Posts Made By: john welch

July 23, 2004 01:59 AM Forum: Telescope Making

cure for condensation

Posted By john welch

Hi Ed,

It's condensation of H2O from the air in and out of the box. Try a desicant or heat in the box.

Thanks,
John

July 23, 2004 05:11 PM Forum: Telescope Making

Richlite

Posted By john welch

Hi Allen,

I used a similar material for making a gear for an equatorial newt. The original gears were designed by Pierre Schwaar using a high density laminate sandwiched into a workable gear facing.
The gears with decent care can last indefinitely. My oldest scope is 21 years old (14") and has been run many hundreds of times. My newest material for the gears has even better promise; HDPE which is high density phenolic. The same material used for cutting boards.
The Big Foot E.Q. mounts from Pierre have some Richlite and formica for panels on the superstructure.
Depending on weather (region of the planet) Richlite IMO would be a perfect and final solution.

Thanks,
John

This is a side view of Pierre's sector gear showing laminate structure.

July 26, 2004 10:58 PM Forum: Equipment Talk

Whatever happened to offsetting the diagonal??

Posted By john welch

Hi Tom,

If you have a slightly larger than necessary diagonal you may be 'ok'. If you do a ray trace it is apparent that an offset is needed away from the focuser to catch the converging light cone.
The 45* flat is closer to the primary (up-stream, into a wider section of the light cone) at the 'away' end of the flat than the front. Without an offset, a portion of the cone is cut-off.

Clean skies!

John W.

July 27, 2004 12:48 AM Forum: Telescope Making

LXD-55 Tripod

Posted By john welch

John,

Yes you should! Terrific stuff!

John W.

August 7, 2004 03:54 AM Forum: Equipment Talk

Please help me identify....

Posted By john welch

Hi Allen,

I have three or four of these. They are generic overseas mounts that work for several finder brackets. One came with an 8X50 Orion finder. Some are black or blue as well. There may other applications......

John

August 16, 2004 07:07 PM Forum: Off Topic Discussions

StellarVision

Posted By john welch

Hi Rich,

Just call Frank at Stellar Vision in Tucson. It's an astro shop and he does this artwork in his "extra time". He actually began this work before the retain side of the business.

John W.

September 6, 2004 05:06 AM Forum: Meade

Meade 2045d battery?

Posted By john welch

Nicholas,
It's been a while since I worked on one, but if memory serves, the 2045D is AC only. One could operate it off a battery and inverter.

John W.

September 18, 2004 02:39 PM Forum: Equipment Talk

Green laser brightness

Posted By john welch

Hi James,

I have the IIIa that is two years old and purchased from Z Bolt. Anything less than IIIa will be aggravatingly dim and ,IMO, a waste of money. I use mine often and have had no mechanical problems. However, if there is no dust, or heavy moisture and if there is a fair amount of local light around you, no one except one or two people very close to you will see the class IIIa laser.

John W.

September 30, 2004 07:23 AM Forum: Solar System Observing

October Astronomical Calendar - Computer Wallpaper

Posted By john welch

Thanks Curt!!

Very useful indeed! You've started something you must continue for at least 50 years. 8O

John W.

October 30, 2004 02:52 AM Forum: CCD Imaging and Processing/Solar System

SunSpot group AR693

Posted By john welch

Hey Paul,

I don't think I've said it, so, here it goes....

I really enjoy your images and posts.

Thanks!

John
Phoenix