March 29th was a completely clear day, but chilly, and very windy. Morning temperature hovered near 55 degrees. Seeing was not particularly good, but there were occasional decent patches of steady images. It remained wonderfully clear all day, so I actually used my telescopes in the morning, afternoon and evening!
Daytime wind was a real problem. Springtime is often surprisingly windy here in Williamsburg. My laptop normally sits in a cardboard box which serves as a sun shield during daylight. Usually, the laptop alone is heavy enough to anchor the cardboard box when it's windy, but this day's wind was particularly strong. Taking the strong wind into account, I put one of my equipment cases on top of the laptop to add more weight and ensure the cardboard box would stay put in the wind while I continued to set up. Shortly after I turned away to get more equipment I heard a sickening crash and watched the box, laptop, and equipment case tumble off my observing table and fall to the ground after a blast of wind. The box with its contents then rolled over on the ground. I felt ill. Fortunately, in spite of the horrendous fall, no harm was done. Incredibly, the laptop still functioned normally. After this near disaster I ditched the box. It was catching too much wind. I held a blanket over my head to shield the laptop for the rest of the morning.
Morning observing began with my Lunt 100mm hydrogen-alpha solar telescope. Only one solitary sunspot was visible along with a couple of modest filaments. The first image below shows lonely sunspot 2526 in good detail with a bright active area to its left. The image is processed to preserve the dark gradations in the umbra which you can see better if you click on the image for a larger view.
In addition to the wedge prism itself, the apparatus includes a neutral density filter and a polarizing filter to dim the Sun's light enough for comfortable viewing. Even with filters fully engaged the eyepiece view was quite bright. Solitary sunspot 2526 showed well, but the surrounding surface granulation was not particularly sharp. Granulation was just barely visible, only hinting at what would be visible with better seeing and, perhaps, better filter combinations. I will have to experiment with an additional neutral density filter in the future.
Next, I tried imaging with the solar wedge. Sunlight reaching the camera was much too bright. Even with zero gain and very short exposure times the images were nearly overexposed with an extremely narrow histogram. I've ordered a UV/IR filter and an additional neutral density filter which, I hope, will further dim the sunlight and allow better imaging in the future.
The image below is the best image I obtained with the wedge. It's colored to approximately match what I saw in the eyepiece. Because I imperfectly processed the image to bring out details in the umbra, there is some distortion in the border of the umbra. Granules are visible on the surface all around the sunspot, but the granule boundaries aren't sharp. (Granules are the tops of upwelling fountains of hot gases continually rising and falling in the solar photosphere.) This image falls far short of the best photospheric sunspot images I've seen. I hope to improve image quality in the future.
As darkness fell I restarted my Paramount mount and synchronized on the star, Rigel. Then I constructed and applied a 6-star TPoint model in an attempt to increase pointing accuracy. (A TPoint model is created by commanding the telescope to point at selected stars. The observer manually corrects the pointing inaccuracy for each of the stars. The computer then makes a mathematical model based on the recorded inaccuracies. The mathematical model is then applied to correct future pointing inaccuracies.) The TPoint model resulted in good, but not perfect pointing. Every target I slewed to throughout the evening was somewhere in the eyepiece field of view, but never exactly in the center of the field.
For the next few hours I looked at 25 objects, including 15 Messier objects. It was fun trying different eyepiece combinations and enjoying the beautiful views of star clusters, double stars, and a couple of galaxies. Unfortunately, many neighbors' lights were glaring into my yard this evening. A solar observing hood draped over my head helped block the offending lights while I looked through the eyepiece, but my night vision was completely destroyed every time I emerged from under the hood. My new red light headlamp and adjustable observing chair were wonderfully helpful for night observing. Sometime before midnight I took my equipment down. I was tired, but content after a full day of fun astronomy.
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