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North America + Pelican Nebulae

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Posts Made By: Jeff Blazey

April 22, 2008 12:27 PM Forum: Bad to the Bone Autos

Ford Pantera.

Posted By Jeff Blazey
Say, isn't that one of the original Cylons? What do you feed that thing anyway?

Jeff

May 22, 2008 10:37 PM Forum: CCD Imaging and Processing/Solar System

Jupiter's 3rd Red Spot

Posted By Jeff Blazey
Thanks John I'll keep an eye out for it.

Interesting how they say it's only a fraction of the size of the GRS...You know like it's SMALL or something. wink

Jeff

May 23, 2008 01:57 PM Forum: Pictures of Me and My Telescope and........

Then and Now

Posted By Jeff Blazey
[I]
Now: 2008, 54 years old with a 1986 vintage 5" F6 AP.

May 30, 2008 03:50 AM Forum: Pictures of Me and My Telescope and........

Me and my AP

Posted By Jeff Blazey
Here's another gem from 1986. This ones an AP130 pre-Starfire F8. I cut the tube back to take my Denks sans OCS, added an AP 2.7" with a D&G back plate. This is a NICE scope. Again sharp, smoooooooth optics, no zones with maybe, maybe, a hint of overcorrection. Color is VERY well controlled despite it being a pre-Starfire, and it's simply not an issue for visual use.

July 23, 2008 12:12 PM Forum: Reflectors

NEW:Orion 190mm Mak Newt Astrograph

Posted By Jeff Blazey
Well you get what you pay for. However, if Orion can pull it off, the package could be very effective...if they can pull it off. I noticed that they are taking "pre-orders". I may just pop for one to check it out.

True, the glass is readily available in good quality. It all comes down to how well it's put together optically & mechanically.

Even though the surfaces are all spherical, they have to be very high quality spherical surfaces. That means not only low PTV & RMS numbers but smoooooothess as well, which, in my experience, is more important, at least for high power visual work, once you get past ~ 1/5 PTV for the system. Then you need high quality coatings

The other thing that gives me pause is what I see as a trend of Synta type suppliers to "ship & fix". That is to get the product out in a hurry and fix the quality & design issues later. Orion can screen that sort of thing but if the reject rate is high, well, it may never see the light of day...I mean night.

Clever though in that they don't take the Intes brand products (MN76 & MN86) on directly except for price.

We shall see.

Jeff

August 1, 2008 07:24 PM Forum: Refractors

Orion EON 120mm F7.5 APO is a winner

Posted By Jeff Blazey
I've noticed what seems to be an awful lot of used 80-100MM ED scopes up for sale lately. Could this be the "EON 120 Effect"?

Jeff

August 13, 2008 11:52 AM Forum: Refractors

A question for all lens experts!

Posted By Jeff Blazey
What Dan said, but I'd first collimate everything (focuser and lens..focuser first). Astigmatism can creep in due to collimation in exactly the way Dan describes.

Use a quality laser that itself is well collimated with an aperture mask that's got a small hole in the middle. Using the mask, adjust the focuser until the beam exits the hole in the mask. Then, leave the mask on but put something black over the lens and use a good Cheshire to adjust the lens so that the dots you see all line up. That will get you close but star testing (using a green filter) at 400X and above is really needed to dial it in. When star testing first go to about 4-5 rings on each side of focus. If there is still astigmatism, adjust the lens collimation screws to make the images round.

Also, I suggest an aperture mask of maybe 6". If that really cleans up the image, then you know the problem is towards the edge, where they usually are.

Good Luck:

Jeff

August 25, 2008 10:40 PM Forum: Refractors

What does "well corrected" mean exactly?

Posted By Jeff Blazey
In regulatory speak, well corrected optics are those that are not poorly corrected. smile

August 26, 2008 06:23 PM Forum: Refractors

What does "well corrected" mean exactly?

Posted By Jeff Blazey
Well, looking at all the stuff above, let's just make it up and let's stick to wavefront error. How about:

Wave front errors for spherical abberation, coma, spherochromatism, astigmatism and whatever all fall inside the Airy disk from C to F on axis.

Jeff

October 16, 2008 11:47 AM Forum: Refractors

Rolando, any idea what glass TV uses?

Posted By Jeff Blazey
Floyd:

I just feel it's a bit inappropriate to ask Roland what Al uses for his glass. Why not just ask Al directly?

Jeff

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