To which magnitude can I photograph asteroids? Ephemeris stacking

[han59]

ASTAP has a new feature to align and stack images of asteroids. The alignment is  called "Emphemeris alignment" and allows to align the images using the calculated position.

As a test, I made in April  57 images of M95 & M96 using 200 seconds exposure. So total a little more than three hours exposure time. M95 & M96 are fairly close to the ecliptic making the images both useful for a galaxy image as for the asteroids. The images where made with my 100mm F/5.8 APO and an ASI1600 MMC camera. The SQM value in my garden  reaches about 20.4 maximum.

First I made a normal stack and annotated asteroids in the image. The number of asteroids in the ASTAP annotation database was set at 200,000 and the limiting magnitude at 20.

Quite a few asteroids are annotated. However, they are not visible due to the self-movement.

ASTAP has the ability to align and stack the images based on the calculated position.

The program will show in a drop down menu the asteroids within the range of the image. Then it is just a matter of selecting one of the asteroids and then to re-stack the image. Eventually I can see that the limiting magnitude for my 100mm telescope (after 3 hours exposure) is about magnitude 19.5. See selection below.

Han

Asteroid 5741 with magnitude 17.9

 

8383 with magnitude 18.4

 

25232 with magnitude 18.9 and 25799 with magnitude 18.8

 

Asteroid 12601 with magnitude 19.4 barely  visible: