Wednesday, October 31, 2007

Comet 17/P Holmes

Tonight, I found a message by my mum on my mailbox - she was quite excited and told me that I should absolutely have a look at this new comet, I probably would have heard about it, and that it was such a great view, so well visible now, have a look at the constellation of Perseus...

Comet Holmes, not in my skylight,
but photographed at 0800 UT on
October 30, 2007 at Costa Mesa,
California - via Wikipedia.
Now, the net has been full of reports about comet Holmes these last days. However, I hadn't really taken note of it - but tonight, the sky above Frankfurt was clear, just a bit misty, bright stars and constellations are clearly visible, and Perseus was close to the zenith - so I looked out of the skylight, and there was comet Holmes: A grey blob to the naked eye, and a quite impressive grey blob in Sabine's grandfather's old binoculars! There is no tail yet, but the blob has some structure, and the comet is bigger than Halley at it's return in 1985/86.

You can find the comet roughly halfway between the bright star Capella in the northern sky and the W of Cassiopeia - have a look at the sky map from heavens above, for example. It's impressive!


  1. Here it's unfortunately pretty cloudy today. Good to hear those binoculars are still in good shape :-) Best, B.

  2. Thanks for this information. I hope to see it if the sky is clear tonight.

  3. There are some interesting links over at UniverseToday, especially the one to Mario Motta's photo. And here's my photo of the comet taken with a digicam, a couple of days ago.

  4. Is it galactic mutant microbes invading, an undiscovered element, space aliens uncloaking, the Photon Belt... that will now end all human civilization (or at least confiscate everybody's lower intestine)? I'm kinda thinking it's a comet.

    What is Not A Space Agency doing about observation across the spectrum, if anything?

  5. It's a Jupiter-Family-Comet, meaning that, while of course it orbits the Sun, its orbital dynamics are driven by Jupiter's strong gravity; C. Holmes' period is something like 6.5 years. The weird thing about this comet is that this brightening occurred way past perihelion (which occurred I think in May of this year), while the comet is moving away from the Sun and it's now somewhere between the orbits of Mars and Jupiter.

    In any case, the first night of brightening was I think Oct. 25th, at which day it looked to me just like a star of ~3rd magnitude to the naked eye distorting the usual shape of the constellation Perseus. With binoculars you could see that there was some fuzzyness to it, and with a good telescope it was definitely non-stellar: nice star-like nucleus, surrounded by a spherical coma, no trace of a tail then. Observed it for a few more days, but the past couple of days have been cloudy here in NorCal...Maybe tonight.


  6. Hi navneeth,

    thanks for sharing the photo! How did you take it? Did you somehow fix the digicam to a small telescope? That's not just the zoom of the camera? And what was the exposure time? You know, one of the reasons why I am sometimes thinking about a new digital camera is that it seems that they are pretty good now for taking astronomy pictures...

    Best, Stefan

  7. Hi changcho,

    thank you very much for all these details!

    I didn't know that the comet is already moving away from the Sun, hm, what a pity, that means that it probably will not become any brighter and larger with a prominent tail and all this? Wikipedia states that the tail is pointing away from us, so that's the reason it appears as a more or less spherical blob - but OK, if it's already beyond the Mars orbit, that sounds reasonable.

    Tonight it's cloudy, so I can't see it anyway...

    Best, Stefan

  8. That's a cool shot, to see a comet when the tail is pointing straight nice and round.
    BTW has anyone gotten a handle on why and how some comets emits so much X-ray, considering their relatively low temperatures?

  9. Your post fired me up..I haven't been active in astrophotography in 2 years (comets are my specialty, the German Comet Group knows of my activity).

    I was leaving for a wacky offroad race, & decided to lug my astrophoto gear. I'm blogging LIVE using my mobile satellite-DSL dish (on top of my 4x4 van). I just finished an astrophoto session) in Afton Canyon (just off 15 fwy between Los Angeles & Las Vegas). Comet is certainly interesting:

    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).

  10. Stefan,
    Yes, it's just the camera's zoom. 12x at that!(36mm-432mm) I used a Canon Powershot S3 IS. I haven't yet tried the 4x of digital zoom, but I'm sure the final photo will not look good.The exposure is limited to only 15s, so that's how long I could keep the shutter open.(at F4.0)

    And yes, digital cameras are simply everywhere in amateur astrophotography, and especially the DSLRs (modded and unmodded). In fact, I first wanted to get a digital camera a few years ago mainly to take pictures of the sky, but I now do more like "normal" photography. :D

  11. Hi Navneeth,

    great, thank you for that info!

    The result is really impressive! I would not have expected such great photos without any further tools.. OK, the Canon Powershot S3 IS, oops, I see, it's not quite for free ;-)...

    Best, Stefan

  12. Here are some images from 11/5 from Hungry Valley/CA (east of Santa Barbara, where B used to work). 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.

  13. I went out 2 days later (Wed, 11/7) & got some more photos. Tail looks different. I also got in a closeup shot of the nucleus w/jet. I also found a new observation area, there are some nice panoramic views of the comet w/Milky Way. I observed 3 neg magnitude meteors..very memorable. 1 had a red nucleus, that left a persistent-trail.

    It was really beautiful in the mountains, I did some 4x4'ing afterwards. Bad weather until about Monday.

  14. Hi Bob,

    thank you for sharing your photos of the comet - they look great! Unfortunately, the sky above Frankfurt has been cloudy since last week, so I have had no chance to spot comet Holmes again since last wednesday...

    Best, Stefan

  15. I'm blogging from Jamau/Baja Mexico over my mobile satellite-DSL on my 4x4 van

    [ I'm here for the 40th anniversary of the Baja 1000 Many international racers are here like rally star Armin Schwarz from Germany. ]

    I've been photographing Comet Holmes for 2 nights (11/12 & 11/13), & the wildly dynamic ion tail seems to have disappeared.
    My 8" f1.5 Schmidt-Camera might have picked up something, but I have to develop the film once I get back home.

  16. I'm blogging from Anza Borrego (Arroya Salado, in a sand wash) east of San Diego, using my mobile satellite-DSL. I drove back from Baja (Jamau), & stopped here on the way back to Los Angeles.

    The comet has lost it's wildly dynamic ion tail, but its coma has increased noticeably from last week. In 10x50 binoculars, you can see this big fuzzball & discern the nucleus (!). More photos here


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