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Posts Made By: Rod Kaufman

December 8, 2002 10:54 AM Forum: Equipment Talk

December 8, 2002 11:01 AM Forum: Equipment Talk

Celestron Ultimas

Posted By Rod Kaufman

I have the 15mm version of the celestron widefield series.A 16 mm version did not exist. The widefield versions were apparently the predecessors of the Axiom series of celestron eyepieces. I find the 15 mm widefield ultima to yield a bright and contrasty image but with coma at the edges.

March 25, 2003 12:53 PM Forum: Equipment Talk

To Plossl or to XL?

Posted By Rod Kaufman

Rob,
I have a Discovery 12.5 truss dob and an Astrosystems truss 16" dob.I believe the pentax units work quite well and my pentax 10.5 does not ghost on Jupiter in either scope. You may also wish to try the university optics orthos or the ultima plossls which have good contrast and little or no ghosting. I read posts from other amateurs claiming their Radians do ghost on bright planets.

May 4, 2003 10:25 AM Forum: Equipment Talk

Comments on Eyepieces and Planets

Posted By Rod Kaufman

I have some comments regarding the application of various eyepieces relative to performance issues on the planets.
Over many nights of observations on Jupiter and Saturn with a Discovery 12.5" dob and an 16" Astrosystems dob, I attempted to discern subtle differences in performance among the eyepieces in my collection.
I have general comments that may be of benefit to some amateurs, First, I am convinced that a battery of eyepieces are necessary to obtain the maximum amount of detail, color variation,and resolution. However,cost effectiveness is an important issue as expensive eyepieces do not necessarily equate to the best performing eyepieces. After re-reading the cloudy nights review on planetary eyepieces and reflecting back on my recent experiences, I have recognised that some relatively inexpensive eyepieces can outperform more expensive units on specific details on the planets. For example, I found that my seibert 7mm eyepiece gave the best overall resolution on the rings of Saturn as compared to my pentax XL, UO ortho and ultima eyepieces. The difference was not subtle but rather obvious. I found that a 7mm pro-optic eyepiece gave the best color rendition on the globe of Saturn with the Pentax unit close but not as good. The overall contrast between the rings of Saturn and the globe was best in the pentax and UO orthos, giving that nice optical snap every amateur loves to see. The ultimas were also very favorable in this regard.On Jupiter, the differences were apparent but more subtle. I found the pentax eyepiece and the UO orthos to give highly resolved details of the belts, bands and festoons. Color variation was more difficult to discern but the pro-optic widefield 7mm unit and the pentax XL were quite close with perhaps the pentax revealing the best color fidelity. The ultimas were also good in this regard,and also quite good in resolution but not quite as good in revealing subtle color variations.
I would like to read comments from other amateurs who have applied a variety of eyepieces in the observation of the aforementioned planets over many hours with similar instruments. Perhaps some kind of a consensus of opinion or at least a trend of recommenmded use of eyepieces for various surface details may start to be realized. Up to now, it's been pretty much, "this eyepiece is better than another". It just doesn't work that way, in my opinion.

November 11, 2003 10:41 AM Forum: Equipment Talk

Discovery Cell/Generic Cell Flaw and Fix

Posted By Rod Kaufman

I have found my Discovery 12.5" mirror cell doesn't hold collimation because the springs in the mirror cell allow a small but significant amount of movement as evidenced by migration of the laser dot from the center of the doughnut to the top of the doughnut on the primary as the scope is moved from the horizontal to vertical planes. I believe virtually all such cell designs will produce this de-collimation effect when used with full-thickness mirrors. The "fix" is borrowed from an old Telescopics mirror cell-design which incorporated three locking screws with nuts that pass through the rear supporting plate to the plate that supports the mirror and are screwed-down after the wing nuts are adjusted for collimation. I drilled four holes through the back-supporting bars of the Discovery cell and passed the screws to the back of the plate that supports the mirror and tightened them after collimation. This effectively stopped the de-collimation. I believe the de-collimation problem is un-recognized by other amateurs and is probably a universal problem. I also think this explains why Ed Ting could not resolve Delta Cygni with a test 12'5" Discovery scope in the Novenber Sky and Tel review; his scope was de-collimating as he moved it but he didn't know it.

January 2, 2004 09:55 PM Forum: Telescope Making

Lightweight Rigid Portable Inexpensive Pier

Posted By Rod Kaufman

Although I do most of my observing with a 16 inch dob, I decided to refurbish an 8 inch newt that I had made as a kid. To make the pier for my old edmund mount and drive, I purchased an aluminum tube from a metal company for $15.00. I notched-out the top of the tube with a hacksaw and dropped the mount into it and sealed it with two tubes of JB weld. The legs of the pier are available from Home Depot exactly as you see them for $9.00 apiece and are large "L" brackets used to attach book shelves to walls. I attached castors with levelers to each leg which are sold by Apogee( three for $16.00)The aluminum-pier tube is about 30 inches tall with a quarter inch wall thickness and weighs only eleven lbs. It's very rigid but my nine year-old daughter can push it with her fingertips. All of these materials are easily obtainable and may be considered by ATMers for future projects.

February 2, 2004 12:14 PM Forum: Eyepieces

Re: Nagler 16 T-2

Posted By Rod Kaufman

Floyd,
It seems quite odd that the nagler doesn't have a coating, are you seeing significant reflections from the eyelens if the bottom lens is capped? It should look dark and without reflections.Don't know quite to what to make of this one! As far as the orion eyepiece is concerned, I am assuming it's not the wideangle version so $35.00 would be fair for this focal length and condition. The 4mm version(vixen) goes for around $70.00 used but the longer focal lengths seem to go for less. I will say the 4mm vixen is an underated planetary/double star eyepiece and everytime I want to buy it used, it's been sold!

April 22, 2004 07:27 PM Forum: Telescope Making

Re: The best pitch for polishing a mirror

Posted By Rod Kaufman

"All About Telescopes" from Edmund recommends Burgundy pitch and shows how to make a pitch lap with individual squares. You could also contact Newportglassworks as they sell optical grade pitch and ask for their recommendation.

April 30, 2004 09:08 PM Forum: Equipment Talk

Dark Skies in Tonopah

Posted By Rod Kaufman

The June issue of Sky and Tel has an ad that caught my eye. It's an ad for dark skies available at Tonopah, Nevada. It's sponsored by the Nevada bureau of tourism and the website is: www.tonopahstartrails.com
Check-out the website as it's a good one and send kudos to the contact link for sponsoring the dark-sky effort. The dark sky site is located midway between Las Vegas and Reno at the intersection of Highways 95 and 6.
I've got to get ahold of Floyd Blue and his crew and they can ride shotgun on our way up there!

June 28, 2004 07:43 AM Forum: Eyepieces

Sky & Tel Article: TMB Monos

Posted By Rod Kaufman

I found the Sky and Telescope article on TMB monos to be interesting and informative. Standards of performance stressed scatter/contrast and resolution. The difference in contrast between the TMBs and other eyepieces was described as "subtle" and the author noted,"This is a far cry from some reports I had read on the Internet that proclaimed that the TMB's contrast "blew away" other eyepieces". The author also states, "can I conclude the TMBs are in fact superior planetary eyepieces? I never saw a difference that was pronounced enough that I would be comfortable making that statement without qualification".
One important point not mentioned in this article is cost-effectiveness. If, as the author states, TMBs are at least as good as the other eyepieces tested(but not significantly superior as vendor hype has suggested) why pay over $200.00 for an 8mm TMB versus $89.00 for a 8mm Televue plossl which provides a much larger AFOV without astigmatism?