Mosaic/Framing Mode

Seestar Wide Fields

I'm enjoying Seestar's mosaic/framing mode lately. It's fun to roam the sky looking for opportunities to capture more than one celestial target in a single image frame. For example, galaxy M108 and colorful planetary nebula M97 appear together in the first image below. These two are separated by 48.25 arc minutes in Ursa Major. M97, a member of our own Milky Way, is in the foreground 1,700 light years away. M108 is 32 million light years distant, well beyond the Milky Way. This image, made on March 18th, is the result of 60 minutes of accumulated exposure time.

It takes much longer than 60 minutes for Seestar to actually collect 360 acceptable individual 10-second frames needed to produce the eventual 60-minute exposure. Many individual frames are rejected due to poor tracking during image capture. While using mosaic/framing mode I can usually make only one image before Seestar's battery is drained. It might take 3 to 4 hours to produce an acceptable final image, so I settle for one target per night. The beautiful thing about Seestar is how it runs successfully for 3 to 4 hours without need for personal attention. I can watch TV or read a book while interesting images accumulate.

On March 26th another entire evening was devoted to capturing (from top to bottom) galaxies M82, M81, and NGC3077. The angular separation between M82 at top and NGC3077 on bottom is 1.15 degrees. In this 90-minute exposure I should have centered the image better and moved M81 further from the edge.

On March 22nd I made another attempt to capture Markarian's Chain in Virgo. This time I made a larger field of view than a previous attempt in order to include more galaxies. The field width here is about 1.7 degrees. The next 76-minute exposure includes 23 galaxies! Some are tiny and dim. (Enlarge the image by clicking on it to see them more clearly). 23 galaxies are identified in the labeled image below. The Hubble Deep Field this is not, but it's pretty amazing for a tiny 50mm telescope in my back yard!

Leo was my next target on March 27th. Five galaxies appear in the following 60-minute exposure. On top, from left to right, are galaxies NGC3389, NGC3384, and M105 in a tight triangle. Below, from top to bottom, are galaxies M96 and M95. The angular separation between the uppermost galaxy and M95 on the bottom is about 1.3 degrees.

I was disappointed by the relatively bright sky background in the previous image, so I made a second attempt on April 16th. This time I chose a smaller field of view and tried a 90-minute exposure. In the next image M95 is not included, and the angular distance between the uppermost galaxy and M96 is about 48.3 arc minutes. The sky background does look slightly darker, but I wonder if 30 minutes extra exposure time really made a huge difference.

I'll continue to look for other wide field targets in the future.