A Great Horsepower to Torque Conversion Chart

I was just working on a project tonight – and ran across this great chart.    It’s an old-fashioned draw-a-line 2D calculator.

So it’s possible to have 100HP at with 10000lbs of Foot-Pounds torque at 60 RPM.  Then you break your engine.  Enjoy!

Thanks to the electric toolbox http://www.elec-toolbox.com/ for the graphic.

Horsepower to Torque Conversion Chart

Does anyone know what kind of butterfly this is?

Hi Everyone;

Just wondering if anyone knows what kind of butterfly this is? I’m really quite sure it’s not a monarch.

Location: Markham (Toronto), Ontario, Canada
Date : September 17, 2008 @ 3pm EDT

Click the image for better resolution.

What butterfly is this?

Update:

I sent an email last night to a butterfly professional.  Here’s the response:

It is a Compton Tortoiseshell butterfly. I photographed a few of these a week
or two ago.
They are very similar to Coma and Question Mark butterflies.
Gord

Thanks Gord!  Look at his great site about butterfly watching in Ontario site at : http://www.web-nat.com/Butterfly/

So Long, Jupiter

As Saturn had passed beyond our visible slice of the heavens earlier this summer, so too will Jupiter. It’s schedule to rise earlier and earlier, eventually escaping the night to ironically be in the horizontal domain of North America’s daylight.

They’ve been hanging around, low in the sky, every night as the summer marches towards shorter days and longer nights.

It’s been a treat to look through a real telescope and actually see the eternal storm as brilliant horizontal rings with my real eyes. It’s much smaller to focus in on through the telescope than Saturn was, but it’s still remarkable. Also, as you relax your eye, some planets begin to appear, Callisto, Ganymede, and Europa. All visible to my human eyeball.

Most of what we know about Jupiter comes from the Voyager Spacecraft.

Here are some photos I’ve taken in the South, early to late evening. Shooting conditions were less than optimal, and this is the first time I’ve used the digital zoom. The first few pictures are taken with optical zoom (using the lens), and the fuzzed out bottom ones are taken with the digital zoom.

Here’s an interesting image. After examining this picture for an image, I discovered that by using a high-contrast, I was able to extract an image from the noise captured.

A real image of Jupiter, taken from the noble traveler, Voyager 2.

And this is the best that I could do through a telescope with my canon.

Voyager 2 – Still Out There, Still Doing It’s Job

Probably the most awesome peice of hardware out there is still out there, and still doing it’s job. The Voyager 2 space probe is powered, and happily sailing along deeper and deeper into outer space.

To this day, NASA employs staff to send command instructions and to receive scientific and telemetry data that Voyager is still sending.

Voyager II was launched on August 20, 1977 to explore Jupiter, Saturn, Uranus, Neptune, and Pluto, then to continue in interstellar space. After having visited Pluto in 1989, every planet in the Solar system has been visited at least once.

Voyager Weekly reports of the activities are available from NASA. Items include details such as how much electricity and propellant are still available, and also telemetry information, like how far away from earth, how fast it’s travelling and how long a signal takes to reach it. Here’s an example from this week:

• Distance from the Sun (Km) 12,788,000,000
• Distance from the Earth (Km) 12,814,000,000
• Velocity Relative to Earth (Km/sec) 23.150
• Generator Output (Watts) 284.2
• Voyager 2 command operations consisted of the uplink of seven bracketed Command Loss Timer Resets sent on five-minute centers using 0.5 Hz steps on 03/26 [DOY 086/2007z]. The spacecraft received three of the seven commands sent.
• There were 53.6 hours of DSN scheduled support for Voyager 2 of which 1.2 hours were large aperture coverage. There were no real-time or schedule support changes made or significant outages during the period.
• Science instrument performance was nominal for all activities during this period. The EDR backlog is 2 day.

Isn’t it incredible how far away Voyager 2 is ? Even at the speed of light, round trip time for radio communications is almost 24 hours. Can you imagine sending a simple instruction to Voyager 2 and not expecting a response until tommorow at this time? Insane! Nowadays, the signal is travelling so far and is so distorted that only half of the commands are ever understand and responded to.

A fantastic document about Voyager 2 with a fun flip-page animation!

Print out all 178 pages (duplex if you can) and you will have an awesome document for reading! The flip-page animation is in the lower left corner and looks like this:

I found this document hunting around the NASA web page. It was written in 1985 about the January 1986 fly-by of Uranus. True history was made with Voyager, because very little was known about Neptune at the time. For example, the guide mentions “one of the five presently known moons of Uranus”, however, after Voyager flew by we now know of 27.

To summarise, simply from telemetry ( reducing Voyager to a simple talking projectile ), we are learning so much about our galaxy and the reach of our Sun. For more information check out this article on the Heliopause, the boundry that seperates our solar system from interstellar space. Thanks Voyager. I know you’ll be out there for a millennial’s worth of human generations.

This document makes a great nighttime reader. Print out a copy. Here’s the index so you know what to expect. Forgive the spaces, but OCR can only do so much.:

1. Introduction
Voyager’s Past
Anticipating Uranus

2 . Uranus
Overview of t h e Planet
The Atmosphere of Uranus
The Magnetosphere of Uranus
The Satellites of Uranus
The Rings of Uranus

3 . Getting The Job Done
Planning
Sequencing
Flight Operations
Commanding
Receiving Data
The Results

4 . Scientific Objectives
Imaging Science Subsystem (ISS)
Infrared Interferometer Spectrometer and Radiometer (IRIS)
Ultraviolet Spectrometer (UVS)
Photopolarimeter Subsystem (PPS)
Radio Science Subsystem (RSS)
Fields and Particles Experiments
Planetary Radio Astronomy (PRA)
Magnetometer (MAG)
Particle Detectors
Plasma Subsystem (PLS)
Low-Energy Charged Particle (LECP)
Cosmic Ray Subsystem (CRS)
Plasma Wave Subsystem (PWS)
Sensor Engineering Characteristics
The Physics of the Optical Target Instruments
Science Links

5 . Voyager Spacecraft
The High Gain Antenna
Spacecraft Attitude Control
Spacecraft Maneuvers
Scan Platform
Spacecraft Power Subsystem
Digital Tape Recorder
The Spacecraft Receiver
The Computer Command Subsystem
The Flight Data Subsystem
The Science Instruments

6. Mission Highlights
Pre-Encounter Test and Calibration Activities
Observatory Phase (OB)
Far Encounter Phase (FE)
Critical Late Activities
Near Encounter Phase (NE)
Post Encounter Phase (PE)
Contingency Sequences
Cruise to Neptune

7 . What’s New
Maintaining a Strong Signal
Discarding Unnecessary P i c t u r e Data
More Accuracy for Fewer B i t s
Taking Good Pictures in Feeble Light Levels
Big Changes in t h e Deep Space Network
The Bottom Line

8. Gee-whiz Facts
Overall Mission
Voyager Spacecraft
Navigation
Science
The Future

9 . How Far and How Fast
The Great Escape
Voyager 2 a t Uranus
Key Events. Distances. and Speeds

10 . Jupiter and Saturn Highlights
Jupiter
Jupiter’ s Rings
Jupiter ‘ s Moons
Jupiter ‘ s Magnetosphere
Saturn
Saturn ‘ s Rings
Saturn’ s Moons
Saturn’ s Magnetosphere

Lunar Eclipse Photos – Feb 20, 2008 – Newmarket, Ontario, Canada

Hi Everyone;

Here’s your first glance at a photo taken 10:17:04 PM EST from Newmarket, Ontario, Canada!

The sky was clear, the weather crisp, and my camera is cold to the touch, but what a wonderful experience to share with my wife.

Also, Saturn is in the lower left, but did anyone else pick up that blue distortion in the lower right? It’s in several of my photos…

Here’s the trick to taking a great photo of the moon with a digital camera:

1. “Tv” (Shutter Speed priority) of 1/60
2. ISO 100 (for better sensitivity to light)
3. Manual focus to infinity
4. A good and sturdy base to cradle at the desired angle
5. Only use optical zoom, not the digital zoom.
6. Use 2 or 10 second delay (to remove the vibration from the motion of pressing the shutter button).

Full Picture Here –> Lunar Eclipse – Feb 20, 2008 – Full Size

Drag CRISIS! The Coefficient of Drag is NOT a Constant!

There’s a mystery out there. Scientists are still working exactly what it is, but it’s real. It’s proven, in theory and in practice.

This article attempts to address an area of aerodynamics and fluid-dynamics which seems to have eluded much of the Internet. I’ve searched long and hard for relevant information. There’s just not a lot out there. Even the all wonderful WikiPedia is begging for someone to update it’s pathetic 100 word explanation.

Aerodynamic drag is a serious business, whether designing ships, cars, aircraft, submarines, or baseballs.

Consider a car at highway speeds…. the majority of power your engine is producing to keep you moving is to overcome two things.

1. Friction of the tires on the pavement. 4000lbs of weight on 4 tires plus gravity = slowing down real fast.
2. Resistance of your vehicle to movement through the air.

One of these two things above will never change, no matter how fast you go. The other does change according to how fast you are going. Air resistance increases with the square of the speed.

At some point, the drag you have to overcome will exceed the amount of power available to you, and you will be pushing a wall of air so thick and hard, that you will never succeed in accelerating beyond it, no matter how much horsepower you throw at it.The penultimate top speed of any design is dictated by the shape and size. The more streamlined, the less drag.

Coefficient of Drag

There is a number that defines how resistive an object is to a flow. It takes a variety of things into consideration, how slippery/shiny/smooth the surface is, how sharp it is (how well air can flow around it), and how big it is relative to the stream of molecules in the flow.

One can even say it’s a number that describes how aerodynamic something is. It’s a number that starts just above 0 and can end WAY WAY up there. We call this the Coefficient of Drag. This can be used in many calculations, and remains a virtual constant, no matter how fast or slow you are going, and no matter what “fluid” you’re in.

A Honda Civic’s Drag Coefficient is 0.36. It doesn’t matter if you’re going 1km/h or 100 km/h, in air, or underwater. The form of the front of that car will always have a drag coeffecient of 0.36

This is a number that we can use to predict the opposing force of motion through a fluid at any given speed.

Knowing the drag coefficient plus the surface area (the frontal area) of the vehicle, we can determine how much opposing force there is “pressing” against the car at different speeds.

Assuming average full-size passenger cars have a drag area of roughly 8.5 ft² (.79 m²), knowing the 0.36 Cd (Coefficient of Drag), and the density and viscosity of air (about 1.2kg/cubic metre), we can use the Drag Equation to find out, in a real world measurements, how much drag a Civic actually produces traveling at different speeds.

Drag Equation

Fd is the force of drag,

ρ is the density of the fluid (Air is about 1.293 kg/m3)

v is the velocity of the object relative to the fluid,

A is the reference area

C_d is the drag coefficient

In order to determine the density of the fluid (in this case air), we can estimate it based on temperature, pressure, and altitude.  In otherwords, the Barometric Formula. For our exercise today, we will assume a cool day down by the ocean, about 1.293kg/m3.

So let’s work it for a few different speeds; 50 km/h, 80 km/h, 100 km/h, 110 km/h, 115 km/h

(1/2)(1.293)(50km/h^2)(0.36)(.79)

=.5(1.293)(13.9m/sec^2)(0.36)(.79)

= .5(1.293)(193.21)(0.36)(.79)

=3.5524479366 kg

(1/2)(1.293)(80km/h^2)(0.36)(.79)
=.5(1.293)(22.2m/sec^2)(0.36)(.79)
= .5(1.293)(492.84)(0.36)(.79)
=9.0615829464 kg

(1/2)(1.293)(100km/h^2)(0.36)(.79)
=.5(1.293)(27.8m/sec^2)(0.36)(.79)
= .5(1.293)(772.84)(0.36)(.79)
= 14.2097917464 kg

(1/2)(1.293)(110km/h^2)(0.36)(.79)
=.5(1.293)(30.6m/sec^2)(0.36)(.79)
= .5(1.293)(936.36)(0.36)(.79)
= 17.2163456856 kg

(1/2)(1.293)(115km/h^2)(0.36)(.79)
=.5(1.293)(31.92m/sec^2)(0.36)(.79)
= .5(1.293)(1018.89)(0.36)(.79)
= 18.7337802294

As you can see, it took from approximately 0-100km/h for the first 10kg of drag force, then only100-120kph for the next 10kg of force! Before we are even beyond 200kph, we have already reached 60kg (130lbs!).

It doesn’t matter how big your engine is, you’ll never make past a certain point (OK, maybe that civic engine can be replaced with a HEMI, but even then, you’d probably only acheive an extra 10kph at best.

Reynolds Number

Here’s another beautiful number we can use. The Reynolds Number is the ratio of inertial forces to viscous forces. In other words, its a number to describe how big and fast something is, compared to the gooeyness and density of the liquid around it. This allows us to build an idea of “equivalency”, and to scale any dataset produced in a test environment (like a wind-tunnel).

Reynolds numbers tells us about “flow regimes”, and allows us to compare the similarity of flows. For example, we can state that dynamically similar aerodynamic realms involving fluid dynamics are only equal if the Reynolds Numbers are equal. NASA explains “It is possible for an experiment with a helium-filled balloon 100 cm in diameter rising in air to be dynamically similar to a 9.60 cm plastic ball falling in water if the Reynolds Numbers are the same.”

Typically, when we find what Reynolds Number we are looking at, we express it as either a number (50,000) or a factorial expression (5x 10^4).

Here’s some examples of Reynolds flow regimes:

Probably one of the most studied elements in fluid-dynamic studies is the sphere. A sphere is easy to scale, and it’s surface is uncomplicated and perfectly smooth. This makes it an ideal candidate to use in our Reynolds number demonstration.

Drag Crisis

The Reynolds number (R), for a baseball is calculated using R=vd/υ. Where the diameter (d) of the baseball is (7.32 cm), v is the velocity relative to air, and υ is the kinematic viscosity of air (about 0.000015 m2/s at 20 C) 6. So the greater the velocity becomes the greater the Reynolds number. A drag crisis occurs when the laminar flow of air in a boundary layer near the ball begins to separate and becomes turbulent. The effect that the turbulence in the boundary layer causes will actually reduce the size of the turbulent wake behind the ball, and reduce the drag force. The drag crisis produces a regime where the aerodynamic drag force actually decreases as the velocity increases.

Links

http://www.brianhetrick.com/casio/tbb1exapumdrg.html -Calculator Programming Tutorial – this was the ONLY broken out equation I saw on the whole internet.

http://www.aerospaceweb.org/question/aerodynamics/q0215.shtml – Golf ball dimples – excellent ideas for reducing drag.

http://www.uam.es/personal_pdi/ciencias/agrait/nico_archivos/docencia/fisica%20de%20fluidos/Life%20at%20Low%20Reynolds%20Number,%20EM%20Purcell%201973.htm – life at Low reynolds Numbers – Excellent read about how things like sperm and cellular life makes motion in the liquid concrete around them

http://en.wikipedia.org/wiki/Density_of_air - Density of Air

http://www.economicexpert.com/a/Drag:equation.htm - A reasonable quick and dirty explanation of the drag equation.

A beautiful shot of the Moon and Venus (the morning star)

Hi Everyone;

Here’s a wonderful photo of Venus and the moon, taken at 5:24:03 am EST on December 5, 2007 from Newmarket Ontario Canada.

They are bright, but fuzzy because of cold overcast clouds that are sure to deliver yet another blanket of snow.

Amateur Astronomy – Watching the sky for the ISS

 

The next couple of weeks are the perfect time to seek out the International Space Station.

The ISS just got a bit bigger over the past week, as they have deployed a massive solar panel, and the space shuttle is currently docked. The extra solar panel makes the ISS brighter. Not that we need the ISS to be brighter in the night, it’s extremely bright and you just can’t miss it.

There is also a remote chance you will be able to see the Space Shuttle chasing behind the ISS, after it un-docks on Monday morning and prepares to come home.

It doesn’t matter where you are on the planet, from time to time, the ISS will pass by. The visit is usually only 3 or 4 minutes until it’s gone from one side of the sky to the other. Usually, from Newmarket, Ontario, Canada, ideal conditions exist at least once per week, sometimes more.

Isn’t it wonderful to see something with the naked eye? You don’t need a telescope, all you need is a sense of direction and time.

What you’ll need to accurately find the ISS as it passes by:

1. A compass. Any old compass will do.
2. An inclinometer. What’s that? It’s quite simply a tool to tell you how high up you’re looking in the sky. Here’s a link on how to make a Home Made Inclinometer for $0.00.
3. An accurate watch. You will need the seconds to be as accurate as possible. Syncronise a wristwatch to just about any computer that’s on the web, or go to the National Research Council of Canada for the official time.
4. A “prediction” web site that will tell you when the ISS is going to pass over. I use Heaven’s Above. Although we call the task of calculating when the ISS will be visible a “prediction”, the truth is that it is accurate. Deadly accurate.

For the Greater Toronto Area, the predicted passes are every morning this week and next!

Some passes are better than others.

Not all predicted passes have a preferable magnitude (brightness). This can be for many factors:

• Day or Night pass
• Angle of the Sun
• Angle and phase of the Moon
• Most of all, because if the ISS does not pass directly overhead, it can be thousands of kilometers away, which means that it will cross the sky low to the horizon. Lower to the horizon means that you look through way more dirty atmosphere – and to be quite honest… it’s just not as exciting.

The best time to view the ISS, is when it passes at night and almost directly overhead. Unfortunately, the ISS will not be swinging around during the night, and all predictions for the week ahead have it passing just before sunrise. This is OK, and should make for an interesting start to most people’s commute.

Here’s a breakdown of the predictions of magnitude (brightness) for the week ahead:

Date, Magnitude, Start time.
5-Nov 0.4 5:52:32
6-Nov -1.8 6:14:35
7-Nov 0.2 5:04:32
8-Nov -1.9 5:27:17
9-Nov -2.1 5:49:47
10-Nov 0.8 4:40:42
10-Nov -1.1 6:12:05
11-Nov -0.1 5:02:52
11-Nov -0.5 6:34:38
12-Nov -0.6 5:24:55
13-Nov -0.5 5:46:53

Given that the lower number magnitude (and even better if it’s a negative number) are the best brightness for viewing, we will narrow down our choices to the better ones.

Date, Magnitude, Start Time, Altitude, Direction, Max Brightness Time, Altitude, Direction, End Time, Altitude, Direction

6-Nov -1.8 6:14:35 10 SW 6:17:23 59 SSE 6:20:16 10 ENE
7-Nov 0.2 5:04:32 17 SSE 5:05:22 19 SE 5:07:33 10 E
8-Nov -1.9 5:27:17 40 SSW 5:28:01 57 SE 5:30:51 10 ENE
9-Nov -2.1 5:49:47 31 W 5:50:49 51 NNW 5:53:39 10 NE
10-Nov 0.8 4:40:42 15 ENE 4:40:42 15 ENE 4:41:21 10 ENE
10-Nov -1.1 6:12:05 16 WNW 6:13:45 26 NNW 6:16:17 10 NE

I have included a little more data on the above chart. As you can see, there are 3 distinct phases of an ISS pass

• Beginninig – this phase is where we hunt. Grab your compass and inclinometer, and stake out a spot in the sky to begin scanning. As the time for the initial visibility comes closer, you may think you’re seeing an airplane, far away… it’s moving slow, REAL slow, but then, it starts to speed up. Then it *REALLY* starts to speed up. It’s moving to the your next milestone in the sky – the Maximum Height. It will be there only another 45 or 60 seconds, so don’t be thinking you can dart inside for a camera.
• Maximum Height – at this stage, it’s really rockin. It’s moving SO fast, you can’t believe it. It’s at this point that the ISS has reached it’s maximum brightness. If you’ve chosen a night where the maximum altitude is around 90 degrees, then your neck should be craned almost directly up.
• Fade away – the ISS will appear to slow down now, and get dimmer as it moves across the sky. It will slow down to almost the rate you saw it appear. Sometimes, the ISS doesn’t just disappear below the horizon, sometimes it disappears in the middle of the sky! The reason for this has to do with the earth’s shadow. Expect this kind of a dissappearing act about 50% of the time.

Time to Choose a night.

I choose:

9-Nov -2.1 5:49:47 31 W 5:50:49 51 NNW 5:53:39 10 NE

for the following reasons:

• Time in the morning is ok – I can get up early to watch it. (what a way to start a day!)
• It will start to appear at 31 degrees up. This means I can see it above my neighbors’ houses
• The whole shebang will last for almost 4 minutes
• The maximum height is 51 degrees up, very high.

Pass Details

Date:	Friday, 09 November, 2007
Satellite:	ISS
Observer’s Location:	Newmarket ( 44.0500°N, 79.4500°W)
Local Time:	Eastern Standard Time (GMT – 5:00)
Orbit:	340 x 344 km, 51.6° (Epoch 02 Nov)
Sun altitude at time of maximum pass altitude:	-13.5

Using the predictions web site, let’s click on the November 9th event and find out more specific details.

By selecting November 9th, we are able to get more accurate information about this pass. Importantly, we can have a better idea of direction, and an idea of the distance in kilometers between me and the ISS. (It’s suprisingly less kilometers than you might think!)

Event , Time, Altitude, Azimuth, Distance (km)
Leaves shadow 5:49:47 31° 274° (W ) 627
Maximum altitude 5:50:54 50° 340° (NNW) 442
Drops below 10° altitude 5:53:39 10° 51° (NE ) 1,297
Sets 5:55:41 0° 57° (ENE) 2,135

Wow! At 5:50 and 54 seconds, the ISS will only be 442 km. away from my eyeball! It’s going to look so close, you WILL want to reach out to it with your hand. I promise!

Some final advice.

BE PUNCTUAL! The ISS waits for no one. Most events, from start to finish, last only 4 minutes at the longest. Imagine the ISS crossing the entire sky in 4 minutes. When the predictions web site says 5:49:47AM, it really does mean 47 seconds!

Line up and identify the 3 positions ahead of time. This will allow you to visualise how the ISS will move across the sky, and will help you identify the best viewing location. (ie. Front yard, backyard)

Photography. Take some pictures of the sky (without flash) in advace. This will give you the opportunity to play with some settings. If you have a simple digital point-and-shoot camera, switch it into the “Shutter Speed Priority” mode, and start off with about a 5 second shutter speed. A tripod or sturdy angled base is very necessary for this amount of shutter time. You will end up with a streak, so it helps to visualise the path of the ISS ahead of time, and position your camera to the known point in the sky where it will cross.

Be excited and pass it on!

Just imagine how those first viewers felt looking at Sputnik for the first time. What a world we live in.

Here’s some pictures I recently took.

Home Made Inclinometer

I made a DIY inclinometer for astronomy. This sometimes is called an “altitude measurer” and can be used to spot how high a model rocket goes.

Mine’s a little Newtonian, and I love it.

I printed out a picture of a protractor, stuck it on a board with tape, and now I can “sight” along the top of the board. That’s right, I can read the angle i am looking at from a string dangling on the side.

That string has a weight on the end. I have a plumb-bob that I like. NICE and heavy.

The string can pendulate, so you can slow it down. When it’s stopped, clamp the string in place along the protractor notches.

And that’ll give’r yer angle.

Here’s the graphic of the protractor. You can scale it and print it out on an 8 1/2 by 11 sheet of paper. When you attach it to the board, hang it down a bit from the top. Drill out a hole in the wood and slip a string through.

Click on the image to enlarge.

 

See my recent article where I used it: http://realworldnumbers.wordpress.com/2007/10/26/hunting-for-comet-holmes-at-home/

Here’s a link for another inclinometer from Make Magazine, but it just doesn’t look as sexy or as rugged mine.

Hunting for Comet Holmes at Home

Hello Maryland, beautiful state of Constitutional importance, flora and fauna, sea technology and sky lovers… you’re flag is interesting and your clicks are feeding into me on October 26.

I was hunting for Comet Holmes in Ontario tonight. You know the one? Have you heard the news?

This thing apparently exploded a day ago and is reflecting a huge amount of light back to earth. Whereas before you needed a telescope to see it, now you can see it with the naked eye.

From http://cometography.com/pcomets/017p.html

The comet was observed at about magnitude 14.5 since July and had showed signs of a slow fading; however, very early on the morning of October 24, Juan Antonio Henr’quez Santana (Spain) reported that the comet was much brighter than expected.

I grabbed the telescope my buddy left here (THANKS!) to try and find the sucker. Thankfully, the molded rubber eye-peice is the exact size of my cameras lens sheath! It easily held the camera in place by itself while the camera took the picture for 3 seconds without disruption or vibration.

How to Find Holmes 17P

In toronto, wait until about 8pm. The following instructions will guide you on how to find the comet around 8:30pm Toronto time. First, you need to grab a compass, and preferably an inclinometer to tell what angle you are looking up at.

Next you need to locate the constellation Perseus. Pretty much the easiest way to do that is to locate Cassiopeia. This looks like a giant sideways “W”. Look down and a little to the right, and you’ll make out Perseus from there.

Find the brightest star in the Perseus constellation. This is called the “alpha” star, as it is the biggest and the brightest (has the lowest ‘magnitude’). The exact position of this “alpha” star is at direction 51° (Northeast) and altitude 34° (up).

Here’s the diagram from my great program called “Cartes Du Ciel“. It is literally the best program ever produced for amateur and professional astronomers, and kicks all other programs I have ever tried in the pants. It has night mode, can integrate with motorised telescopes and GPS, has extensive international libraries, supports tonnes of languages, and it’s free. GET IT.

Then, you look a little to the left of the alpha star to find the comet.

Information and Resources

You can find some other information about Holmes from:

The wikipedia page about holmes – http://en.wikipedia.org/wiki/17P/Holmes

This is a great page that tells all about the recent comet Holmes explosion and show in pictures how it’s changing. It also describes how the comet was originally found in November 6 1892 by E. Holmes from England.

Spaceweather.com has a great page with photos of Holmes from amateur astronomers. You should sign up for their email alerts! They’re great! If you live in toronto, remember, the Spaceweather.com maps are drawn for people who live at The Equator, so their representation of where the constellations are different than we see the sky here up north.

Heaven’s above has sky charts that are localized for your city. You don’t have to sign in to select your location, but I did so that Newmarket is my default. Unfortunately these guys haven’t re-classified the magnitude of Holmes, so you’ll have to find the constellation Persuis. Update : Heavensabove has just updated their page to now include Comet 17P Holmes.

Geocentric Data
Right Ascension (J2000) 3h 51.6m
Declination (J2000) 50° 15′
Constellation Perseus
Magnitude 2.9
Distance from Earth 1.631 AU

Orbital Data
Distance from Sun 2.446 AU
Perihelion 2.053 AU
(4-May-2007)
Aphelion 5.184 AU
Period 6.88 years
Eccentricity 0.432564
Inclination to ecliptic 19.1°

Snapshots

This is only the small version, the big version is AWESOME, but it’s 4MB. Please email me if you want a copy.