You probably heard, and perhaps already observed comet NEOWISE, one of the most remarkable objects of this year’s summer sky. Watching a transient celestial event such as a comet is always a moment to remember!
In this post, we will guide you through a few relatively simple steps to observe the comet and record the observation with your eVscope, including something to spice up your observation.
1: When and where can I see a comet?
Use a planetarium app, such as Stellarium or Sky Safari, to learn at what time you can observe the comet and in which direction it will be observable.
Remember, your eVscope requires reasonable darkness to point accurately at the sky, typically one hour after sunset.
Here is an example with the SkySafari app.
2: In which direction should I point?
Most of the time, in the Explore tab of your Unistellar app, you can type the name of the comet to have your eVscope point at it.
However, with so many comets in the sky and many being detected a short time before they visit us, some may not be available in the app. Here is how you can enter its coordinates manually:
Find its celestial coordinates, aka Right Ascension (RA) and Declination (Dec), for instance using The Sky Live. Here is a link to get comet NEOWISE’s RA and Dec: https://theskylive.com/c2020f3-info
Then there are a few simple steps you need to follow:
- First, on the top of the page, enter your location.
- Then, go to the ephemeris calculator on the right column. Input the time at which you want to observe the comet in the ephemeris calculator. (You can get the correct time from the planetarium app.) Please note that the time displayed here is in UTC; you will need to adjust to your local time.
- On the result page, you will find the Right Ascension (RA) and the Declination (Dec).
- Finally, go to the bottom of the Explore tab of your app. There you will be able to enter the RA and Dec coordinates.
Following these simple steps, your eVscope will point toward the comet of your choice so you can enjoy observing this breathtaking show!
3: Ready to stitch?
Since a comet is such a large body, getting a complete image of it — including its entire tail — is usually impossible with just a single observation. Expert users have been able to stitch multiple and consecutive images of the comet. One of them, Julien de Lambilly, gave us a few tips explaining how he found a way to stitch together this image of comet NEOWISE:
“• I decided to install Photoshop, Gimp (open source software) should work too. The essential feature is to be able to make the image you want to paste transparent enough to be able to visually align it with the image underneath. So it is the layer management feature that is key. It allows you to stitch together images that are superimposed on each other, by playing on their respective opacity.
• Before the observation, it is necessary to plan the shooting path. From bottom to top, from top to bottom, zigzagging from left to right or vice versa, etc.
• To switch between shots, do not give more than 3 or 4 pulses on the eVscope joystick. This should allow overlapping of approximately 50% between shots.
• When moving the eVscope to the left, it is advisable to end with a pulse to the right. E.g. to move 3 points to the left, do 3x left and end with 1x right.
• For a bright object (such as NEOWISE), it is best to use the live view mode and adjust the exposure and gain manually to the desired result.
• Each image of the panorama should be made with the same exposure and gain settings in live view mode. In enhanced vision mode, this point becomes less important if each image is captured with a cumulative exposure greater than 5 or 10 min.
• In live view mode, the field rotation may vary between shots. The user will then be better advised to rotate the image to be pasted in Photoshop, in addition to the up/down and left/right translation maneuvers. In enhanced vision, the problem does not exist since the software performs a derotation while compiling the images.
• To make a screenshot in live view, you must place the application in landscape format and tap on the image so that the control buttons and menus disappear.
• In enhanced vision, depending on the field rotation, the image may show stacking artifacts at the edges. The user will then have to cross the edges of each image before being able to paste them together.”
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Comets, the ephemeral night sky beauties, are now yours. It is time to observe, enjoy and share this moment with the world!! ☄️