September 2014 - Picture of the Month
NGC 6888 The Crescent Nebula in Cygnus
Image Courtesy of David Davies, Cambridge, UK. Please click on the image for the high resolution version.
For more images from David please visit his
It's been a little while since I've shared anything from the deep sky. I managed to be away during several of the clear nights we've had recently.
My observatory was completed just over one year ago and the first object I observed from it was the Crescent Nebula. It seemed fitting to return to it this year and see if I could do any better.
So I've spent several nights during August (17, 28 and 31) gathering narrow band data on the Crescent Nebula and further time learning how to process narrow band images. The attached is the result.
I now have the benefit of automatic focussing which is helping I think by enabling me to refocus by remote control during the night. I'm using a Lakeside focus motor and the Scopefocus application from Kevin Sipprell in the US that works with my image capture software, Nebulosity.
Viewing conditions were almost universally poor with poor transparency and high thin cloud.
This image comprises 100 minutes of H-alpha and 200 minutes of OIII data in 20 minute subs, five hours in total, captured with a 254mm Newtonian and QSI 583 camera equipped with 3nm Astrodon filters.
Processing was done in Pixinsight where H-alpha was assigned to red, OIII to blue and a synthetic green was generated using 85% blue and 15% red. I did try to combine the H-alpha and OIII with a normal green image and the result was just awful.
I'm fascinated by this object. The great bubbles of OIII extend well beyond the normally visible object and are also evident throughout its internal structure.
I'm continuing to capture RGB data and it would be interesting to see if I can combine the RGB and narrow band data in the future.
September 2014 - Double Star of the Month
H 1 48 (21 13 42.46 +64 24 15.1) is a very rare example
of one of William Herschel's close discoveries which retains its
original designation instead of being absorbed into the catalogue
of F. G. W. Struve, as many of his pairs were. It is also remarkable
as being a fairly short period system which has both high eccentricity
and high inclination.
It is characterized by periods of rapid angular motion at very small
separations and then stretches of decades when it is visible to the
medium aperture. The brightness of the stars (7.2 and 7.3) means that
it is never an easy object in small telescopes but may well be visible
in 15-cm after 2020 or so when the separation slowly increases to 0".9.
The ephemeris for the 81.7 year orbit by Marco Scardia and colleagues
gives a separation of 0".72 and PA 243° for 2015.0.
The pair can be found 1 deg south preceding 6 Cephei which is, in turn,
3 degrees north of alpha Cephei.
BSO 15 (21 48 15.75 -47 18 13.0) is a naked eye star in Gruis
about 4 degrees preceding and slightly south of alpha. It was found to
be double by Thomas Brisbane in the early 1830s. The primary is a GO
dwarf of V = 5.6. Hipparcos places this star at a distance of only 52
light years and as a consequence it has a fairly substantial proper motion
of almost one-third of an arc second per year. The mag 8.8 companion
is not connected and is being rapidly left behind by the proper
motion of A. The pair was first accurately measured by John Herschel
in 1836 when he found B at a separation of 30.3" in PA 14°.
Last year the writer measured the pair again and found a distance of
78".9 in PA 350.2°, in good agreement with the prediction given in
the USNO Linear Elements Catalogue. This pair has not been observed by
either Hartung or Haas and the writer didn't note any significant colour
in either component. Recent observations by the infra-red Herschel
telescope show there is a large proto-planetary dust ring around this
star stretching from about 100 to 180 AU.
Bob Argyle - Double Star Section Director
Object of the Season - Summer 2014 & Autumn 2014
The Webb Deep-Sky Society
Nebulae & Clusters Section Director Wolfgang Steinicke
has requested observations for the following deep-sky objects.
Please click on images for high resolution versions.
Object of the Season (Summer 2014)
Planetary nebula NGC 40 in Cepheus was announced in DSO 164,
and the results will be published in DSO 166.
Our thanks to Stefan Binnewies, Rainer Sparenberg and
Josef Pöpsel of the Capella Observatory
for the use of this image of NGC 40.
Object of the Season (Autumn 2014)
The chain of open clusters
M 35, NGC 2158 and IC2157 in Gemini
will be announced in DSO 165, and the results will be published in DSO 167.
The complete schedule, including further objects,
is published in the Deep Sky Observer (DSO).
Observations should be sent to
Wolfgang Steinicke , Gottenheimerstr. 18, D-79224 Umkirch, Germany.