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Posts Made By: Dennis Persyk

February 20, 2006 06:17 PM Forum: CCD Imaging and Processing/Deep Sky

Comet Movie of Currently Brightest Comet

Posted By Dennis Persyk
Comet C/2005 E2 McNaught is the brightest comet in the sky at present observable from Northern Illinois. It is magnitude 10.0.

E-160, 45 x 1 minute unguided; SXV-H9; AP-1200GTO

This is a rapidly moving comet, tooling along at 2.1 arc seconds per minute. That makes imaging a bit challenging as you will be imaging a moving (relative to the star field) target. Give it a try.

Images, little (157 kB) movie, and supporting information at
http://home.att.net/~dpersyk/new.htm

Thank you for visiting my site.

Clear skies,

Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL

March 4, 2006 09:04 PM Forum: CCD Imaging and Processing/Deep Sky

Pojmanski is bright, so no excuses <G>

Posted By Dennis Persyk
C/2006 A1 Pojmanski is the brightest comet in the sky at present.

This is a rapidly moving comet, racing along at 7.1 arc seconds per minute. That makes imaging a bit challenging. It was fairly low on my horizon, 15 degrees elevation, putting it smack dab in the middle of Chicago’s sky glow on my eastern horizon. I estimate the VLM there to be -2. Yes, minus two! If I could image it, anyone can. It was not visible in a 50 mm finder nor in 7x 50 binoculars. From a dark site it would be a naked eye object.

E-160, SXV-H9, 26 x 45 seconds, AP-1200GTO

Images, finder chart, imaging and processing tips and supporting information at
http://home.att.net/~dpersyk/new.htm

Thank you for visiting my site.

Clear skies,

Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL


March 13, 2006 06:43 PM Forum: CCD Imaging and Processing/Deep Sky

Making a Comet Movie

Posted By Dennis Persyk
C/2006 A1 Pojmanski had a very fast relative speed of motion, 7 arc seconds per second on March 4, making it a prime candidate for animation. (Now it is 5.9 arc seconds per minute, still pretty fast.) You can’t image for long due to the speed (unless you guide), so you wind up with lots of short exposure frames. Ideal movie material.

Images and short (593 kB) movie at
http://home.att.net/~dpersyk/new.htm

Here’s what I do in ImagesPlus:

1) Stretch the midpoint frame to pleasing histogram shape and apply that histogram to all images. The sky background may vary considerably from beginning to end, but it will look fine in the movie.
2) Convert FITs to JPGs
3) Align on the stars. This is important! If you align on the comet head, the animation will not look as pleasing.
4) Crop all images down to a small size, like 300 x 200 pixels. Please . Most viewers don’t want to download a 15 – 20 MB movie!

Next, in Ulead GIF Annimator:
1) Click on Annimation wizard and import the jpgs
2) Preview and remove any bad frames
3) Under Optimize, reduce the color bit depth from 256 bits to 16 (or less) bits. This has a profound effect on reducing file size. Experiment with different settings to make the file size as small as you can without sacrificing image quality too much.
4) Hope the Academy Awards will nominate your movie .

Notes on the software I described:

Of the many image processing aps I use, ImagesPlus seems best suited for handling a hundred or so frames at once. The “Apply to all images” command is greatly appreciated when dealing with a whole bunch of images simultaneously.

Ulead GIF Animator replaced my all-time favorite Animagic. When I got a new computer I somehow lost the password to it and now it’s broken. The Ulead ap is ok, gets the job done, and is easy to use. I’ve not tried other animation aps so I don’t know how it compares.

Give comet movie making a try. It is fun and a good way to use up all of those frames you took.

Thank you for visiting my site.

Clear skies,

Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL


March 29, 2006 07:17 PM Forum: CCD Imaging and Processing/Deep Sky

C/2003 WT42 (LINEAR)

Posted By Dennis Persyk
This comet is presently at magnitude 13.6 in UMa. It is not as bright or exciting as Pojmanksi or 73P with its many fragments, but has a nice 2 arc minute long tail.

Images and supporting information at
http://home.att.net/~dpersyk/new.htm

Thank you for visiting my site.

Clear skies,

Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL


April 5, 2006 10:03 PM Forum: CCD Imaging and Processing/Deep Sky

73P Fragment B -- a Bright, Beautiful Comet!

Posted By Dennis Persyk
Comet 73P/Schwassmann-Wachmann 3 was featured in the May Sky&Telescope and Astronomy magazines. It has fragmented into many pieces which are growing brighter as they approach the sun.

I imaged fragments B and C last night. Fragment B was considerably brighter and had a beautiful tail over 35 arc minutes long. It is forecasted to become a naked eye comet in the coming months. I have posted the B images on my web page linked below.

Images and supporting data at
http://home.att.net/~dpersyk/new.htm

Thank you for visiting my site.

Clear skies,

Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL


April 16, 2006 01:44 AM Forum: Birding Optics and Photos

Downy Woodpecker

Posted By Dennis Persyk
I’m just learning my way around my new Canon 20D. 300 mm; f/5.6; overcast day; processed in ImagesPlus.

Best regards,

Dennis

April 22, 2006 04:28 PM Forum: CCD Imaging and Processing/Deep Sky

Abell Galaxy Cluster 1367

Posted By Dennis Persyk
This is one of the densest galaxy clusters in the sky. I captured only about 1/9 of the total area with my 58 x 43 arc minute FOV.

Takahashi E-160 astrograph @ f/3.3
LRGB 120:30:30:30 in ten-minute subframes
AP1200GTO mount
SXV-H9 camera
Acquired in AA3; Processed in ImagesPlus

Image and matching SkyMap Pro 10 screen shot
http://home.att.net/~dpersyk/new.htm

I’d appreciate feedback on this image. In the past I always reduced the image size so viewers wouldn’t have to scroll around to see the whole image. But this subject just does not look as good in a smaller format. Do you mind the larger size? Let me know what you think. Thanks.

Clear skies,

Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL

New Images http://home.att.net/~dpersyk/new.htm

April 26, 2006 05:46 PM Forum: CCD Imaging and Processing/Deep Sky

73P B Split Nucleus

Posted By Dennis Persyk
I measured a centroid-to-centroid spacing of the two nuclei of 16 +/- 2 arc seconds in my latest images. For the first time ever I was able to guide on the head and take 6-minute subframes. The relative motion was 2.5 arc seconds per minute so guiding really helped me obtain a good SNR.

In past attempts the autoguider would latch onto a star in the comet’s path and get lost. On my 23 April 0330 UT imaging session there were no stars brighter than magnitude 16 in the comet’s path. That seldom occurs.

Images and supporting data at
http://home.att.net/~dpersyk/new.htm

Thank you for visiting my site.

Clear skies,

Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL



May 3, 2006 05:44 PM Forum: CCD Imaging and Processing/Deep Sky

73P B Split Nucleus Movie April 23

Posted By Dennis Persyk
I’ve added a short movie to my web page illustrating the rapid motion of 73P-B against the fixed star field. It comprises 7 six-minute frames during which time the comet moves 1.8 arc minutes.

Tips for comet movies:
1) Crop around comet to keep file size small
2) Align on stars, not comet, for smooth viewing
3) Use minimum bit depth and lots of compression to keep file size small
4) Throw out frames that do not follow a smooth comet motion

I emphasize small file size because of late I’ve seen comet movies of 10-20 MB file size that would look just as good at 100 kB and would attract more viewers.

Note: Mine is a dial-up-friendly movie. It is only 68 kB.

Movie and supporting data at
http://home.att.net/~dpersyk/new.htm

Thank you for visiting my site.

Clear skies,

Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL




May 18, 2006 02:55 AM Forum: Birding Optics and Photos

Chipping Sparrow with 80 mm Telescope

Posted By Dennis Persyk
20D on Orion 80 mm aperture Acromatic 480 mm focal length f/6 telescope. 1/500 second ISO 400.

Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL

New Images http://home.att.net/~dpersyk/new.htm

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