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A sketch of 17P/Holmes October 31, 2007

Posted by dorigo in astronomy, personal, science.

I observed comet 17P/Holmes this evening from my terrace in Venice. Tonight the sky was clear, and despite the rising moon and the street lamps below, there were quite a few stars. I estimated a limiting magnitude of about 5. This is of course quite a turn-off for a die-hard visual observer, but the comet above my head made me forget about my usual pickiness.

I looked at the comet with 25×100 binoculars. The magnification is quite the right one for this object, it seems: one can see the comet, which spans almost 25′ across, in a rich background of milky way stars. I took note of the position and appearance of the comet, and upon coming back inside I drew the following sketch on a sheet of paper:

I apologize for the poor quality of the sketch and the paper… However, the picture shows more or less what I saw. Note the small Mv=9.5 star just to the right of the coma.

In two days I am planning to have a chance of looking at the comet from extra dark skies with the 16″ scope… I cannot wait!



1. Stefan Scherer - November 1, 2007

Hi Tommaso,

tonight I’ve seen comet Holmes for the first time, from within town in Frankfurt – the sky is just a bit misty, but the comet is clearly visible. Right now, it’s close to the zenith, and in fact I can see it through the skylight above the bed – it’s great 🙂

Best, Stefan

2. Tommaso - November 1, 2007

Yeah, one of the nice things about this object is that it is ideally placed for northern observers. For Italy and Germany it is circumpolar, it never sets… And it culminates indeed near the zenith.


3. changcho - November 1, 2007

Nice sketch! I have been trying to observe comet Holmes for the past several days, but it’s been cloudy here in NorCal. I have observed the comet, but have not made a sketch of it; with luck I will try tonight.

4. chimpanzee - November 2, 2007

I’m blogging LIVE from Afton Canyon (just off 15 fwy, between Los Angeles & Las Vegas..I’m on my way to a wacky offroad race). I just finished an astrophoto session for Comet Holmes:


The closeup photo (using 5″ f8 refractor..1016mm focal length) shows some interesting near nucleus activity. You can see a “negative” bow-shock.

I forgot the counterweights for my German equatorial mount!! In true amateur-astronomy fashion, I jury rigged a quick fix..2 8 amp-gel cells duct taped to the shaft. I also brought my 8″ f1.5 Schmidt-Camera (using hypered TP2415 film), with the hope of photographing the faint ion tail. I forgot my ice-box..containing the film & film holder!!??

I should have further opportunities to photograph the comet thru Sunday. This offroad race is out in the desert (California & Nevada state-line).

5. dorigo - November 4, 2007

Hi Chimpanzee, nice pictures on your site! And thank you for the account of your efforts… I did not image the comet (other than large-field things such as the one you can see in my slideshow a few posts up), but I had a wonderful observing session at a star party last Friday. The comet is huge! And a very nice object to look at from a dark site with big dobs.


6. dorigo - November 4, 2007

…And I had not heard of TP2415 for a LONG time now 🙂 Are they still around ?


7. chimpanzee - November 5, 2007


Since I imaged the comet (Nov. 1), the comet has developed a significant ion-tail. (see 1 & 2). I tried going out on Fri & Sat, but wasn’t able to because of sleep deprivation (due to commitments to the offroad race). I tried going out on Sun evening, but there were clouds. I will try Mon evening & the next couple of weeks.

About TP2415..I still have some unhypered rolls in my freezer. I have 1 roll hypered from 2004 (done for me by Martin Germano, a famous amateur astrophotographer..you probably recognize the name if you subscribe to Sky & Telescope). It was a remnant of my last comet shoot back in Dec 2004 (Comet Macholz), see my blog link..it’s the title image. 99% of amateur astrophotographers have switched over to digital SLR or CCD cameras. Because of this weird multimedia project I got involved with, I am behind in this “tranasition”.

BTW, I have had queries from Coelum (Italian amateur astronomy magazine) for some of my comet photos in the past. Like you, I have an interest in meteor astronomy (photography that is). I met some Italian amateur astronomers at the Sallum/Egypt ’06 eclipse.

8. dorigo - November 5, 2007

I see, very nice images! I think the tail is hard to see from suburban skies 😦 I will have to wait for a better occasion.

I read coelum now and then, and contribute to their forum… It is there that the big controversy about color in nebulae has taken place recently. See http://www.trekportal.it/coelestis/showthread.php?t=14344


9. chimpanzee - November 8, 2007

Here are some images from 11/5 from Hungry Valley/CA (near Mt. Pinos, a famous amateur astrophotography site). I’m just beginning to get the “hang of things” after 3 yrs of inactivity in amateur astrophotography. The revolution in digital SLR is impacting this field, & these are some of my 1st DSLR astrophotos.

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