Astromart

December 15, 2008 12:01 PM Forum: Politics

Bush gets the boot!

You have probably seen this...

http://www.youtube.com/watch?v=dmt2_wyDKJI&feature=bz301

That was not a lame duck, really.

December 20, 2008 12:13 PM Forum: Politics

Obama has named Harvard physicist John Holdren and marine biologist Jane Lubchenco to top science posts. Holdren will become Obama's science adviser as director of the White House Office of Science and Technology Policy; Lubchenco will lead the National Oceanic and Atmospheric Administration.

Wow. Actual scientists! The best part of the announcement for me was Obama's comment:

"Because the truth is that promoting science isn't just about providing resources — it's about protecting free and open inquiry. It's about ensuring that facts and evidence are never twisted or obscured by politics or ideology. I could not have a better team to guide me in this work."

How refreshing.

January 2, 2009 04:57 PM Forum: Digital SLR AstroPhotography

M42

Posted By Steve Mathis

Hey, all...Here is my latest attempt at M 42 and surroundings. This was taken with a Nikon D70 through an Orion 8" f/5 OTA (purchased used on AM!). 4 x 5 min at ISO 1600, with the core filled in with shorter exposures (150, 75, 40, 20, 10, and 5 sec). Lots of geostationary satellites crossing the field, as usual.

Thanks for looking!

January 2, 2009 11:48 PM Forum: Digital SLR AstroPhotography

M45

Posted By Steve Mathis

Another from the same dark-sky trip...The Pleiades. Not a great job framing. This is 7 x 5 min, ISO 1600. Same camera and scope as in the above post. Thanks for looking!

January 24, 2009 12:19 PM Forum: Digital SLR AstroPhotography

Yet another M42

Posted By Steve Mathis

Here is an image of M42 taken last Tues. night. Nikon D70, C11 SCT @ f/6.3 (Antares FR). Manually guided with a tandem-mounted C130 Mak. The main body of the image is 4 x 5 min, with the core filled in with 150, 75, 40, 20, and 10 sec exposures. All at ISO 1600. And, of course, the host of geosynchronous satelllites gracing the image! Thanks for looking, comments and criticism welcome!

January 25, 2009 11:47 PM Forum: Digital SLR AstroPhotography

My First Crab

Posted By Steve Mathis

Here is M1, 7 x 5 min, ISO 1600, Nikon D70 on a C11 SCT @ f/6.3. I was happy with the result from my poor old unmodified D70. It was pretty windy (and cold) while I was doing this...

Thanks for looking!

February 10, 2009 07:37 PM Forum: Celestron

Cracked secondary mount?

Posted By Steve Mathis

Hey, all...
I have an older C11 (purchased used here on AM). I recently noticed a crack in the plastic outer cover than holds the collimation screws for the secondary. So I have a few questions...

Did I cause this crack by over tightening Bob's Knobs?

Is the pivot that the secondary is centered on bearing on this plastic, and is it trying to come through?

Is this plastic structural, or cosmetic?

The plastic is bulging outward at the location of the crack. I feel compelled to try to fix it. Is it glued to the corrector?

If I remove the corrector, and remove Bob's Knobs, the secondary will come off, right? Would I then be able to get access to the cracked part?

When using the knobs to collimate, one of the knobs seems to bottom out, making final collimation difficult. It seems I have lost some range of motion, thus the concern and the desire to FIX!

Any help (Uncle Rod...anyone??) would be appreciated!

Steve

February 14, 2009 03:54 PM Forum: Digital SLR AstroPhotography

H-alpha filter on a DSLR

Posted By Steve Mathis

I just got a used modified camera (Nikon D50), and am happy to finally be able to capture more H-alpha. So I'm wondering, would it make sense at all to use an H-alpha filter for some of the frames, and "RGB" for others? I know the CCD'ers do it...would it do any good on a DSLR?

February 17, 2009 01:12 PM Forum: Equipment Talk

Bahtinov mask question

Posted By Steve Mathis

Hey, all...I've made and used several Bahtinov masks, and find that they work remarkably well. I don't have a laptop with focusing software, so I rely on this method. My question relates to the width of the slits in the mask. The formula for constructing the mask implies that the slit width should be 1/150 to 1/200 of the focal length of the scope. I've been trying to figure out the physics of this, mainly why should it matter, and why those numbers. In fact, I made a mask with the "wrong" slit width, and it seemed to work just fine. So, does anyone have any ideas?

February 27, 2009 11:19 PM Forum: Digital SLR AstroPhotography

Mardi Gras Lulin

Posted By Steve Mathis

I was lucky enough to have clear skies at my dark site Tues. night and got this image of Comet Lulin with an 8" f/5 Newtonian, and a modified Nikon D50. This is a stack of 5 x 3 minutes, ISO 800, stacked with DSS using the mode that allows for point stars (instead of streaks). Thanks for looking, comments always welcome!

Image of the day

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Posts Made By: Steve Mathis

Bush gets the boot!

Something to be happy about

M42

M45

Yet another M42

My First Crab

Cracked secondary mount?

H-alpha filter on a DSLR

Bahtinov mask question

Mardi Gras Lulin

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