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Posts Made By: Roland Christen

December 6, 2006 06:59 PM Forum: CCD Imaging and Processing/Deep Sky

Big M31

Posted By Roland Christen

Hi All,

With the plethora of M31's that have been posted, can you take one more? This one is too big to post directly, so here is the link:

This is an on-going project with color hopefully being added eventually. I don't have really dark skies, so it does not go super deep. It is posted as a full size image (caution: big file) in order to show the maximum detail.


January 3, 2007 05:25 PM Forum: CCD Imaging and Processing/Deep Sky

In praise of long focal ratio

Posted By Roland Christen

Hi All,

Lots of us who were brought up on film astrophotography have always known that a fast focal ratio results in better signal to noise and shorter exposures for a given density. Actually, this is true only for film. For linear devices like CCDs, the focal ratio is not important for signal to noise, only the aperture. Fast F-ratio gives you wider field, slower F-ratio gives you higher resolution potential. Here are a couple of images taken at F14.6 with my 10" AP Mak-Cass.


January 16, 2007 05:51 PM Forum: CCD Imaging and Processing/Deep Sky

Cone and Fox Fur Nebula

Posted By Roland Christen

This is an image taken by Ray Gralack that shows these regions very nicely. 160EDF at F5.7, STL11000, 6nm Ha filter. Image taken during full Moon!


January 19, 2007 10:58 PM Forum: Refractors

Re: Achromatic Lens

Posted By Roland Christen

The lens probably had severe spherical aberration (overcorrection) in its normal configuration due possibly to poor workmanship. Luckily for you, the reversed configuration with flint leading has added the reverse amount of spherical aberration (undercorrection) that just cancels out most or all of that in the lens. I have seen a few amateur-made lenses that would not work in their normal mode, but worked reasonably fine when reversed.


January 31, 2007 04:21 PM Forum: CCD Imaging and Processing/Deep Sky

IC405 Flaming Star

Posted By Roland Christen

It was finally clear (and very cold) last night, which gave me the opportunity to do some testing on a telecompressor for the 155EDF refractor and STL11K camera. IC405 was very near the almost full Moon, but with H-a filter there was minimal problem capturing this nebula. Exposure 7 x 5 minutes @ F5.3


February 5, 2007 09:11 PM Forum: Astro-Physics

Pure sex - the setup

Posted By Roland Christen

I've been testing the F5.3 Telecompressor on the AP 155EDF to see how well it will cover the STL11K format. Here is the setup: 155EDF, F5.3 TCC, STL11k, all mounted on the Mach1 mount, Eagle 1 Pier. The performance of this system is second to none, as you will see in the next post ...


February 20, 2007 07:01 PM Forum: CCD Imaging and Processing/Deep Sky

Galaxies galore

Posted By Roland Christen

Spring is coming, and along with that comes the realm of galaxies. Here is another superb shot by Ray Gralack:

A couple nights ago I collected some LRGB data of the M87/M86/M84 region but the
red didn't finish before sunrise so I just made a luminance image until I can
get the red data. This image consists of 140 minutes (7 x 20 minutes) luminance
with my AP160 at f/5.7. The camera used was an STL-11000M.

M87 is in the upper left and M86/84 lower right. I think there are literally
thousands of galaxies total visible in the full-sized image. I stretched the
image so that the background is bright enough to see all of the faint galaxies.
Besides using DDP to tame the large dynamic range of M87/86 and 84, I did a very
slight unsharp mask to highlight some galaxy detail.

This is reduced to 1/3 full size:

This image is full-size (warning 2MB+ download!!)

-Ray Gralak

March 2, 2007 09:59 PM Forum: Bad to the Bone Autos

Is 800hp enough?

Posted By Roland Christen

Japanese 800hp electric super car with 8 wheels:

March 2, 2007 11:28 PM Forum: CCD Imaging and Processing/Deep Sky

First Horsehead this year

Posted By Roland Christen

I took advantage of 3 hour window between storms to take a 3x20 minute H-alpha exposure with a 155EDF at F5.3 and STL11K camera. I tried a different orientation than normal just to be ornery, and maybe see if it would reveal anything new. Image is reduced to 25% size.


March 19, 2007 03:32 PM Forum: Astro-Physics

155 and 160 Telecompressors

Posted By Roland Christen

To All,

We just posted the new information. Here are some useful links:

We have a few 155 and 160 Telecompressors that can be made right away. Additional telecompressors can be shipped in April after we finish some mechanical parts. New orders for 160 field flatteners will be available in a few months after Roland finishes the optics.

Marj Christen
Astro-Physics, Inc
11250 Forest Hills Road
Machesney Park, IL 61115
Phone: 815-282-1513
Fax: 815-282-9847