Astromart

September 1, 2003 02:23 PM Forum: Equipment Talk

smallest scope & least mag. for Mars detail?

I can see the SPC and limited dark shading with my 80's vintage Celestron/ Vixen 60mm F5. If I remember correctly, I used 83x and 120x and the views were surprisingly good at both magnifications. I have also used a Vixen FL80S fluorite scope (80mm, F8) quite a bit on Mars. I have been able to discern the "Eye of Mars" (Solis Lacus) and Mare Sirenum as well as Syrtis Major and a couple other features using a variety of magnifications. I use 178x and 145x most often with that scope.

September 12, 2003 01:13 PM Forum: Equipment Talk

How to make an artificial star?

Posted By Joplin Motisher-Chittenden

The best way I know to make a precision pinhole with basic materials is to "drill" them in brass shim stock with a needle. I've used this technique to make numerous pinhole apertures for pinhole cameras. If you do it correctly (use a pin vise to hold the needle and turn it by hand) you can get precision pinholes down to the .005" range that will still be much cleaner than one drilled with a bit. For reference, the pinhole aperture used in the Digitec Optical artficial star is about .004" in size. If you want the cleanest possible pinhole I would get a commercially made one. I'm not sure how much rough edges would effect the usefulness for an artificial star but I think it's safe to say the cleaner the pinhole, the better it will work.

Joplin

September 23, 2003 12:26 AM Forum: Telescope Making

HDPE for Telescope Tubes?

Posted By Joplin Motisher-Chittenden

It weighs about 3/4 as much as standard PVC so it would be limited to similar size applications (short tubes no larger than 4 or 5 inches in diameter).

Joplin

September 23, 2003 10:34 PM Forum: Eyepieces

ST80 30 mm

Posted By Joplin Motisher-Chittenden

I use one with my 10" F6 newtonain and find it to be a superb eyepiece for the money. Fantastic views of extended objects like the Veil nebula when used with narrowband filter. It works great at F6 and above, the edge of the field degrades too much at F5. Since the C-8 is F10 it should work great. There will be some field curvature (you may need to fiddle with the focus to get a good image across the field of view). At least half the people at star parties who have borrowed mine decided to buy one themselves.

Joplin

October 10, 2003 09:54 PM Forum: Equipment Talk

Hydrogen Beta Filter Question

Posted By Joplin Motisher-Chittenden

You may be able to pick up the horsehead with a 10" and hydrogen beta filter if you have very dark skies. I tried last winter with my 10" and a lumicon 1.25" hydrogen beta filter but I never could see it. Another member of my club claimed he could see it, but just barely. The skies that night were around magnitude 5. My advice - don't bother with a 2" since it has such limited uses and the horsehead covers a small area of sky anyway.

Joplin

October 11, 2003 07:15 PM Forum: Equipment Talk

Digital Camera Recommendation Please

Posted By Joplin Motisher-Chittenden

I have a Nikon Coolpix 995 (predecessor to the 4500) which works fairly well for a multi-use digital camera. I've also used a friend's Coolpix 4500. The menus on both cameras are a big hastle in my opinion and the battery life is only so-so. These cameras also have a slow processor so the camera is quite slow to operate. The only real advantage these cameras have over competition is the internal small diameter lens which makes fitting an eyepiece to it easier. That advantage isn't as great these days since there are a large variety of eyepiece/ digital camera adapters available to suit most cameras. If I had a choice of buying a camera new it would be the Canon Powershot G3 rather than the Nikon Coolpix series. I've had a chance to use one and the camera is lightning fast compared to the Coolpix cameras. The lens is also of better quality than the 4500. Finally, the battery lasts about 2 hours longer than on a Coolpix 4500.

Joplin

November 15, 2003 07:38 AM Forum: Chinese Optics Imports

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Posts Made By: Joplin Motisher-Chittenden

smallest scope & least mag. for Mars detail?

How to make an artificial star?

HDPE for Telescope Tubes?

ST80 30 mm

Hydrogen Beta Filter Question

Digital Camera Recommendation Please

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1278 First light observing report

1278 First light observing report

1278 First light observing report

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