My Astronomy

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My Telescopes

My Main Telescope - C14 and Paramount ME

My new Paramount MyT and 8-inch Ritchey-Chretien Telescope

MyT Hand Controller

My Meade 12 inch SCT on a CGEM (Classic) Mount

My 4 inch Meade Refractor with Sky Watcher Guidescope and ZWO camera on a CGEM (Classic) Mount

Skywatcher Star Adventurer Mount with Canon 40D

 

My Solar setup using a DSLR and Mylar Filter on my ETX90

DSLR attached to ETX90. LiveView image of 2015 partial eclipse on Canon 40D

Astronomy Blog Index
About the Site

 I try to log my observing and related activities in a regular blog - sometimes there will be a delay but I usually catch up. An index of all my blogs is on the main menu at the top of the page with daily, weekly or monthly views. My Twitter feed is below. I am also interested in photograping wildlife when I can and there is a menu option above to look at some of my images. I try to keep the news feeds from relevant astronomical sources up to date and you will need to scroll down to find these.

The Celestron 14 is mounted on a Paramount ME that I have been using for about 10 years now - you can see that it is mounted on a tripod so is a portable set up. I still manage to transport it on my own and set it all up even though I have just turned 70! It will run for hours centering galaxies in the 12 minute field even when tripod mounted.

 

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« North aligning the camera. | Main | Galaxy Run 16th October 2009 »
Saturday
Nov142009

Testing Imaging at f/10 instead of normal f/6.3

At my normal focal ratio of f.6.3 images are approximately 20 minutes square which gives a good field of view but means that many galaxies are quite small. Also there does tend to be vignetting of the image. Whilst incorporating a new external focuser to get around image shift problems I thought I would try imaging at f/10 and check the practicality of centring the images (at the smaller field of view) for a galaxy run. On 9th Nov the sky was clear with drifting cloud which eventually became thick cloud - limiting the test. I tried it out with one object - NGC 744 - see the image below.

Clearly it is quite well centred. Here is the Deep Sky Survey Image - courtesy of The STScI Digitized Sky Survey.

The above image was obtained from STScI by completing the table below

The plate solution is shown here - 21 matched stars - RMS 0.08 which is a good astrometric solution.

This (as represented in the first image above) shows that the camera is not North aligned  - the Position Angle is given as 347.57 degrees. There was not time to rotate the camera to the 360 or 0 degree position as clouds set in. The matched stars on the image are shown here.

This is the image plotted onto the Sky Chart solution showing that it is indeed NGC 744

 

 and the Object Information Box

 

 

and the exact match of the Sky chart to the image. Note the direction of North corresponding to the discussion above.