A couple of planetary nebulae for you

Just got finished unloading the EdgeHD11 and re-mounted the GT102 on the AP1100 to image some winter wide field objects. With the weather as it is lately, I spent some time processing some images I took weeks ago (I actually have a backlog of images to process due to that string of clear nights awhile back).

Here are two planetary nebulae, IC 289 and NGC 1514, known as the Crystal Ball Nebula.

Planetary nebulae (PN) are poorly named - they are not planets! They are the remains of intermediate-mass stars. As these stars run out of fuel, they expel their outer layers of hydrogen, oxygen, sulfur and other gases. The result is a small, short lived (astronomically speaking of course) sphere of rapidly expanding hot gases, while the source star collapses into a super dense white dwarf. In many PNs the central star can be easily seen. 

PN appear rather small in the sky, hence the need for a large telescope to pick them up. But they are also fairly bright. Since the main components are ionized hydrogen, oxygen and sulfur, narrowband imaging is ideal for these deep space objects.

First up is IC 289, a small PN in the constellation Cassiopeia. Located about 5000 light years away it is 40 arc-seconds wide (about 1/100 degree) which makes its diameter of 1 light year.

IC 289 - October 8, 2020
EdgeHD11 with ASI1600mm Pro; f/11
35x300 Ha; 45x300Oiii

For this object I imaged using the Ha and Oiii filters (I rarely spend time with capturing the sulphur component, Sii, as it is typically very faint compared to the Ha and Oiii subs). I captured 35 five minute subs of Ha and 45 of Oiii. I used the HOO palette, mapping the Ha to red and the Oiii to blue and green. 

Next is NGC 1514, the Crystal Ball Nebula, found in the constellation of Taurus the bull. It is 2000 light years away and spans a bit over 3 arc-minutes (1/20th a degree), which corresponds to a physical diameter of 2 light years across.

NGC 1514 (Crystal Ball Nebula) - Nov 9 and 17, 2020
EdgeHD11 with ASI1600mm Pro; f/11
49x300 Ha; 50x300Oiii; 29x120 R; 30x120 B; 30x120 G

As true in most PNs, I imaged this in Ha and Oiii as well, but also added some broadband (RGB) subs as well - 49 five minute subs of Ha and 50 of Oiii combined with 30 each of 120 seconds in RGB. 

There are many more PNs to image, but for the next few months I'm moving back to wide field with the 102mm APO.