Leo 1 & Hickson 50 challenge
Posted 21 February 2014 - 03:42 PM
Posted 21 February 2014 - 03:44 PM
Posted 21 February 2014 - 04:46 PM
Posted 21 February 2014 - 05:05 PM
Posted 21 February 2014 - 05:08 PM
Posted 21 February 2014 - 05:52 PM
Thomas, it should be relatively easy in your 150mm f/8 refractor. When I was testing and playing with 150mm f/6 refractor that my friend just acquired, even complete novices were able to glimpse it. Before that, I could detect it also in 100mm refractor. All it requires is to run on good night.
Getting a good night is precisely the problem. Spring around here usually gives us very damp nights with lots and lots of haze, which will completely wash out Leo 1. On the few very good nights during this season we've had, I've simply forgot looking for it.
Oddly, the somewhat hazy nights doesn't seem to harm other galaxies too much, as long as they're not near any bright stars. Or maybe I'm just so used to humid nights, that I have nearly forgot what a really clear night looks like. I do get one or two each year, if I'm lucky.
Frankly, I have a feeling, that that's the case.
Posted 22 February 2014 - 12:41 AM
Once on a perfect winter night I was able to make out Leo 1 with my 6" dob from my back yard. In my opinion observing this object depends/relies on good transparency.
Hickson 50 took a bit more. The first time I located this group was using the 25" eq mounted newtonian at a school observatory a few km down the road from my place. Since then I've seen it a few times with my 20" from my driveway. This an object where visually at least aperture rules.
Posted 26 February 2014 - 11:36 AM
The first time I looked for HCG 50, I found a single very dim object at the right position that I assumed was HCG 50A. It seemed virtually stellar, but I had seen the group resolved in a 48" in good conditions and I knew they were very tiny.
On a later observation, though, at higher power (450x), I realized that the object I took for HCG 50A previously was a mag 16-16.5 star shown in Maurice's image just to the lower right of the galaxy group! When HCG 50A "popped", it was clearly fainter than that star and only visible intermittently.
Posted 26 February 2014 - 08:21 PM
Posted 26 February 2014 - 11:32 PM
Several years back I was at the 90th birthday party for the Plaskett Telescope here in Victoria where Dr. Paul Hickson served us the cake http://rascvic.zenfo...942ac#h105942ac I had a nice conversation with him and thanked him for presenting us visual observers with such a wonderful challenge. His comment was, "thanks and they are also so pretty to look at."
Posted 26 February 2014 - 11:38 PM
Very nice image of HCG 50. Do you know how far from Earth this group is? The farthest Hickson group that I have seen visually in my C14 from a yellow zone is Hickson 94 while some of the faintest groups were Hickson 57 and 56.
Bill, HCG 50 is a very distant group with a redshift of z = .139, corresponding to a light-travel time of ~1.8 billion years. That's 80% more distant than the Corona Borealis cluster!
Posted 27 February 2014 - 12:26 AM
Posted 27 February 2014 - 10:53 AM
48" (4/15/10): Four members of HCG 50 = Shkh 5 from mag 18.7( to 19.6( were visible at 623x and 701x. Three members were seen immediately at 623x and the 4th picked up and sketched at 701x (without prior reference to an image). All 4 members were very small (at most 10" diameter) and crammed into a region measuring 40"x24".
50A: at 700x appeared very faint, very small, 10" diameter. Situated 20" NE of a mag 16 star.
50B: the "B" component of HCG 50 lies 16" E of 50A (closest member) and 35" NE of a mag 16 star. At 700x, it appeared very faint and small, roundish and a little fainter than 50A. No elongation was noted.
50C: the "C" component lies 27" N of a mag 16 star and 25" NW of 50A. This was a difficult object at 700x (faintest of 4) with a low surface brightness and less than ~6" diameter.
50D: third brightest of 4 viewed in HCG 50. At 700x it appeared extremely faint and small, ~6" diameter. Forms the northern vertex of an equilateral triangle with 50A (22" S) and 50C (24" SW).
Posted 27 February 2014 - 07:23 PM
Posted 27 March 2014 - 10:17 PM