I imaged the spiral galaxy M61 last night. I have only a short time to image galaxies in Virgo due to the surrounding trees and the height of my observatory wall. I was able to image M61 last night. I started at about 9:30PM and concluded at about 2AM, however the last hour's worth of images were just about aimed at my observatory wall so I had to delete those subs.
I used my 11 inch SCT with ZWO ASI2600 OSC camera. Autoguiding was with ZWO ASI2900 and Stellarvue SV90 scope. The night was crisp and clear. Autoguiding was good throughout the night. Reviewing the subs showed that I did not have to discard any subs due to guiding issues.
I used SGP4 to manage all equipment including Falcon rotator, Optec focusers (2), mount, imaging camera, autoguiding camera.
I took 132 images of 2 minutes binned 1x1, -10C temp, and gain 100. Of those I ended up with 112 usable images. I also took 52 flats at 0.16 seconds.
Processing was with Pixinsight. My last two imaging sessions I had problems getting the star alignment process to accurately stack all images. One of the problems could be using 'old' dark library. My camera may have developed additional hot pixels which Pixinsight is showing as stars. So I generated a new dark and bias master. I then went through my normal set of processes and found all subs accurately stacked. I will have to test this with my previous nights images to verify if the stacking issues were due to hot pixels. I am not convinced the problem is with hot pixels.
M61 (NGC 4303) is an intermediate barred spiral galaxy. M61 was discovered by Barnaba Oriani in 1779 6 days before Charles Messier discovered the same galaxy. Messier actually observed this galaxy on the same night as Oriani but thought it was a comet. M61 is one of the largest members of the Virgo Cluster of galaxies. It is weakly-barred and moderate loosely wound spiral arms.
M61 is 6 arc-minutes in size and about 52.5 million light years away. It is classified as a starburst galaxy since it is undergoing extremely high rate of star formation.
As with most galaxies in the Virgo Cluster, there are several other galaxies nearby.
Roger
- M61 Master_DBEdiv_SPCC_BXT_NXT_GHS_MLTsharp_Curves_MLT5321-Curves_Crop.jpg (2.15 MiB) Viewed 639 times
- M61 Platesolve.jpg (100.39 KiB) Viewed 639 times