It is just as well I don’t have the funds available to proceed with the mini-WASP concept as it has given me time to think about the whole system.  Since coming up with the idea of multiple imaging scopes to effectively cut down the total imaging time on an object, I have had real trouble trying to couple the colour imaging system with the narrowband imaging system.  Basically, no combination of scopes and cameras could cover what I wanted to achieve.

But sometimes a walk with the dog over the forest can achieve wonders, and it came to me that I should not try to combine both systems in one.  It would make far more sense to keep the Hyperstar III system as is for taking the colour data, although this will mean a 4-frame mosaic for each object, and use the mini-WASP array with its FSQ106 scopes and 35mm format mono cameras for just taking the narrowband data.  The colour and narrowband data can then be put together by Noel to create unique wide field images.  In addition the framework of the mini-WASP can be adapted to hold up to 10 scopes plus a finder scope, so this flexible system allows for a variety of FOVs to be taken.  Since the mini-WASP array will now only be used for narrowband imaging I have renamed it the Narrowband Imaging Platform or NIP.  Now all I need is a substantial Lottery win!

This Month’s gems are a pair of beautiful emission nebulae in the constellation Auriga.  Of the two, IC405 is the more famous as it is the well-known “Flaming Star” nebula, a region of H-alpha emission, but with an amazing reflection nebulosity in the “head” of the nebula caused by the reflection of short (blue) wavelengths of light by dust particles.

The star that lights up IC405 is AE Aurigae, a runaway star that was thrown out of the Trapezium, in Orion, millions of years ago.  So IC405 is being lit up by a star that just happens to be passing through, and at some point it will “go out” as AE Aurigae continues on its travels.

You can see from my image below that the field of view required to capture both IC405 and IC410 in a single frame is quite large.  My image is 3.33 by 2.22 degrees, and as you can see I didn’t do a particularly good job at capturing the whole of IC405, I needed to rotate the camera by a few degrees to get IC405 in completely.  However, to be on the safe side, you should probably aim for a field of view around 4 by 2.5 degrees, and this of course might mean creating a mosaic.

 These nebula are fairly bright so that exceptionally long subs are not required.  Imaging at f#4.5 meant 10-minute subs for the colour data for the M25C.  However, as per any region of emission nebulosity, your image will benefit greatly by the addition of some narrowband H-alpha data.  I used 20-minute subs for the H-alpha data using the M25C.  The beautiful blue reflection region does not benefit from narrowband imaging as this type of radiation is broadband.

 November means long dark nights, so it is probably worth spending at least two evenings on this one, one evening to collect the colour data, and a second evening to get the H-alpha.

Clear November skies!

Noel & I have an image today on the International Year of Astronomy’s website as “Astropic of the Week”.  It is our image of NGC6914 - a reflection nebula in the huge Gamma Cygni nebulosity IC1318.  Excellent!!!

For us deep-sky images I’m afraid the Moon is simply a nuisance, especially as it approaches full.  Well tonight I wanted to do some imaging - so there’s only one choice really, and that’s the Moon.  This image was taken with the Canon 40D and the 100-400 mm zoom lens with a x1.4 teleconverter giving me an overall 560 mm focal length. (more…)

Now that the Hyperstar III is going to be the main imager for some time to come, I have just made some system hardware changes.  The (relatively) heavy Sky 90 has been removed as the guide scope and replaced with the old Celestron 80mm wide field refractor.  This refractor is extremely light and I needed to remove several counterweights from the C11 to achieve balance.  When I originally used this scope for guiding on the Hyperstar I, I routinely had an error graph showing less than 0.1 pixel excursions for the whole imaging session.  Using the Sky 90 as a guidescope I have never had such good guiding and typically errors would be around the 0.5 (or greater) pixel level during 3-4 hours of imaging.  We’ll have to see if this change produces sharper images from the Hyperstar III - I have the feeling we will see a marked improvement.

This month I have chosen one of my all-time favourite objects, and one that I feel is a bit of an enigma.  IC1396 is a huge emission nebula in Cepheus that doesn’t have a “popular” name.  It contains the beautiful Garnet star - mu Cephei, and the well-known “Elephant Trunk” nebula VdB 142, as well as a number of other fascinating regions of dark nebulosity.  Yet - not only does this nebula not have a popular name, it isn’t imaged that much either. (more…)

Here is an aerial view of the NFO.  The house on the end where the road bends round is home to the NFO, and you can see the dome as a white circle at the bottom of the garden.

I now realise that the initial case I considered - a page of text facing a mirror with the page parallel to the mirror - was a very special, and very restrictive case - so it wasn’t really the best way to discuss “how a mirror works”. (more…)

A while back I wrote how you get lateral inversion (”mirror writing”) in a mirror.  I worked out the solution independently of the (same) one given by Martin Gardner in his book “The Ambidextrous Universe”. (more…)

Not everything on this site is deep-sky stuff, occasionally I publish something interesting that’s associated with the photographic process. (more…)