(IAAC) Arp List in 8" Scope
As many of you may be aware, the Astronomical League has started an Arp
Galaxy observing certificate. Like the Messier, Herschel I and II and
others, the AL encourages setting and meeting observing goals. The Arp list
originally started as an imaging certificate where it is necessary to image
(CCD or film) 100 of the 338 objects on Arp's Catalog of Peculiar Galaxies.
It was later decided to allow visual observers to work towards the
certificate as well.
This past weekend I managed (just!) to observe my 100th Arp galaxy using a
Celestron 8" SCT. Many of these objects are much fainter than the working
limit of my old C-8, but there are (according to the AL observing club
webpage (http://www.mcs.net/~bstevens/al/obsclub) at least 100 galaxies of
mag 13.5 or brighter. 195 Arp galaxies have NGC numbers and it was these
that I pursued.
This is not nearly as easy an observing goal as the Herschel 400 list! I
spent 5 hours one night before positively identifying a single Arp galaxy,
after having tried for at least half a dozen. While a few of the Arps are
very bright (M82, M51, M101, M87... etc), many require the darkest skies you
can find and a lot of patience and persistence. However, it is rewarding to
know that the certificate can be completed with an 8" scope even though a
12.5 incher is recommended on the Arp page.
If you have finished the Herschel 400 and are looking for another observing
challenge, give the Arp list a try. Next on my observing schedule - the
Herschel 2. I now have 103 of those and counting!
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