We use a google calendar as a group calendar. Motivation for this is documented at the end of this page, but it mainly comes down to better support for google calendar in the different calendar clients people use.
Warning: any work related sensitive data should not be put on a google calendar, but use then an outlook calendar instead.

Existing Group Calendars

sws social events

purpose: publish social events in the SWS department
owners: Harco Kuppens, Mairieli Wessel, Sven-Bodo Scholz
access to public calendar readonly (no authentication required):
- using a webpage: https://calendar.google.com/calendar/embed?src=673803b665fea319a9af80e9f39d3d7c3310200ca9db88ed073fa872f86a80e5%40group.calendar.google.com&ctz=Europe%2FAmsterdam
- using an ical url: https://calendar.google.com/calendar/ical/673803b665fea319a9af80e9f39d3d7c3310200ca9db88ed073fa872f86a80e5%40group.calendar.google.com/public/basic.ics

note: the webpage of "sws social events" calendar is also linked from the "SWS seminar" page on the SWS website for easy access.

Using the Group calendar

Viewing the group calendar

We make the group calendar public, making it viewable in a browser(html page) or in a calendar client(ical url) without needing any authentication. The webpage is directly viewable in a browser. In your calendar program you can subscribe to the ical url to view the calendar in that program. See above for the specific urls for the specific group calendar.

subscribe to ical calendar in outlook

The procedure to subscribe to an iCal calendar in the outlook desktop application is very strange: you have to login to the online https://outlook.com web version of outlook and subscribe there. Then automatically the subscription will appear in your outlook desktop application. Subscribing online is done using the following steps:

login with your ru-credentials to https://outlook.com
goto the calendar view
on the left panel press on the item "Add calendar"
in the popup window select on the left panel "Subscribe from web"
then supply your iCal URL, and press the "Import" button.
Note: the name "Import" is wrong, because you really "subscribe" and you get to see also all new events added to the calendar.
then the calendar is added! You can change its name and color to your own liking.

Src: https://office-watch.com/2022/yes-you-can-add-an-online-calendar-to-outlook-for-mac/

subscribe to ical calendar in apple calendar

goto menu "File" -> "New calendar subscription"
in the popup menu fill in the iCal URL and press the "Subscribe" button
then you get another popup window in which you can configure how the calendar is displayed and how often it gets synchronized. I would say synchronise every day would be ok. Then press the "OK" button.
you calendar should be added now and visible on the left panel under section "Other".

subscribe to ical calendar in thunderbird

open the calendar view in thunderbird
right click in the left "calendar panel" a popup menu appears
in the popup menu select "New Calendar..."
in the new popup window select "On the Network" and press the "Next" button
in the new window leave the "Username:" box empty,
and fill in the iCal url in the "Location:" box
and check the checkbox "This location doesn't require credentials"
then press the "Find Calendars" button
it finds you calendar (with name "basic")
with the "Properties" button you can configure display and sync settings.
The "properties" can also be edited later on.
press the "Subscribe" button to finally subscribe!

Editing the group calendar

To be an editor of the group calendar you need a google account to authorize yourself at google. This google account is used in your calendar program to access the group calendar editable.

You have to ask another group member which has owner rights to give you edit rights.

Owner sends calendar invite for editing

An owner can give another group member edit rights to the group calendar as follows:

On your computer, open Google Calendar.
On the left side of the page, click My calendars.
Hover over the calendar you want to add someone to, and click Options and then click Make changes to events.
In the "Share with specific people" section, click Add people.
Enter the email address of the person or group you want to make an owner.
In "Permissions," select Make changes and manage sharing.
Click Send.

Editor: First step: add calendar to your google account online

The new editor gets an invitation link sent to its google account. He first has to click on this link to add the calendar to his google account.

Editor: Second step: add google account to your calendar application

Then in a second step, the new editor can open the calendar in its calendar program by adding his personal google account to this calendar program. Note: also for Outlook desktop application it is possible to add your google account, and then edit its calendars!

Important: to add your google account to your outlook calendar you have to first enable imap in your google account settings, and then enable 2FA for your google account, such that you can create an app password for the "Outlook" application alone. Detailed instructions are here.

If your google account is added to your calendar program for Apple Calendar and Outlook Calendar then, the calendars belonging to the google account, become automatically visible.

UPDATE: In the online outlook.com website and the Outlook desktop application for Mac we get automatically also the calendars available in outlook. However in windows version of Outlook desktop application the calendars do not come available. Seems the windows version of Outlook only supports the mail of your google account, but not your calendar.

However for Thunderbird you still have to add the calendar explicitly. You can do this by right-clicking in the left calendar pane and choosing "New Calendar..", and then choosing "Google Calendar". It then allows you to select which calendars to show from your google account.

Note: if a reader/editor deletes the calendar, then the calendar itself is not deleted, the person just did unsubscribe.

Note: as an editor you can change the name of the calendar, but that is only for yourself. Others will see the unedited name.

Background info about google calendar as a group calendar

Why we use google calendar as a group calendar

Microsoft calendar is only supported by outlook clients you cannot open this in other calendar programs. Because in our group people use other clients like thunderbird and apple calendar we needed to search for another solution. Note: another problem was that it was also not possible to publish the Microsoft calendar online on a website for easy read-only access.

Google calendar however is supported in other calendar programs which you can access read-only for a public calendar without needing credentials however, you must have a google account credentials for editing.
EXCEPTION: only on windows the google calendar does not work in the Outlook desktop program, however works for online outlook and outlook for Mac. As a workaround for windows you can use thunderbird as desktop client for your google calendar.

Because only for editing the calendar a google account is needed, and most people have such an account, we decided that it won't be a problem to use google calendar as a group calendar.

Conclusion:
Microsoft calendar is a nightmare to cooperate with other calendar programs. Google provides a solution, but for editing you need a google account. Most people already have a google account, so I don't see a problem there.

Features google calendar

Overview features google calendar:

readonly viewing (no credentials needed)
You can make a google calendar public, making it viewable in a browser(html page) or in a calendar client(ical url) without needing any authentication. I can put these urls in our intrawiki and initially send them around in an email.
editable by sharing (google account required)
You can share the calendar editable, by inviting a new editor using its google account. The new editor gets a invitation link sent to its google account. He first has to click on this link to add the calendar to its google account. Then in a second step the new editor can open the calendar in its calendar program by adding his personal google account to this calendar program.
Note: if your google account is added in your calendar program then in Thunderbird you still have to add the calender explicitly, but for Apple Calendar and Microsoft Outlook it will automatically be added.
multiple owners
You can give ownership to multiple google accounts, so we are not becoming dependent on a specific person doing the administration of the calendar. An owner can give edit rights to google accounts.

Setup a google calendar as group calendar

The calendar can be made public so that everyone can read it without needing to do any authentication. This is convenient and for most calendars also not a problem when the calendar events don't need to be private.

Each calendar has an owner. The owner can handout edit rights to group members. If the owner of the calendar leaves the department we can transfer the calendar to another owner. We can even have multiple owners in a shared ownership. The ownership can only be given to a google account. So setup the calendar such that you have multiple owners. When one owner is sick, then still another owner is available. However be careful with handing out ownerships, because each owner can permanently delete the calendar.

Steps to create a group calendar:

Create a google calendar in your own google account.
Go to calendar settings:
- make the calendar public:
  - at the integrate calendar section you can find Public URL to this calendar and Public address in iCal format.
    Document these URLs above in the "Existing Group Calendars" section of this wiki page.
  - check the checkbox Make available to public
- add more owners:
  - your account is by default owner which you can see because it has by default the Make changes and manage sharing permission
  - then add more owners by giving their google accounts the Make changes and manage sharing permission
  - document the owners above in the "Existing Group Calendars" section of this wiki page, so that people know who to contact for getting edit rights.
  - Note: be careful with handing out ownerships, because each owner can permanently delete the calendar.
Done!

Share ownership of the group calendar

To become an owner of the group calendar you need a google account to authorize yourself at google.

You have to ask another group member which already has owner rights to give you also ownership.

An owner can give another group member also ownership of the group calendar as follows:

On your computer, open Google Calendar.
On the left side of the page, click My calendars.
Hover over the calendar you want to add someone to, and click Options and then click Settings and sharing.
In the "Share with specific people" section, click Add people.
Enter the email address of the person or group you want to make an owner.
In "Permissions," select Make changes and manage sharing.
Click Send.

The new owner gets an invitation link sent to its google account. He first has to click on this link to add the calendar to his google account. Then in a second step, the new editor can open the calendar in its calendar program by adding his personal google account to this calendar program. Note: if your google account is added to your calendar program then in thunderbird you still have to add the calendar explicitly, but for apple calendar, it will automatically be added.

Note: I had the idea to make each editor also an owner, so each editor can also give edit rights to other group members. In this way, we distribute the edit management between the editors. However, I discovered that as an owner you can permanently delete the calendar. The risk exists that some editor by accident deletes the calendar. So I decided to keep owners and editors separate. To get edit rights you have to ask an owner.

Group Calendar

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