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Posts Made By: Roland Christen

September 1, 2004 09:58 AM Forum: CCD Imaging and Processing/Solar System

NGC7662 Blue Snowball

Posted By Roland Christen

Hi all,

This past Monday night we had superb seeing here in northern Illinois. Even though it was hazy and the full Moon was high in the sky, I thought I would try imaging this tiny planetary through all that murk. I managed a personal best in resolution of 1.5 arc sec FWHM at F11 and 1.3 FWHM at F22. Normally around here it is tough to get better than 2 arc sec.

The wide field image was taken at F11 with my 10" F14.6 Mak-Cass, ST10XE, color filter wheel, on AP 1200 mount. The closeup in the upper right corner was taken with a Barlow at F22. The image is half size in order to fit mostly on the computer screen.

Roland Christen

September 4, 2004 04:33 PM Forum: CCD Imaging and Processing/Solar System

NGC6543 Cat's Eye Planetary

Posted By Roland Christen

Hi All,

Just a quick note. I took this image Thursday night, similar setup as the Blue Snowball. Shot with my 10" Mak-Cass at F22. Seeing was not quite as nice, only achieved 1.7 arc sec FWHM resolution. Still came out fairly nice.

Roland Christen

September 6, 2004 01:38 PM Forum: CCD Imaging and Processing/Solar System

Moon Crater Walter

Posted By Roland Christen

Here is an ST10 image of this crater. Stack of 3 taken at F11 with 10" Mak-Cass.

Roland Christen

September 11, 2004 01:09 PM Forum: CCD Imaging and Processing/Solar System

Uranus image - 10

Posted By Roland Christen

Here's my effort taken with AP 10" F14.6 Mak, ST10XE, Color Filter Wheel at F22 resampled for larger size. 150 each LRGB images 0.2 second each in reasonably good seeing. All processing done in MaximDL.

Roland Christen

September 14, 2004 07:37 AM Forum: CCD Imaging and Processing/Solar System

NGC6905 Blue Flash Planetary

Posted By Roland Christen

This little gem was named the Blue Flash by John Mallas. Although it appeared exceedingly faint in my individual exposures, it can be seen easily with a 4" refractor in pristine dark skies. The severe light pollution at my observatory prevented me from capturing the outer extensions in any detail. Some day I would love to record this one at a real dark sky site.

10" AP Mak @ F22. ST10XE camera with color filter wheel. Total exposure 1 hour Luminance 1x1 binned, 20 minutes RGB 2x2 binned. Image is 1/2 size from original.

Roland christen

September 14, 2004 03:19 PM Forum: CCD Imaging and Processing/Solar System

NGC6818 Planetary Nebula

Posted By Roland Christen

Hi all,

Here is another electric blue planetary, sometimes called the Little Gem planetary. I caught it late at night as it was sinking toward the south western horizon.

AP 10" Mak-Cass @ F22, ST10XE, CFW
Luminance exposure 50 min total @1x1
RGB exposures 20 min total @2x2 bin

Roland Christen

September 18, 2004 11:33 AM Forum: CCD Imaging and Processing/Solar System

Egg Nebula

Posted By Roland Christen

Hi All,

This image was the result of a challenge by someone on the APUG to see if any detail could be captured in this obscure nebula (Hubble, of course did a super job on it: http://www.cnn.com/interactive/space/0307/gallery.hubble.heritage/gal.05.egg.nebula.jpg).

So here is my attempt using my AP 10" Mak-Cass at F22. 1 hour L, 30 min each RGB. Processed in Maxim using DDP, etc. This thing is small and the outer extensions are extremely faint.

Roland Christen

September 23, 2004 08:28 AM Forum: CCD Imaging and Processing/Solar System

Einstein Cross

Posted By Roland Christen

Last week Cord Scholz challenged me with what I though was an impossible image, the Einstein Cross. After trying for several nights under less than ideal conditions, and getting no resolution of the quasar, I got one night of very good seeing where I was able to capture it with partial resolution. The image of the quasar itself took 15 hours of total exposure.

The object is centered on a 15th mag galaxy which is lensing the more distant quasar. The quasar is split into 4 parts by this foreground galaxy.

It was my most difficult object yet because of the extreme faintness, and the close separation of the components. In the closeup image I have compared it to the north component of eLyra. The 4 components of the Einstein Cross are separated by 0.9 arc seconds.

Roland Christen

October 12, 2004 09:20 AM Forum: Chinese Optics Imports

Spot diagrams

Posted By Roland Christen

Hello,

Just for clarification, I have done a quick achromat design using crown and flint combination which lie along the Abbe Normal line for an optimized F6 achromat at best focus. You can compare the spot diagram to the Semi-apo posted on the Burgess site.

Rolando

October 15, 2004 12:49 PM Forum: Equipment Talk

Re: Sidewalk Test

Posted By Roland Christen

I used premium and not so premium EPs so that the test would show the differences. Though if you look they are not as profound as you would have imagined.
Well, what do you think?
Floyd


You did everything quite wrong, I'm afraid, so your pictures are not very meaningful.

First, the reason it is called the sidewalk test is so that you place them well away from you when yopu photograph them. You cannot place them on a table and then photograph a row of them. Only the middle ones will be at a shallow enough angle. Second, you did them in bright sunlight. You must go somewhere in shade so that only the light from the sky above must illuminate the the glass. Make sure that the sky is above, and not have some building overhang bloch the direct diffuse rays of the sky. Having the sun shine on them from an angle is no good. Place them in shade in a circle if you want, so that all are at nearly the same angle to the camera lens. Then get as far away as possible (even a ladder) and use a zoom eyepiece to get the picture.

Roland Christen