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A Tale of Two Globulars

Started by markvcostello3, 10/19/2015 02:20PM
Posted 10/19/2015 02:20PM Opening Post
Hello, everyone. I just thought I'd check in with an account of different impressions of two globular clusters during a couple of observing sessions last week. I'm trying to work in my routine some jaunts down the "road less traveled." That is, I'm working in observations of deep sky objects seen by me for the first time. Last week they included first time observations of Open Clusters NGC 6800 and NGC 6830. Also, I observed for the first time Globular Cluster M71 and then in a different session came in to do a "comparison" with Globular M15, an object that has graced the field of view in my rig a number of times. The interesting thing about these two is that while M15 is easily the brighter cluster, I was able to dig out more detail in M71. After prolonged observation, drawing, and note taking, it seemed that I could catch some individual stars in M71. It wasn't anything close to full resolution, just a star here on the edge, a couple more over there, then a tied set of two or three strings of stars across its face. On the other hand, M15 didn't show any individual stars. The most I was able to get was a bit of mottling.

Later on, I read about the two clusters. Leave it to me to first look at something then later read about what I was looking at. :lol: But it made sense. M15 is rated as one of the densest globulars while M71 is so loose that it could be mistaken for a denser open cluster (like M11). I believe that the stars I saw were a few of the really bright stars in M71....

The telescope used was an ES AR127. The eyepieces used for the prolong observations gave powers of 69X, 92X, 118X, and 165X.

Best Regards,

Mark Costello
Matthews, NC, USA

"I hear you're mechanically inclined. Did you ever do anything with perpetual motion?"

"Yeah, I nearly had it a couple of times."
Posted 10/19/2015 04:43PM #1
Nice observations, Mark! I love deep sky visual - especially objects that are challenging for whatever instrument I'm using. And I also will pick a category and compare: Like planetaries tonight, globulars tomorrow, galaxies next time. Even very bright stars just to see what might be lurking in the same field. Globulars especially lend themselves to aperture. They are fascinating in my 5-inch refractor and mildly resolvable. The big reflector zooms them right in with uncountable stars. Tom Dey

29-inch Dob in a dome
36-inch upgrade soon
LUNT 80/80 solar scope
FLI 6803 cam
APM 100mm APO Binos
JMI RB-16 Night Vision Binos
Zeiss 20x60 IS binos
Posted 10/20/2015 07:32AM #2
Mark - sounds great, those are a couple nice globulars. M71 is unusual, when I was a kid it was classified as a dense OC, at some point they officially decided it's a diffuse globular. Observing a bunch of GC's in a row is fun because you see the different characteristics of each one.

This time of the year there aren't many GC's to view, but the OC's in the winter Milky Way are numerous and bright.