Image of the day

Captured by
GERALD KREITZBURG

Eastern Veil Nebula

About Astromart

My Account

New to Astromart?

Register an account...

Need Help?

Posts Made By: Matthew Warren

February 23, 2004 02:00 AM Forum: Telescope Making

Mirror Protection

Posted By Matthew Warren
Hi,

I'm looking for suggestions on protecting the primary mirror of a truss dob when not in use. Youngsters, pets, accidentally dropping things, etc. I like the cookie tin idea, but those seem like unobtainium now that Christmas is over. This would be for a 10" mirror, btw.

Thx,
Matt

February 29, 2004 04:36 AM Forum: Telescope Making

Finally Truss Dob Progress

Posted By Matthew Warren
Just got in from assembling the mirror box for my 10". Started the cell disks a few days ago, but never finished due to everything...

Tomorrow is the stand. Then the hard stuff ;-)

Thought I'd need to borrow my brother's circular, but my cheapo table saw is working better than I expected.

Now it's cleanup time for the night.

Matt

March 4, 2004 12:12 AM Forum: Equipment Talk

Digital Setting Circles

Posted By Matthew Warren
I tried to look through the archives on this but quickly got lost. I'm intrigued by the concept of Digital Setting Circles. While I don't necessarily want Go To, the ability to accurately set a RA/Dec setting sounds like a great way to find those harder objects. Is that really what DSCs are about?

Can anyone point me to some makers? I've seen one or two, but who are the players that really drive the market?

Matt

March 22, 2004 05:05 PM Forum: Telescope Making

Dob Alt Bearings

Posted By Matthew Warren
Hi, got first light with my 10" Dob this weekend. It was the first clear night in several (seemingly a long time). Truly serendipitous. Now the but...

The scope was beautifully balanced and smooth in motion until I added the finder! I plan on using both a finder and a Telrad, so the additional weight of the telrad will really tip the scale.

Is this something I can fix with a material of different friction? I used those teflon furntiture slider disks you find at Home Depot. Or do I have to try to get it closer to pivot point (more invasive).

Thanks,
Matt

March 22, 2004 05:35 PM Forum: Telescope Making

Truss Dob Shroud

Posted By Matthew Warren
Hi,

Can anyone point me in the right direction for a shroud for my truss dob? I have some ideas in mind, but I was wondering how you did yours.

Mine would be for a 10" dob. I'm thinking elastic at top and bottom with either snaps or a long zipper along the length. What would you recommend?

Thanks,
Matt

March 26, 2004 04:47 PM Forum: Telescope Making

6" F8 Truss Dob?

Posted By Matthew Warren
Now that I whipped up my 10" F5, I'm toying with the idea of converting my Meade Starfinder to a truss dob. First problem I envision is balance problems due to length. Anyone out there built a 6" F8 truss dob? How'd it turn out? I'd rather avoid couterweights if poss, but due to the low mirror mass, might be more difficult. The 10" recipe won't apply. I guess make the mirror box longer is one option.

In case anyone wonders why I would wanna do it, just because ;-) Really to improve my woodworking skills.

Matt

March 26, 2004 07:13 PM Forum: Telescope Making

Secondary Mirror Sizes

Posted By Matthew Warren
Greets,

Are there any references online that give the science or what is the rationale behind selecting a secondary mirror on a Newt? I've read that a smaller mirror is better for planets and larger better for deep sky. I imagine there's a sliding scale where at some point the secondary creates too large a CO. What would the ideal range be for say a 10"?

Thanks,
Matt

April 6, 2004 04:25 AM Forum: Telescope Making

10 Inch Dob Ghosting

Posted By Matthew Warren
I'm stumped. I can't get rid of this ghosting problem (if that's what you'd call it). I took an afocal photo of Venus with a digital cam locked at infinity focus. It's actually in better focus than the image shows, but the ghosting is what I'm illustrating. It also has rays coming from Venus.

This is an F5/10" mirror, eyepiece is 9.6 mm Meade SP.

Any ideas? This is a truss dob. Hoping it's some light shielding problem that is fixable.

Matt

April 21, 2004 03:36 PM Forum: Equipment Talk

Aperture Like Decibels?

Posted By Matthew Warren
Hi,

Is there any way to quantitatively relate aperture to human eye response? In the audio world, the deciBel is used. At a given sound level, a doubling in power will result in 3 dB increase. To double the actual sound pressure level, a 10 fold increase in power is necessary.

Is there an analogous situation in telescopes in terms of the apparent brightness to the eye? Or is the relationship purely linear with aperture?

Cheers,
Matt

May 1, 2004 08:32 PM Forum: Telescope Making

Re: What's a Truss Dob Worth Now-a-Days

Posted By Matthew Warren
'Tis a society raised on volume and economies of scale, many of whom equate anybody with a business to be an evil, greedy corporation.

At $26/hour, it's truly a labor of love! Good for you for building your own business!

Matt

Funding Member

Sponsors


View all sponsors

Search