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courses:phy100:4 [2023/10/15 00:12] – [2.2 Size] asad | courses:phy100:4 [2023/11/14 23:44] (current) – asad | ||
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- | ====== 4. Imaging with iTelescope | + | ====== 4. Imaging with Unistellar eQuinox |
- | https:// | + | https:// |
- | + | ||
- | We will use iTelescope to take pictures of deep-sky objects. Browse their website using the link given above. | + | |
- | + | ||
- | ===== - Utah desert observatory ===== | + | |
- | {{url> | + | |
- | + | ||
- | {{url> | + | |
===== - Object selection ===== | ===== - Object selection ===== | ||
- | The very first thing an astronomer does as part of her observation is to select an ' | + | Select |
- | Each group has to use the [[https://go.itelescope.net/ | + | {{:courses: |
- | Remember that you have to give the time in the current | + | The numbers below follow |
+ | - Targets: select **Deep Sky**. | ||
+ | - **Location** and **date**: either select 'Use my current | ||
+ | - Moon: the moon is in ' | ||
+ | - Sunrise and sunset times, and the astronomical **sunset** (from when it is totally dark) times are given. | ||
+ | - **Weather**: | ||
+ | - Search parameters need to be set for selecting a sample of your desired targets. The target should be **visible** from around 6:30 pm (astronomical sunset) to 9 pm. | ||
+ | - Minimum **altitude**: | ||
+ | - Object **type**: select galaxy, globular cluster or interstellar matter. | ||
+ | - Distance from the **moon** of the target should be at least 90 degrees, as far as possible. | ||
+ | - Apparent magnitude (**brightness**) of the target should be between 5 (barely visible with naked eye) and 10 (faint but observable with our telescope). | ||
+ | - Apparent **size** of the target must be between 10 arcminutes and 40 arcminutes because the **field of view** of our telescope is around 40 arcminutes. The object should fit within the field of view, that is the **frame** of the picture. | ||
+ | - 7 results | ||
+ | - The list can be sorted by various things, here sorted according to ' | ||
+ | - M 110 is the first galaxy | ||
+ | - On 17 Nov, it will rise at 06:02 pm, reach its highest altitude at 08:50 pm and set at 11:48 pm. | ||
+ | - The track followed by the galaxy in our sky is shown here. Its maximum altitude from the horizon will be 72 degrees at 08:50 pm and it will be toward north during that time. | ||
- | Next, select a few types of object that you are interested in. I suggest you go for **galaxies**, | + | ==== - Visibility |
- | + | ||
- | You will see a list of observable astronomical objects with their name, preview picture; and details about their position, brightness (magnitude), | + | |
- | + | ||
- | ==== - Transit time ==== | + | |
The **visibility** has three numbers, the first one is the rising time, the second one the **transit** time, and the last one the setting time. The difference between the rising and setting time is usually around twelve hours, and the transit occurs when the object is right above our head, when the object reaches the highest position in the sky on a given night. | The **visibility** has three numbers, the first one is the rising time, the second one the **transit** time, and the last one the setting time. The difference between the rising and setting time is usually around twelve hours, and the transit occurs when the object is right above our head, when the object reaches the highest position in the sky on a given night. | ||
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==== - Size ==== | ==== - Size ==== | ||
- | The **size** of an object is also very important. It should be too small or too big compared to the **field of view** (FoV) of the telescope. The size and FoV are measured in angles, so we need to understand the units of angle **degree**, **arcminutes** and **arcsecond**. | + | The **size** of an object is also very important. It should |
{{: | {{: | ||
- | The angles within a complete circle are conventionally measured in **degrees**. A circle has a total of 360 degrees, each of the four quadrants having exactly 90 degrees. One degree is divided into 60 arcminutes (' | + | The angles within a complete circle are conventionally measured in **degrees**. A circle has a total of 360 degrees, each of the four quadrants having exactly 90 degrees. One degree is divided into 60 arcminutes (' |
$$ 1^\circ = 60' = 3600'' | $$ 1^\circ = 60' = 3600'' | ||
- | because $1'=6-'' | + | $$ 1 \text{ deg } = 60 \text{ arcmin } = 3600 \text{ arcsec } $$ |
- | ==== - Magnitude | + | |
+ | because $1'=60'' | ||
+ | |||
+ | In this course, you will encounter astronomical objects that have sizes of around a degree or a few arcmins. For example, the size of the sun or the moon is around 0.5 deg, that is around 30 arcmin. On the other hand, the size of the Andromeda Galaxy in our sky is more than 3 deg, too big for our telescopes. | ||
+ | |||
+ | Our telescopes have FoVs of around 1 deg. | ||
+ | |||
+ | ==== - Brightness | ||
===== - Observation ===== | ===== - Observation ===== |
courses/phy100/4.1697350328.txt.gz · Last modified: 2023/10/15 00:12 by asad