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Erwin Forbragd

Leo Triplet

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Posts Made By: Jeff Blazey

December 18, 2009 02:27 PM Forum: Refractors

Triplet Semi-Apo?

Posted By Jeff Blazey

Everybody seems to be getting all hung up over the color correction. No suprise here.

To me, the seller has been very careful and clear that this is a specialized instrument for visual use. Looking at the spot diagram, the blue does not seem that far out to me at all for such a fast scope. How people react to that visually is the stuff arguments are made of.

However, based upon the 6" F10 oiled triplet I got from Roger, I can speculate the figure of the lens for visual use is exceptional and will take your breath away upon first view.

Jeff

December 19, 2009 02:21 PM Forum: Equipment Talk

trying to reconsile mirror test data with observat

Posted By Jeff Blazey

Dan Ritts said:

I found a few things surprising about these results: First, that a mirror with such a low Strehl could produce an image of the orion nebula that was everyone thought was hard to fault at 107x. Second, that a Galaxy mirror did not clearly outperform the Tectron of known low quality. Third, that the AP blew away a Galaxy mirror in the out of focus star image with much smoother outer ring and much more visible inner ring structure.

Well 107X is not a lot of magnification for a 14.5" scope. That's just 7X per inch of aperture. At that low of a magnification, you may have a hard time resolving the flaws even with perfect seeing. In the 80's we occassionally got one of the older Coulter dobs into the shop on trade. Truly terrible mirrors but on low power deep-sky views they would shock and awe even seasonned observers.

How did orion look thru the 5"?

Jeff

December 19, 2009 10:57 PM Forum: Telescope Making

Istar Doublet

Posted By Jeff Blazey

Another view

April 13, 2010 10:53 PM Forum: Birding Optics and Photos

May 6, 2010 02:36 AM Forum: Equipment Talk

Can Losmandy GM8 Handle a C9.25

Posted By Jeff Blazey

No problem for the GM8 at all for visual use.

Jeff

June 20, 2010 10:24 PM Forum: Equipment Talk

August 9, 2010 01:32 AM Forum: Solar System Observing

Learning Solar System Imaging

Posted By Jeff Blazey

Tom Wilson said:

Hi All,

I'm learning Solar System imaging. This is my best image from my first month of imaging Jupiter.

Umm, while you're "learning" can you teach me?

Great stuff there!!

Jeff

September 18, 2010 04:36 AM Forum: Solar System Observing

Uranus close to Jupiter

Posted By Jeff Blazey

Now it's really , really close to Jupiter!

October 9, 2010 04:39 PM Forum: Solar System Observing

Transit of Io

Posted By Jeff Blazey

Hi Mike:

Yes I saw it too and the 3D effect with the binoviewers was indeed pronounced. However, I saw the moon entering transit across the face of Jupiter. As it started transit it was extremely bright and could be easily followed across the face of Jupiter. Later, the shadow started as a bite on Jupiter's limb and that's when the 3D effect was most pronounced. The Skies were very steady last night which allowed me to use the full aperture of the 11" D&G. Normally, I use 7", 8.5" or 9.5" stops to better match the prevailing seeing and can only use the full aperture for lunar/planetary work a few times a year.

BTW, as I mentioned in a previous thread, as the moon approached the edge of Jupiter, I found it much easier to resolve as a disk, and especially easy as it was crossing Jupiters face.

And another BTW, don't forget Uranus, which is right next door. At 380X it was a very distinct and rather large disk. During moments of the steadiest seeing, which I guaged by the sharpness of the disk, I could make out a gradation of color and brightness across it's face.

Thrilling really.

Jeff

October 14, 2010 06:33 PM Forum: Eyepieces

New Product Announcement

Posted By Jeff Blazey

Cool. What type of coatings do they have?