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Posts Made By: Charles Ryder

July 27, 2002 03:20 AM Forum: Takahashi

Re: New Taks

Posted By Charles Ryder

What will TAK do with the 128's? At the same price as the new 130, who'd buy one? Will they lower the price of the 128 or discontinue it?

I'm disappointed that the 130 weighs over 22 pounds. AP's 130 weighs 16 does the extra focal length add 6 pounds? I doubt it.

September 28, 2003 02:54 PM Forum: Takahashi

Re: Alternative Dust Cap for FS102

Posted By Charles Ryder

One tip Fred at TNR gave me for tightening up the fit of the "man hole cover" is to take a wire brush or firm bristled tooth brush and fluff up the green felt strip lining the cover. This decompresses the felt and makes the cap fit noticably tighter.

I tried Fred's tip and it works!

January 1, 2004 08:49 AM Forum: Telescope Making

Chuck Does it Again!

Posted By Charles Ryder

As the recent recipient of Chuck Fellows' latest 8" dob masterpiece, I thought I'd report my initial impressions to those interested who may have followed the progress of the scope during the course of its construction as referenced by Chuck in prior postings to this group.

All I can say is "WOW!!!". The pictures you may have seen of the scope posted by Chuck--as beautiful as they were--do not capture the full splendor of the scope when seen in person. I appreciate fine workmanship and this scope embodies it. The design, wood selection and graining, joinery, and ergonomics are incredible.

I gave the scope first light on X-Mas. I was treated to all 6 stars in the Trapezium in M42. E and F stood out cleanly with direct vision--a first for me in my west of Boston suburban skies. Castor split as cleanly as I've seen, Saturn was crisp through 220X with great contrast, Rigel's companion popped right out, etc.

I knew the Mark Harry 8" f/6 primary was a special mirror when I originally purchased it as part of someone's partially completed sonotube dob project. I also knew Chuck Fellows was the person to build a special scope deserving of the fine components; having seen some of his prior work. What I didn't know was how Chuck would outdo even himself and create what I believe is the most beautiful and ergomically friendly dob I've ever had the pleasure of seeing or using.

There are few people around who are capable of such fine craftsmanship and who are also such a joy to work with. I want to thank Chuck publicly for the opportunity he gave me to work with him and be the recipient of such a superb finished product. Thanks,Chuck!!!

Charlie Ryder


January 24, 2004 08:20 AM Forum: Takahashi

AP binoviewer with FSQ?

Posted By Charles Ryder

Anyone have success using an AP/Baader binoviewer with an FSQ? I have an FSQ with Extender Q and 2" adapter. I have been unable to get my AP/Baader Mark V binoveiwer to reach focus with ANY eyepieces. What do I need?

Thanks,
Charlie Ryder

October 10, 2006 10:46 AM Forum: Eyepieces

Nagler Typr 6 vs. Pentax XW

Posted By Charles Ryder

I've generally been a TeleVue eyepiece addict for several years but recently decided to try the Pentax XW line. I've been very happy with my Type 6 Naglers but my worsening asigmatism is increasingly forcing me to either wear eyeglasses or use a TeleVue Dioptrx while observing. At
anything more than about a 1mm exit pupil I benefit from viewing through a corrective lens. Since the Type 6 Naglers won't accept Dioptrx I revcently took advantage of an opportunity to buy 5 and 7 XW's due to their generous eye relief, 70-degree FOV and generally very positive comments I'd read from other observers.

For those rare nights of great seeing I have some TMB SuperMono's and Pentax SMC Orthos. But those nights are few and far between in my area and, since I'm almost exclusively an alt/az mount user, the wider fields available with the Naglers and XW's are more practical most of the time.

I spent almost two hours this past Sunday night doing a head-to-head comparison of the 5 and 7 XW's to my 5 and 7 Type 6 Naglers using the Moon as my target. I chose my TMB 100/800 as the "test scope" because it has exceedingly good optics and I wanted to minimize any adverse effects caused by the scope's optics as opposed to eyepiece produced
effects. The two major lunar features observed were Petavius and Langrenus, both of which offer a nice range of crater wall and floor features as well as central peaks which produce small shadows and enhance the ability to make sharpness and contrast comparisons.

I limited my comparison to optical performance and not ergonomics but I find both eyepieces easy and comfortable to use. I've read comments about eyelash oils getting on the Nagler optics but I've never found that to be an issue with me. The XW's, of course, are widely touted for their "comfort" and I'd concur.

Despite both the Naglers and XW's having relatively large FOV's (82 degrees and 70 degrees, respecively)I tend to view objects at higher powers on axis or at least within the central 50% of the FOV. As a result, differences in performance beyond the central 50% of the FOV were not studied.

Without going into excessive detail, I found that fine details plainly visible in the Nagler were seen with more difficulty in the XW's, if at all. Contrast differences on lunar features were similar but the surrounding sky through the Naglers was definitley darker. I'm not sure whether this was due to the Nagler having superior contrast or whethet it was due to some form of ghosting effect
produced by the Pentax. I'd heard reports of slighly warmish tones imparted by the XW's but I found no appreciable tonal differences in lunar views between the eyepieces.

There's no doubt that both eyepieces are great performers and I'd be happy with either one. If my vision were such that glasses or Dioptrx weren't needed, I'd choose the Nagler over the XW based on my comparisons. Of course, I'd want to cmpare performace on other targets and in my other scopes before drawing final conclusions.

My next move will be to try some Radians, since Dioptrx will fit all of them and they are reputed to be very good lunar/planetary performers.

Of course, these are my personal, subjective findings only and "your mileage may vary".

Charlie

March 5, 2007 09:20 AM Forum: Birding Optics and Photos

Zeiss Diascope 65

Posted By Charles Ryder

I posted for sale a mint Zeiss 65 Diascope package (scope, zoom, case, window mount, etc) in Classifieds in case anyone's interested.
Superb scope but I guess I'm not a birder and I need to fund more astro gear! I hope it's OK to mention this in this forum. If not, let me know and I'll remove this posting.
Charlie Ryder

September 25, 2007 10:34 AM Forum: Refractors

Perplexing Astigmatism in a Triplet

Posted By Charles Ryder

I recently came across a triplet apo that displayed astigmatism in the outer 30% or so of the field of view yet stars in the central 70% of the field showed nice tight, round airy disks in focus and concentric circular ring patterns on either side of focus.

I always assumed that astigmatism would manifest itself across the entire field of view. Is it possible that perhaps the lens is not inherently astigmatic at all and that something else could have caused this effect (poor collimation, decentering of lens elements, etc.)?


February 4, 2008 06:52 AM Forum: APM

80/480 and 80/600 LOMO triplets to be available ag

Posted By Charles Ryder

I just saw on the APM web site a return of listings for 80mm f/6 and f/7.5 triplets in William Optics, APM/TMB, and carbon fiber tubes to be available again starting in April. The description of the William Optics tube 80/480 version mentions Russian made optics and specifically states that a LOMO lens will be used.

My understanding was that LOMO 80mm lenses would not be made available any longer. Has there been a changee in plans such that LOMO 80/480 and 80/600 triplet-based scopes WILL be available again? And, if so, are the lens specifications the same as before?

This woould be great news, as I know from past experience that the LOMO 80mm triplet lenses are superb performers.

August 4, 2002 05:20 AM Forum: Takahashi

New Taks address old problems??

Posted By Charles Ryder

Vito's issues are right on, in my opinion. My first apo was an FS-78 followed by an FS 102. I sold both scopes primarily because of poor ergonomics, lack of case (hard or soft), location of the finder and necessity to remove it when storing the scope, lack of sliding dew shield, tendancy for the "man hole cover" cap to fall out after the felt gets slightly worn or when in cold conditions, and exhorbitant cost for TAK accessories, some of which were of poor design (e.g. 2" compression ring style visual back that lacked a flange to prevent it from disappearing into the focuser housing when racked all the way in).

After I sold the FS-102, I vowed to never purchase another TAK. Since then I have owned a TV-85, TV-101, TMB 105, TMB 100, AP Traveler, AP 130/6, Starmaster 11 EL and a 3.5" Questar; several of which I still own and plan on keeping. The optical performance of these scopes I have found to equal or exceed that of my 2 TAKS and none of them suffer from the long list of shortcomings (personal opinion) inherent in the TAK. Obviously, there ARE plenty of loyal TAK owners who would disagree with me. But for me, I think there's too many competing scopes of similar or lesser price that deliver equal or better perfomance without some of the things I found so annoying with the TAKs.

Good to see there will finally be a sliding dew shield!

Got to go and put on my bullet proof vest.

Charlie

September 14, 2003 02:46 PM Forum: Takahashi

FS 102 dew shield

Posted By Charles Ryder

Vincent- It unscrews (at the blue ring). The threads are very fine so be cautious when replacing it so as not to strip the threads.