Posts Made By: James Barnett

Hi all. I thought I would relay a story of personal woe and the recent happy ending. Several months ago I purchased a new Celestron AS-GT mount from Orion and picked it up at the Orion retail store in Cupertino, California. When I got the mount home to Petaluma (90 or so miles from Cupertino), I unpacked it and verified that all of the components were present and accounted for. The next morning, before I had my coffee, I proceeded to assemble the mount in our library*. Maybe it was the lack of caffeine, but for some reason I lost my grip on the mount head as I lifted it to the top of the tripod and it spiraled to earth with a *BLAM!*

Okay, more like a dull thud as it landed on a rug and then glanced off the foot of a bookcase. Shock and awe. I was horrified and had a queasy feeling in the pit of my stomach. I examined the mount head and to my dismay both plastic covers on the drives were cracked. I hurriedly assembled the mount and tested it, and fortunately it appeared to operate perfectly. This was confirmed under the night sky later that eveining.

At first, I thought: "No big deal. It still works fine. It won't be new forever anyway." But that obsessive-compulsive streak in me wouldn't let well enough alone. So finally, two days ago, I e-mailed Celestron customer support explaining that I screwed up and broke my motor covers (totally my fault) and wondered whether I could PURCHASE new ones. To my surprise, later that very day Celestron e-mailed me and said they would send me replacements gratis if I would provide my shipping address, which I promptly did. Today, at zero cost to me I received replacement covers from Celestron. They ate the cost of the covers and the $4.80 in express shipping. I'm stunned. Never has Celestron's customer support been so good in my experience.

I say kudos to Synta and the *NEW* Celestron.

Clear skies,

Jim

* Lest you think I'm being snobbish, let me explain the "library." Marriage is a combination of joys and compromises. The "library" is one of those compromises that resolved in my favor. Three years ago when we purchased our home in Petaluma, we set about to plan decorating, furnishings, window coverings and the like. As you can imagine, with a very few exceptions, the home decorating decisions were compromises in which I found myself on the short end. The home featured our first dining room. In my view, a dining room is a large amount of square footage generally allocated for events that happen once per year or even less frequently, furnished with extremely expensive furniture that takes so little use that you could in most cases hand it down to your great, great, great, great, great grandchildren. We are not formal people. When we entertain, we have our guests share the same space our family shares (kitchen, family room, patio, etc.). In short, that dining room was going to see very scant use. Then it dawned on me - we read and two of my contributions to the marital community were one elegant, antique, floor-to-extended-ceiling-almost, breakfront bookcase and a very large, very elegant panel Kirman Persian rug. Seizing the thought I broached the subject of converting the dining room into a clubby library instead. To my utter amazement, she agreed. The only catch was that we needed more shelving, so I had to have a local craftsman construct a semi-reproduction mate to my antique bookcase. Done deal. So you see, our "library" is nothing more than a table-less dining room full of old wood, clubby overstuffed leather chairs and ottomans, books, repro vintage artwork, and, of course, telescopes. If you have a little-used dining room, I highly recommend a library conversion. We took a space we would scarcely use and turned it into a space we use many times per week.

I have an Orion (Synta) 150mm MCT, and am really happy with its performance (especially) for the modest $599 price. Sure there's a tiny amount of mirror "wiggle" when focusing, it takes quite awhile to equlibriate, and it wouldn't win any beauty contests, but for a compact high-mag easy-mounter it's brilliant.

That said, there are a couple of flecks of something (pretty sure that it's flecks of blackening material used on the baffle) on the surface of the aluminized secondary spot. I would like to remove the debris, but before doing so wanted feedback from knowledgable MCT owners. This is my fourth CAT and only second MCT, and the first MCT was a 3.1" el-cheapo. It appears that removing the meniscus assembly is simply a matter of (1) marking the tube and one of the three screw holes attaching the meniscus assembly to the tube (for later orientation during replacement), (2) unscrewing the three screws, and (3) sliding off the meniscus assembly.

Is it really that simple?

If so, I plan on using a camera air bulb ONLY to see if I can dislodge the debris. If I cannot, I'll probably just leave it be.

Thanks,

Jim

Hey all. I just purchased the 105mm f/14.4 "Vixen Spec" achromat. I have a few photos that I'll post in this thread. The price for the OTA, rings, finder, bracket and Crayford is $650 US. Here's the "big picture." The pier shown is an Antares 48" pier. The saddle on the equatorial head is approximately 5'5" high.

Finally we had clear, marine-layer-free skies until about 2am last night. I used the opportunity to christen my new Antares 105mm long focus achromat. The setup included the Antares refractor mounted on a Celestron AS-GT Equatorial head on a 48" Antares Pier. Also used were a Meade 2" Dielectric Diagonal (quite nice, actually) and the following eyepieces: 8mm Vixen LVW, 9mm University Ortho, 12.5mm University Ortho, 18mm University Ortho, 21mm Pentax XL and 40mm University MK-70.

Though the scope is supplied with a 2" compression ring extension tube, it was not needed to bring any of these eyepieces to focus, and actually prevented the 40mm University MK-70 from reaching focus when it was installed. I am not sure why the adapter was included.

Overall the AS-GT on the Antares Pier (using an Orion 13" SVP dovetail bar and the stock Antares tube rings) was adequate for visual use. Slewing, moderate breezes and focusing induced vibrations that took 3 or so seconds to dissipate. This is about the upward limit of my tolerance for vibration dampening. Next session (tonight hopefully) I will try some VSPs and perhaps switch to the tripod legs from the AS-GT plus an Orion 16" pier extension. Nonetheless, for visual use it was tolerable if not optimal.

Optically the Antares refractor was very, very good. Star testing on Arcturus revealed nice concentric rings virtually identical on each side of focus using the 12.5mm University Ortho (120x). Arcturus and Antares showed virtually no false color using any of the eyeieces listed. I did not use Vega as it was nearly directly overhead (and thus hard to view due to diagonal placement near the zenith) when I was checking for chromatism, but tonight I will use Vega and some very high magnifications to better describe the level of chromatic aberration visible at various magnifications on very bright objects.

The long focal length (1500mm) coupled with modest aperture (105mm) makes for some fairly narrow TFOVs and some dark backgrounds using eyepieces you wouldn't consider "high power" in a faster refractor. The nice aspect is that you can attain decently high magnifications without the extra elements of a Barlow and retain a goodly amount eye relief.

Other observing targets included some wonderful late-Summer globulars: M22, M10, M12, M13, M4, M80; the "Wild Duck" M11, "Ptolemy's Cluster" M7, and the "Butterfly" M6; planetary nebula M57; double stars Rasalgheti (Alpha Herculis), Albeireo and Epsilon Lyra (as the last object of the night) and a series of emission and reflection nebulae in Sagittarius, including M17, M8 and M20. The scope performed admirably on each, showing good resolution of globulars save for M80, which only hinted at resolution, hints of the darkest gulf/channel in M20, significant detail in M17, the nebulosity in M8 directly observable. The double stars were easy prey. The Double-double, in particular, was ultra-cleanly resolved at 120x and relatively easy to separate at 75x.

One curious thing I will mention regarding M57 which has been bugging me for years is the following. When I think back to my first observations of M57 25 years ago with a 6" f/8 Newtonian, I vividly recall the object looking like a faint smoke ring with a distinctly darker center "hole". As time has marched on, now no matter what aperture I use on M57, I see more nebular material in the area of the "hole". The edges certainly are brighter and "ring-like", but the middle is not as dark as it used to be. It doesn't seem to matter which aperture I use either. The center "filling" is there at 3" and at 12". I am guessing that maybe my eyes have changed? Dunno.

All in all, the scope performs about as well as a 4" can perform, and at $650 shipping included it is a relative bargain to boot. Over the next couple of weeks I will be assessing just how much of a "bargain" it is in same-night side-by-side comparisons with an Orion 100ED. The moon should become more usable as a fine detail target during this period. Unfortunately Jupiter is too low for use as a testing target.

More later.

Cheers,

Jim

Here are some shots of the current 150mm Orion MCT.

Close-up of nicely multi-coated corrector.



Image showing scale of OTA compared to CG-5 class mount head.



Rear view showing primary collimation adjustment allen screw locations.



Regards,

- Jim

Hiya. I have a Meade 127ED (the old 5" f/9 Made in the USA variety, not the new triplet). Normally I mount the 127ED (and a 5" f/10 D&G) on a non-Gemini GM-8. Using star hopping and/or mechanical setting circles, I find it generally takes me several minutes to locate less frequented DSOs.

Coincidentally I have a pier-mounted AS-GT that I've been using for time-contrained sessions with a couple of 4" refractors and a 6" MCT. I have an adapter that will allow me to use the 127ED with a Losmandy Dovetail on the AS-GT. My question is whether the AS-GT can handle the 127ED.

The fully quipped 127ED (cradle, Losmandy plate, 7x50 RA finder, OTA, 2" diagonal) weighs about 20# and is a little over 4-feet long from dew shade to diagonal. I have plenty of counterwieghts to balance the OTA on the AS-GT. I also noticed that Celestron sells the 27#+ C-11 OTA on this mount.

What do you think? Will the AS-GT handle the 127ED for visual use?

Regards,

Jim

Five and a half feet of seemless aluminum tubing capped with a classic C-F Japanese-made doublet and shrouded with a proper nine inch deep dew shade, all bathed in glossy white enamel. :sigh: A thing of beauty.

Okay, I've been through the online Schott data sheets and haven't been able to locate "Schott FK61" anywhere.

The closest I've found is Schott N-FK-51A (which used to be called simply FK51). By the numbers this looks less like FPL-53 and more like FPL-51. A bit better than FPL-51 but much closer to it than to FPL-53. H-FK61 by CDGM in China has the same specification as FPL-51. CDGM is the only "FK-61" reference I've been able to find.

Can anyone confirm whether there's any such ED glass as "Schott FK61"?

I am aware of Rolando's comments here:

http://www.astromart.com/forums/viewpost.asp?forum_post_id=627874&poll_id=&news_id=&page=

"Schott does not make FK61. The Chinese make an ED glass called H-FK61 which is a first generation ED glass similar to Ohara FPL51. There is no availability of any Schott ED glass last time I checked with them. They just don't make it in any production quantity.

You will find just about all ED lenses made in China will use the Chinese made H-FK61 material, no matter what the US marketeers try to tell you."

But this seems to directly conflict with Mr. Maris' claims here:

http://tech.groups.yahoo.com/group/Stellarvue/message/96600

"Schott FK51 is very close to OK4, Schott FK61 is close to FPL-51 and
Schott makes Calcium Fluorite (CaF2). Recently Ohara was considering
making CaF2 but they decided against it. I really do not have time
to start visiting inconsistently moderated chat rooms right now but
if it is being stated that Schott does not make ED glass, that is
just wrong. Sounds like someone is very misinformed."

Note that there's also a reseller called Astrotelescopes in Applegate, california, that sells a 102mm f/7 which it claims uses "Schott FK-61".

I would hate to be "very misinformed" whether due to my own inadequate research or due to a reseller making false claims. I also have an agenda, and it is not too sell telescopes but rather to discover the truth about available glass types. And yes, I can handle the truth.

Thanks!

- Jim

We all know how the WTO, Freemasons and Muslim Fundamentalists hide secret messages in plain sight to harass and infuriate us God-fearing, gun-loving fundies. Have you ever noticed this?

SARAH PALIN is an anagram for both:

SHARIA PLAN and

HAS IRAN PAL!

OMG! It's as plain as Scripture! She's a terrist...er...terorist...uh...terrorist! I always did think she looked a little too Arabic to be a real patriot. Maybe we should limit our loyalties to those with blond hair and blue eyes. Oh wait, that's already been done by a different group of right wing whackos. Sorry.

In any case, better switch to coffee or else be branded a terrist...terorist...terrorist.

- Jim

Hi. I was wondering whether presently or even anytime recently (last 5 years) either Schott or Ohara were producing true fluorite blanks (i.e., not low dispersion glass such as FPL-53 which has some fluorite in its formulation, but actual CaF2 crystal blanks)?

I'm interested in smallish ones in the 4" and under size, in particular. I remember when William Optics used to advertise small ED-glass optics as "fluorite", and have a feeling another vendor may be doing the same now.

I'm just trying to separate the "fact" from the marketing malarkey. Thanks in advance for your help!

Regards,

Jim