Estimating the Length of Star Trails in Astrophotographs

The earth rotates, sweeping the star field across the sky. If we take a long exposure of the stars, with the camera stationary, the stars will appear as star trails in the image. We can estimate the length of the trail on our image. This is a useful number if we want to accentuate the trails or adjust the exposure time to minimize the star trails.

New Spin on an Old Poem for Amateur Astronomers

"Twas the night before Christmas and all through the house… "  is the way the classic poem by Major Henry Livingston Jr. 1748 – 1828,  begins. Over the years, 849 variations have been created each with different spins and Matthew Monroe has complied everyone of them.

Some are about Chanukah, like:
Twas the month after Chanukah, and all through the house
Nothing would fit me, not even a blouse.
The cookies I’d nibble, the latkas I’d taste
At Chanukah parties had gone to my waist.

Some are about computers, like:
‘Twas the night before Christmas, when all through the house
Not a peripheral was stirring, not even a mouse;
The modem was hung by the keyboard with care
In hopes that a download soon would be there.

But my favorite of all is about amateur astronomers. This version is credited to Jane Houston Jones of San Rafael, CA, which she wrote on Dec 21, 2002. She calls it

"The Week Around Solstice"
by Jane Houston Jones

Summer Science Camp for Big Kids

If you missed out on summer camp as a kid, as I did, it’s not too late. But this time, you don’t have to rough it.

For the last few years, I’ve attended various star parties during the summer. These are gatherings of enthusiastic amateur astronomers (not all of whom are Geeks) who get together for a few nights during a new moon with telescopes, campers and tents, to look at the stars and share the sky. They typically span 3-5 days.

Daytime is pretty casual with some events for kids, but mostly time to sit back, read, sleep and chat with folks. Most star parties also schedule a professional astronomer or scientist to speak after dinner. Night time is the time to bring out your scope and observe.

 

Essential Telescope Principles: The Real Meaning of Focal Length

This is part 1.

The properties of telescopes are often presented in a confusing way. In fact, it is simple if you keep in mind what a telescope is really doing.

Essential Principles of Telescopes: Field of View (FOV)

This is part 2. To read part 1, click here.

The focal length of a mirror system is a direct measure of the translation of the angular size of an object to its spatial size on the image plane.

 

Fixing a Reset Problem with my Celestron SCT C6 Telescope Hand Controller

I’ve had a recurring problem with my Celestron SCT C6 telescope since I received it in Feb, 2008. Every now and then, especially when I am slewing the scope, and more often in cold weather, the scope stops working and the hand controller resets to the power up state.

This means I have to re-align the scope to its initial position and re-initialize the hand controller. This problem even happened while just tracking in RA (right ascension). There have been times when this happened so often I could not get any observing in.

I found two root causes to this problem. It’s a combination of a poor fitting power plug into the telescope and an undersized power supply.

When the motion of the telescope jostled the cold and stiff power cable, it would cause an intermittent to the power feed and the hand controller would reset. After this loose plug problem was fixed, I found that under some slew conditions, the hand controller would still reset.

By using a power brick that could supply more current, this problem was completely eliminated.

Here is the complete story…

The Difference Between Astronomy, Astrophysics and Cosmology

Astronomy is the study of what you see in the sky and the dynamics of objects in space. I think of it as about what you can see when you observe the sky with your eyes or through a telescope. What I love about astronomy is that it is accessible to everyone. You walk outside on a clear night and you can participate in astronomy

This is the age of the great space observatories and all their incredible pictures are available to all on the web, like the Hubble Gallery.

Single-handed Camper Hitch Hook-up

When you are all alone in the middle of the wilderness, how do you hook-up a camper to your car’s hitching ball?

If the camper is not secured, you will be stranded in the middle of nowhere. I found a simple method, using a web cam dangling from the back of the car and viewing its image of the hitching post on my laptop resting on the front seat.

I used to camp in my tent when I visited the dark sky site of the Astronomical Society of Kansas City, in Butler , MO. While this was cheap, it was always a bit of a hassle, both in the set up and the tear down.

Observing from my Back Yard

We had a patch of clear skies before the moon rose which afford a chance to set up my telescope in the backyard and get some pictures. I have a Celestron C6, six inch Schmidt Cassigran with a Canon xsi DSLR camera.

Alignment is the tricky part, but two new techniques dramatically simplify the process. I bought a telrad and attached it to the telescope body. This is a lifesaver. Second, Celestron updated the firm ware of their goto hand controller to implemented a new processes they call Any Star Alignment.

After initial polar alignment, and 2 star alignment, I point to a bright star and click polar align. then I move the telescope mount until the bright start is perfectly aligned. This is better than a polar align, as Polaris is about 0.5 degrees off the true polar axis.

Here’s a shot of my set up on March 14, 2009. Newton is laying beside the system, keeping the critters away.