az mount, I still have difficulty orienting myself to these celestial coordinates. With my eq, regardless of where the scope is pointed in the sky I know that moving in RA gets me E-W and moving in Dec gets me N-S. For example, if I know that a target is 5° due east of a naked-eye star, I can put this information to use with my eq much easier than my alt-az. You can also hop from one object to the next - this is how I navigate through galaxy clusters without go-to, drives or DSC's.

As you correctly point out an alt-az mount is cheaper, lighter, easier to set up and also can be just as stable as an eq mount. But IMO there is a place for both even if you are not imaging. Try it, you'll like it!

Milt

January 12, 2005 06:51 PM Forum: Refractors

New ED100 Arrived

Posted By Milton Wilcox

My scope had the lens cell cross-threaded
The focuser needed tweeking

Terry, thanks for your report. You have undoubtedly done this already, but Orion needs to be informed that they have QC issues with these scopes. Glad to hear that you sorted them out to your satisfaction, however.

Milt

January 12, 2005 07:13 PM Forum: Takahashi

FS128 and Mewlon 210

Posted By Milton Wilcox

Steve,

If you have not already done so, you need to spend some search time on the Yahoo! UncensoredTakGroup:

http://groups.yahoo.com/group/UncensoredTakGroup/

The FS and Mewlon have been compared extensively over the past year and there are several members who own one of each and feel that it gives them the best of both worlds. And many others who wish they could do so... smile

Good luck,
Milt

January 23, 2005 02:22 AM Forum: Beginning Astronomy?

Central obstruction / light grasp question.

Posted By Milton Wilcox

Dannon,

Simply take the diameter of the C.O. in inches and square it just as you did for the diameters of your primary mirrors. Subtract each C.O. squared diameter from the corresponding squared primary diameter before doing your ratio.

You will probably find it doesn't make much difference in area ratio. Where it will show up is in image quality. See H.R. Suiter's Star Testing Astronomical Telescopes for a good explanation of this.

With regard to elimination of the corrector, it theoretically would help but reflectivity differences in the mirrors could make as much difference.

All other things being equal, a 2x area ratio will result in 2.5log(2)=0.75 magnitude difference in light grasp.

Milt

February 5, 2005 07:14 PM Forum: Binoviewers

Email from Denkmeier

Posted By Milton Wilcox

Russ and his company are good, honest people who have made a lot of contributions to our hobby.

Nils, I am in complete agreement. Over several months of evaluating a Denkmeier product last year I gave Russ much unsolicited "constructive criticism," not all of which was deserved, and we had many exchanges via email and phone. He was extraordinarily patient and went out of his way to try to satisfy my requirements. Never once was he abrupt or antagonistic toward me.

Milt

February 11, 2005 01:06 AM Forum: Binoviewers

Burgess Binoviewer diopters

Posted By Milton Wilcox


the eyepiece holder is only around 25.5mm deep. The barrel on an 18mm Radian is 35mm long. So you need to have the adjustment screwed in all the way before fully inserting your eyepieces. If not the holder just slides down the bottomed out eyepiece and it appears as if the diopter is not working.


Hi Don,

You are likely to find the same thing in the Denk II's that you have coming. The reason given for the shallow ep holders is to keep the overall path length as short as possible. Radians have a longer than normal barrel causing the problem you encountered.

You are actually lucky that the holder did slide along the eyepiece barrel since there is the potential for jamming. There is also an annoyance factor since each time you change ep's with long barrels you have to reset the diopters; otherwise, the ep's will just fall back down the holes and you lose your adjustment.

Milt

February 13, 2005 01:40 AM Forum: Binoviewers

First light with TV-102i

Posted By Milton Wilcox

Don,

Very nice setup! Your TV102i looks more like a 101, except for the reaching focus part. grin

Enjoy, Milt