Gaining Experience

Seestar Limitations

Although it was clear on February 19th, an unfortunate 83-percent illuminated gibbous Moon significantly brightened the sky. Because cloudy conditions were forecast for many future days I took this opportunity to use my new Seestar automated telescope in spite of natural lunar light pollution.

The Horsehead and Flame Nebulas were well placed near the meridian. I employed a light pollution filter and captured a stacked image equivalent to a 92-minute single exposure. The resulting imperfect image was framed nicely as you can see below.

At some point during the 92-minute exposure a neighbor's spotlight was turned on and glared directly onto the telescope from the side. The combined effect of moonlight and spotlight left a diagonal brightness band running from upper left to lower right across the image. Clearly, it makes no sense to attempt long exposures of dim nebulae on moonlit nights! Thus ends lesson number one. It would also help to have an extended lens hood to block some surrounding neighborhood light. I've ordered a lens hood for the Seestar.

Even though moonlight brightened the sky, clouds remained absent. I thought bright stars might be more appropriate targets. I was curious to see how certain red stars would show up in Seestar images. The next disappointing image is a 5-minute exposure of the pulsating semi-regular variable star, Y Canum Venaticorum, also known as "La Superba". It is supposed to be one of the reddest stars in the sky, but,  as you can see, it looks more yellowish/orange than red.

Actually, only the outer halo of the star is yellow/orange in the picture above. The central part is overexposed into a white color because red, green, and blue pixels all have the same overexposed maximum value. This was lesson number two: try shorter exposures to reveal more color in bright stars. I'd like to try capturing other red stars by trying shorter exposures and trying dimmer candidates than "La Superba".

Cloudy days drearily persisted until a very brief one hour window opened in late afternoon on February 25th. An enormous sunspot had been growing on the Sun, and I was hoping to get at least one image. I quickly set up the Seestar and managed to record one decent 90-second AVI video clip of the Sun before it dropped below a neighbor's roof. The next image is a stack of 100 frames from a 1,080 frame video.   

Giant sunspot 3590 is above center. It produced several powerful solar flares in the days before this picture was taken. It would have been a great target for my dedicated hydrogen-alpha solar telescope, but clouds made imaging impossible. Five smaller sunspots can also be seen. Arranged diagonally down in order from top to bottom on the left are sunspots 3595, 3594, 3592, and 3591. Sunspot 3586 is about to rotate out of sight near the limb on the upper right.

A Seestar software update provided new magnification options for solar imaging. I tried recording a video using the new 2X magnification, but found the final processed image disappointing. There was no increase in detail, just a slightly bigger overall image. The default 1X magnification gave a more pleasing image. So final lesson number three was to ignore magnifications higher than the 1X default. Now I'm settling in for another extended period of clouds.