Three Multiples; Struve 1604, Dun 116 and SHJ 143
Before the moon brightened on the evening of June 25, 2020, I made a trip to the summit of Haleakala for an evening of observing. The weather forecast was not the greatest and I took a chance that I could observe some multiple systems before they set in the west for the summer
I started out with Struve 1604 in Corvus, the image we use for our logo and pin on the AstroLeague Multiple Star Observing Program found here. This is a very colorful system: yellow, red and blue! If you would like to test your eye and optics for color, this is a great system to observe. The Primary is yellow, the B component is red and the C component is blue. The Lit. for the system can be found in Stelle Doppie here. Steve Smith and others cover it very well in Dave’s post here. John Nanson covers it well in his WordPress blog, “Star Splitters” including a sketch of it by me back in 2014, here. It was pretty humid at 60% after fog rolled through just before I set up. The wind was light at <8 mph and the temperature a comfortable 45°F. I was working with my C925/CGEM and started out with my Explore Scientific 9mm at 261X after centering the object in a wide FOV EP. Pow! The object has such color! On the sketch I utilized my Televue Delos 6mm at 392X for the high power view. B.T.W., the B component is dimmer than the C at Mag. 10. There was a nice airy disc around the three stars, probably because of the humidity. I labeled three field stars for kicks and giggles, (and to anchor the system in the FOV). I"m posting an image from my Gallery here:
Off to the next as the wind was increasing as the humidity dropped. It was now fully dark at 2131 and I needed to get that 11th Mag. C component on Dun 116 in Hydra. Stella Doppie has the Lit. here. The AB pair are considered physical and decreasing. With my Explore Scientific 18mm at 130X, I could easily make out the trio. I grabbed a blank log sheet and started to fill out the details. I was in a hurry and the sketch came out wrong on the Position Angle of the B component. I plotted three of the field stars in the FOV and I’ll get back to it on a better night.
Little did I know that SHJ 143, 12 Com, in Coma Borealis would be the last system I would observe in this session. The wind was increasing to 20 mph and it wasn’t even 2100. I had observed this object back in April and wasn’t satisfied. This system is found in Stelle Doppie here. I spent almost an hour working on this sketch including three field stars.. The B and E components are tricky. I got a wide FOV with three field stars with an Explore Scientific 18mm at 130X, 0.6° FOV. I tried a 9mm at 261X and couldn’t pry the B companion out of the glare of the primary. With the Televue Delos 6mm at 391X, 0.18° FOV I got what I think is the B companion although the Lit. says its further out at almost 36”, (the B is 59”). So, I’ll have to go back to it under better conditions. The E component is a tough Mag. 14.4!!! John Nanson in his WordPress blog, “Star Splitters” has a good sketch and description here. His posts are always very entertaining and informative!