First Light Horse-Head

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Jan 312013

I recently bought a new 130mm f/7 APO Refractor and have already posted one or two images from this new bit of kit. However, one of the reasons I wanted it was because it comes with a nice focal-reducer/field-flattener that brings the f-ratio down to about f/5. This gives a slightly wider field of view and is optically ‘faster’. In fact it is nearly twice as fast because the speed is related to the squares of the f-numbers being considered. So (7×7) / (5×5) = 49/25 = 1.96.

I’ve had the kit since November 2012, but, I was unable to achieve focus with the reducer in place! To cut a long story short, the reducer went back and it was discovered that the lenses had been assembled wrongly!

Anyway, here is my ‘First-light’ image of the Horse-Head Nebula in Orion. It is an H-alpha image (because the Moon was about) and consists of 11 exposures each of 20 minutes.


 Posted by at 4:55 pm

Cosmic Tadpoles

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Jan 022013

A Happy New Year to all!

This is my first astro image of 2013, taken on New Years Day evening. It shows a nice emission nebula IC 410 in the constellation of Auriga. Maybe ’emission’ is an appropriate word here, as these two bright streamers in the stellar winds look like two sperm (or sperms – both seem to be correct) trying to enter an ovum!


This image is taken through a 130mm F/7 APO refractor, using a 7nm H-alpha filter. Recorded with an ATIK 383L CCD camera, this is the result of stacking 15, 20 minute exposures. Not as sharp as I had hoped – I think the seeing was a bit poor last night, as precise focusing was very difficult!

 Posted by at 1:53 pm