Sky this Week » Globular Cluster

Terzan 11 Globular Cluster in Sagittarius

Vern — Wed, 12 Sep 2007 23:58:54 +0000

The image below is of a faint globular cluster in Sagittarius called Terzan 11. Dark area surrounding cluster is probably caused by obscurring dust which extinguishes light from an area that is rich with Milky Way stars (compare to star field on the left). The globular is listed as magnitude 16.4 so it is a tough object even for large aperature scopes. Tough to guess the classification as it so faint. Location was confirmed with DSS POSS2 image. I should have posted this before but I mis-filed the images and didn’t come across them until this afternoon.

Images were taken at Fox Park in Wyoming on July 15, 2007 at 03:35 am MDT with a Celestron Nexstar 11 telescope, F3.3 focal reducer, and Stellacam II video Camera. Stellacam set at 14/14 gain, medium gamma, and 256 frame integration (8 sec). Registax4 used to dark subtract, flat field correct, align, stack, end brightness enhance 30 frames.

Sky was mostly clear, some high thin clouds, transparency generally quite good despite the high humidity 70%, dew on everything, temperature about 38°F, and no wind.

Messier 13

Vern — Fri, 01 Jun 2007 03:05:15 +0000

On a clear, dark, summer night I always love taking a look at the great globular cluster Messier 13 when its high overhead. It looks good in small scopes, but the view in a large scope such as my friend Gary’s 30″ dob is stunning. So many worlds, hundreds of thousands of suns in close orbits. Their skies must be filled with bright stars — maybe so many and so bright that their view of the universe is limited.

Image taken around 1 am Sunday morning May 27, 2007 from Louisville, CO with a Celestron Nexstar11 telescope, a F6.3 focal reducer, and a Canon Xti camera. Camera was set to ISO 800 and a 30 second exposure. Registax4 was used to align, stack, and enhance brightness. Sky was mostly clear, temperature 58° F, turbulence between 5 and 6/10, no wind, and transparency was quite good.

Messier 15 and Pease-1

Vern — Thu, 07 Sep 2006 06:33:18 +0000

Messier 15 located in the constellation Pegasus is one of the densest planetaries known. Located northeast of the center of the globular is a challenging object to find, planetary nebula Pease-1. This was the first nebula discovered within a globular by Francis Pease in 1928.

Follow the directions by Doug Snyder to locate this planetary which very near the core of M15 — you’ll need a high power eyepiece, an O3 filter, dark skies, and large scope to observe it directly.

Image taken on Sept 5, 2006 around 07:25 UT with a Celestron Nexstar11, Meade F3.3 focal reducer, and Astrovid Stellacam II. Temperature was 51°F, 75% humidity, sky was clear, transparency was very good, and turbulence about 6/10, in bright moonlight. Stellacam II set at 9/14 gain, integrate 128 frames (4 sec exposure), medium gamma. The 15 minutes of video was dark subtracted; flat field and bias corrected with ImagePlus; aligned and stacked with with Registrax3; enhanced and cropped with Photoshop Elements2.

NGC 6760 Globular cluster

Vern — Wed, 28 Jun 2006 20:51:52 +0000

Globular cluster NGC 6760 in constellation Aquila has a Shapely class X density (on a Roman numeral scale of I to XII, I being the most dense).

Image taken from Louisville, CO June 27, 2006 at 0:14 MDT with Celestron Nexstar11, F3.3 focal reducer, and Astrovid Stellacam II video camera. Camera settings: integrate 128, gain 9/14, medium gamma. Images were dark subtracted, flat field and bias corrected with ImagePlus. Aligned and stacked 150 images with Registax3. Brightness enhanced with ImagePlus, cropped with Photoshop Elements. Sky was clear, temperature 57°F, 45% humidity, transparency very good, turbulence 6/10.

NGC 6229

Vern — Wed, 21 Jun 2006 18:36:33 +0000

NGC 6229 is a faint, 9th magnitude, globular cluster in Hercules with a compact central core and some granulation appearing in the outer halo.

Image taken June 20, 2006 at 05:33 UT, Louisville, CO with Celestron Nexstar11, AptAstro wedge, Meade F3.3 focal reducer, and Astrovid Stellacam II video camera, gain 9/14, integerate 128 , and medium gamma. Temperature was 68°F, no wind, partly cloudy, transparency good, and turbulence was 5/10. Dark subtracted, flat field and bias corrected.

Messier 92 (NGC 6341)

Vern — Wed, 21 Jun 2006 05:03:22 +0000

The M92 globular cluster in the constellation Hercules is not as impressive as its neighbor M13, but it is still a great object. The core is bright and very compact and surrounded by an outer core.

Image taken June 20, 2006 at 05:33 UT at Louisville, CO with Celestron Nexstar11 on AptAstro wedge, Meade F3.3 focal reducer, and Astrovid Stellacam II video camera at 128 integration (4.25 sec), medium gamma, 9/14 gain. Weather was party cloudy, temperature 68°F, transparency good, no wind. 10 min video was dark subtracted, flat field and bias corrected, aligned and stacked with Registax3.

Messier 5, NGC 5904

Vern — Mon, 22 May 2006 20:42:29 +0000

Messier 5, located in constellation Serpens Caput, is an impressive globular. It appears to be slightly elliptical in the NNE to SSW direction.

Image taken with Celestron Nexstar11, F3.3 focal reducer, and Stellacam II video camera. Clear, 62 °F, transparency very good, no wind, turbulence 5/10.

Messier 13, Hercules globular cluster

Vern — Tue, 16 May 2006 19:27:24 +0000

One of my favorite objects to visit is the Hercules globular cluster M13. It is a stunning object to view when you are at a dark sky site and the sky is transparent.

Below image taken from light polluted metro Denver with a Celestron Nexstar11 telescope, Meade F3.3 focal reducer, and Astrovid Stellacam II video camera. Intregration set at 128 (4.25 sec), gain 9/14, and medium gamma. Stacked from 20 minutes of video, dark subtracted, flat field and bias corrected. Sky was clear, temperature was 56 °F, no wind, transparency very good, and turbulence fair (5 to 6/10).