Comet Holmes Update

[Speed]

It's still there, and it's still visible!

It is now 0.7 degrees across. For reference, the full moon is 0.5 degrees across.

For the full story (which includes a finder chart) go to this link:

http://www.skyandtelescope.com/obser.../11886291.html

The story also includes a photo which: "This may also be the first published astronomical shot taken with Nikon's new D300 DSLR camera." How cool is that?

And here's my original post, complete with photo's and camera settings:

Comet Holmes

[SmartWombat]

Hoping for a clear night, clouds galore here in the UK

[Tel]

Is it still gonna be out tonight?

I didn't know anything about this. D:

[Speed]

Hoping for a clear night, clouds galore here in the UK

I hear you! It was sunny yesterday morning, and clouded up as the went on. This morning we woke up and it was drizzling. The next three days are suppose to be clear though, so I'm hoping to get out and get some more photo's.

[Speed]

Is it still gonna be out tonight?

I didn't know anything about this. D:

Yes. It is going to be out through at least March. How bright it will be remains to be seen, but right now it is still nice and bright, and easy to find.

[cyberlord]

I finally got a shot of it. Click the image for the full sized image.

[Speed]

Cool!!!!!!!!!!!!!!!

[SmartWombat]

It'd be a lot easier to find if those green lines were in the sky
Still raining, still cloudy

[cyberlord]

A couple more from tonight. The lens was in focus better this time. I couldn't see it with the naked eye tonight, to many Christmas lights up in the neighborhood.

Both images 70mm 30" f2.8 ISO 100. Second image is a 100% crop of the first.

[SmartWombat]

I'm not sure about this, 30 seconds seems too short for decent star trails.
And yet too long for a decent comet exposure.

I wonder how many stacked images it would take of relatively short exposure to bring out the comet?
Time to research some astrophotography software ...

[cyberlord]

I don't think 30 seconds is too long for the comet exposure, I think it could be longer. It's just that 30 seconds is my max shutter speed without bulb exposure. The comet is very dim barely visible to the naked eye as a faint glow if you have dark enough skies. The stars are 100s of times brighter as you can tell they are way over exposed in the image.

I don't think with the difference in brightness between the stars and the comet you could get a decent star trail image with the comet visible. At f5.6 on my 300mm I can't get the comet to register on the sensor. I think it's moving to fast across the FoV to register. I'd love to get a 300mm view of Holmes and have been trying. Need some faster supertele glass.

And remember, the comet is moving just like the stars, so a long bulb exposure for star trails will also distort the comet.

[SmartWombat]

And remember, the comet is moving just like the stars, so a long bulb exposure for star trails will also distort the comet.

From your image, I'd say it isn't moving just like the stars.
The comet although fuzzy doesn't seem elongated in the direction of star movement.

this looks good: http://www.astronomie.be/registax/Re..._Revision1.pdf
as does this: http://www.fvastro.org/articles/digital.pdf

these are great! http://www.astropix.com/HTML/SHOW_DIG/SHOW_DIG.HTM
this is holmes: http://www.astropix.com/HTML/SHOW_DIG/063.HTM
Note the 20Da camera ?
Basically a 20D with the IR filter removed, sold by Canon specifically for astrophotography.

[cyberlord]

Trust me, the comet is moving just like the stars, or I should say appears to move. It's the earth that is moving in reality. The comet is about 150Mill miles from earth, out past Mars, so it will appear to be rotating along with the stars. It is orbiting around the Sun in about a 6.8 year orbit so it will slowly move through Perseus and leave that constellation by March 08. Not sure if it will be visible during that time, it is fading every night.

[SmartWombat]

Then the fuzz ball appearance is hiding the movement.
It looks as if the stars have more movement.

[Speed]

The focus was much sharper on this one. Kudo's!

[Speed]

I've done enough astrophotography to know it depends on your lens focal length. At 300mm with my N80 (back in my all film days), eight seconds gave pronounced star trails. At 50mm, 30 seconds gives slight star trails.

Vary your exposure - ISO and apeture - to get the amount of exposure you want/need.

[Speed]

It is actually moving faster than the stars!

When it made it's appearance, it was below Mirfak. Now, less than two months later, it is above it.

The fuzziness of the coma does indeed "hide" it's movement. The coma is a giant dust cloud, which is by definition, fuzzy.

;-)