Deep Sky Astrophotography Equipment
A basic deep-sky astrophotography equipment setup typically includes an equatorial mount, telescope, camera, autoguiding system, and a slew of additional accessories required to run the camera throughout the night. My personal astrophotography equipment profile has evolved substantially over the years, (and yours may too).
My “Primary” Deep-Sky Telescope Rig (2020)
- Mount: Sky-Watcher EQ6-R Pro
- Telescope: Sky-Watcher Esprit 100
- Camera: ZWO ASI294MC Pro
- Filter: Optolong L-eNhance
- Guide Scope: William Optics 50mm Guide Scope
- Guide Camera: ZWO ASI290mm Mini
While all pieces of the puzzle must unite for a successful deep sky image, the undeniable foundation of it all is the equatorial telescope mount. When it comes to astrophotography, it’s the telescope mount that must accurately track the apparent movement of the night sky. This is often the first step beginners take when building their first deep-sky astrophotography rig, and an important one.
Choosing a telescope well-suited for astrophotography using either a DSLR or a dedicated astronomy camera is next, and there are many different types and models to choose from. For the best results early on, I recommend an apochromatic refractor telescope, as they are compact, lightweight, and capable of superb deep-sky images.
The astrophotography equipment road you travel down will depend heavily on the type of astrophotography you plan to enjoy. For example, a setup for wide-angle Milky Way photography will look much different than one intended for high magnification deep-sky imaging.
You do not need a telescope to enjoy astrophotography. In fact, some of my all-time favorite images were captured using a beginner-level DSLR camera and a wide-angle camera lens. As you progress through the hobby, I think you will find that there are endless ways to accomplish your goals.
I believe it is extremely important to consider the overall user experience a particular path will take, before buying your next telescope or camera. The last thing you want to do is to set yourself up for a discouraging night. Remember, astrophotography involves capturing images at night, in the dark.
Choose a kit that you understand, and learn the basics before heading out into the unknown (or your backyard at night).
A camera and telescope set up for a night of deep-sky astrophotography.
For example, a traditional Schmidt–Cassegrain telescope (SCT) may seem like an obvious choice to a beginner because of it’s impressive aperture and focal length. However, these qualities magnify issues in tracking and autoguiding accuracy, which may be very discouraging and difficult to address early on.
My goal for this article is for you to get a closer look at the gear amateur astrophotographers use to photograph the night sky. Below, you’ll find everything I use to produce deep sky astrophotography images from my backyard in Ontario, Canada.
My personal imaging tastes involve using apochromatic refractor telescopes that offer a wide field of view. An apochromatic refractor has several benefits when it comes to deep sky astrophotography including excellent contrast and color correction.
These telescopes are capable of capturing detailed portraits of many of the most incredible galaxies, nebulae, and star clusters. Choosing the right telescope to suit your personal photography goals is important, but when it comes to astrophotography, the telescope mount should be your first priority.
A typical deep sky astrophotography setup.
To photograph deep-sky objects in the night sky, several long exposure images must be captured to produce an image that reveals the faint light emitted by an object in space. This means that the telescope mount must compensate for the rotation of the Earth to precisely track your imaging target.
I use a Sky-Watcher EQ6-R Pro GoTo equatorial mount for the majority of my deep-sky astrophotography sessions. This is a robust computerized equatorial tracking mount with a 44-lb payload capacity. It includes an onboard hand control computer system that allows me to select objects in space from a large database, and the telescope will then slew to the desired position.
This can only take place after the polar alignment, and star alignment processes have been completed successfully. The EQ6-R is considered to be an intermediate-level telescope mount for astrophotography and is capable of accurate, and precise tracking of deep sky objects in space.
What Kinds of Pictures Can You Take?
If you’re getting started in astrophotography, the amount of equipment needed upfront can be a little overwhelming. I do my best to explain the basics in this video, if you’re transitioning from daytime photography, or have little to no experience in photography at all.
The good news is, once you learn the basics, capturing deep-sky images of nebulae and galaxies in space are within your reach. Seasoned veterans will devote several hours into each project, but that is not necessary to start understanding and enjoying the hobby.
The following image was captured using a dedicated astronomy camera, through a 100mm refractor telescope. The subject of this image is the Eastern Veil Nebula, a supernova remnant found in the constellation Cygnus.
The Eastern Veil Nebula captured using a Sky-Watcher Esprit 100ED telescope on the EQ6-R Pro
Nebulae are one of my personal favorite subjects to photograph because they are often very large and colorful. Very few galaxies are this large in the northern hemisphere, with the exception of the Andromeda Galaxy and Triangulum Galaxy.
Image Processing and Computer Equipment
Of course, these images are not possible without the second half of the race, image processing. You can think of astrophotography in two stages; the image acquisition stage, and the image processing stage. Your job is to educate yourself in both disciplines so that you too can capture incredible pictures of space from your own backyard.
There are many software options available for processing astrophotography images. I use DeepSkyStacker to register, calibrate, and integrate my images, and Adobe Photoshop to edit the image creatively. The acquisition stages of astrophotography benefit from dedicated software as well.
Astro Photography Tool is an application that lets you automate a sequence of images and control important camera settings in the field.
For a complete breakdown of the software I use for astrophotography, please see the resources page.
If you would like to see how my astrophotography images are processed, have a look at this image processing tutorial using Adobe Photoshop. I also have a premium image processing guide (PDF) available for those looking to dip even deeper into the specific techniques that I use.
If you are looking to build your first deep-sky astrophotography imaging setup, consider investing in a portable star tracker first. This is a great way to experience every stage of astrophotography, without many of the headaches involved with a more advanced setup.
My Current Deep Sky Astrophotography Setup
This section of the website is in a constant state of evolution, and I will try to keep it as up-to-date as possible. For the latest information about what I am currently using, please sign up for the email newsletter, or follow AstroBackyard on YouTube.
- Celestron 8″ RASA F/2
- Celestron EdgeHD 11″
- Radian Raptor 61
- William Optics RedCat 51 Petzval APO
- William Optics Zenithstar 61 (Z61) APO Refractor
- William Optics Zenithstar 73 (Z73) APO Refractor
- Sky-Watcher Esprit 100 ED Super APO Triplet
- William Optics Fluorostar 132 Refractor
- Explore Scientific ED102 CF APO Refractor
- StarField 50mm Guide Scope
- StarField 60mm Guide Scope
- William Optics 50mm Guide Scope
- William Optics GuideStar 61
- Sky-Watcher HEQ5 Pro SynScan
- Sky-Watcher EQR-6 GoTo Equatorial Mount
- Celestron CGX-L Computerized Telescope Mount
- Sky-Watcher EQ8-R Pro GoTo Equatorial Mount
- ZWO ASI2600MM Pro
- Canon EOS Ra
- Canon Rebel T3i (Modified)
- Altair Hypercam 183M
- ZWO ASI294MC Pro Color
- Starlight Xpress Trius SX-42
The ZWO ASI294MC Pro Cooled CMOS Camera.
- SkyTech CLS for Canon EOS
- SkyTech CLS-CCD for Canon EOS
- Baader Moon and Skyglow Neodymium (2″ Round)
- Optolong L-Pro (2″ Round)
- Optolong L-Pro for Canon EOS
- Radian Triad Ultra 2″ Round Mounted Filter
- Astronomik 12nm Ha, OIII, SII (2″ Round)
- Optolong LRGB + Narrowband Filter Set (2″ Round Mounted)
- Pegasus Astro Pocket Powerbox
- Pegasus Astro Stepper Motor Kit
- Kendrick Dew Heater Straps
- ZWO ASIair WiFi Camera Controller
- Xagyl 5-Position Filter Wheel
When traveling with my gear (to star parties, camping, etc.) I usually pack my telescope in this multi-purpose carrying case. It is made from a soft material but is strong enough to hold my medium-sized refractors such as the Sky-Watcher Esprit 100.
The company is called Rhino BagMate, and you can order them on Amazon. My favorite feature of this bag is that I can keep the guide scope, camera, and guide camera mounted to the refractor and still fit it inside the bag.
The Rhino BagMate is a quality case for telescopes under 40″ long.
Types of astrophotography
The term astrophotography encompasses many types of photography styles and techniques. For beginners, a DSLR camera and a tripod are all you need to start taking pictures of the moon and stars above. Modern cameras and kit lenses (The ones that come with entry-level DSLRs) are well equipped to capture the Moon, Auroras, the Milky Way, and much more.
Landscape Astrophotography is a beautiful form of photography and can be done with nothing more than a camera and tripod. Below is a photo of the constellation Scorpius, and the Planet Mars.
The photo displayed above is a stack of several 30 seconds exposures. This type of astrophotography involves using a camera lens in place of a telescope, often called “nightscapes”. The individual exposures can be manually stacked in Photoshop to reduce the amount of noise in the image.
You can later expand your astrophotography equipment to include hardware that can help you capture beautiful deep-sky photos. Some of those items include a telescope, an autoguiding system, dew heaters, and filters. Start slow, and acquire the gear you need as you learn.
The video below should help you understand the basic equipment needed for imaging deep-sky objects in the night sky with a DSLR camera. I still own most of the astrophotography equipment featured in this video, but I have since upgraded every aspect of this configuration from the mount, to the camera.
If you watched the video, you’ll know that I began my astrophotography journey capturing images with an entry-level DSLR camera. Since then, I have explored the world of cooled CMOS astronomy cameras, and even a CCD camera.
My astrophotography equipment continues to evolve (and expand) each year, in an attempt to improve the quality of my images, and my personal enjoyment of the hobby. By sharing my experiences on this website and the AstroBackyard YouTube channel, I have the unique opportunity to test and review new astrophotography products on a regular basis.
As my focus is currently deep-sky astrophotography, my equipment and reviews are geared towards items that aim to achieve success by this method. An alternative set of equipment and camera may be a better option for other types of astrophotography including planetary or lunar imaging, but I am not nearly as experienced in those areas.
Deep-sky images of nebula and galaxies are what pulled me into this hobby, and what keeps me coming back for more. Here is one of the earliest successful deep sky images I captured, the Andromeda Galaxy.
The image above was captured in 2012 using a stock Canon Rebel DSLR camera and a small telescope.
Astrophotography can change your life by providing you with a creative outlet like you have never experienced before. There are endless options when it comes to astrophotography equipment that can produce high-quality images.
Some hobbyists get carried away with the “gear” aspect of the hobby, and I can see why. There have never been so many options available to track and photograph the stars above. It is important to research the astrophotography equipment you are looking to purchase before you buy it. AstroBin is a great place to browse what others are using.
Complete deep sky astrophotography setup
Deep-sky astrophotography requires some specific equipment to get the job done. The hardware and accessories will vary widely, but there are a few common traits of nearly every astrophotography equipment rig:
- Equatorial Telescope Mount
- Primary Imaging Telescope
- Field Flattener/Reducer
- Primary Imaging Camera
- Camera Filters
- Autoguiding Telescope
- Autoguiding Camera
- Dew Heaters and Controller
- Field Laptop
- Power Supply
This does not include the adapters, cables, software, and many other items required to run these components. I’ll cover those items below.
Connecting Your Camera to a Telescope
A camera adapter will connect the telescope to the front of your DSLR as if it were a large camera lens.
A T-ring and T-adapter will allow the camera sensor to point through the focuser tube of the telescope. The T-ring locks on to the front of the DSLR like a camera lens, while the adapter screws into the t-ring and is inserted into the drawtube. Make sure to purchase the T-ring that is compatible with your brand of camera.
Connect your DSLR to the telescope with a T-Ring and a Prime Focus Adapter (step-by-step instructions)
This is one of the first steps you will need to take if you want to take deep-sky images through your telescope. Later on, you may want to replace the prime focus adapter with a field flattener/reducer for an improved overall image. The field flattener you choose will depend on the specifications of your telescope.
1. Explore Scientific ED102 CF Apochromatic Refractor
I upgraded from the ED80 Refractor to the ED102 CF in June 2016. This telescope has all of the features of the ED80 Triplet Apo from Explore Scientific, with a larger aperture and constructed with Carbon Fiber.
The increased focal length (714mm) allows me to get a deeper view of deep-sky objects and produce images of nebulae and galaxies in higher resolution than I could with the 80mm.
The lightweight of this telescope makes it excellent an excellent choice for astrophotography. You can add an autoguiding scope, guide camera, and DSLR camera to the payload, and still maintain a relatively light overall weight – in my case, requiring only a single counterweight.
I currently use a 2″ StarField 0.8X reducer-flattener/reducer when imaging through the Explore Scientific ED102 telescope. This provides a large 2″ opening to the sensor of my Canon T3i sensor.
It corrects the field of view so that my images contain sharp stars right to the edge of the frame. This lens also reduces the f-ratio and focal length of the telescope by 0.8X. Light is collected faster, and I am able to capture a larger area of the night sky.
This flattener/reducer screws directly into the T-Ring attached to your astrophotography DSLR. When it comes to field flatteners, it’s important to get the spacing right. The manufacturer will usually list the required spacing needed between the camera sensor and the lens of the adapter.
The Best Beginner Astrophotography Telescope
If you are looking to purchase your first astrophotography telescope, I have put together a resource that may help you make your decision.
I consider a small apochromatic refractor like the one listed below to be the best possible choice for beginners looking to get into astrophotography. The forgiving field of view, portability and reliability make an APO (apochromatic) refractor an excellent choice.
2. Explore Scientific ED80 Triplet Apochromatic Refractor
I no longer own this telescope! I have since upgraded to the larger ED102 CF.
This 80mm Apochromatic Triplet Refractor was my primary instrument for astrophotography for 5 years. This is a high-quality wide-field instrument. It produces sharp, high-contrast images due to the air-spaced triplet optical design, and low dispersion ED glass that virtually eliminates chromatic aberration.
ES ED80 Specs:
- Focal Length: 480mm
- Diameter: 85mm
- Focal Ratio: f/6
- Weight: 7.5lb
- Dovetail: Vixen
Perfect for astrophotography
There are several things I love about this telescope. Weighing in at 7.5 lbs, and including a high-quality aluminum padded case with a handle, this refractor is a breeze to transport. I also love the consistency of the images it produces.
I rarely use it visually, but the photos I take with it are always crisp and sharp with pin-point stars. With a focal length of 480mm, and Aperture of f/6, this telescope is perfect for wide-field astrophotography. The beefy 2 inch, dual-speed focuser makes imaging that much more accurate and stable.
Compact and convenient
The only downside would have to be this telescope’s small aperture. An 80mm telescope is not going to produce the stunning detail observed in a large reflector. Not having to collimate the scope before each use more than makes up for that!
Explore Scientific ED80 Example Photos
German Equatorial Mount
The Sky-Watcher HEQ5 pictured on the left is a modestly priced GEM (German Equatorial Mount) that has earned solid reputation among astrophotographers. This mount provides extremely high precision tracking, with a built-in autoguider port. I have since upgraded to the larger EQ6-R Pro version of this telescope mount.
Dependable and Stable
The Sky-Watcher HEQ5 is a great balance between stability and portability. It is lighter and smaller than the NEQ-6, but can still handle a 13.7 kg payload capacity. The go-to object database containing Messier, NGC and IC catalogs is a necessity for me.
With my heavy Orion Astrograph Reflector mounted to it, both of the included counterweights are needed. This is close to the maximum payload for this particular GEM. When shopping for an astrophotography mount, make sure you have accounted for the extra weight that your camera and autoguiding unit will add.
The Sky-Watcher NEQ6 is the next step up from the HEQ5. This equatorial mount shares all of the features of the EQ5 version, but with a heavier payload rating. HEQ5 vs. NEQ6 – Comparing astrophotography mounts.
The telescope mount is the single most important element of your astrophotography equipment.
Skywatcher HEQ-5 Pro Specs:
Mount Type: German Equatorial Mount
Counter Weight: 2 x 5.1Kgs
Motor Drive: 1.8 degree stepper motors
Hand Control: GoTo SynScan
Payload Capacity: 13.7 kg
Canon EOS Rebel T3i – Modified for Astrophotography
Full Spectrum Mod (Naked Sensor)
This camera was modified for astrophotography by removing the IR cut filter. This allows for more reds from emission nebulae and more to be collected by the camera sensor. The full spectrum method disables the camera’s autofocus functionality and negatively affects picture quality of the camera for daytime use. Since I use this DSLR exclusively for astrophotography, those issues do not impact me.
It is also wise to use a clip-in filter to protect the sensor of a full spectrum mod DSLR. I use an IDAS LPS filter when imaging RGB photos, and an Astronomik Ha filter when imaging H-Alpha. To learn more about modifying DSLR’s, visit Gary Honis’ website on the subject in detail.
I did not modify this camera myself as I did with my previous astrophotography camera, the Canon Xsi. This 600D was modified by a professional from a service called Astro Mod Canada.
Canon 450D (Rebel Xsi) modified
This is a popular, yet aging Camera model for DSLR Imagers. The live-view focus, inexpensive cost, and ability to mod quite easily make this a classic among astrophotographers. There is a fantastic video available from Gary Honis explaining in detail the steps needed to modify the Canon Xsi for Astrophotography.
I modified this camera for astrophotography.
It took longer than it should have, but I got the job done thanks to Gary’s thorough video. I also use an aftermarket battery grip to double my battery power for an imaging night.
Canon EOS 60Da
The Canon 60Da is Canon’s second (and currently latest) DSLR camera built for astrophotography. The 60Da shares many of the same characteristics of the original Canon 60D, with one important difference: The camera is more sensitive to the h-alpha emission line (656nm).
This sensitivity to to the hydrogen-alpha emission line comes in very handy when photographing emission nebulae targets such as the Eagle Nebula, or North America Nebula. This is the reason why many amateur astrophotographers remove the stock IR cut filter in their DSLR camera.
The Canon EOS 60Da is a bit of a collector’s item, and can be difficult to find these days. They stopped manufacturing the 60Da many years ago, and have not released a dedicated astrophotography camera since. Along with the 20Da, the 60Da is a rare find in the used Canon DSLR market.
Powering the camera all night long
Your imaging sessions will involve running the DSLR in low temperatures, which causes the camera battery to lose it’s charge even faster. Even a brand new stock camera battery will not make it through an entire night.
There are two ways to go about powering the camera for a night of imaging. An AC adapter is best, as it will never run out of power. Alternatively, a Battery Grip can provide you with enough power to image over 8 hours, even in the extreme cold. I ordered the AC adapter seen below on Amazon. Polaroid AC Adapter for Canon T3i.
I control my DSLR with my laptop running an application known as Astro Photography Tool. Using this software I am able to set the number of exposures I would like to take, achieve accurate focus, frame my target, and much more. I can also review each frame as I take it, on a large laptop display rather than on the back of the camera.
I use an A-Male to Mini-B USB cable to connect the DSLR to the computer. A longer cord will give you more flexibility when it comes to organizing your setup with all of the cables. Velcro ties do a great job of securing and organizing your cables.
Optolong L-Pro Filter
The Optolong L-Pro is currently my favorite broadband filter to color images from the city. This filters selective bandpass transmissions allow for a more natural-looking image, while ignoring many of the known wavelengths associated with artificial lighting.
The term “broadband” or “broad spectrum” simply means that it collects light across a broad area of the visible light spectrum. In contrast, narrowband filters isolate a very thin emission line and ignore almost everything else. A broadband filter is a smart option to choose when photographing broad-spectrum targets like galaxies, and reflection nebula.
The image below shows the dramatic difference this filter makes when photographing the night sky in the city. (Bortle Scale Class 8) For more information about light pollution filters, see this article.
Optolong L-eNhance Filter
The Optolong L-eNhance filter is a specialized dual bandpass filter designed to collect light on deep sky objects emitting light in the Ha and OIII lines. It also collects a small amount of the Hb line, but I have not been able to justify this in terms of solid data. Regardless, the L-eNhance is my go-to filter for emission nebulae targets such as the Omega Nebula.
I use this filter with my one-shot-color astronomy camera, the ZWO ASI294MC Pro. This filter was designed to be used with color cameras like this, or a DSLR.
Astronomik 12nm Clip-In Ha Filter
By combining regular RGB data (A typical color image) with images using a Ha filter, you can capture extraordinary astrophotography images.
A clip-in filter for your camera such as the Astronomik H-Alpha 12nm CCD filter makes it easy to start gathering Hydrogen-Alpha images with your existing DSLR.
This is called a narrowband filter and lets the h-alpha light of emission nebulae pass through to the camera sensor while blocking almost all of the other light spectrum.
SkyTech CLS-CCD Filter
In late May 2017, I reviewed a new Canon Astrophotography Filter: The SkyTech CLS-CCD. This is an affordable option for modified DSLR camera owners, and it does a great job of boosting the contrast of your DSO while reducing city glow.
Astrophotography Autoguiding System
Autoguiding is required to take successful exposures on a tracking mount longer than 3 minutes. The CCD Camera (In this case, the Meade DSI Pro II) takes quick 1 second exposures through the 50mm mini-scope. I use a program called PHD2 guiding to communicate the star movement in the DSI, to my Sky-Watcher HEQ-5 mount. The software sends signals to the tracking mount, making small adjustments to allow you to track objects with extreme accuracy for long periods of time.
It sounds more complex than it is.
The miniature Orion 50mm guide scope does exactly what it was designed for, and it does it well. It is lightweight and easy to focus. It was very affordable and I would highly recommend it.
Dew Heater Controller and Straps
I use dew heaters and a controller to keep my telescope lenses free of moisture. This is a crucial precaution when imaging at night as the ambient temperature drops and condensation can form on your optics. The dew heater bands are powered via a dew controller, and keep the telescope objectives dry all night.
Sony VAIO VGN-NW150D
The laptop is a very important element of my astrophotography equipment. I use my old daily work computer, an old Sony Vaio machine from 2009. A laptop that is reliable is essential for a headache-free night of deep-sky imaging. The computer runs the autoguiding software and controls the camera via the BackyardEOS application.
Update: I updated my computer for astrophotography in 2020, to an Acer ENDURO N3.
I keep the laptop computer in a plastic tote container on its side. This is a popular method as it keeps the laptop protected from the elements, and shields any stray light produced by the computer from your precious dark skies. I cut small holes in the sides of the container to run my cables through, as well as put the lid back on while I am imaging.
This setup allows me to leave the camera running throughout the night. The computer is protected from dew and the cold when the lid is on the container.
Tip: Keep the battery pack for the laptop inside the container – it will keep the computer warm!
Portable Power / Battery Pack
Eliminator 1000A/700W Power Box
If you are traveling to a dark sky location such as a campsite or park, you will need to have a way to power your astrophotography equipment away from electrical outlets. You do not need to buy an expensive power box like this to power your telescope and laptop. A deep-cycle marine battery with a converter will also work just fine.
Personally, I enjoy the convenience of a power box as I use it to power an assortment of electronics while camping. This particular power supply has 3 AC outlets, 1 DC outlet, and a USB port. The digital display shows me how many watts any particular device is using. This single unit powers my laptop, telescope mount, Kendrick dew heater controller, and the dew heater straps.
Adapters and Cables
Shoestring GPUSB, Cables, Dew Heaters
I use the Shoestring astronomy GPUSB adapter to connect my laptop via USB to my telescope mount for autoguiding. It has worked very well for me and has never let me down.
I have had to replace my RJ-12 cable before. If you are experiencing connection issues between your PHD guiding software and your mount, make sure to check to make sure that it is not a faulty cable! (This tip would have saved me a lot of headaches!) Over time, you will learn the quirks of each piece of your astrophotography equipment, and how to deal with issues as they come up.
Below, is the Shutter release timer remote control I use with my Canon T3i. This remote plugs into the DSLR, and opens the door to timed and long exposures from a safe distance. I purchased this on Amazon.
Photographing the night sky on a budget
My gear could be classified as “budget-astrophotography”, as I do not have the luxury of spending a fortune on this hobby. By no means do I own the best telescope for astrophotography, or a top-of-the-line camera.
Much of my gear was purchased second-hand from websites such as Canada-Wide Astronomy Buy and Sell, and Astromart. I bought my beloved Explore Scientific ED80 used from Astromart, and my Sky-Watcher HEQ-5 used from Astro Buy-Sell.
Astrophotography forums are also a great place to meet buyers and sellers.
Visual Astronomy with a Telescope or Binoculars
For visual observing through the eyepiece, I now use an Apertura AD8 Dobsonian reflector. The 8-inch aperture provides impressive views of both deep-sky objects and planets.
The Dobsonian mount design makes observing the night sky enjoyable with a comfortable viewing position, and a simple way of moving the telescope. The combination of affordability and performance is why I think this is the best astronomy telescope for complete beginners.
Binoculars are another affordable way to take your observing to the next level. The Celestron Skymaster Giant 15 x 70 Binoculars are a favorite at my local astronomy club.
I think every member owns a pair. They offer the “wow-factor” as far as views of star clusters, the moon, bright galaxies, and nebula under dark skies. Before owning these, I had no idea how amazing a nice wide view of the milky way could look when you use both eyes.