using opendns.com's servers i am able to resolve this hostname (10AM pacific time, 1 oct 2012)
; <<>> DiG 9.6-ESV-R4-P3 <<>> update.pixinsight.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 43361
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;update.pixinsight.com. IN A
;; ANSWER SECTION:
update.pixinsight.com. 14400 IN A 173.205.125.124
;; Query time: 108 msec
;; SERVER:
;; WHEN: Mon Oct 1 09:59:35 2012
;; MSG SIZE rcvd: 55