Archive for May 2010

A 4-Inch (102mm) Refractor Can Be An Excellent Deep-Sky Telescope: Finally Sirius B, Barnard’s Galaxy, and Much More….

May 23, 2010

All Observer’s Challenge Reports to-date: 147 consecutive months as of April 2021.

      Walter Scott Houston, most often used his 4-inch Clark refractor for his observations of deep-sky objects while writing the monthly “Deep-Sky Wonder’s” column in “Sky & Telescope Magazine” for 46 years until his death in December, 1993.  

     When Sue French picked up DSW’s where Houston left off, she seemed to favor the use of her 105mm refractor for so many observations over her twenty years writing the column.  

      I purchased my 102mm f/9.8 refractor in 1997, and have enjoyed using this scope over the years.  It provides for a nice velvety black background with excellent contrast of faint deep-sky objects within its reach.  

      On nights of good seeing, it will easily exceed Dawes Limit:  

       One thing I especially like about this scope:  It’s compact and portable enough to take out for those short observing sessions, when time is limited. 

      Double and multiple stars have always been of interest to me, and I’ve observed hundreds of close double and multiple stars over the years with this telescope.  At current, I’m working my way through another double star list with the refractor, taking my time to sketch each double, noting the colors, checking the position angle and also drawing a few field stars. 


The value of a correct image diagonal:

I’m now using a correct image 90º diagonal.  The view through a standard 90º diagonal, whether using a refractor, Schmidt-Cassegrain or Maksutov-Cassegrain makes it impossible to correctly draw “scientifically” a deep-sky object.  

I like to make my sketches as they are truly oriented in the sky, with north at the top and west to the right on my sketch card.  (See some sketches using my 10-inch reflector below) 

From Orion Telescope and Binoculars:

I finally purchased an Orion 1.25-inch correct-Image diagonal for my Orion/Vixen 102mm Refractor. The precision 90º diagonal provides a right-side-up, non-reversed image. 

I have really enjoyed observing with my refractor, but didn’t like the reversed mirror image, due to the 90º standard diagonal. On many occasions I would choose my Newtonian, as it’s so easy to make a correctly oriented pencil sketch. For many years, I’ve wanted to try a correct image 90º diagonal, but thought the views might suffer.  I’d been using a 96% enhanced reflectivity mirror diagonal for many years.  

A correct image prism diagonal, also known as an Amici:

Within a few days after making my purchase, the diagonal arrived, and on March 5th, 2014, I set up my 102mm refractor for the big test. I started with a very high magnification of 200x, to examine the Trapezium stars and see how the view would compare to my current enhanced standard 90º mirror diagonal.

The stars were beautiful in both, and even the “E” star could be glimpsed intermittently in both diagonals.  

I then went to my favorite galaxy pair, M81 and M82 at 57x, and immediately loved the non-reversed and correct image view of these two beautiful galaxies.  I really couldn’t see any difference between the quality of the two diagonals. The next test would be Jupiter, and again both diagonals presented excellent views. The cloud bands appeared very sharp with an incredible amount of detail visible in both diagonals. 

It is my opinion, the correct-image diagonal, seemingly passed all tests with flying colors.  I plan on using this diagonal for all of my observations and pencil sketches in the future.  


NGC 4889 and NGC 4874 – Galaxies in Coma Berenices – 10-inch reflector @ 143x

May 23, 2010

Faint galaxies in Coma

NGC 4889 and NGC 4874 10-inch reflector @ 143x

NGC 3190 – Galaxy Cluster – 10-inch Reflector at 114x – FOV 1/2º

May 23, 2010

NGC 3190 Galaxy Cluster - 10-inch Reflector @ 114x

NGC 3190 compact galaxy cluster; Leo

M40 Double Star, and Galaxies NGC 4290 (M11.8) NCG 4284 (M13.5) Telescope: 10-inch reflector @ 142x

May 22, 2010

M-40 Plus NGC4290 And NGC4284

The above sketch was made using a white charcoal pencil on black card stock.   Please note the very faint galaxy, NGC 4284 to the left, making a triangle with two faint stars.   Double Star, M40 makes for an excellent starting point to assist in locating the two galaxies.   roger

NGC 2903 galaxy in Leo, 10-inch reflector @ 143x

May 21, 2010

NGC-2903 10-inch jpg

NGC 2903 Galaxy in Leo, 10-inch reflector @ 142x

M105, NGC 3384, NGC 3389, 10-inch reflector

May 21, 2010

M105, NGC 3384, NGC 3389

M105, NGC 3384, NGC 3389

NGC 253 galaxy in Sculptor, 14.5-inch reflector

May 21, 2010

NGC 253

NGC 253, galaxy in Sculptor, 14.5-inch Reflector

“The Virgo 9” Nine Galaxies All within a 1° Field of View, When Centered on M86

May 21, 2010

     A great galaxy group of nine galaxies when (centered on M86) however, there are a number of other galaxies in this area in very close proximity.  

     The “Virgo 9” allows anyone with an 8-inch or larger telescope, the opportunity to use a wide-field eyepiece with greater than a magnification of 100x to observe all nine.  

     I thought this unique galaxy group needed a unique name, and a modern name at that:  The “Virgo 9” sounded perfect.  

       Don’t expect the following view visually, as the three faintest galaxies will require a magnification of 150x or greater, at least for me, using a 10-inch reflector from a suburban back yard.  

      I first found out about this galaxy cluster, from the late Tom Lorenzin, author of “1000+ The Amateur Astronomer’s Field Guide to Deep-Sky Observing.”


     Tom asked me while waiting for darkness in a cow pasture in (March 1993) if I’d ever viewed all nine galaxies within a 1° field of view, when centered on M86.  I had not…

      However, my attempt would come a few years later on March 16, 1999.  My notes from that night are listed below, and my sketch is following: 


M 84:  (mag. sfc. br. 12.6)  Bright, with a brighter more concentrated middle, mostly round.

M 86:  (mag. sfc. br. 13.2)  Bright, brighter middle, round, very similar to M84, but not as well concentrated.

NGC 4387:  (mag. sfc. br. 12.9)  A very faint mostly round blur. Difficult at best, requiring averted vision.

NGC 4388:  (mag. sfc. br. 13.1)  Low surface brightness, elongated slash with an E-W orientation.

NGC 4402:  (mag. sfc. br. 13.0)  Very faint slash, low surface brightness.

NGC 4413:  (mag. sfc. br. 14.3)  Small, very faint and dim, diffuse with little concentration, mostly round.

NGC 4425:  (mag. sfc br. 13.2)  Very faint, elongated, axis N-S, small and dim.

NGC 4435:  (mag. sfc. br. 12.6)  Fairly bright, mostly round, stellar nucleus, smaller than NGC 4438.

NGC 4438: (mag. 13.8)  Bright, elongated with a brighter middle. 

Roger Ivester

The following images by James Dire:

Date/Location:   April 18, 2015 KEASA Observatory, Barking Sands, Kauai, Hawaii
Camera and Settings :   SBIG STF-8300C CCD Camera -10°C
Telescope:   William Optics Star 71 – 71mm f/4.9 apochromatic refractor
Mount :   Paramount ME
Exposure :   100 minutes (10 x 10 min)

At a star party on Kauai, using two 14-inch reflectors, and a 26mm Nagler with an 82º AF, and an 82x magnification for a perfect 1º true field, many counted ten galaxies in both scopes.

As following: My widest-field image of the galaxy cluster, using a 72mm f/3.9 apochromatic refractor.

Two hour exposure with a SBIG STF-8300C CCD Camera. James Dire

M2 and dark lane, 4-inch refractor

May 21, 2010

M2 Globular Cluster, Aquarius

M2 and Dark Lane, Scope: 4-inch refractor @ 175x

Helix Nebula – 12-inch reflector @ 60x

May 21, 2010

Helix Nebula 12-inch @ 60x

Helix Nebula 12-inch Reflector @ 60x