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Lawrence Parchman

Sculptor Galaxy (NGC 253)

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Posts Made By: Mark Holden

March 9, 2006 01:34 PM Forum: Ask rating questions here

What sort of rating should this be?

Posted By Mark Holden
My limited experience with Losmandy parts implies they're not very expensive. (I just paid about $45 including 2 day shipping for a replacement gear box for a servo motor)

I'd look up the cost of the various parts that need to be replaced to correct the condition of the mount to match what he described, and ask for that.

A $500 adjustment sounds steep.


March 11, 2006 02:43 PM Forum: Beginning Astronomy?

Barlows Are They Worth It ?

Posted By Mark Holden
I'll disagree with the folks who say a barlow won't degrade image quality.

When you add a barlow to the optical path, you're adding more elements, and more glass to air surfaces. This will have an impact on contrast.

About the only time I use a barlow is if seeing conditions are good enough to go with higher power than my shortest eyepiece, or for more magnification when imaging.

Folks who need or like more eye relief will like them too, although eyepiece makers are starting to design shorter eyepieces with more eye relief.

But when your eyepiece choices are limited, a barlow will give you more options.

March 11, 2006 05:32 PM Forum: Politics

Corrupt!

Posted By Mark Holden
Darrell Fichtl said:

Here we go again!


http://www.cnn.com/2006/US/03/11/claude.allen.arrest/index.html

I smell impeachment still, and the smell is getting stronger!

[SIZE="Large"]D[/SIZE]

Someone could pass wind and you'd smell impeachment.

President Bush had nothing to do with the guy scaming stores.

March 13, 2006 09:14 PM Forum: Equipment Talk

Need help on deciding which scope to buy!!

Posted By Mark Holden
All of the ones I saw in your link remind me of toys.

The tripods don't look sturdy.

The mounts look like they're mostly plastic.

You'd probably be better off getting a push to system for your existing scope.

March 14, 2006 02:51 PM Forum: Equipment Talk

Advice on Light Pollution Filters

Posted By Mark Holden
Peter Glus said:

Does anyone recommed a good light pollution filter? In in NYC and would hope that this helps somewhat.

- Peter

The Orion Ultrablock is a pretty good one to start with.

March 14, 2006 10:41 PM Forum: Equipment Talk

Declared value

Posted By Mark Holden
Paul Weiler said:

Hello,
I am planning to ship my beloved 13.1in mirror to be refigured and recoated. This might be a stupid question but is the declared value option the same as insurance?
I can't find the word insurance anywhere on fedex's website
And I want to make sure I'm covered
Thanks
Paul

You might consider adding coverage for the value of your telescope to your homeowners insurance policy.

Tell your agent you want it "scheduled".

I pay under $20 per thousand of value per year.

It's exceptionally broad coverage. Besides covering things while they're being shipped, It'll cover my scope at star parties, or even if I drop it while setting it up.

In spite of having this coverage, I always declare the full value when shipping my equipment - I hope it gives them some incentive to pick someone elses package for the "who can toss the fragile box the farthest" competition. The hassle of repairing or replacing damaged equipment goes beyond dollars.

Otherwise, I've heard packages sent by air are less likely to be damaged than ones sent by ground.

Good luck.

March 15, 2006 08:30 PM Forum: Refractors

TEC 140 pricing

Posted By Mark Holden
Robert Swafford said:

How does Yuri produce a 140mm f7 oil spaced triplet apo with 3.5" Feathertouch for $4750 when all of the other premium apo makers usually charge $6K for a 130 f6?? is it harder to produce the smaller lens at f6 than the larger one at f7 ??? or are their other factors to consider ??

I'm sure there are other factors, but I understand an f7 objective is easier to figure than an F6 one.


March 16, 2006 08:52 PM Forum: CCD Imaging and Processing/Deep Sky

Does false color show when imaging w/achromats?

Posted By Mark Holden
Gary Smith said:

I was looking at this http://www.astromart.com/classifieds/details.asp?classified_id=416874 and I was curious if color would show up when imaging with an achromat such as this? Also I dont have much experience with an achromat, is the reason this design is used on DSO's vs. using them for viewing the moon and planets is the inherent problem of color with this design over an APO? Is the color in a higher end achromat such as this very small and difficult to detect? Thanks.

If you used a monochrome camera with a filter wheel and refocused for each color, you'd probably get decent results, but I wouldn't expect apo like images.

The problem is the focal length for an achromat is a little different at the red end of the spectrum than the blue, so even if you get the focus right, things won't line up perfectly. I suppose you could scale things slightly in photo shop though.

But for imaging DSO, you don't really need a big lens unless you're looking for image scale. I've seen some beautiful images that were taken with an 80mm f6 apo.

March 16, 2006 09:21 PM Forum: Equipment Talk

bulk "pluck" foam

Posted By Mark Holden
carol anderson said:

Anyone have a source that sells "pluck" foam in sheets? I have an unusual case that I need to replace the pluck foam & can't find the insert needed. Thanks!

B&H Photo Video probably has replacement foam for doscocil cases.

But other than the convenience of setting it up, I think you will be happier in the long run with the regular foam you have to cut yourself.

March 22, 2006 03:17 PM Forum: Equipment Talk

Source for graduated scales for setting circles?

Posted By Mark Holden
Bill Barrett said:

I am very dependent upon setting circles & I have an old Meade 826 mount on which I have worn the graduated scale on the 3" RA setting circle & would like to replace it. The scale appears to be a metal tape with the graduations etched in. Is there someone who would sell or make these?
I have a computer program I could use, but it would print them out on paper which I doubt would last. thank you, Bill

Could you "back print" them on transparency film?

If so, after you printed them, you could apply a white spray paint to the printed side, and then you'd have a reasonably well sealed scale that would be reasonably easy to read and last a while.

Back printing is also known as reverse or mirror printing. The print looks normal when you look at the non printed side.

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