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The Ultimate Guide to Manual Guiding Telescope with Free Software Programs Online
Manual Guiding Telescope Download Free Software Programs Online
If you are interested in astrophotography, you probably know that one of the most challenging aspects of capturing stunning images of the night sky is keeping your telescope aligned with your target object during long exposures. This is where manual guiding comes in handy. Manual guiding is the process of making corrections by centering a guide star on a set of crosshairs at high magnification and using the right ascension and declination motor controls to keep the star centered when it starts to wander off. In this article, we will explain what manual guiding is, why it is important for astrophotography, and what software programs are available online for free to help you with manual guiding.
Manual Guiding TelescopeDownload Free Software Programs Online
What is manual guiding and why do you need it?
Manual guiding is different from tracking. Tracking is how your telescope's mount compensates for the Earth's rotation by moving at a constant speed along the right ascension axis. Most telescopes have basic tracking built in or can add it as an option. However, tracking alone is not enough for astrophotography because there are many factors that can cause tracking errors. These include:
Poor polar alignment: If your mount is not aligned well with the celestial pole (the point around which the stars appear to rotate), your telescope will drift away from your target object over time.
Periodic error: This is due to imperfections in the gears or motors of your mount that cause it to lag behind or speed up with each revolution. This results in a zigzag pattern of star trails in your images.
Atmospheric refraction: This is the bending of light as it passes through the air, which varies with temperature, pressure, and humidity. This causes your target object to appear slightly higher or lower than its true position, depending on its altitude and direction.
External disturbances: These include wind, vibrations, cable drag, etc. that can affect the stability of your mount and telescope.
Tracking errors can ruin your long-exposure photos of deep-sky objects, such as galaxies, nebulae, and star clusters. These objects are faint and require long exposures to capture their details and colors. However, if your telescope is not tracking accurately, you will end up with images that have star trails, elongated stars, or blurred objects. Here is an example of a photo of M31 (the Andromeda Galaxy) that was taken without guiding:
You can see two problems in this photo: one is that the stars trail off at an angle and the other is that the star trails have a zigzag pattern. The first problem is caused by poor polar alignment or incorrect tracking speed. The second problem is caused by periodic error.
To avoid these problems, you need to guide your telescope. Guiding is the process of making sure your telescope is tracking well by monitoring a guide star and making small corrections when it starts to drift off. You can do this manually or automatically. Manual guiding involves using a guide scope or an off-axis guider (OAG) attached to your main telescope and a crosshair eyepiece with an illuminated reticle. You look through the eyepiece and keep the guide star centered on the crosshairs by using the RA and DEC motor controls of your mount. This way, you can compensate for any tracking errors and ensure that your target object stays in the same position on your camera sensor.
What are the advantages and disadvantages of manual guiding?
Manual guiding has some advantages and disadvantages compared to autoguiding, which uses a small CCD camera and a computer to make corrections automatically. Here are some pros and cons of manual guiding:
Pros
Cons
You have more control over the guiding process and can adjust it according to the conditions.
You need more skill and experience to guide well and avoid mistakes.
You feel more involved in the astrophotography process and can enjoy the view of the guide star and other stars in the eyepiece.
You have to spend more time and attention on guiding and less on other aspects of astrophotography, such as framing, focusing, etc.
You can save money on buying a guide camera and a computer.
You may need to buy a guide scope or an OAG, which can add weight and complexity to your setup.
You can avoid potential problems with software compatibility, drivers, settings, etc.
You may miss some features and benefits that software programs offer, such as calibration, drift alignment, dithering, etc.
If you decide to try manual guiding, here are some tips and tricks that can help you:
Choose a bright guide star that is close to your target object. This will make it easier to see in the eyepiece and reduce the effects of differential flexure (the slight bending of your telescope or mount due to gravity or temperature changes).
Adjust the guiding tolerance according to your focal length, optical quality, sensor resolution, and seeing conditions. The guiding tolerance is how much the guide star can wander from the center of the crosshairs without affecting your image quality. It depends on how big the stars are in your images and how much elongation you can tolerate. A general rule of thumb is to use about 1.5x the star size as a guiding tolerance. For example, if your stars are 25 microns in diameter on average in your images (which corresponds to about 5 arc seconds for an Astro-Physics 130 EDT f/8 refractor), you can use about 37.5 microns (or 7.5 arc seconds) as a guiding tolerance.
a prism or a mirror to divert some light from your main telescope to a guide camera or eyepiece. A guidescope has the advantage of having a wider field of view and being easier to focus and align. An OAG has the advantage of avoiding differential flexure and being more compact and stable.
Practice manual guiding before attempting long exposures. You can start with short focal lengths, low magnifications, and bright guide stars. Then you can gradually increase the difficulty by using longer focal lengths, higher magnifications, and fainter guide stars. You can also use a stopwatch or a timer to measure how long you can keep the guide star centered on the crosshairs.
What software programs can help you with manual guiding?
Manual guiding does not require any software programs, but there are some free software programs that can assist you with manual guiding by displaying the guide star image on your computer screen and providing some useful features and tools. Some of these software programs are:
PHD2 Guiding: This is one of the most popular software programs for guiding, both manual and automatic. It is easy to use, compatible with many guide cameras and mounts, and offers sophisticated guiding and analysis tools for experienced users. It also has a built-in polar alignment tool, a drift alignment tool, a dithering function, and a comet tracking tool. You can download it for free from https://openphdguiding.org/.
GuideDog: This is another software program for guiding, both manual and automatic. It is simple and lightweight, but still provides some useful features such as exposure control, gain control, histogram display, star detection, etc. It also supports ASCOM drivers for guide cameras and mounts. You can download it for free from http://barkosoftware.com/GuideDog/index.html.
AstroSnap Pro: This is a software program for capturing and processing images from your main camera or your guide camera. It can also be used for manual guiding by displaying the guide star image on your computer screen and providing some basic features such as exposure control, gain control, zoom function, etc. You can download it for free from http://astrosnap.com/.
How to download and install these software programs?
To download and install these software programs, you need to follow these steps:
Go to the official website of the software program you want to use and click on the download link.
Save the installation file to your computer and run it.
Follow the instructions on the screen to complete the installation process.
Connect your guide camera to your computer and make sure it is recognized by the software program.
Connect your mount to your computer via a serial cable or a USB adapter and make sure it is recognized by the software program.
Adjust the settings of the software program according to your preferences and equipment.
Note: Some software programs may require additional drivers or components to work properly with your guide camera or mount. You can find these drivers or components on the website of the manufacturer of your guide camera or mount.
How to use these software programs for manual guiding?
To use these software programs for manual guiding, you need to follow these steps:
Polar align your mount as accurately as possible using a polar scope or a polar alignment tool.
Align your guidescope or OAG with your main telescope by pointing them at a bright star and adjusting their positions until they are aligned.
Focus your guidescope or OAG by using a Bahtinov mask or a focusing aid.
Select a bright guide star that is close to your target object and center it on your main camera sensor.
Start the software program and select your guide camera as the source.
Adjust the exposure time and gain of your guide camera until you get a clear image of the guide star on your computer screen.
Center the guide star on the crosshairs of the software program by using the arrow keys or the mouse.
Start the guiding function of the software program and monitor the guide star image on your computer screen.
Make small corrections to the guide star position by using the RA and DEC motor controls of your mount when it starts to drift off the crosshairs.
Start the exposure of your main camera and keep guiding until the exposure is finished.
Note: Some software programs may have different names or options for some of the steps above. You can refer to the help file or the manual of the software program for more details.
Conclusion
Manual guiding is a skill that can improve your astrophotography results by ensuring that your telescope is tracking accurately during long exposures. It can also be a rewarding and enjoyable experience that makes you feel more connected to the night sky. However, manual guiding requires some practice, patience, and attention, and it may not be suitable for everyone. If you want to try manual guiding, you can use some free software programs that can assist you with manual guiding by displaying the guide star image on your computer screen and providing some useful features and tools. In this article, we have explained what manual guiding is, why it is important for astrophotography, and what software programs are available online for free to help you with manual guiding. We hope you have found this article helpful and informative. Happy guiding!
FAQs
Q: How long can I expose without guiding?
A: It depends on your focal length, pixel size, tracking accuracy, and image quality standards. A general rule of thumb is to use the 500 rule: divide 500 by your focal length in millimeters to get the maximum exposure time in seconds without noticeable star trails. For example, if your focal length is 1000 mm, you can expose for up to 500 / 1000 = 0.5 seconds without guiding. However, this rule is only an approximation and may not work for every situation. You can experiment with different exposure times and see what works best for you.
Q: How do I choose a guide star?
A: You should choose a guide star that is bright enough to be easily seen in your guide camera or eyepiece, but not too bright that it saturates or blooms. You should also choose a guide star that is close to your target object, preferably within a few degrees, to minimize the effects of differential flexure and atmospheric refraction. You can use a star chart or a planetarium software to find suitable guide stars near your target object.
Q: How do I measure the guiding tolerance?
A: You can measure the guiding tolerance by using a micrometer eyepiece or a ruler on your computer screen. You need to know the pixel size of your main camera sensor and the focal length of your main telescope. Then you can use this formula to calculate the angular size of one pixel in arc seconds: pixel size (in microns) x 206 / focal length (in millimeters). For example, if your pixel size is 5 microns and your focal length is 1000 mm, one pixel corresponds to 5 x 206 / 1000 = 1 arc second. Then you can measure how many pixels or millimeters the guide star can move from the center of the crosshairs without affecting your image quality and multiply it by the angular size of one pixel to get the guiding tolerance in arc seconds.
Q: What are some alternatives to manual guiding?
A: Some alternatives to manual guiding are autoguiding, unguided imaging, or using a tracking platform. Autoguiding uses a small CCD camera and a computer to make corrections automatically based on the guide star image. Unguided imaging uses short exposures and high ISO settings to capture images without guiding and then stacks them together using software. A tracking platform is a device that moves your camera or telescope along with the Earth's rotation without using a mount or motors.
Q: Where can I learn more about manual guiding?
A: You can learn more about manual guiding by reading some articles, books, or forums on astrophotography and guiding. Some examples are:
Manual Guiding - Astrophotography - Articles - Cloudy Nights
li>Guiding a Telescope for Imaging Like a Pro - Sky & Telescope
The Handbook of Astronomical Image Processing - Richard Berry and James Burnell
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