NGC 3293 - The Gem Cluster Astrophotography in Carina
- Antoine & Dalia Grelin
- 3 minutes ago
- 8 min read
NGC 3293 is a beautiful open cluster visible in the southern hemisphere. It is found in the constellation Carina, very close to the large Gabriela Mistral Nebula. In this post, you will find information, images, and tips to help you photograph this exciting open star cluster.
Object Designation: NGC 3293, Collinder 224, Melotte 100
Also known as: The Gem Cluster
Constellation: Carina
Object Type: Open Cluster
Distance: 8,400 light-years away
Magnitude: 4.7
Apparent Size: 8.2'
Discovery: 1751 by Nicolas-Louis de Lacaille
NGC 3293, which is also called the Gem Cluster, is awesome to capture and process because it lies over so much nebulous gas! This one is not possible to capture from my location in the North, so I used telescope.live to get the data and processed it. You can use code TL4GH to get your first month free!
NGC 3293 Astrophotography of the Gem Cluster
July 2026
The constellation Carina is impossible to see from my latitude. Therefore, I had to find another way to capture this target.
The data was taken from Chile, under beautiful Bortle 1 skies and at an altitude of 5,000 feet using Telescope.live.
The telescope is a PlaneWave CDK24 (A 24" aperture telescope with a focal length of 3962mm and an F-ratio of F/6.5). The camera is a QHY600M.
Below you can see the result, with a total of 8 and a half hours of total integration time. I love the colorful background and the mix of dust and gasses. I show you exactly how I processed this from start to finish in my Cluster PixInsight Processing Guide.
Click the image to see it in high-resolution!
Would you like to process this data? Get a free stack on Telescope Live!
GEAR USED:
Camera: QHY600M
Telescope: PlaneWave 24" f/6.5 CDK
Mount: Mathis MI-1000/1250 with absolute encoders
Observatory: Observatorio El Sauce
Processing: PixInsight (Watch tutorial)
ACQUISITION DETAILS:
Total Exposure Time: 8 hour and 35 minutes
Exposure Time per frame: 5 minutes
Filters: S/H/O
How to find the Gem Cluster?
The Gem Cluster can be found in the southern constellation Carina, and is always above the horizon for southern observers. It is easy to find because it is right by other popular objects, like NGC 3372 (The Carina Nebula), and NGC 3324 (The Gabriela Mistral Nebula). These all lie at the edge of the constellation, towards Vela and Crux.
You can star-hop to your target by starting from the bright star Canopus, then west to Avior, Aspidiske, and then NGC 3293.
NGC 3293 is just 2 degrees northwest of the very bright multiple star system Eta Carinae. Some popular deep-sky objects in that area include the Wishing Well Cluster (NGC 3532), the Banana Nebula (NGC 3199), the Statue of Liberty Nebula (NGC 3576), the Southern Pleiades (IC 2602) and of course the ones I named earlier.
A little further, you'll also find the Running Chicken Nebula, which I also was able to process thanks to Telescope Live.
The Gem Cluster by ESO
NGC 3293 was photographed by the ESO space agency. The image below was taken with a 2.2-meter telescope at the La Silla Observatory in Chile.
The cluster has more than 100 stars with a magnitude brighter than 14.
The brightest star is a red giant with a magnitude of 6.5. It is surrounded by hot and young blue stars, which you can easily see on the picture. The nebulosity around is also very visible on this shot. Unlike mine, this one was processed in "true color" meaning the Hydrogen Alpha is red. Mine was processed as a "Hubble Palette" style.
Online Premium Astrophotography Course
Want to learn all aspects of astrophotography in the most efficient way possible?
The Galactic Course includes access to all our astrophotography courses, processing guides, and downloadables. Step into an ever-growing realm of knowledge and learn at your own pace. Make life-long friends and connections with other members, and get tips from instructors that truly care about your journey and progress under the night sky.
Processing the Gem Cluster on PixInsight
Processing NGC 3293 is truly exciting, especially with a long focal length as the background is completely filled with nebulosity!
There are three main things to pay attention to in this case. The first one is, of course, the nebulosity. You'll want to work on revealing all of its details and colors as soon as you get your starless file. This is fun and not difficult to do as the data is very clean, so very little noise pops up.
The second thing is that since there were no RGB files for the stars, these will end up with a very unnatural color! In my case, because I did an S-H-O combination, my stars are all magenta. This is completely normal, and the exact same thing happened to me when processing NGC7000 in my Nebula Processing Guide.
It's an easy fix though, as you can either use the "Correct Magenta Stars" script, or do it manually by inverting the image (Command + I), applying SCNR to remove the green, and then re-inverting the image.
The third important thing is to protect your cluster stars with a mask before reducing the size of your stars. Doing a star size reduction on all your images is great, and helps your target pop out more, but when there is a cluster, always be sure to protect it! If not, your cluster stars will also get reduced, and the object will itself look much less impressive. You can use a mask like the GAME mask (free script) to do so.
I show you how to do all of these, step by step, in the Cluster Processing Guide. In there, you'll also find different case studies with text and walkthrough videos for all types of clusters!
What did each broadband channel look like?
Below you can see what the stacked frames look like for each channel. Three filters were used to capture the Gem Cluster:
Hydrogen-Alpha
Sulfur II
Oxygen III
As you can see, the Hydrogen-Alpha shot (left) is the one that looks the cleanest and shows the most nebulosity. This is normal in 99% of cases whenever dealing with regions of nebulae. The Sulfur II shot (middle) shows some of the gasses, but the Oxygen III one (right) barely shows any.
Equipment Used to Capture the Gem Cluster
Here is some more information about the equipment used to capture this object.
Telescope used:
PlaneWave 24" f/6.5 CDK
Telescope tube weight: 240 lbs.
Focal length: 3962 mm (156 inches)
Focal ratio: f/6.5
Aperture: 610 mm (24 inches)
Image Circle: 70 mm
Cost: $73,000
Mount used:
Mathis MI-1000/1250 with absolute encoders
Computerized Mount
Head Design: Fork
Instrument Capacity: 320 lbs
Latitude Range: 25 to 56 degrees
Mount Weight: 220 lb
Cost: $66,516
Camera used:
Manufacturer: QHYCCD
Model: 600M
Pixel Array: 9576 x 6388
Pixel Size: 3.76 microns
Sensor Size: 36mm x 24mm
Cost: $5,000
NGC 3293 FAQ
In which constellation is NGC 3293 located?
You can find the Gem Cluster in the constellation Carina.
How big is NGC 3293?
The Gem Cluster has a diameter of approximately 13.2 light-years. From Earth, it has an apparent size of 8.2 arc minutes.
How old is the Gem Cluster?
NGC 3293 is 12 million years old.
How far is NGC 3293?
The Gem Cluster lies approximately 8,969 light-years away from Earth.
How long should my exposure times be when photographing NGC 3293?
This is an open cluster with a lot of nebulosity around, so I recommend doing between 300 to 600-second exposures. Your signal to noise ratio will be great and the gasses should look good!
Should I use a filter to image the Gem Cluster?
Yes! The nebulosity behind it is full of HA and SII, so you'll want to use some narrowband filters. Although the OIII is very low, it might still be worth it dedicating some time with it so that the overall colors blend better. Don't forget, of course, to use RGB filters for the stars (or not filter if you're using an OSC camera).
Gem Cluster Processing Video Tutorial
You can learn how to process this target and many other clusters with the Galactic Course's Cluster Processing Guide. It includes text lessons, tutorial videos, our custom process icons, raw data, and more! The course is updated whenever I decide to tweak my workflow or add more to it, and you always get the updates for free! Several additional "Case Studies" show you how to process various clusters from start to finish.
Other processing guides are available for galaxies, nebulae, comets, and smart telescopes. You can also get the Processing Bundle to get them all at once!
Final Thoughts
I'm happy with this image of the Gem Cluster, which was a very fun one to process! I've always loved open clusters that are located near or around nebulosity, and this one did not disappoint!
I would like to thank Telescope Live for the opportunity of getting access to this high-quality data of a target I physically cannot shoot from my location. If you'd like to get some yourself, you can use the coupon code "TL4GH" to get 50% off your first 2 months (AKA one full month free)!
Have you captured the Gem Cluster? Attach your image in the comments and let us know your acquisition details!
Clear Skies,
Galactic Hunter
GALACTIC HUNTER BOOKS
Description: Discover 60 Deep Sky Objects that will considerably improve your Imaging and Processing skills! Whether you are a beginner, intermediate, or advanced astrophotographer, this detailed book of the best deep sky objects will serve as a personal guide for years to come! Discover which star clusters, nebulae, and galaxies are the easiest and most impressive to photograph for each season. Learn how to find each object in the night sky, and read our recommendations on imaging them in a quick and comprehensive way. Each target in this guide contains our advice on imaging, photos of expected results, and a useful information table. We've also included a few cool facts about each target, a map to find it in the night sky, and more!
Description: The Astrophotographer’s Journal is a portable notebook created for the purpose of recording observations, cataloguing photographs, and writing down the wonderful memories created by this hobby. This book contains more than 200 pages to memorialize your stargazing and imaging sessions, as well as a useful chart on the last pages to index exciting or important notes. Read back on the logs to see how much progress you have made through the months, the problems you overcame, and the notes taken to improve in the future. Just as the pioneers of astronomy did in their time, look up and take notes of your observations as you are the author of this star-filled journey.
Description: The Constellations Handbook is a logical guide to learning the 88 constellations. Learning the constellations is difficult. Remembering them is even harder. Have you ever wanted to look up to the night sky, name any pattern of stars and be able to tell their stories? This book groups the constellations in a logical order, so that the reader can easily learn them by their origin, and see how their stories interact with one another as a group. The last pages of this book include an index of all 88 constellations, each with a slot where you can write your own personal tips and tricks in order to memorize them with ease. The Constellations Handbook is not just another guide listing all the constellations from A to Z and their location, it is the perfect companion for stargazing, and a learning journey through the ages.
Comments