Updated: 6 days ago
If you like difficult and rarely photographed deep-sky objects, then give Sh2-224 a go! In this post, you will find information, images, and tips to photograph the supernova remnant known as Sh2-224, or the Rice Hat Nebula.
Object Designation: Sh2-224, LBN 769
Also known as: The Rice Hat Nebula, the DouLi Hat Nebula
Object Type: Supernova Remnant
Distance: 14,700 light-years away
Sh2-224 is a very faint supernova remnant in the constellation Auriga. It is located just 3.5 ° Southeast of the bright star Capella and is best photographed in the Winter season.
The Rice Hat Nebula is difficult to capture as well as process, so we wouldn't recommend a complete beginner to attempt this target until they gain some experience in the hobby. Sh2-224 is known as the Rice Hat Nebula because it is shaped just like a Rice Hat, found in several Asian countries!
Below you will find our best attempt at imaging Sh2-224, with over 47 hours of total integration time!
Sh2-224 in Bicolor with a Refractor Telescope and Monochrome Camera
I imaged this target with my 655mm refractor telescope and full-frame camera under beautiful Bortle 2 skies. This object is not often photographed, because it is very faint and not easy to process. Because of that, I decided to aim for 50 hours of total integration time, and ended up keeping 47 hours after removing frames affected by passing clouds or other issues.
As you can see below, the object is mostly made up of Hydrogen Alpha (red) but also contains some Oxygen III (blue). You can scroll down further in this post to see what each master file looked like before combining them.
Click the image for the full-resolution version!
Want to process your images following our own workflow? Download our PixInsight PDF Guide!
Telescope: Stellarvue SVX130
Mount: 10Micron GM1000 HPS
Guiding: ZWO ASI 290MM Mini
Accessories: Moonlite Nitecrawler focuser / Pegasus Astro Ultimate Powerbox
Processing: Pixinsight, with RC-Astro plugins
Total Exposure Time: 47 hours
Exposure Time per frame: 10 minutes for HO, 1 minute for RGB
Filters: Chroma 3nm R/G/B/H/O
Utah Desert Remote Observatories
This image was shot from the dark skies of Southern Utah, with our own gear controlled remotely. Our telescope is hosted by Utah Desert Remote Observatories, which allows us to image on every clear night without setting everything up or driving out to the desert. Be sure to watch the video below for more information! The most exciting part about this is that we now can take our time and spend more hours on each target, which is why we now always aim for around 50 hours of exposure time whenever we image a new object!
If you would like to permanently host your telescope next to ours under amazing desert skies, you can contact the owner at firstname.lastname@example.org
How to find Sh2-224?
Being a faint target and only part of the Sharpless and LBN catalogs, Sh2-224 is not very popular and can be tricky to find. Unlike the Messier objects and brightest objects from the IC and NGC catalogs, Sh2-224 does not appear on most common maps like the one above. To find it, just look for the brightest star in the constellation Auriga: Capella. the Rice Hat nebula can be located just 3.5 ° Southeast/East of the star.
Do not expect to spot Sh2-224 with your telescope or binoculars. The object is way too faint to be seen with the eyes and the fact that it is made up of HA and OIII does not help visually!
The Rice Hat Nebula is located approximately 14,700 light-years away from Earth, and has an apparent size of 20 x 3 arc-minutes. Its true diameter is 163 light-years across. Sh2-224 is a supernova remnant, meaning it was formed when a star reached the end of its life and exploded.
Sh2-224 is made up of two distinct parts, one being a massive round ball shape, and the other having the shape of a triangle. The way the triangle-shaped section lies by the round ball makes the nebula look like a person wearing a conical hat.
The photo on the left shows the nebula outlined with the cone hat and face, so that you can picture it better.
Below you can see an annotated version of our image. It shows several of the main stars around Sh2-224. You can also see a bright nebulous cloud in the bottom right, which I sadly had to crop out because of tilt issues. If you visit the high-resolution image on our Astrobin you might be able to spot a few galaxies in the background as well!
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Processing Sh2-224 was very difficult. The act of doing a bi-color combination with the HA and OIII filters, and using RGB for the stars was simple, but bringing out the faint gases and details within the nebula was very hard. It is very tricky not to bring up a lot of noise and artifacts when you are focused on revealing the main gases in your image.
The key was to process this image very conservatively and create some duplicates often in case I realized I went too far and wanted to get back to an earlier version. I definitely do not recommend a beginner astrophotographer to attempt this target until they have processed a few dozen of other images first!
How much data can you get with each filter on Sh2-224?
Just like most of our images taken with our monochrome camera, we like to show everyone what the master files for each channel look like before combining them into a single color image.
Below you can see what our master file for Hydrogen Alpha looks like on the left, and Oxygen III on the right. As you can see, the HA data has a lot more gas than the OIII one, but the Oxygen data does have important gases that need to be combined with the HA.
Our Pixinsight Processing Wofklow for Nebulae
If you would like to learn how I process all our images, you can get our PixInsight processing workflow for nebulae HERE.
It includes text lessons, 18 tutorial videos, our custom process icons, and raw data!
As a bonus, you will also find a full walkthrough guide about how to download professional data from NASA and the James Webb Space Telescope!
The file is updated whenever I decide to tweak my workflow or add more to it, and you always get the updates for free!
How did the Rice Hat Nebula get its name?
Sh2-224 got the nickname of "Rice Hat Nebula" or "DouLi Hat Nebula" because it looks like the Asian conical hat.
In which constellation is Sh2-224 located?
You can find Sh2-224 in the constellation Auriga.
How big is Sh2-224?
The Rice Hat Nebula has a diameter of 163 light-years and a radius of 81.5 light-years. From Earth, it has an apparent size of 20 x 3 arc-minutes.
How far is Sh2-224?
Sh2-224 lies approximately 14,700 light-years away from Earth.
How long should my exposure time be when photographing Sh2-224?
To image the Rice Hat Nebula, we suggest taking 5 to 10-minute exposures, and spending at least 15 hours on it. If you can, keep going to spend up to 50-60 hours and you should get a great result when stacking it all.
Should I use a filter to image Sh2-224?
Sh2-224 is a great bi-color target, so it is a good idea to image it with Hydrogen-Alpha and Oxygen III filters. You can also attempt imaging this target with a color camera and a duo-band filter.
Don't forget to also spend a couple of extra hours shooting it in regular RGB (or without filters) in order to get natural star colors.
What equipment do I need to photograph the Rice Hat Nebula?
You can technically capture the Sh2-224 with a DSLR/mirrorless camera and telescope, but this is a faint and difficult target, so we suggest using a monochrome camera with narrowband filters. A good field of view for this object would be about 600mm of focal length, preferably more.
For a beginner telescope, the Askar FRA600 can be a good option for the price. We don't recommend attempting to image Sh2-224 without a telescope. Using just a camera lens and star tracker will likely result in a disappointing image for this specific target.
Sh2-224 is a difficult target for amateur astrophotographers, but it is fun to process and very rewarding! If you are a patient person, please take the time to spend several nights on this object if you wish to get a satisfying result. Using just two filters (HA and OIII) is perfect and will yield nice signal.
Have you imaged the Rice Hat Nebula? If so, upload your picture in the comments! We'd all love to see your work :)
If you're looking for high-quality astrophotography data to practice your processing skills, our Raw Data page has several datasets for many targets, including this one! These master files have been calibrated and prepared for you to easily open in the processing software of your choice.
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