New Seestar Features

New Level and Mosaic Mode

Late January clear nights gave me a chance to try two new Seestar features. One was the Apertura Easy Leveler whose red adjusting screws are shown in the first image below installed between Seestar's tripod and base. Seestar must be leveled before every observing session. Accomplishing this by adjusting tripod legs was difficult and time consuming. The new device made leveling quick and easy with a few screw turns. It worked perfectly!

The second new feature was Seestar's mosaic/framing mode. This software upgrade allows users to capture objects too large to fit in the standard field of view. (Seestar's standard rectangular field of view has a fixed N-S orientation with angular dimensions 0.72 X 1.28 degrees, or 43 X 77 arc minutes.) For example, the famous Rosette Nebula, NGC2244, in the constellation Monoceros is too big for the standard field of view. You can see this in the next standard field image where only part of the full circular nebula shows up in a 60-minue exposure taken on February 3rd, 2024.

Mosaic/framing mode works by allowing the observer to expand and rotate the desired field of view on Seestar's included sky atlas before initiating an exposure. As the actual exposure proceeds in 10-second steps, Seestar moves slightly between each step, sweeping out a kind of rectangular spiral of individual overlapping exposures until it has covered the larger field of view. All these separate exposures are automatically combined and stacked to present the final larger image. On January 20th, with light pollution filter engaged, I made my first attempt using mosaic/framing mode and obtained the following 90-minute exposure of the Rosette Nebula.

As you can see, the entire nebula was nicely captured in one mosaic field of view. I have to confess being pleasantly surprised by the result! I must also honestly confess that it took more than four hours of repeated exposures to get 90 minutes of actual stacked images in the final picture! A LOT of 10-second exposures were discarded during four hours because they contained tiny tracking errors. Also, I think the nebula is dimmer than it would appear in a 90-minute standard field exposure because all parts of the nebula were not exposed for the full 90 minutes. This initial experience taught me that I may need to devote an entire night to a single mosaic image in order to get good exposure.

The Rosette Nebula image above was cleaned to remove a satellite track and possible meteor trail. In the original uncleaned image (shown below) the satellite track is in the upper right, and the meteor trail is an interrupted streak below center. Enlarge the image to see the trails more clearly. If you look closely at the enlarged image, you can see a faint extension of the meteor trail before the trail brightens in an apparent meteor disintegration.

On other nights during this late January clear spell I used Seestar in regular mode to capture five more Messier objects for my collection. Two of the five are galaxies shown below. First is a 31-minute exposure of galaxy M63 in Canes Venatici. Two other dim galaxies share the field of view. The smudge above M63 is galaxy UGC8313, and the smudge below M63 is UGC8365.

Next is a 40-minute exposure of galaxy M96 in Leo.

Finally, on January 29th, I tried a 45-minute exposure of NGC2359, also known as "Thor's Helmet". This is a bubble-shaped nebula formed by strong emissions from a powerful Wolf-Rayet star at its center. The image shows green nebulosity, but not the red fringe on the lower left edge which appears in longer exposures with bigger telescopes. I didn't know what to expect when I began capturing this. Then I was astounded to watch the image gradually emerge over 45 minutes!

After these January observation sessions I need to capture only 21 more objects to complete my Messier collection.