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