20 April 2026 - Moon, double stars

 Got set up about 22:15 MDT. IJust did a SkyAlign using three bright stars. First was Arcturus, but I forgot to note the other two. That's something I need to be sure to do from now on.

NELM was about 3.5-4. Stars not twinkling very much st zenith, but twinling more as you looked lower. Transparency was about 3/5 and got worse as the night progressed. I initially thought it was possibly moisture in the air, but humidity was only about 34% and dew neve formed on any surfaces. It turned out to be smoke haze. By 08:00 the next morning the smoke in the valley was thick enough to smell and there was a haze over everything.

The Moon was about 17% waxing. I wanted to observe it before it went behind the trees to  the west so it was my first target. I started out using the 25mm Plossl eyepiece (81x), and worked north along the terminator from the south edge. After getting a good overall view I went to Mare Crisium. While scanning around it a detail I hadn't noticed before caught my eye. I could see three faint "fold" lines on the floor. They paralelled the edge just a little ways inside it. Using the S&T Mirror Image Field Map I identified them as Dorsum Oppel, Tetyaev, and Harker. I was able to go up to the 8mm eyepiece (254x). The image wavered quite a bit but had enough periods of steady seeing so I could make reasonable observations. The seeing was probably bouncing between Antoniadi III and IV.  While in that vicinity I also identified craters Picard, Pierce, Swift, and Yerkes. I moved to Mare Fecunditatus to see if I could locate similar features there. I found Dorsum Geike, Mawson, and Cato. 

Dorsum are wrinkle ridges formed by tectonic forces. https://www.jpl.nasa.gov/news/study-finds-new-wrinkles-on-earths-moon/

 About 22:45 the Moon finally started going behind the trees. I decided to try Jupiter just to see if I could push magnification like I was able to on the Moon and see more detail. With the 8mm eyepiece the view wouldn't stay focused enough to allow any real observation. I may have caught glimpses of faint bands above and below the equatorial bands. The image steadied significantly with the 13mm and 25mm eyepieces, but they only revealed the two equatorial bands without any real detail.

I decided to try some of the double stars from "Turn Left At Orion" (TLAO) to see how the telescope would do.  First target at 22:54MDT was 54 Leonis. This was a fairly tight double in the 25mm Plossl, but I was able to split them . The pair are about 6.5 arc seconds apart. They both appeared basically white with no discernible color difference. In looking at the information on this star, it seems there should be some bluish tint visible, but I couldn't see it. 

23:10MDT started observing Iota Cancri. This is a very wide double in the 25mm eyepiece. Data shows it has a separation just over 30 arcseconds. The main star appeared to have aslight yellowish tint that flickered back and forth to white from effects of seeing. The companion showed a very slight blue tint. 

Other double stars from TLAO weren't in the database  on the SE mount. Since the sky wasn't very good I decided to try a star from the handset database. Went to NJ Draconis                 (Nu Draconis?). This was a very wide double in the 25mm eyepiece. Both appeared the same color, basically white. They also appeared to be the same brightness. I did note that there was a much dimmer and smaller double in the lower left of the FOV.

23:05MDT, looked at Pollux and Castor. Castor was an easily split double, but I didn't record the color. 

Just a side note here. I was getting spike s off of stars, and not sure if it was due to seeing or collimation. It resolved later, so probably seeing. I noticed when changing eyepieces and looking down through the diagonal that I could see an almost perfect donut. The central obstruction seemed to be perfectly centered. It also appears centered in the diffraction rings when viewed through th eeyepiece. It appears that collimation is pretty good.

The diffraction rings seem to match the pattern shown shown for good collimation but poor seeing in "Star Testing Astronomical Telescopes" by Suiter. Both inside and outside of focus. This seemed to be reinforced by the spikes on stars disappearing when I went back to Castor to check on it. The stars became pinpoints again.

For finishing updoubles in TLAO, I'll have to rely on Right Ascension and Declination coordinates to locate those that aren't in the SE database.