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Posts Made By: William Chang

June 9, 2006 04:08 PM Forum: Investment Discussions

Market saved by a miracle

Posted By William Chang

Wednesday afternoon the market unambiguously signalled, and started, a "mini" crash. Whereas it had dropped at a rate of 1% per week for 3 weeks, followed by 1% per day for 3 days, between 1pm Wednesday and noon Thursday it was dropping nearly 1% per hour (especially NASDAQ). The gap between falling prices and moving averages had expanded by 50% beyond even the widest recent gaps. Wednesday afternoon, I thought only a miracle could save the market -- and Thursday morning it came, from Iraq. That positive psychological boost gave the market a Patriotic Rally, reversing Thursday's losses and setting a trading volume record. So for one day at least, the market was given a reprieve... but Death Watch continues.

April 3, 2008 10:13 AM Forum: Equipment Talk

Would you rather have a bigger SN or a smaller MN?

Posted By William Chang

Ignoring considerations such as mounting, which optics would you rather have, a bigger Schmidt Newtonian or a smaller Maksutov Newtonian? In particular how would you mix-rank these:

SN10, SN8, SN6, versus MN86, MN76, MN66, MN56

(I have the SN10 and SN6 but have not owned/used an MN.)

Here's my heuristic: rank by aperture*(1-(CO%-15%)), i.e. 15% CO considered nearly indistinguishable from unobstructed. Then using CO guesstimates of 34-38% for the SN, 22% for the MN, and ignoring coma:

SN10->8", MN86->7.4", MN76->6.5", SN8->6.1", SN6->4.8", MN56->4.6"

Comments please, -- William (Saratoga, CA)

March 3, 2003 06:33 PM Forum: Equipment Talk

Piecing together help

Posted By William Chang

I have heard some good things about the Orion SkyView Pro which is supposed to handle easily and smoothly a 20lb OTA. Only about $300 but no GOTO (don't know about after-market).

I'm fairly new too (alas always lived in metro areas) but had so much fun recently with a 4" Genesis that I decided not to pursue GOTO. If in a single evening I can star-hop to find >20 objects I hadn't seen before, why bother with GOTO? Eventually, to track down more elusive objects or when I'm travelling to Southern skies, maybe.

Depending on where you are, you might have to invest in a Lymax air cooling system. Now, I don't have an SCT but recently considered getting one and that's what I heard.

Good luck,
-- William Chang, Saratoga CA

March 3, 2003 10:40 PM Forum: Equipment Talk

Way more help than needed:Celestron 9.25 SCT

Posted By William Chang

Thank you for the story! (and lessons!)

Now... is your C9.25 comparable to your old C11? And have you resisted the urge to look through a new C11 which is supposed to be great and only slightly bigger/heavier? ;-)

How are your skies?

-- William Chang, Saratoga CA

March 3, 2003 10:51 PM Forum: Equipment Talk

Tube Weight from 1800Destiny - 50# for 10" mirror

Posted By William Chang

Thanks for the warning; I was looking at those tubes but for a slightly different application: 3-section retractable OTA cut out from a single short-length (hard to describe without a picture), so weight would be (somewhat) less of an issue. Still, from your info (50lb) I will be able to compute the weight for a smaller/shorter one.

Suggestion: if the tube is as strong as suggested, you might try cutting large circular holes in a hex pattern all over it with a drill saw to create a semi-open tube. If you do, please let me know how easy it is to work the material. (And you may want to post in the ATM Forum.)

Good luck,
-- William Chang, Saratoga CA

March 5, 2003 12:49 AM Forum: Equipment Talk

Light Pollution Filters

Posted By William Chang

Orion UltraBlock is "on sale" until at least March 7 (heard from one source). 2" about 1/3 what it used to cost, 1.25" about 1/2. I bought one of each 5 weeks ago on sale but still at much higher prices, oh well (yes I have put them to good use). At 16X the background sky would have been too bright where I am, so I use the 2" UB with a 32mm eyepiece and see more stars than without the UB. The 1.25" I use on M42.

One question is whether Orion is about to release a new version. Since they have a 30-day return policy you really can't go wrong...

$60 for the 2" and $55 for the 1.25", I believe.

-- William Chang, Saratoga CA

March 21, 2003 12:07 AM Forum: Equipment Talk

converting Sigma 600/8 mirror lens to spotter

Posted By William Chang

Alan, about 20 years ago I bought something that turned a telephoto lens into a spotting scope. I think it came with a built in eyepiece (10mm?) and possibly an erecting prism assembly. But, it didn't perform well enough for me to use it. Here's what I would suggest:

Bore a hole through a rear lens cap, and glue or otherwise mount a plumbing flange/pipe with 1.25" ID.

Let us know what you decide/do. Contrast might be low. Good luck,

-- William Chang, Saratoga CA

March 31, 2003 11:50 AM Forum: Astro Binoculars

A Newly Designed Chinese 9x63 Bino

Posted By William Chang

Thanks for the tip. What's the name/location of the store?

I agree binocs are better than a camera if I could bring only one or the other... Best,

-- William

May 9, 2003 09:47 PM Forum: Equipment Talk

What I am standing on

Posted By William Chang

Ivan, does the "rubber mulch" smell or outgas? Thanks, -- William

May 25, 2003 07:46 PM Forum: Equipment Talk

Airline carry-on scope/optics

Posted By William Chang

Thanks everyone!

The Uti is attractively compact (wish it were at least f/6). Or a Cat up to 8", or a real short 4" APO, appear to be the only commercial choices at this point. If I find anything else (especially > 8") I'll post here...

-- William Chang, Saratoga CA