| Observing Location | PSC & MetOval |
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| Observational Period | 2145-2300 EDT |
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| Atmospheric Conditions |
It was chilly but there was no wind or perceptible humidity so it wasn’t bad.
It didn’t look great during the day. When I was out around 2000 EDT it looked like the clouds were breaking up. It looks like extratropical cyclone Noel sucked all the clouds out as it moved north. Every time I heard a forecast today they changed the amound of cloud cover up or down but it ended up mostly clear and we got at least that.
I want to say that transparency was excellent but can’t bring myself to do it. I think Orion should have been high enough for me to have seen it over the apartment buildings and trees, and I have previously seen it from where I was observing, but I couldn’t find it. Views other places were great. I didn’t count the Pleiades but they were easily visible and the Hyades looked very crisp in the binocular. There was no wavering of the image in either optic.
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| Instruments | Golden Gate 8x21 binocular - Charlie
SAR: Coulter CT-100 Newtonian reflector - Charlie
- Celestron Omni 20mm (21x)
- Celestron Omni 2x Barlow
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| Observing Party | Charlie Ridgway
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I looked out the kitchen window at 2145 to see if there were any stars out and saw one very bright one then noticed that it appeared to be moving. I didn’t notice navigation lights so think it was a satellite, my guess was the ISS. I checked Heavens Above and CalSky and there was no ISS pass tonight and there weren’t any satellites brighter than Mag 4 after 2000 EDT. I am not sure what I saw. My kitchen window faces basically west.
| Target | 17P/Holmes |
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| Constellation | Per |
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| Category | Comet |
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Time
yyyymmdd.hhmm | 20071103.2155 EDT |
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| Comments | Since it looked like it had cleared off I went up to PSC to estimate the comet’s brightness. I had the Golden Gate binoculars with me and looked around a bit but my focus was on the comet.
It seems like I am getting better at judging the relative brightness of stars. It isn’t taking me as long to make my assessments, I am not getting as many erroneous assessments, and the two stars that I judged to be of equal brightness to 17P/Holmes were within ±0.04 of a magnitude of my assessment of the comet.
| Object | Mag. | Description |
|---|
| &alpha Per | 1.79 | brighter |
| α Ari | 2.01 | brighter |
| &beta Per | 2.09 | brighter |
| β Ari | 2.64 | brighter |
| ζ Per | 2.84 | brighter |
| ε Per | 2.90 | brighter |
| γ Per | 2.91 | brighter |
| β Tri | 3.00 | brighter |
| α Tri | 3.00 | brighter |
| δ Per | 3.01 | brighter |
| ε Aur | 3.03 | brighter |
| η Aur | 3.18 | brighter |
| ρ Per | 3.32 | brighter |
| α Tri | 3.42 | brighter |
| ζ Aur | 3.39 | brighter |
| δ Aur | 3.72 | dimmer |
| 17P/Holmes | ~3.75 | |
| η Per | 3.77 | brighter |
| ν Per | 3.77 | equal |
| κ Per | 3.79 | equal |
| ω Per | 3.84 | dimmer |
| γ Ari | 3.88 | dimmer |
| τ Per | 3.93 | dimmer |
| γ Tri | 4.03 | dimmer |
| ι Per | 4.05 | dimmer |
It was so clear out that I went home and got SAR and went up to MetOval to make an assessment of the comet’s size. At low power I estimated 9 comets would fit across the 2.3° FoV for a size of .26°. At high power I estimated 3.5 comets would fit in the ~1° FoV for a size of .29°. I am estimating the comet’s size to be .28° or 16.8’ or 16’48”. That is 56% as large as the Moon is tonight.
| Date | Diam. |
|---|
| 30Oct07 | 9’30” |
| 1Nov07 | 12’17” |
| 3Nov07 | 16’48”
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From the distance to Earth figures in Planetarium it appears that 17P/Holmes is near perigee. It is 0.01 AU closer now that it was when it first erupted. It will stay at this distance for about 12 days then go back out by 0.01 AU and stay there for a while until it will probably no longer be a naked eye object.
| Date | Distance |
|---|
to Earth
AU | to Sun
AU |
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| 25Oct07 | 1.63 | 2.44 |
| 26Oct07 | 1.63 | 2.45 |
| 27Oct07 | 1.63 | 2.45 |
| 28Oct07 | 1.63 | 2.46 |
| 29Oct07 | 1.63 | 2.46 |
| 30Oct07 | 1.62 | 2.46 |
| 31Oct07 | 1.62 | 2.47 |
| 01Nov07 | 1.62 | 2.47 |
| 02Nov07 | 1.62 | 2.47 |
| 03Nov07 | 1.62 | 2.48 |
| 04Nov07 | 1.62 | 2.48 |
| 05Nov07 | 1.62 | 2.49 |
| 06Nov07 | 1.62 | 2.49 |
| 07Nov07 | 1.62 | 2.49 |
| 08Nov07 | 1.62 | 2.50 |
| 09Nov07 | 1.62 | 2.51 |
| 10Nov07 | 1.62 | 2.51 |
| 11Nov07 | 1.62 | 2.51 |
| 12Nov07 | 1.63 | 2.51 |
| 13Nov07 | 1.63 | 2.52 |
| 14Nov07 | 1.63 | 2.52 |
| 15Nov07 | 1.62 | 2.53 |
I am surprised that my size estimates are as close as they are at the two magnifications as each has its own challenges. At low power I have to move the scope more and there is more room for error positioning the left edge of the comet where the right edge had been before. At high power there is less scope movement, but the comet is fainter so it is harder to estimate where the edge of the cloud is.
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| Target | M31, Andromeda Galaxy, NGC 224 |
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| Constellation | And |
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| Category | DSO: Gal |
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Time
yyyymmdd.hhmm | 20071103.2250 EDT |
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| Comments | The galaxy does not look very impressive after seeing 19P/Holmes. It is neither as big nor as bright as the comet.
I had trouble finding it. It was up in the Dob hole.
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Rather than trying to sight across the tube of the scope to locate the comet I have been looking its elevation up in Planetarium and using a contractor’s protractor to point the scope at that angle. All I have to do then is pan up a little and sweep from side to side and the comet is right there. It is almost like having setting circles, which is why I bought the protractor in the first place
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