Click on the image to see a GIF video of pulsating RR Lyrae stars (there are MANY in the video - I have arrows to show some of them so you know what to look for in the video...)
Object: |
M3 Globular Cluster |
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Date(s): |
17-19 March 2016 |
Location: |
AZcendant observatory, Rancho Hidalgo, NM |
Telescope: |
Takahashi TOA-130 at f/7.68 |
Mount: |
Celestron CGE |
Camera: |
SBIG ST-4000CM |
Single-Shot Color: |
Yes |
Exposure: |
23 20 minute shots used to create a GIF video |
Comments: |
The GIF video is comprised of 23 images labeled with an "A" or a "B". Each image is labeled in the upper right corner. Each image was a 20 minute shot. Both the "A" series and the "B" series cover a span of about 4 hours. The "A" images were shot on the night of 17 March. The "B" images were shot on the night of 18 March. The upper arrow points to a star that gets brighter during each series' 4 hour span. Notice that the other nearby stars maintain about the same brightness although you can see some minor brightness variations in the "constant" stars because M3 was low in the sky (dimmer because of looking through lots of atmosphere) then brighter as it rose in the sky. So you are looking for stars that either get brighter or dimmer compared to the relatively "constant" stars in the video. The star pointed to by the upper arrow seems to reach maximum brightness at approximately 0209 on 18 March and again on 0042 on 19 March. Assuming no intervening peak brightnesses during the times M3 could not be imaged, then the period of that star would be approximately 22 hours and 30 minutes The lower arrow points in the direction of two stars one of which is getting dimmer and one of which is getting brighter during the "B" series images. This is from: http://www.daviddarling.info/encyclopedia/R/RR_Lyrae_star.html
I was only vaguely aware of RR Lyrae stars until Tom Polakis published a short video on Facebook showing some of them blinking in a video he created from a few frames covering a 4 hour period on 6 Feb. This was a LOT more work than I thought it would be. :-) Putting the arrows into each frame caused me about 3 hours PhotoShop research. Also since these were made up of individual frames, cosmic ray hits causing red, green, and blue dots had to be removed by hand. Again I researched Photoshop and developed an algorithm to automatically handle most of them. On 24 March, I updated the GIF video to also include the previous night's images. The images are each 20 minute images. There is a 5 minute or so delay between each image due to automatic telescope refocus operations using FocusMax. These are the times of each shot: The images with A prefix in the upper right hand corner label were downloaded from the camera on 17/18 March 2016 at these MST times: A1 2141 The images with a B prefix in the upper right hand corner label were downloaded from the camera on 18/19 March 2016 at these MST times: B13 2055
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