winds brought in clouds at 2026. By 2200 the sky looked a little better with the sky meter reading was 18.43. Better than I expected with the clouds rolling through. It is somewhat clear now but high thin clouds are in parts of the sky. As I've been hunting Herschel objects in Ursa Major, I decided to give Messier 81 a try with the new camera.
I had more issues with large dark circles forming on the images. If I turn the camera's cooler off or at least set it to above 0 C, the circles disappear. However they reform once I turn the cooler back on. Clouds rolled in and ended the observing session at 2300 hours.
March 25, 2017
H 160-2, NGC 3686
This is a small face on galaxy in the constellation Leo and is ~ 53 million light years from earth. In the FOV with at least 2 other galaxies. The image is 21 x 180 seconds at gain = 400.
The subject galaxy is nearly circular with a prominent bar running NS. Off the N end there is an arm circling to the E and back around to the S. From the S end of the bar is an arm circling W and back around to the N. The second galaxy is a faint eliptical around 20 ' away to the ESE. THis galaxy has no discerable core. This is NGC 3691, a mag 12.4 galaxy that is 1.4 x 1'. The third galaxy is also eliptical with a brighter core. It is ~ 15' to the NE. This is NGC 3684, a mag 11.4 galaxy that is 3.1 x 2.1 ' in size. Galaxy cluster Abell 1264 is also in this frame but would require much more magnification to resolve.
H 21-1, NGC 3810
A face on spiral galaxy in Leo that resides approximately 50 million light years from earth. The core is not overly bright. Multiple 4 minute exposures was insufficient to pull out any detail. I do note that the stars are a little elongated so apparently my guiding was lacking a bit. Also the camera cooler was off as I was having issues with a dark circular region forming due to the high humidity. The image is 8 x 240 seconds at gain = 400. I'll have to try this object again to see if I can pull out any hint of the detail shown in the Hubble image.
March 31, 2017
Based on feedback from ZWO, I installed the auxillary desiccant tablets onto the camera a couple of days ago. Hopefully that will dry out the air in the chamber housing the chip and avoid dew or ice formation. They also advised to cool down the camera slowly. I setup the ASI071MC-COOL at prime focus with the 2” Lumicon DS filter. I started the cooler at mild cooling 16 c and will stair step it down.
Decided to try this object again to see if I could pull our a bit more detail. The image below is 5 x 360 seconds at gain = 400 and the camera is operating at -10 C. The frames were stacked in SharpCap. Uncharacteristically I used GIMP to adjust the brightness and contrast, which yielded an improved image. Perhaps I'll try using AstroToaster instead of SharpCap's to stack and adjust brightness and contrast next time. I had no issues with dew or ice formation in the camera.