ERROR: The certificate of `raw.githubusercontent.com' is not trusted

Question

I am trying to use wget to retrieve some file from github over a remote server (ssh), here is what I get:

$ wget  https://raw.githubusercontent.com/aseemk/seadragon-ajax/master/seadragon-min.js
--2014-11-26 09:30:14--  https://raw.githubusercontent.com/aseemk/seadragon-ajax/master/seadragon-min.js
Resolving raw.githubusercontent.com (raw.githubusercontent.com)... 185.31.19.133
Connecting to raw.githubusercontent.com (raw.githubusercontent.com)|185.31.19.133|:443... connected.
ERROR: The certificate of `raw.githubusercontent.com' is not trusted.
ERROR: The certificate of `raw.githubusercontent.com' hasn't got a known issuer.

Same goes for curl:

$ curl -o bla  https://raw.githubusercontent.com/aseemk/seadragon-ajax/master/seadragon-min.js
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0curl: (60) SSL certificate problem: unable to get local issuer certificate
More details here: http://curl.haxx.se/docs/sslcerts.html

curl performs SSL certificate verification by default, using a "bundle"
 of Certificate Authority (CA) public keys (CA certs). If the default
 bundle file isn't adequate, you can specify an alternate file
 using the --cacert option.
If this HTTPS server uses a certificate signed by a CA represented in
 the bundle, the certificate verification probably failed due to a
 problem with the certificate (it might be expired, or the name might
 not match the domain name in the URL).
If you'd like to turn off curl's verification of the certificate, use
 the -k (or --insecure) option.

Using wget option: --no-check-certificate seems like a hack, what could I be missing ?

Answer 1

The solution was simple, from my debian system simply install:

$ sudo apt-get install ca-certificates