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What do you need for astrophotography? It is possible to get started on a low budget, but I generally advise that anybody wanting to go deeper into this hobby should consider getting the best camera, a quality telescope and mount or tripod at the least.
Let’s look at the equipment you need to get started in astrophotography, and how this varies for Milky Way, Deep Sky Photography, or Planetary astrophotography.
For astrophotography, depending on your target, you will need a camera, a lens (or telescope that acts as a lens), a tripod or mount, and a computer to stack and process the images. For longer exposures, you may also need a guide scope and camera to keep your target from moving.
Equipment for Basic Setup for Milky Way and Landscape Astrophotgraphy
Equipment list:
- DSLR camera
- Tripod
- Remote shutter
If you use a DSLR camera on a tripod, you are going to need a remote control device such as an intervalometer to activate the camera without touching it. This is important if you want clean pictures.
Whatever tripod you use it needs to be a sturdy one so that it doesn’t vibrate or move in windy conditions. Go for quality. More on choosing a tripod here.
Equipment List for Deep Sky Astrophotography
For this kind of astrophotography you’ll need the following:
- Camera (DSLR or Astro Camera)
- A telescope or Lens
- Mount (Az Alt or better, EQ). Find out more about mounts here.
- Possibly a laptop or other controller such as an ASIAIR.
- A guidescope and camera. Learn all about guiding here.
What do you need for Planetary Astrophotography?
Here’s what you’ll need if you want to image planets and other solar system objects:
- A high quality telescope with a long focal length with good magnification.
- A barlow lens to double the focal length and magnification, normally used for visual.
- An alt az mount is good enough as exposures are short.
- A goto system or a laptop to find planets or the object you want to photgraph.
- A good quality camera preferably an astro camera designed for planetary work. A DSLR can be used.
The equipment you need for astrophotography is one thing, but how do you do astrophotography or astronomy as a beginner? That is quite another question.
Getting the equipment is not the real challenge; knowing what you need and what will suit you is. It helps if you choose items like a telescope from one of the top telescope manufacturers. Once you have the equipment, you’ll need time and practice to learn how to use it.
Do you Need a Laptop for Astrophotography?
I have a page dedicated to answering this particular question, so check this out about using a computer or laptop for astrophotography, in particular for imaging. The reason why I am mentioning this here is that you will need to use an astrophotography laptop or other computer if you plan to use a dedicated astronomy camera and it can also be helpful when you consider other aspects of imaging such as guiding, running an imaging plan or using plate solving which all require specialized astro software that is often free.
Suggested Video about Astrophotgraphy Equipment
I include this excellent video by Cuiv the Lazy Geek in which he goes through the different pieces of equipment you need for a setup that will allow you to start imaging deep sky objects (DSOs):
I hope you find this video as interesting and informative as I did!
What camera for astrophotography: mono vs colour
When considering whether to buy a cooled camera, I saw that some models were mono and some were colour. These colour cameras are also referred to as OSC – one-shot colour cameras. I actually decided to buy an OSC rather than mono, but did I make the right choice?
It’s not easy to answer this one because, on the one hand, it is easier and more familiar to me to use a color camera. You just point and shoot and you have an RGB colour image. With a mono camera, you need to take at least three photos to get an image, one with a red filter, one with a blue, and another with a green filter. After this, you can put the three images together and you’ll have an RGB colour image.
The photographic quality is better for the mono camera because to get the RGB colour image in the OSC camera, the sensor has filters of red, green, and blue already over the pixels of the sensor. The pixels are divided up into the pattern RGGB which means for every four pixels of a color camera sensor, one is red, one blue, and two are green.
A mono camera has no filters over the pixels and so 100% of them are available to image the target and one filter is then placed over the whole sensor.
This means that while a mono camera uses all of the sensor’s pixels for an image the OSC divides the image into three channels. However, it will take much longer to get your final image in full colour.
According to Chris Woodhouse (2017), a monochrome camera will have a slightly better resolution than a colour camera. I decided to research this to discover how much better image resolution would be for a monochrome camera compared to an OSC colour camera using data from several sources (see below).
My Research: How much better is image resolution for a monochrome camera vs. a colour camera.
The aim of this research was to determine how much difference there is between the resolution of an image created by a monochrome camera sensor compared to that created by a colour camera or OSC. This should be very helpful for anyone who is considering buying a monochrome camera, and is probably more familiar with colour cameras. This would mean making a change and the natural question here is whether or not it is worth the extra time and effort of using a monochrome camera rather than a colour camera.
The data I used for this research is from the following sources:
- PixelRajeev.com – Color vs Monochrome Sensors – Use of Bayer Filter4
- Chris Woodhouse. (2017). The Astrophotography Manual. A practical and scientific approach to deep sky imaging.
Each pixel on a monochrome sensor captures 3 times as many photons of light as that on a colour sensor and the sensitivity is improved 1.5 times, resulting in finer details in the image, (PixelRajeev.com).
The Bayer Matrix in a colour sensor reduces the light captured by each pixel to 33% according to the above source. This is illustrated below:
This seems oversimplified and so taking the data given we can make some calculations to see if this is true and then propose an accurate answer that might help to settle this issue for someone looking at using a monochrome sensor.
Assumptions: the filters in the Bayer Matrix are perfect in that they only transmit the colour it is designed for, in reality, there is some small overlap. Also, it is assumed that pixels are all registered as capturing the light of the filter colour, whereas in reality software demosaics the image, meaning it actually adjusts some of the pixels and may change the colour to get a better picture. Demosaicing only happens in colour cameras.
So here is what I have found from making calculations on the data:
- It takes three times longer to get an OSC-comparable image with a monochrome camera because we need to image through three filters – red, green, and blue.
- Light captured by OSC camera captures 25% red and blue light and 50% of green.
- If you image with an OSC camera for one hour and a monochrome camera for one hour on each filter you will capture 3.33 times as much light and if you image for one hour total divided amongst the three color filters the difference in the light captured is 1.11 times, a slight improvement.
Conclusion: in reality, the actual difference in any resulting OSC image is likely to be even less. Many astrophotographers claim that monochrome cameras provide much better quality images and that only appears to be true if you take the time to image through filters which takes three times as long.
In order to determine the actual difference of resolution between a monochrome camera and a colour version would be to compare the MTF chart or Modulation Transfer Curve of both types of camera. This gives a good comparison such as the one here that compares the MTF curves of a Canon 30D for different colors and shows the effect of the Bayer Matrix filters. There is a sharp fall at higher frequencies for contrast and resolution of the image. MTF charts are usually given to compare lenses but it can be used to compare two cameras that have the same lens and optical setup.
The only valid comparison, therefore, is to compare a full colour and a black-and-white picture and to see which has better resolution. The monochrome image will win. But, we care about colour, don’t we?
Just remember that if you are thinking about whether it is worth buying a mono or colour camera, there is no clear winner. The colour camera is convenient and saves time, the monochrome camera can produce better pictures but takes longer. Perhaps just take more images with an OSC?
Another piece of equipment that could be added to this list is an auto-guiding setup composed of a guide scope and guide camera. This will improve your images and enable longer exposures.
Final Words
We have looked at what you need for astrophotography and by now you should have a much better idea of the kind of camera, mount or tripod, telescope or lens and if you need guiding or not. The research I have carried out should guide you to choosing the right equipment for the type of astrophotgraphy you want to do. I’ll be glad to answer any questions you have, just ask me here.
Enjoy the equipment you get and have fun imaging!
References
[1] Richard S. Wright Jr. How to Modify Your DSLR for Astrophotography. Retrieved from https://skyandtelescope.org/astronomy-blogs/imaging-foundations-richard-wright/modifying-your-dslr-astrophotography/
[2] Teledyne. Thermal Control for Long Exposures – Technical Note. Retrieved from https://www.photometrics.com/learn/exclusive-product-features/thermal-control-for-long-exposure-imaging-retiga-e7-cmos-tech-note
[3] – Wikimedia Commons. Bayer pattern on sensor. Retrieved from https://commons.wikimedia.org/wiki/File:Bayer_pattern_on_sensor.svg
[4] Color vs Monochrome Sensors – Use of Bayer Filter. Retrieved from http://www.pixelrajeev.com/color-vs-monochrome-sensors-use-of-bayer-filter/
[5] Wikimedia Commons. Bayer pattern on sensor profile. Retrieved from https://commons.wikimedia.org/wiki/File:Bayer_pattern_on_sensor_profile.svg
