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VdB 141 Ghost Nebula

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Posts Made By: jess tauber

May 24, 2007 09:18 AM Forum: Solar System Observing

quadruple occultation surgery

Posted By jess tauber
I was so fascinated to be able to witness Io pass over Jupiter the other day, and tonight all the moons again were lined up on one side of the planet, that I started wondering: Is there ever a time when ALL the moons disappear from the sides, either because they are all behind or ahead, or a mixture of both? And if so, is there a clock somewhere that will tell us the dates and times? This is something I'd REALLY like to see.

Jess Tauber

May 25, 2007 09:22 PM Forum: Eyepieces

Erfles, Circle V, T how different?

Posted By jess tauber
I just purchased an old Celestron 20mm Erfle to pair with the one I already had for binoviewer use. When it arrived I was a bit flustered to find it was very different from the one I had. One was Circle V, the other Circle T, the latter with little obvious coatings, the former fully coated. Lens housings are different as well.

Its hard enough to match eps for such use- how different are these different makes and is it probably just better for me to find a trade somewhere? Thanks.

Jess Tauber

May 31, 2007 06:29 PM Forum: Refractors

ManGrin?

Posted By jess tauber
Do any of you know whether one could theoretically create a GRIN-based Mangin mirror that didn't have to have a particular figure, if the GRIN could be tailored to the curvature at each point? Or would rays diverge depending on angle of incidence? I'm just having trouble visualizing this. :S

If it would work, then you could just grab any old smooth surface and make an optic out of it- even float glass. Big IF though.

Any thoughts?

Jess Tauber

June 12, 2007 06:36 PM Forum: CCD Imaging and Processing/Deep Sky

One Dumb Question

Posted By jess tauber
This is a newbie astroimaging query. Are there any systems out there that are able to keep track of the configurations of what is being imaged and automatically stack coordinate-corrected data? That is, no need to stay exactly on track- any shifting this way or that would be compensated for by pattern recognition software and the data cumulated in the correct coordinates.

Jess Tauber

June 14, 2007 01:37 AM Forum: Telescope Making

Round and round we go!

Posted By jess tauber
Some time back in 2006 there was a thread briefly discussing Fresnel lenses for astro use. I am now curious as to whether Fresnel lenses are ever made with a SPIRAL track/groove rather than concentric series. It just seems to me offhand that a spiral will 'fill in' missing pitches in the system- dunno what that would do to the diffraction. Also, would it help if this lens was rapidly rotated (here is where the old 'crazy eyes' x-ray glasses imagery kicks in! grin - two rotating in opposite directions playing on the brain's integrative processes...). But seriously?

Jess 'You Vill Obeeeeey' Tauber

June 19, 2007 01:02 AM Forum: Politics

The Price is Too High?????

Posted By jess tauber
I don't know if its a joke or not- I heard just a few hours ago that Rosie late of 'The View' will be the new host of 'The Price is Right' taking over from retiring Bob Barker.

I guess the big question is: who is the bigger barker?? So what will the offerings be on the new version of the show? What am I bid for this genuine piece of proof of Bush Administration collusion in 9/11? Will she shout down contestants for their political views?

What's next- an actor as President???

Jess Tauber

June 20, 2007 11:19 PM Forum: Telescope Making

Mercury Impacts Moon!

Posted By jess tauber
Ermanno Borra, the scientist spinning up big mercury mirrors, sees the future of such scopes on the Moon: see http://news.yahoo.com/s/afp/20070620/sc_afp/astronomymoontelescope

I talked with him a couple of years ago- I'm NOT sure that the folks there are entirely right about the Hg not affecting them- shades of Alice in Wonderland? grin

Jess 'reflections on lunacy' Tauber

July 11, 2007 02:59 AM Forum: Eyepieces

Minimum focal lengths for ep's?

Posted By jess tauber
I've seen 2mm ep's offered- I got one a while back that was terrible. My question is how low do they go commercially, or by private individuals? Do the lowest FL ep's require premium primaries or will they work on run of the mill optics? Eye relief the ultimate limitation?

I'd also like to know which types (ortho, plossl, etc.) do best in the smallest FL ranges, and what makers can be relied upon to give quality product. Any vintage makers come to mind as well? Thanks.

Jess Tauber

July 13, 2007 01:41 AM Forum: Telescope Making

Re: Support Mirror On Astroturf?

Posted By jess tauber
I can already hear the roar of the crowds... grin Maybe they used this when grinding the mirror for the HUDDLE Space Telescope?

In an earlier time, this particular use of Astroturf might have been promoted by Joe Nasmyth.

Finally (one hopes....), GIANTS mirrors supported in this manner are excellent for Astro-SCRIMMAGING.

I know you're a good guy, Herb. Someday you'll forgive me... grin

Jess 'Hello to all the JOKES' Tauber

July 19, 2007 06:33 AM Forum: Telescope Making

Fork-mount load capacity?

Posted By jess tauber
I have a short tube 8" newtonian reflector I've been thinking of putting on the sort of fork mount one uses for Cats- these show up occasionally for sale w/o tripod or OTA. I'm wondering whether my longer tube can be handled by such a fork- what is the usual load capacity for a cast fork mounting for an 8" OTA? Anyone know? Thanks!

Jess Tauber

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