Comet 17P/Holmes continues to put on a show for skywatchers willing to brave the cold weather. After an incredible run of clear skies through much of the fall, skies turned snowy here in Park City. Storms have been passing over or very near the area for much of the last week or so. This wasn’t too bad as it coincided with the large phases of the moon. Now that the moon has vacated the scene, its nice that skies have taken a break. I was wondering what Comet Holmes would look like after this extended absence. I was also wondering where it’d moved to. Well, first of all, its still very near Mirfak (alpha Perseus). Now, a couple of degrees to the southwest of the bright star. Quite easy to find once my eyes were dark adapted. The comet isn’t quite as bright as it was a couple of weeks ago but it continues to grow. It’s almost filling the eyepiece, perhaps 3/4* in diameter?

The accompanying image represents (3) 60 second exposures and (1) 100 second exposures at ISO1600 using the Canon Digital Rebel XTi at prime focus through my Astro Physics Starfire 160 Refractor. I stacked the raw images using RegiStax 4 and then ran it through the Curves function in GIMP. Finally, I reduced the noise using Neat Image.

This image has a bit of a reddish color to it. This comes mostly from the 100 second exposure. I think there was a bit of moisture in the atmosphere that got picked up at ISO1600. It was a sharp, detail filled image, so I left it in. I’m now too sleepy to reprocess it… so this is how its going out the door

Astro Photo Details:

* Designation: Comet 17P/Holmes
* Constellation: Perseus
* Magnitude: 3?
* Size: 45′ (roughly 50% larger than the diameter of the full moon!)

Astro Photo Processing Details

* Canon Digital Rebel XTi
* Astro Physics Refractor
* 4 x 60s exposure at ISO1600 (comet)
* Gimp Levels
* Neat Image

Comet 17P/Holmes burst onto the astronomy scene just three weeks ago. In that time, its captured the attention of astronomers worldwide. Brightening one million fold literally overnight, the comet has grown steadily as well. From its earliest days, Comet Holmes has proved to be far more interesting than almost anyone would have imagined.

Here are a couple of interesting pictures taken last night. Both of these were taken using my Canon Rebel XTi. The first was what I went out to capture, Comet 17P/Holmes passing by the bright star Mirfak (α Per). As you can see, the star appears within the growing expanse of the comet. Set against a background of stars in the constellation Perseus, the comet continues on its merry way.

While I was out, I figured I might as well snag a shot of the waxing gibbous moon. Since it was dominating the night sky, I figured I might as well catch a couple of shots. Views of the moon were particularly crisp last night as well. I’d heard people compare the growing size of Comet Holmes to the moon, so I figured I’d compare images. Low and behold, the comet was at least as big, if not bigger than the moon!

I processed both images separately in Gimp (linux version now and then created a new image that was exactly twice the size of the originals. I then did a select all and copy and paste for each. As you can see, the two are almost an identical size. I actually have a slightly over processed version of the comet that shows it to be a bit larger than even this image indicates. I had a problem with that image and time prevented me from re-processing and using that image.

Anyway, if you’ve not gotten out to view the comet yet, now is as good a time as any, perhaps better. As the comet is almost sitting on top of Mirfak, the brightest star in the constellation Perseus, it is even easier to find than usual. Simply head outside after dark and look to the northeast. Perseus is due east of the ‘W’ shaped constellation Cassiopia. Many people are familiar with its signature shape. Due east of Perseus is the constellation Auriga lit up by bright Capella. Once you’ve identified Perseus, Mirfak is the brightest star in the constellation (along the northern ‘edge’ of stars). You likely won’t see Comet Holmes at this point as the brightness of Mirfak tends to obscure it. As the two separate in the coming days, the comet should reappear. This is a beautiful binocular or telescope object. If you have access to optics of any size, be sure to point these towards the scene. At roughly the size of the moon, this is one large object to digest. In larger telescopes, Comet Holmes will fill your eyepieces from edge to edge. This is a sweet sight. I don’t know how long the show will last, but the constellation Perseus will be visible at night through the winter. Be sure to take as many views of the comet as you can. It will undoubtedly be changing considerably over the coming weeks and months.

Astro Photo Details:

* Designation: Comet 17P/Holmes
* Constellation: Perseus
* Magnitude: 2.5
* Size: 15′ (roughly 1/2 the diameter of the full moon!)

* Designation: The Moon
* Constellation: Perseus
* Magnitude: roughly mag -8
* Size: roughly 1/2*

Astro Photo Processing Details

* Canon Digital Rebel XTi
* Astro Physics Refractor
* 1 x 60s exposure at ISO1600 (comet)
* 1 x 1/15s exposure at ISO100 (moon)
* Gimp Levels and Curves

I got out an snagged some sweet views of Comet 17P/Holmes again this evening. I viewed through both the Astro Physics Starfire 160 (6.2″) and the ObDob, a 25″ Obsession Dobsonian Reflector. Views were sweet in both, but I have to say… at least as far as telescopes go… size does matter

The comet just about filled the 31mm Nagler eyepiece. This is my lowest power, widest field of view eyepiece. At 100x and roughly 0.8*, the comet seemed to be bigger than the estimates I’ve heard. The prominent core seems to have faded… or been hidden behind all the cometary debris encircling this comet.

This comet had already blown me away with the unexpectedly great show it’s put on. I’d not expected have a comet to look forward to for quite some time. Even when I first heard about it, I figured it’d not likely be all that great. Wrong! This comet has put on an amazing show… and it’s not not done yet. I has moved a few degrees though the constellation Perseus in less than 2 weeks.

Here’s an image I processed on Saturday night from images captured on Tuesday night (11/07). That particular night, I was hoping to image the recently detected tail of the comet. I saw that a few astrophotographers had taken much longer exposures than I had. While I was trying to portray the comet as it appeared in the eyepiece, these individuals were looking for details well beyond what could be seen visually. So, I opted for 30 minutes of exposure time via (18) x 75 second expousres. I went all the way to ISO 1600 to make sure I grabbed every possible photon. When I stacked the images, I was depressed to see that I had absolutely no tail to show for my efforts. Subsequents images seen online as well as comments seemed to indicate that the comet’s tail had disappeared almost as quickly as it appeared. Comet 17P/Holmes had once again proved to be no ordinary comet.

Astro Photo Details:

* Designation: Comet 17P/Holmes
* Constellation: Perseus
* Magnitude: 2.5
* Size: 15′ (roughly 1/2 the diameter of the full moon!)

Astro Photo Processing Details

* Canon Digital Rebel XTi
* Astro Physics Refractor
* 18 x 75s exposures at ISO1600
* Stacked using RegiStax 4
* Neat Image
* Photo Shop Levels
* Gimp Levels

I got out under some pretty sweet skies and checked out Comet 17P/Holmes again. It is an amazing object. It has grown immense over the last few days. Reports indicate that it is now roughly 1/2 the visual diameter of the moon! This is colossal. I could even see that the comet no longer looks star-like to the naked eye. It has grown fat Pointing the scope at it, revealed a bunch of new details. First up were the background stars visible through the haze of the comet. These gave a nice sense of place to the comet. It is out there, cruising through our solar system. I didn’t get to pull the big scope out as I was hoping to snag some images quickly.

This shot was one of those images, a 30 second exposure at ISO 800 with the Canon Rebel XTi shooting through a 2x barlow connected to my F/7.5 Astro Physics Starfire 160 refractor. This puts me at about f/10 if I did my match correctly. Click on the image to view it full sized. At this size, you’ll note that the haze surrounding the comet has got some serious size to it.

Need more? Checkout Comet 17/P Holmes at higher power and Comet 17/P Holmes II with some background stars. More recently, see how the comet has grown in Comet 17P/Holmes II.I.

This shot is the second of a series taken on Thursday night (11/25/07). I took this shot of Comet Holmes without the barlow used in the first image. This (slightly) overexposed the inner portion of the comet, but nicely pulled in the surrounding stars to put the comet in perspective. Click on the image to see a higher resolution version.

For this shot, I used the Canon Digital Rebel XTi for a 15 second exposure at ISO200. I was shooting at prime focus through my Astro Physics Starfire 160 refractor. This is a pretty quick system… at f/7.5 over 1200mm focal length.

Need more? Checkout Comet 17/P Holmes at higher power and Comet 17/P Holmes II with some background stars. More recently, see how the comet has grown in Comet 17P/Holmes III.

I went out for a 2nd night of Comet Holmes… this was even better than the first Even the brightest full moon of the year couldn’t put a damper on the views. I pulled out the BIG scope just to get a feel for things. There is truly no substitute for aperture… 25″ worth of Obsession Dobsonian in this case. Anyway… I went back to the refractor to snag a couple of images. I exposed for a bit longer today… and revealed a greater extent in the comet and its surroundings. The first image made use of a 2x barlow thru which my Canon Rebel XTi shot at prime focus thru an Astro Physics Starfire 160. This revealed considerably more detail inside the comet. The second shot was without the barlow. This (slightly) overexposed the inner portion of the comet, but nicely pulled in the surrounding stars to put the comet in perspective.

Need more? Checkout Comet 17/P Holmes at higher power and Comet 17/P Holmes II.1 with some background stars. More recently, see how the comet has grown in Comet 17P/Holmes III.

I didn’t expect to get any deep sky imaging in because of the full phase of the moon. I figured I do some tweaking on my system (I actually did some). Then, I got an email alert of a new comet suddenly brightening to naked eye visibility. I figured, what the heck… I’ll go out and see if I could see it. Well… duh…. I certainly could… it was right there… as if a new star had been added to the venerable constellation Perseus. Reports were indicating that the comet had brightened from mag 17 yesterday (this is beyond the reach of backyard telescopes) to mag 2 (easily naked eye visible). This is a 500,000x increase in brightness… for the mathematically challenged Maybe there was more to it than I’d expected? Only a look through the telescope would tell for sure.

I’d rebalanced the telescope earlier in the day, so I figured I’d do a quick 3 star alignment. I did this quickly and pointed the scope towards what I assumed was Comet Holmes. At low power (40x) there wasn’t any doubt that I was looking at a non-stellar object. A round, ‘fuzzy’ star. I quickly cranked up the power and a bunch of detail in the comet’s core was instantly visible. The core was a bit oblong and somewhat off-centered. It was also surrounded by a bright, hazy coma. This was a really sweet surprise

Ok, so this is an astro photography site, right. Well, I did post an image of the comet… though I spent a fairly sizable portion of my time outside glued to the eyepiece. The accompanying image was a 2 second exposure at prime focus using a Canon Digital Rebel XTi at ISO 100. I was shooting through my Astro Physics Starfire 160 refractor.

Because of the nature of the comet, I had some trouble getting properly focused initially. I decided to slew the scope over to nearby Capella in the constellation Auriga. This object was bright enough that I could get a good focus. Next, I slewed over to Mirfak in Perseus. This was the nearest star to comet Holmes. From here, I slewed and centered by hand. I took a variety of exposures from 1/4 of a second up to about 20 seconds. The longer exposures were completely over exposed… showing none of the comet’s inner details. A series of stacked shorter exposures likely would have been the best approach. This would have given me the short quick detailed images… that combined would have given me the larger extent of a longer exposure. Regardless, this surprise comet was a welcome treat. I’m not sure how long it’ll be visible (its currently visible all night long… rare for comets), but previous outburst comets have stayed visible for many weeks. I’m hoping that Comet Holmes will spend a bit more time with us as well.

Need more? Checkout Comet 17/P Holmes at higher power and Comet 17/P Holmes II.1 with some background stars. More recently, see how the comet has grown in Comet 17P/Holmes III.

Astro Photo Details:

* Designation: Comet 17P/Holmes
* Constellation: Perseus
* Magnitude: 2.5
* Size: 15′ (roughly 1/2 the diameter of the full moon!)
NOTE: Now roughly 30′… same size as the full moon

Astro Photo Processing Details

* Canon Digital Rebel XTi
* Astro Physics Refractor
* 18 x 75s exposures at ISO1600
* Stacked using RegiStax 4
* Neat Image
* Photo Shop Levels
* Gimp Levels