(On that same note, while Ptolemy's Cluster M7 (
Anyway ... just asking.
Thanks!
Mike M.
Thanks. That was my intuition, but it helps to hear that from someone who knows. I did a lot of sweeping because I know that the eyes often catch movement. I will work more slowly and put more effort into averted vision.Bigzmey wrote: ↑Tue Jul 27, 2021 8:28 pm M4 does not stand well to LP. When I observed it in 90mm refractor from home, it was very dim, just a ted brighter than the background, easy to miss when you swing by. Try to identify the spot by surrounding stars and then sit on it for awhile. Employ averted within and try different powers.
Well, I have a 102. So, we're in the ballpark.Don Pensack wrote: ↑Tue Jul 27, 2021 6:40 pm This cluster is fully resolved in a 100mm scope and mostly resolved in an 80mm.
Tomayto, tomahto. I was born in November. but... moving right along...Don Pensack wrote: Here is what I suggest:
... Scorpius (the name of the constellation--Scorpio is an astrological sign) is ...
AZ mount of course and with a correcting prism so that right and left are right and left.Don Pensack wrote: point at Antares and move due west (or clockwise in azimuth if an alt-az mount)
--when you think you may be detecting it, increase the magnification to at least 100x.
See the userbox: I am in Austin, Texas. 30 North. Scorpio-ius is higher than the rooftops. Pretty easy to spot. Back in May when I was not finding the head of Virgo, I turned my attention to Corvus. (On my blog at https://necessaryfacts.blogspot.com/202 ... corvi.html )Don Pensack wrote: That will darken the background sky in the eyepiece and make a lot of fainter stars visible.
At that point, even if it is low in the muck, it should be visible. At -26.5°, even at 51°N, it will be 12.5° above the horizon.
So I am told. Hence the frustration. But thanks for the pointers. Everything helps.Don Pensack wrote: It is the nearest, and probably brightest, of all the globular clusters visible to northern sky viewers.
Thanks. My kind of town... that toddlin' town... I am farther south. Thanks also for the navigation tip. I know that it is between Antares and Sigma Sco but the "triangle" image fills in the picture. Darker skies.... Yes, don't we all wish for them. But I would trade them all for an industrial society because absent the pollution, we could not have the telescopes in the first place. You know, North Korea has dark skies. Actually, that's what star parties are for and I might actually get around to traveling to one next year or the year after or whenever. It's just me: wet blanket. But I appreciate your reply and your assistance.pakarinen wrote: ↑Tue Jul 27, 2021 1:27 pm I was perplexed when I first started searching for it. It's not visible from my home skies (B7-8) with my 80mm and only occasionally is it visible with my 120mm. It seems sensitive to LP / being low in the muck (or my skies just really are garbage). It is a pretty easy target under a darker sky.
When I've succeeded in seeing it at home, I've centered on Antares and then scanned west to the triangle of Antares, M4, and Sigma Sco. It shows up as a faint smudge, which I confirm is really there by wiggling the OTA a bit. I don't think I've ever seen it when the moon was up. Good luck!
Will do... try and try again. 8-inches is my largest reflector and it is still in the boxes for now. (The collimating tools arrived today. I put them and the Star Testing book in the crate, too. Now, it's a package.)helicon wrote: ↑Tue Jul 27, 2021 1:27 pm I've been able to see it in my 15x70 binos as a puffball near Antares. Through the ten inch, it shows rather well and has resolution. It is not as impressive through my 6" Achro and I have yet to see it through my 5.1" newt. So my light pollution is probably just as bad as yours is. I would keep trying to see it.
Yeah, I know that there's a rich field available. I'm just trying to find it all, starting with what should be the easiest. I am signed up for our club's dark sky site in August. We are having an astrophotography tutorial. I am not up for that, but I am interested in seeing how the instructor works the problems and how my comrades fare. So, I plan to take all of my telescopes and spend the night overnight.helicon wrote: Here are some more bright globulars near Antares...Of course, if you get out to some darker skies there is a globular even closer to Antares than M4...NGC 6144 shining at magnitude 9.3. I also have observed this one as a faint patch with no resolution.
MistrBadgr wrote: ↑Tue Jul 27, 2021 9:22 pm I had to get down to a pupil size of 2.5mm ... My best view was at about 1.5mm. pupil. ... "
Thanks. Arithmetic is easy. I will do the maths and make a chart for my notebook. Good to know.MstrBadgr wrote: To get the pupil size, divide the active diameter of your mirror or the actual opening diameter of your refractor by the magnification you are using and you will get your pupil size in mm. A short cut version is to divide the focal length of your eyepiece by the focal ratio of your scope.
Thanks, again. I turned to Harrington's Star Ware first and then went out online and now I have quite a bit of background in pupil size. It is pretty easy to calculate and I made a table for my notebook. I am not sure that the numbers tell me anything I care to know, versus say, Field of View.MistrBadgr wrote: ↑Wed Jul 28, 2021 2:02 am Hi Michael, Pupil size is the size of the image when it enters your eye. Going by pupil size is a pretty good way to relate ...
And it does not face downtown Austin, another plus! I already know well that although it is nominally on or near theDon Pensack wrote: ↑Wed Jul 28, 2021 2:14 pm At 30°N, M4 culminates (crosses the meridian) at an altitude higher than Polaris ...
Good advice. I can try several combinations. I can mate my 2X Barlow with my 5X focal extender with the 6mm ocular for 1100X. If nothing else, I can check my viteous humor for proteins.Don Pensack wrote: ↑Wed Jul 28, 2021 2:14 pm
Worry more about the magnification than the amount of glass. ... If the field is darker, it's because of magnification, not the number of glass elements in the focuser.
There is this Allen key trick you can use to measure your pupil size - although, probably not fully dark-adapted.mikemarotta wrote: ↑Wed Jul 28, 2021 11:08 pmThanks, again. I turned to Harrington's Star Ware first and then went out online and now I have quite a bit of background in pupil size. It is pretty easy to calculate and I made a table for my notebook. I am not sure that the numbers tell me anything I care to know, versus say, Field of View.MistrBadgr wrote: ↑Wed Jul 28, 2021 2:02 am Hi Michael, Pupil size is the size of the image when it enters your eye. Going by pupil size is a pretty good way to relate ...
I agree with your closing observation that a lot depends on personal parameters. On that basis, I also made an appointment with my optmetrist to get my own pupils measured for full dark dilation.
Best Regards,
Mike M.
Thanks! I went to the O'Reilly site and read the out-take from the book. The book looks interesting on it own merits, also. I did have to follow a different link to get the picture of Barbara using the Allen wrench. The verbal description was not clear to me. The picture made it obvious.turboscrew wrote: ↑Thu Jul 29, 2021 7:24 am There is this Allen key trick you can use to measure your pupil size - although, probably not fully dark-adapted.
I guess the actual largest pupil size when observing is more important than a "hypotethical" maximal pupil size, that never happens in actual observing.mikemarotta wrote: ↑Thu Jul 29, 2021 2:45 pmThanks! I went to the O'Reilly site and read the out-take from the book. The book looks interesting on it own merits, also. I did have to follow a different link to get the picture of Barbara using the Allen wrench. The verbal description was not clear to me. The picture made it obvious.turboscrew wrote: ↑Thu Jul 29, 2021 7:24 am There is this Allen key trick you can use to measure your pupil size - although, probably not fully dark-adapted.
My backyard is never going to be fully dark, but the process can be helpful. And according to the motto of Faber College (from Animal House), "Knowledge is good."
Best Regards,
Mike M.
Thanks, again. I never noticed that. I never perceived the differences. The other night when I was going for the highest powers but using lower powers (32mm = 20x; 40mm = 16X) for locating, I saw how much brighter the background was.Don Pensack wrote: ↑Wed Jul 28, 2021 2:14 pm If the field is darker, it's because of magnification, not the number of glass elements in the focuser.
Same here, I was able to see Milky Way from the patio - not any more.mikemarotta wrote: ↑Wed Aug 04, 2021 2:15 pm Also, over all, the neighborhood skies were more transparent five or six years ago. I have notes about the Milky Way which now is just a rumor.
Bigzmey wrote: ↑Wed Aug 04, 2021 4:59 pmSame here, I was able to see Milky Way from the patio - not any more.mikemarotta wrote: ↑Wed Aug 04, 2021 2:15 pm Also, over all, the neighborhood skies were more transparent five or six years ago. I have notes about the Milky Way which now is just a rumor.
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