Starship Asterisk*

The Ladd Observatory is planning to install a sky camera in the next month or two. Due to the light pollution in Providence we will just be using a simple commercial SBIG sky camera. Images will be available on our website in real-time. The camera will be used for public outreach and classroom projects in the local schools. The camera should be arriving in the next week or two, and we'll be testing into early april. We're looking into adapting the software used by night sky live to process our images for uploading to the website.

-mikeu

Ladd Observatory
Brown University

http://physics.brown.edu/ladd

The manufacturer (SBIG) has informed us that they are having trouble building the camera that we ordered. The lens they have been using for these cameras is no longer in production. We're evaluating our options and considering a different camera. In any case this will delay our installation. I'm now looking into the camera used at MMTO. If anyone knows of other inexpensive cameras I would appreciate some pointers.

-mikeu

Our sky camera project is now back on track. The camera just arrived and we'll begin testing this week.

Here is a test image from the new sky camera. The bright streak at left is a satellite flare from Iridium 39 which has a magnitude of about -5. It is a 10 sec. exposure taken at 1:08:08 UTC on Apr. 17, 2008. The bright moon is behind the chimney. North is at top, west is at right. -mikeu

Congratulations on the "first light". Could you post more details as what is this camera and how deep does it go?
Best,
Noah Brosch

nbrosch wrote:Congratulations on the "first light". Could you post more details as what is this camera and how deep does it go?
Best,
Noah Brosch

Thanks.

Ladd Observatory is located in an urban environment, so we decided to use a very inexpensive off-the-shelf camera. The system is made by Santa Barbara Instrument Group (SBIG) and the specs are at http://www.sbig.com/products/allsky.htm

The field of view is 140 x 90 degrees. It uses a red filter to reduce light pollution (sharp cutoff below 630nm and the camera is sensitive out to almost 1 micron.)

I'll upload some more images this week. More recent test images (when the moon was below the horizon) show stars down to 6 mag. We captured a few satellites below 3 mag. We are near a major airport so there are a lot of airplanes in the images...

Right now we are upgrading our internet connection and I hope to have the camera permanently installed in the next couple weeks. In late May I will start working with a student on the software to process the images.

-mikeu

I am not familiar with this SBIG product, however the red filter is a good addition that would minimize moonlight and street light contamination. You would have to be careful with water on the window, either from dew condensation or from rain. I suggest mounting the enclosure with a slight inclination to let rain drops slide off the window before drying on it, and perhaps adding a heater from the inside of the box at the top part, to prevent dewing.

Another very useful addition, if you could fit it, would be a simple rotating chopper between the filter/window and the fishyee lens. This can be a thin rectangular piece of sheet metal mounted on a spindle witha small motor, so that it interrupts the light coming to the CCD. For a slight reduction of the throughput you would get interrupted meteor tracks and with a little work in the Physics B lab (stroboscope) you can measure the angular velocity of the meteors.

Cheers,
Noah Brosch

nbrosch wrote:I suggest mounting the enclosure with a slight inclination to let rain drops slide off the window before drying on it, and perhaps adding a heater from the inside of the box at the top part, to prevent dewing.

There is an electric heater on the window. We're currently looking at the best way to mount the box.

nbrosch wrote:Another very useful addition, if you could fit it, would be a simple rotating chopper between the filter/window and the fishyee lens.

The space inside is very tight. The lens needs to be very close to the window and it looks like it would be difficult to mount anything in between.

-mikeu

If you cannot fit a rotating chopper, I suggest you consider a vibrating chopper. If in resonance this requires only low power and the the only thing you move is a thin pellicle

Here's another test image. The bright moon is out of the field of view to the lower left. This is a 60 sec. exposure taken at 2008-04-18 01:21:16 UTC

http://upload.wikimedia.org/wikiversity ... 080418.JPG

-mikeu

mikeu wrote:Here's another test image. The bright moon is out of the field of view to the lower left. This is a 60 sec. exposure taken at 2008-04-18 01:21:16 UTC

http://physics.brown.edu/physics/common ... 080418.JPG

-mikeu

Is that the Big Dipper in the middle of the image?

Nice. I see you also caught a plane at the top right part of the pix, just coming out from behind to dome and above the trees.
Noah Brosch

Yes, the Big Dipper is near the center. Polaris is up at the center, and the bright star at low-left is Arcturus.

This is a composite of 40 x 10 second exposures taken between 1:14 - 1:22 UTC on 2008-04-22.

http://upload.wikimedia.org/wikiversity ... 080422.JPG

The big dipper is just to the upper right of center. Polaris is at the right edge. Saturn is the brightest one just to the left of center. Mars is at bottom (with the twins of Gemini just above it.)

-mikeu

After a great deal of delay, we now have the sky camera mounted on the roof. The images are not yet available live on the web. I tried to use the Night Sky Live software, however the tarball appears to be corrupted. I'm looking for an alternative method to process the images. -mikeu

[quote="mikeu"]After a great deal of delay, we now have the sky camera mounted on the roof. The images are not yet available live on the web. I tried to use the Night Sky Live software, however the tarball appears to be corrupted. I'm looking for an alternative method to process the images. -mikeu[/quote]
Yours is an SBIG product and you probably received MaxIM DL with the camera. This s/w should allow you to do som eimage processing and, with a bit of fiddling around, cobble a routine that will keep the camera taking images, subtracting darks, and storing the results on your disk.