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June 2011 Blog Posts (8)

listen on to my last song

listen on ,composer Milou Pulinx ,to my last composition Ekam ,love at first sight

Added by Emile.M. Pulinx, MD on June 25, 2011 at 11:28am — No Comments

Update on Differential Flexure

Not satisfied with the results of my previous testing, I decided to try again. This time I used a technique that is directly applicable to imaging rather than a theoretical measurement of worst-case flexure. What I did was to simply capture 30 images at 2 minute intervals while guiding, then measure the position of a star in each frame to see how it varies in RA and DEC over the hour. Obviously, there is some "noise" in the measurements and I didn't bother trying to filter that out (such as… Continue

Added by Greg Marshall on June 16, 2011 at 12:25pm — No Comments

Clear Skies

Apparently i've got clear skies all next week. Hopefully it materializes my setup works great and nail a shot per night, that would be really nice.

Added by Charles Dunlop on June 10, 2011 at 10:44am — No Comments

Full Time Astronomy?

Got laid off today! It was only part time work and the lay off was expected - not a big deal. So now I can spend all (well, most) of my time on astronomy.

Coincidentally, my previous employer, Xerox, announced today that they are outsourcing most engineering to India. It has been my opinion for some time now that the company was run by fools. This is proof positive.

Added by Greg Marshall on June 8, 2011 at 8:00pm — 3 Comments

Flexure and Field Flatness Tests

Neil gave me the idea of testing to see how much differential flexure I have in my side-by-side setup and I got around to doing that last night when we had partly cloudy skies such that I didn't want to try real imaging, not knowing how long it would last. My AT111EDT (with QSI 583 camera) and Orion ST80 (with Meade DSI camera) are mounted on a 3/8" aluminum plate, about 8" apart. Recently I also added an aluminum bar across the tops of the rings to couple the 2 scopes there in addition to the… Continue

Added by Greg Marshall on June 5, 2011 at 10:00pm — 1 Comment


Mazatlan sucks. I'm feeling really sorry for the people there, drug wars stopping tourism, the city is falling apart, it's super sad. But the town is going criminal in a big way as regular folks are being financially pressed to the exteme Aweful to be walking through there knowing what' coming for those people. Horrible.

Added by Charles Dunlop on June 5, 2011 at 7:06pm — 2 Comments


I am thinking of purchasing a Sony@550 which has a CMOS sensor and my current Sony has a CCD. What are the pros and cons in DSLR astro? I want the 550 for its live view and it is a 14 megapixel while mine is 10. Comments please Thanks Al

Added by Al McAdam on June 2, 2011 at 4:38pm — 5 Comments

A Direct Comparison Of 200mm f/4 and a 90mm f/7 Scopes

I've had a few conversations recently about the difference between my Vixen R200SS and my Vixen ED103S.

The R200SS

Aperture: 200mm (8")

F Ratio: f/4

Design: Newtonian

The ED103S

Aperture: 103mm (masked down to 90mm due to spacers in the light path causing unwanted diffraction spikes)

F Ratio: f/7.7 (but f/8.8 after the masking and f/7 after introducing the reducer)

Design: Apochromatic… Continue

Added by Neil Heacock on June 1, 2011 at 1:00pm — 11 Comments

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