| 2nd March|
M1 Crab Nebula
While the large scope is under repair, the 6" is back on the mount.
After many weeks of poor weather there was a brief spell tonight with no Moon and no clouds.
The seeing was very good for about 45 minutes but then haze and clouds rolled in.
This image is 5x10 minutes of M1. The first three frames were excellent, but conditions rapidly deteriorated.
Negative of the central 2/3rds of the frame. Probably the most pinpoint stars I have managed so far.
Some stars were almost as small as a single pixel.
M1 Crab Nebula
More frames added... Total time now 180 minutes in 10 minute frames.
Noise is much reduced.
Wide field view
Tracking plot over 180 minutes. Only a few excursions - the majority of deviations were less than 0.2 pixels.
Reprocessed using Entropy Weighted Average to stack the images. I tried Maximum, Average, Median, Kappa Sigma Clip,
Median Kappa Sigma, Weighted Average and found Entropy Weighted Average gave the smoothest rendering with the least noise.
After stacking a few images of M45, the Pleiades, I noticed a short streak close to the star Merope...
The object was moving very slowly. The above trace lasted 50 minutes so it was unlikely to be a man made satellite.
Perhaps my first asteroid discovery? Could this object be on collision course to wipe out the Earth?
A hunt on the Internet found a website run by Jodrell Bank
You enter your location, date and time, and the area of sky you are interested in and it plots a map.
I entered the coordinates for Merope and it produced this:
Superimposing the chart over my image showed that the mystery object was the asteroid Arachne (407).
I am amazed at how accurate these predictions can be - the chart position aligns perfectly with the start of the track!
There were three other asteroids in the area at the time, but much fainter at magnitudes 18 or 19.
Arachne is mag 14 which the 6" scope can pick up easily.
M45 Pleiades 'Seven Sisters' Stack of 9x10 minutes
M45 got very low in the sky so I moved to M82.
If the skies remain clear I will attempt to recover Arachne. It should be somewhere close to the Red arrow point.
The green arrow shows the position on March 6th.
9 additional 10 minute frames taken. The nebulosity is much enhanced, and the asteroid Arachne can be seen exactly where predicted.
More M81 frames added. This is now 29x10 minutes
The 10" scope is now on the mount and the new secondary mirror is in place (see February 2011 for details)
This is the first light for the new secondary, 14 by 10 minutes on M81
Still quite a noisy image, but more data will be added when possible.
Same data - different processing. No flats taken so a big 'doughnut' on the galaxy...
Zoomable negative image. Flats, bias and dark frames used to give even background.
Numerous distant galaxies to be found.
Click on image to start zooming.
Full screen version...
Another asteroid discovery! In the same Pleiades image that Arachne was found,
there is another dimmer asteroid right on the edge of the frame.
The Jodrell bank website identifies it as Asteroid Happelia, magnitude 15.2.
Animation of the Arachne asteroid.
The strange orange appearance is due to the software 'PinPoint' being used to 'blink' through the FITS images.
23rd March Some more frames of M81 taken.
Total is now 28x10 minutes.
Some more frames taken. Sky was clear but hazy with thin high level cloud.
Total time 37x10 minutes
Perseus Double Cluster through lots of cloud.