Image of the day

Captured by
Erwin Forbragd

M27, The Dumbell Nebula

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Posts Made By: Roland Christen

March 23, 2007 05:56 PM Forum: CCD Imaging and Processing/Deep Sky

Byebye Horsey

Posted By Roland Christen
Hi All,

I've been adding to my Horsehead image this last week, trying to outrun
it before it slips into the sunset and trying to get that final shot. Here are results I was able to
get with my 6" refractor (which by the way illustrates the tremendous
veratility of this type of telescope):

Low resolution shot:
http://geogdata.csun.edu/~voltaire/roland/horsehead.html

Full resolution shot:
http://geogdata.csun.edu/~voltaire/roland/horsefull.html

Byebye Horsey!

Rolando

(for comparison of detail captured, there is a magnificent Horsehead
shot taken with a 0.9 meter telescope on Kitt Peak:
http://www.noao.edu/image_gallery/images/d4/horseheadx.jpg )

April 24, 2007 10:49 PM Forum: Astro-Physics

Re: What is it worth?

Posted By Roland Christen
Why do you need a 155 with 4" focuser? That scope was made specifically for imaging. Is that what you plan to do?

Rolando

June 7, 2007 09:28 PM Forum: Refractors

Re: More portable than you think (FS128)

Posted By Roland Christen
>>The attached picture shows an FS128 optics and the Moonlite focuser packed for travel in a plastic tool box 10x10x19.>>

So where's the tube?

Rolando

June 11, 2007 07:06 PM Forum: Equipment Talk

Re: Optical testing of Big SCTs

Posted By Roland Christen
>>I would also imagine the thin corrector is most stressed when horizontal. Perhaps these are marginal considerations. >>

It is a misconception that a thin corrector, or for that matter any corrector, would be subject to stresses from bending. SCT and Mak correctors are essentially zero power windows, and you can bend and stress them all you want with no effect on the image. The reason is that whatever pretzel surface that you put on the front, you automatically put the exact opposite on the rear when you bend these elements (up to a point, of course). Thus the front and rear aberrations cancel out (do not confuse this with aberrations that can be polished in during polishing and figuring when the element is not supported properly). A mirror, of course, needs to be mounted totally stress-free because there is no opposite surface to cancel any stress induced errors.

Rolando

June 12, 2007 10:18 PM Forum: Bad to the Bone Autos

0-60 in 1.04 seconds

Posted By Roland Christen
1/4 mile in 8.168 seconds

http://www.killacycle.com/

mama mia!

June 13, 2007 08:15 PM Forum: Astro-Physics

NGC6888 with 140mm refractor

Posted By Roland Christen
Had some good seeing last night and decided to shoot some H-alpha with the new 140F7.5. The image was taken at F5.7 with the TCC and STL11K camera. 6x10 minute exposure, reduced to 1/4 size. The nebulosity above NGC6888 reminds me of parts of the Veil.

Rolando

June 13, 2007 08:30 PM Forum: CCD Imaging and Processing/Deep Sky

NGC6888 wide field

Posted By Roland Christen
Good seeing last night. I used the new 140F7.5 operating with TCC at F5.7, STL11K camera, 6x10 minute exposure.

The nebulosity above NGC6888 looks a lot like parts of the Veil.

Rolando

July 23, 2007 03:37 PM Forum: CCD Imaging and Processing/Deep Sky

M17 with 140F7.5 refractor

Posted By Roland Christen
We had a clear night and i was able to get a few shots off before the nebula sank into the south-western horizon. I will probably re-shoot this one to include S2 line also.

2x20 minute exposure 140F7.5 refractor at F5.7. Red = H-a, green = 1/2(Ha + O3), blue = O3. This is a crop of the full size image.

Rolando

September 17, 2007 11:23 PM Forum: CCD Imaging and Processing/Deep Sky

Bubble in two color modes

Posted By Roland Christen
Hi Folks,

I'm posting an image of the Bubble nebula in RGB and HaRGB to show how adding H-a adds some detail and maybe detracts from the ascetic appeal.

This first image, a pure RGB, was taken by Anthony Ayiomamitis in Greece with an AP160 refractor and ST2000 CCD (Anthony likes diffraction spikes so these were added via string across the aperture). It shows the bubble as an ethereal bubble hanging in space, almost 3-D like.

Rolando

October 17, 2007 12:16 AM Forum: CCD Imaging and Processing/Deep Sky

Re: M1 From new observatory

Posted By Roland Christen
I would first post a smaller version. The image is really too big for a typical monitor. I did a bit of color enhancement of the brighter portiong of the nebula. First, I copied the red channel and used it as a Luminance channel. This brought out the tendrils. I then did a bit of unsharp masking of selected regions and increased the color saturation. You really have quite a bit of detail showing. Don't be afraid to experiment with the image in Photoshop.

Rolando

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