Archive for October 2018

NGC 147 and NGC 185 – Galaxies in Cassiopeia – November 2018 Observer’s Challenge Report #117

October 29, 2018

More information to come….please check back.  

Concerning surface brightness magnitudes:  

Information from Observing handbook and Catalog of Deep-Sky Objects” by Christian B. Luginbulh and Brian A. Skiff :  

“The surface brightness magnitudes (sfc. br.), also from the * RC2, represent the brightness (in V or B, depending on the color of the integrated magnitude ) of a square arc minute patch averaged over the galaxy within the dimensions given for each.  Since this value is an average, the central parts of the galaxy will typically have higher surface brightness and the outer parts lower.”

For complete information concerning (sfc. br.) refer to pages 10-11 Observing Handbook and Catalog of Deep-Sky Objects.”   Luginbuhl and Skiff. 

* RC2 =  “….nearly all data on galaxies are from the Second Reference Catalogue of Bright Galaxies (RC2) by de Vaucouleurs, de Vaucouleurs and Corwin, and the Southern Galaxy Catalog (SGC) by Corwin, de Vancouleurs, and de Vancouleurs.” 

Images provided by Mario Motta from Massachusetts using a 32-inch reflector. 

Photographic information:  NGC  147 was a total of 70 minutes, taken August 10, 2015 with my 32 inch, SBIG STL camera 1001E.  NGC 185 was taken August 15, 2015 total of 50 minutes (must have had a bad frame and dropped, I almost always do at least 60 minutes)   Mario Motta

NGC 147:  Visual magnitude 9.5,   (sfc. br.) 14.5  

2169290_2_NGC147

NGC 185:  Visual magnitude 9.2,   (sfc. br.) magnitude 14.3 

2169290_3_NGC185

Observing notes and sketches by Sue French from New York:

254/1494mm Newtonian

43×: By sweeping westward from Omicron Cassiopeiae, NGC 185 is immediately visible ensconced in a isosceles triangle of three 8th- to 10th-magnitude stars, the brightest one golden.

68×: The sketch was done at this magnification, where NGC 185 and NGC 147 just fit together in the 72 arcminute field of view.  NGC 185 has a small core that grows gently brighter toward the center. NGC 147 is more slender than its companion and very faint.  There’s a dim star superimposed on NGC 147, barely west of the galaxy’s center. Both galaxies lean roughly northeast by east, with plump NGC 185 have a slightly greater position angle. Most of the stars visible near the galaxies were sketched, but far too many showed in the richly populated Milky Way for me sketch all the field stars.   Sue French 

Pencil sketch with inverted colors:  SF 

image001

 

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NGC 7129: Cluster+Nebula In Cepheus, October 2018 Observer’s Challenge Report #116

October 26, 2018

The Observer’s Challenge report is currently “in-progress” and will be posted when all participant reports are received, so please check back.  

NGC 7129: Cluster + Nebula.  Magnitudes;  nebula 11.5;  stars 10 

Image by Mario Motta from Massachusetts: 

30 minutes luminance, 15 minutes each of red-green-blue filters, total 75 minutes imaging.  The image was taken with a 32 inch f/6 reflector. 
A difficult object, and could not use narrowband filters as NGC 7129 is a reflection nebula.  I used color filters, but with the bright stars in the image allowed star bloat, so subs had to be short, 3 minutes each.   Mario Motta 

NGC7129

 

254 mm  1494 focal length  f/5.9  Newtonian Reflector – Notes and sketches by Sue French from New York 

43x: Swept up by moving 1.4 degrees west from the pretty blue and gold optical double Argyle 43 (ARY 43; WDS magnitudes 6.4, 6.8; separation 100 arcseconds).  The nebula appears fairly faint but is readily visible.

115x: The sketch was mostly executed at this magnification, but it was slightly touched up in a couple places at 213x. The brightest part of the nebula occupies a region that includes four stars. The northernmost star in the haze is very dim and couched in its own tiny halo of light.  It stands out better at the higher power. Insubstantial mist trails west-southwest from the main mass, but its extent and form are difficult to perceive.  The southernmost star on the sketch glows with a golden hue.   Sue French 

Pencil sketch with inverted colors:  SF

NGC 7129 inv

 

NGC 7129

 

Notes and sketches by Roger Ivester from North Carolina

In my 10-inch reflector a cluster of four brighter stars with some fainter members, enveloped by nebulosity with greater concentration around the two northernmost stars.  The nebula has fairly high surface brightness, and easy to see at 57x, but best seen at 114x, and without any type of filter.  The sparse cluster and nebulosity is very easy to locate and see, and stands out prominently in the star field.   Roger Ivester 

Pencil sketch using a 10-inch reflector @ 114x.   RI

NGC 7129 Sketch

Pencil sketch with inverted colors:   RI 

Rogers NGC-7129 Inverted

 

Observing Venus Near Inferior Conjunction: By Guest Host, Richard Nugent From Massachusetts

October 23, 2018

    Venus passes through inferior conjunction every 19 months and during the week prior to and after I love to observe her. Why? Because during inferior conjunction Venus is passing between the Earth and the Sun. Its angular diameter is large because it is closest to Earth and it offers a unique view of the planet: a razor-thin crescent! This month, on October 26, Venus will be a generous 6°20’ from the sun making this inferior conjunction particularly easy to observe. Her disk will be slightly larger than one arcminute and she will be 0.6% illuminated. So, how do we observe this!

    The region of the sky this close to the sun is a perilous place to be observing. Your telescope will be unfiltered so aiming the telescope is critical. You do not want to be sweeping in this part of the sky!  In order to know where to look I use SkySafari Pro but any planetarium program will work. If you have a go-to or push-to telescope, carefully align the scope and let the computer guide you to Venus. If you are using good, old-fashioned setting circles make sure your mount is polar aligned, set the R.A. circle to the proper sidereal time, get the right ascension and declination for Venus and go to that spot.  I live in the alt-az world so I get that info from my program and then use the phone’s compass and tilt meter to get to the correct spot. I find the tilt meter to be more accurate than the compass so I get close then carefully…I mean CAREFULLY sweep in azimuth until I spot Venus. I typically use a 10-inch, f/5 dob with an 80mm Finder. Today, Venus was easily visible as a crescent in the finder. Once it’s in the finder you’re home free!

   One important tip is to pre-focus your eyepiece. If Venus is out of focus it’s crescent will smear out and blend into the bright background. I start with a low power eyepiece and graduate to my 16mm Nagler. This gives about 75x with a generous amount of sky around Venus. The seeing is usually terrible during the day but I find that an aperture mask is particularly useful in reducing the turbulence. Today, I ran the scope at 60mm. [f/19.9 with a 0.8mm exit pupil] The crescent was magnificent! During moments of steadier seeing I thought I could see the entire limb of Venus but that just might have been my brain connecting the cusps to complete the circle. I’ll look a little closer towards inferior conjunction when the effect should be greatest.

    I’m really a visual astronomer but sometimes I can’t resist the urge to snap a picture. The image here was taken by holding my iPhone (8 Plus) up to the eyepiece. I use the camera zoom to focus the telescope then zoom out a little and shoot bursts of images. I select the best shots, crop them, and adjust the exposure if necessary.

   We only get a couple of weeks every 19 months to observe Venus this way so I use every clear opportunity to make observations. The next inferior conjunction of Venus wont be until June 3, 2020 but Venus will be too close to the sun to view. In that case, I’ll observe Venus up until a few days before then wait a few days after the actual conjunction. My strict limit is 3-4 degrees away from the solar limb. As I said…perilous!

    I’d encourage you to try to see Venus this week. Have fun but please be careful!   RN 

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NGC 6818 – Planetary Nebula – Sagittarius – September 2018 – Observer’s Challenge Report #115

October 12, 2018

SEPTEMBER 2018 OBSERVERS CHALLENGE – NGC-6818

Pencil sketch from the eyepiece using a 5 x 8 blank notecard, and 6-inch f/6 reflector @ 129x

NGC 6818 Sketch

Pencil sketch averted color

Rogers NGC-6818 Inverted