sponsored by psychohistorian.org

DOCdb

Deep Sky Observer's Companion – the online database

 

Welcome, guest!

If you've already registered, please log in,

or register an observer profile for added functionality.

List:

log in to manage your observing lists

 browse:

 

 position:

 

 next:

 

 options:

summary

rename

prune

trim

remove

close

copy

combine

plan

bookmark

load

new

delete

marathon

favourite!

Full database:

Entire DOCdb database of 18,816 objects.

 browse:

 position:

Seven Sisters of the Pole (1 of 18,816)

 next:

oc gc pln bn dn gx gxcl ast aka lost

show browsing

Winter Observing Session: 27th August 2011

By Richard Ford. Published 2011 September 04.

After the winter rain we had in Cape Town on Friday, there was a sign of relief when the weather cleared for the weekend. It was however that the weather gods for August were looking after us for a change. By keeping up to date with the weather forecast, I went onto one of the weather sites online to see what the predictions for Saturday evening was. The weather predictions that evening indicated that we were going to expect clear viewing conditions up to 11:30pm.

After all I gave dark sky a serious thought. At 4:00pm I decided to update the voicemail on the ASSA Cape Centre’s starline for all the members and anyone who dares to come along to dark sky at Perdeberg. On this voicemail message I recorded. I informed everyone that the weather conditions will be clear for the evening and anyone wishing to come along must beware that there could be a possibility of a strong wind blowing in the evening and that the weather could become partly cloudy after midnight.

With a last minute decision I decided to pack all my observing equipment, including my 12-inch scope, equatorial platform mount and a various combination of eyepieces and filters which I brought along in the back of my Ford Bantam Bakkie. My advanced star atlases and starcharts worked hand in hand for the evening.

At 5:00pm I drove off in my bakkie to the observing site at Perdeberg. On the way to Perdeberg and on the way back to Brackenfell I listened to new age music like Jean Michel Jarre’s ambient hit singles “Oxygene” and “Fourth Rendezvous”. This electronic music put me in a melodramatic frame of mind to explore the hidden treasures of the night sky. Level 42’s hit singles “Leaving Me Now” and “Running in the Family” brought back memories of old times.

Just before I arrived at the dark sky site. I nearly missed the turn-off where the white marker flag entrance was situated leading to Hawie’s Mansion. I could have kicked myself forgetting to turn off at this entrance. Not knowing that another man was following me to the dark sky site. Upon reaching the dark sky site at Hawie’s place. It was Leslie Rose who followed me.

At the dark sky site we had a clear sky with a little bit of wind blowing. Thank goodness it was not a gale force. Shortly afterwards I unpacked all my observing equipment out from the back of my bakkie.

My scope was ready to go into action together with my equatorial platform mount tracking the celestial objects in the sky.

As the sky was getting darker I was busy observing the deep-sky mosaics in the constellation of Sagittarius where M24 (Sagittarius Star Cloud), M8 (Lagoon Nebula), M21 (Trifid Nebula) and M17 (Swan Nebula). These objects were well overhead in the sky.

While I was busy observing the Sagittarius Star Cloud. This large open cluster’s star fields filled the entire field of view which blew my mind-out. It made feel quite small in the universe.

As I was sky sweeping within the vicinity of M24, I came across M18, a relatively bright open cluster which is a moderately small cluster which consisted of 5th to 6th magnitude stars. This open cluster first discovered by Charles Messier on the 3rd June 1764, noted this is a cluster of small stars.

By keeping busy with my observations, shortly afterwards Leslie and I were observing the night sky with our scopes. Soon Wimpie and Gerhard joined our ranks this evening. We were well armed with three telescopes of which my one was the largest. The other two telescopes were 8-inch scopes. Leslie took breathtaking photographic images of deep-sky objects like the Ring Nebula and the Dumbbell Nebula with a Sony S.L.R. Camera mounted onto his 8-inch Schmidt Cassegrain Telescope.

As I was enjoying every moment of being under the night sky. Two open clusters that I had in were M23 and M25 both in Sagittarius. These two brilliant open clusters looked so awesome to observe that these clusters sparkled like bright diamonds in my dobby under a black velvet sky. They looked like bright jewels to me. However M23 and M25 are both relatively young open clusters in Sagittarius that has started their lives as main sequence stars.

After observing these two fantastic open clusters in the bright spiral arms of the Milky Way galaxy. I decided to plot a position to locate the faint globular cluster M72 in the constellation of Aquarius. By carefully making a detailed study of one of my starcharts “Atlas of the Night Sky” under a red L.E.D. headlamp. I maneuvered my telescope towards this cluster.

At first sight it was no problem for me to locate M72. All it took was patience and practice. Upon observing this globular cluster in my dobby, M72 was a relatively faint globular cluster which looked like a concentrated snowball being seen in my scope.

As Leslie and I was observing this globular cluster. He was absolutely fascinated of how faint this object appeared in my dobby.

Another prominent globular cluster to observe was M30 in the constellation of Capricornus. This bright cluster first discovered on the 8th August 1764 by Charles Messier noted that it looked like a nebula.

These globular clusters individual stars were partially resolved into hundreds of thousands of stars which was concentrated towards each other like a swarm of bright suns. All the bystanders like Wimpie and I enjoyed observing these old globular clusters which are the oldest clusters in the Milky Way.

These globular clusters which we see through our telescopes on earth are the oldest stars in the universe which has moved closer together as a result of gravity and velocity dispersion over time.

One of the oldest globular clusters which I decided to pay attention to that I haven’t observed for three years was M75 in the constellation of Sagittarius. By observing this faint cluster in Sagittarius. It is the most difficult globular cluster to observe in this constellation. It was so great to observe M75 again. The last time I observed this cluster was back in the year 2007 at Contermanskloof. For all of us this clusters stars had the resemblance of a bright round snowball in my scope. It was somewhat unimpressive to observe this object.

Once again by carefully making a detailed survey of one of my starcharts under a red L.E.D. headlamp. I came across a planetary nebula, NGC 6818(Little Gem Nebula) in Sagittarius. This planetary nebula being seen by everybody in my 12-inch scope had the appearance of a smoke ring which almost looked like the Ring Nebula in Lyra. Although this nebula is much smaller. By making use of my 7mm Ultra Wide Angle Eyepiece inserted into my dobby Leslie, Wimpie, Gerhard and I could almost discern this nebula’s pale green surface through my scope.

After seeing this nebula they were star struck of how much surface detail was observed in this nebula.

By word of mouth Leslie informed me that there was a bright comet situated close by to the globular cluster M71 in Sagitta. He told me all about Comet Garradd being up in the night sky. At first I asked him where it is situated in the sky. So he told me.

Before I started to observe this comet, I decided to maneuver my telescope in position towards the globular cluster M69 in Sagittarius. While I was busy observing this cluster all the individual stars were partially resolved into a swarm of bright stars in M69.

At 10:00pm, however I decided to take my chances to locate Comet Garradd. While I was busy observing the globular cluster, M71. I carefully manoevered my dobby south east of this cluster, whereby I finally at last tracked this comet down. At first this object looked like a fuzzy snowball but afterwards I realized that this object was the comet I was looking for.

However upon observing, Comet Garradd: This comet’s central nucleus was evenly bright as an out of focus globular cluster. It looked almost like a globular cluster.

By observing this bright comet all the bystanders like Leslie, Gerhard, Wimpie and I were absolutely star struck of how bright the coma of the nucleus of this comet appeared in my scope that evening. By observing Comet Garradd at dark sky it was such an awesome experience to capture the thrill by sharing this comet with everyone this evening. All the bystanders being present at Perdeberg thank me for showing the comet to them.

Let me briefly give you a general background about the significance of this comet and when it was first discovered:

Comet Garradd was first discovered by the astronomer G.J. Garradd at the Siding Spring Observatory in Australia in August 2009. At this time the comet was extremely faint at a magnitude of 17.5. Now the comet has grown brighter at a magnitude of 8. Last month it crossed past the globular cluster M15 in Pegasus and this month it is within easy reach of the cluster M71.

After Leslie enjoyed observing the comet with me. He told me he had observed NGC 253, the Silver Dollar Galaxy in his 8-inch scope previously. He wanted to see how this bright galaxy was going to look like in my 12-inch dobby. With great pleasure and honour I briefly showed him how NGC 253 appeared in my scope. Leslie could easily discern the bright spiral detail in this galaxy. It was such an awesome and mind-blowing experience to observe this spiral galaxy and to share this object with everyone being present at dark sky.

Very low on the western horizon before midnight I managed to the globular cluster NGC 5897 in Libra. Although seeing conditions below the horizon was not favourable. I somehow managed to observe this cluster. NGC 5897 was well observed as an unusually loosely structured globular cluster.

One of the last globular clusters for the evening I decided to concentrate to locate was M14 in Ophiuchus. These bright clusters stars were concentrated like a large oval snowball where all the individual stars in this cluster were partially resolved.

Leslie and I had great pleasure observing this cluster with me this evening that he enjoyed every moment of it. As the clouds slowly started rolling in I took my chances to locate a faint planetary nebula in Aquila. With the aid of my starcharts I knew exactly where NGC 6803 was located.

With careful perfection I just managed to locate NGC 6803. As I was observing this planetary nebula. This nebula’s annular shape was somewhat slightly oval and well defined. NGC 6803 was well observed as a pale green blur of light through my 7mm Ultra Wide Angle Eyepiece inserted into my scope.

My last deep-sky challenge that I wanted to explore was an extremely faint planetary nebula in the constellation of Sagitta. NGC 6886 was in the magnitude range of 12.2. At first this object was daunting and challenging to locate but finally afterwards I reaped my awards by locating it.

NGC 6886 was oval and well defined. Upon observing this planetary nebula, this nebula was well observed as an out of focus ball of light in my scope.

Before I decided to call it a night. I returned to observe Comet Garradd. As I was observing this comet. This comet’s nucleus was plainly bright in my scope. This comet’s nucleus is well made up of frozen gas and dust.

In the next few months time Comet Garradd will be a brighter object to see in the night sky. If it comes closer to the sun we will be able to see this comets tail through our binoculars and telescopes on earth.

However in September and October Comet Ellenin should peak at a magnitude range of 6 in our skies.

As the sky became cloudier, I decided to unpack and I had all my observing equipment packed in at the back of my bakkie. On the way back after everyone had already left. I collected the Cape Centre’s board signs and drove home.

The Bug Report

DOCdb is still in beta-release.

Known issues, feature requests, and updates on bug fixes, are here:

> Bug Report

Feedback

Found a bug? Have a comment or suggestion to improve DOCdb? Please let us know!

> Contact us

Help!

DOCdb is a free online resource that exists to promote deep sky observing.

You could help by sharing your observations, writing an article, digitizing and proof-reading historical material, and more.

> Find out more

 

Everything on DOCdb.net is © 2004-2010 by Auke Slotegraaf, unless stated otherwise or if you can prove you have divine permission to use it. Before using material published here, please consult the Creative Commons Attribution-Non-Commercial-Share Alike 2.5 License. Some material on DOCdb is copyright the individual authors. If in doubt, don't reproduce. And that goes for having children, too. Please note that the recommended browser for DOCdb is Firefox 3.x. You may also get good results with K-Meleon. Good luck if you're using IE. A successful experience with other browsers, including Opera and Safari, may vary.