Posts Made By: Dennis Persyk

I’m an equal-opportunity imager. I have images from my Epsilon f/3.3 astrograph with SXV-H9 and my Televue 4-inch refractor with Canon 20D. I also have a “digital sketch” of what my eyeball perceived looking though the refractor.

This is truly an amazing comet to observe and/or image – don’t pass it up!

Here is the link to my New Images page featuring the comet in three modalities and supporting data – please take a look at the link below:
http://home.att.net/~dpersyk/new.htm

By now you have all seen images and posts regarding comet 17P Holmes. It is truly an amazing comet. In the space of just 14 hours, the comet increased in brightness by 17 magnitudes -- that's a factor of six million times brighter (2.51^17) ! You can view it by naked eye, binoculars, or telescope. Imaging is easy because it is so bright.

Be forewarned – this very bright comet has not yet developed a tail – it will look like a bright, fuzzy, double star. Really fuzzy.

Here are a few links that I employ to scrounge up data on the comet I’m going to image -- you may find them helpful for observing and imaging:

General source – magnitude, sky charts, background info
http://www.cometchasing.skyhound.com/index.html

Light Curve
http://www.aerith.net/comet/catalog/0017P/2007.html

Orbit
http://neo.jpl.nasa.gov/orbits/

Ephemerides, including arc-seconds per minute relative motion (important to determine maximum imaging time – want less than one pixel blur per exposure)
http://cfa-www.harvard.edu/iau/MPEph/MPEph.html

Thank you for visiting my site.

Clear skies,

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

Pier Design Paper: http://home.att.net/~dpersyk/Pier_Design.htm

C/2007 N3 Lunin is a magnitude 11.8 comet in Sagittarius. It has a relative motion of 2.36 arc seconds per minute so I was limited to 120 second exposures when I imaged it to avoid blur.

Conditions were exceedingly poor in north central Illinois on the morning of July 27. The comet was only 27 degrees high and I could see no stars at all in the area. The only thing I saw in the area by unaided eye was Jupiter, and I saw one magnitude 7 star through my 4-inch refractor.

I was amazed that the Epsilon 160 f/3.3 astrograph and SXV-H9 camera could pick out details from the murk.

Images, associated data, and imaging notes at
http://home.att.net/~dpersyk/new.htm

Please take a look and give me some feedback. This was quite an imaging challenge for me. Thank you for visiting my site.

Clear skies,

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

Pier Design Paper: http://home.att.net/~dpersyk/Pier_Design.htm

C/2007 N3 Lunin is a magnitude 11.8 comet in Sagittarius. I imaged it four days ago under poor conditions so I tried again last night. I was able to make only a small improvement. This comet is starting to annoy me!

On my web page linked below I’ve included an illustrative example of how to relate a camera image to a planetarium program display of similar scale. The camera captures so many more stars than the planetarium program depicts that picking out similar star patterns is difficult.

I had a lot of difficulty doing this when I first started imaging, so I’ve posted this little exercise/example to help others that have similar visualization problems.

There is also a comet track star map illustrating why one should use current coordinates to locate the comet. It is literally a “moving target”.

Images, associated data, and imaging notes 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

Pier Design Paper: http://home.att.net/~dpersyk/Pier_Design.htm

Comet 6P d’Arrest is a magnitude 8.8 comet in Microscopium. The 6P designates it is a periodic comet. It comes around about every six years. The comet was discovered in 1851. I can’t imagine how guys discovered comets in those days without modern technology.

Images, associated data, and imaging notes 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

Pier Design Paper: http://home.att.net/~dpersyk/Pier_Design.htm

Last night I imaged three comets in Gemini:
C/2007 N3 Lunin mag 9.1
144P Kushida, mag 11.5
C/2006 OF2 Broughton mag 12.2

Epsilon 160 f/3.3, SXV-H9 camera binned 2x2.

Conditions were terrible – full moon and VLM ~ 2.0 in the imaging sector due to sky glow. But I’ve not been able to image for many months, so I needed practice.

OF2 was right on top of a bright star, so its image was not successful. In retrospect, I’d have been better off going for T2 Cardinal in nearby Auriga at magnitude 9.8. I was pushing saturation with meager 90 second exposures with so much background light.

Images, associated data, and imaging notes 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

Pier Design Paper: http://home.att.net/~dpersyk/Pier_Design.htm

Last night I imaged five comets in Gemini and vicinity:
C/2007 N3 Lunin mag 9.6
C/2009 F6 Yi-SWAN mag 9.9
C2008 T2 (Cardinal) mag 11.6
144P Kushida, mag 11.8
116P Wild mag 12.7

These are all fairly easy imaging targets if you have current ephemerides to locate them. I use SkyMap Pro planetarium program, but you can get up-to-date RA/Dec coordinates for your observing time at
http://www.cfa.harvard.edu/iau/MPEph/MPEph.html
Enter the exact name (very critical!) in the box below the “Get ephemerides/HTML Page” box and click on it.

Epsilon 160 f/3.3, SXV-H9 camera binned 2x2. Exposures were typically 8 x 4 minutes.

Images, associated data, and imaging notes 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

Pier Design Paper: http://home.att.net/~dpersyk/Pier_Design.htm

Comet C/2007 N3 Lulin is fading rapidly into the western sky. But it is still a good target, with a 20 arc minute long tail, magnitude about 9.5, and fairly high in Gemini. It also has an incredibly slow relative motion of only 0.01 arc seconds/minute, so you can take long exposures without blurring the comet.

Last night I imaged it under terrible seeing, but fortunately one doesn’t need good seeing to image a comet. When I focus using AstroArt 3.0, a medium bright (mag 8 star) lights up just one pixel in focus mode. Last night the focus image was bouncing back and forth between 4 and 7 pixels! Probably 6 or 7 arc second seeing. But I got a reasonable image at 5.0 arc seconds per pixel (binned 2x2).

My sky brightness was 19.0 magnitudes/ square arc second (measured with a Sky Quality Meter, as my 68 year old eyes aren’t very sensitive any more). That translates into an NELM (naked-eye limiting magnitude) of about 4.7. I live 40 miles west of Chicago.

Images, associated data, and imaging notes 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

Pier Design Paper: http://home.att.net/~dpersyk/Pier_Design.htm

Comet W3 Cristensen is currenly the brightest comet in the sky at magnitude 8.6. I imaged and observed it last night.

My sky brightness was 18.7 magnitudes/ square arc second (measured with a Sky Quality Meter, as my 68 year old eyes aren’t very sensitive any more). That translates into an NELM (naked-eye limiting magnitude) of about 5.0, or Bortel 6. I live 40 miles west of Chicago.

I was disappointed that I could barely see it in my 11-inch Celestron SCT. I wonder if other visual observers have had any better luck, I have posted a “digital sketch” of what I saw though the eyepiece at the link below to give you an idea of the visual conditions.

Images, associated data, and imaging notes at
http://home.att.net/~dpersyk/new.htm

Thank you for visiting my site.

Clear skies,

Dennis Persyk
Igloo (now Roll-Off) Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL

Pier Design Paper: http://home.att.net/~dpersyk/Pier_Design.htm

Comet W3 Christensen is still currently the brightest comet in the sky at magnitude 8.3. Although the head is very bright, the surrounding 3-4 arc-minute coma is faint, and there is yet no evidence of a tail, at least not in my images. The comet is embedded in a dense star field in Aquila now. Additionally, the nearly-full moon is 34 degrees away. It is still an easy imaging target.

Images, associated data, and imaging notes at
http://home.att.net/~dpersyk/new.htm

Thank you for visiting my site.

Clear skies,

Dennis Persyk
Igloo (now Roll-Off) Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL

Pier Design Paper: http://home.att.net/~dpersyk/Pier_Design.htm

The Good News:
Comet C/2008 P1 is the only comet in the sky right now with a nice long tail. I imaged it last night with a 4-arc minute long beautiful tail. Unlike C/2006 W3 which everyone is currently imaging and is just a round ball of luminosity, P1 has a real tail and looks like a real comet.

The Bad News:
Whereas tail-less W3 is a healthy magnitude 8.3, P1 is a dim little mag 15.4. Combine that with the skyglow from Chicago about 40 miles east giving me a NELM of about mag 3.5, and you have a real imaging challenge. But I did it!!!!!!!!

I used a Takahashi E-160 astrograph which is a fast f/3.3 and a Starlight Xpress SXV-H9 camera binned 2x2. I could only image for 3 minutes before I ran into sky glow saturation (mine is not a dark site). I only took four exposures, because when I looked at the raws in the observatory monitor I couldn’t see the comet. It was only later in the house when I processed the images in ImagesPlus that I saw I had captured it. Darn. I wish I had taken more frames now.

Anyway, images of this dim little fellow with a tail and accompanying documentation are at http://home.att.net/~dpersyk/new.htm I hope you’ll check it out.

Clear skies,

Dennis Persyk
Igloo (Now Roll-Off) Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL