Here’s how the two beer can pinhole cameras look on the South-facing wall of my house.  I hope we are not intending to sell within the next year or so as potential buyers may be put off by the sight.  However, pinhole camera number 1 is already operating (between the Equinoxes) and I shall start off pinhole camera number 2 in December to image between the Solstices.

I have just made up 2 beer can pinhole cameras (see Justin Quinnell’s website to see how to do this) and fitted them to a wooden frame on a South-facing wall of the house.  I have opened the shutter (removed the black tape from the pin hole) of one of the cameras, and will start the exposure on the second camera in about a week.  Time for the total exposure?  Somewhere around 6 months  This will be the longest photographic exposure I have ever taken!  What will it show if it works?  Hopefully we will get the path of the Sun across the sky (for those days not covered in cloud) for the period of the exposure.  Clearly the data will also allow the plotting out of an analemma as a bonus.

Conventional narrowband filters (12nm or smaller bandwidth) do not work with the Hyperstar III system due to its very low f#.  The cone angle of the rays passing through the filter are so far from normal incidence that the actual operating wavelength of the filter (at the incident light angle) is no longer at H-alpha wavelengths.  One possible solution to this problem is to use a filter with a very large passband.  I have just purchased a 35nm bandwidth H-alpha filter from Ian King Imaging and can’t wait to see if the Hyperstar III will work with it.  My first target for testing the new combination will be CTBI, the supernova remnant in Cassiopeia that I have had trouble imaging before as it is so faint.  It will be very interesting to see if the new filter allows me to get a decent image of this difficult object.  If it does, I might just give Simeis 147 a go – I have always left this one well alone as it is so large and faint.

Well I managed to get out and try the kit even though earlier in the day I had a 4 and a half hour traffic nightmare coming back from the West Country – managed to hit the Bank Holiday traffic.  Never mind, got out with the AstroTrac TT320X, the Canon 40D and a 28-200 mm zoom lens. Read the rest of this entry »

Coming back from a short break in Devon I was pleased to find the tripod and accessories for the Astrotrac had arrived.  It was also good to find that all the threads were compatible with fixing the Astrotrac to the tripod and the Canon 40D to the ball-head fitting. Read the rest of this entry »

Well it has rained and/or been cloudy every day since the Coathanger image was taken.  You can almost believe there is a higher order deliberately out to frustrate the fun I can have with the new Hyperstar III.  Never mind, if I can’t work extra-terrestrially, it will be panoramas and macros with the Canon 40D. Read the rest of this entry »

The Robofocus guys are getting a new website together and asked for photos of the Robofocus on customers’ systems.  This is how the Robofocus looks on my Tak Sky 90 which is piggy-backed on the Celestron Nexstar 11 GPS.

The only modification I made was to beef up the supplied aluminium motor mount with a 2mm thick aluminium stiffener plate which runs along the top.  The whole mount is now extremely rigid allowing fast, fine focusing.

Two weeks ago I bought a Canon 40D DSLR camera for terrestrial work.  While playing with this beast it struck me that by using the same mosaic techniques that we use in creating big deep-sky panoramas – we could actually create gigapixel images! 

Why should we want to do that? 

Well, one reason is that we could print out very large images at extremely high resolution – something that wouldn’t have been seen before – so this might have some interesting effects on the eye-brain system.  Secondly – if kept on the computer monitor – you would be able to zoom in to see incredibly small detail. Read the rest of this entry »

At 8.00 a.m. this morning an upgrade to Photoshop CS3 arrived.  Within half an hour I was creating mosaics from frames that Photoshop CS2 simply couldn’t handle. 

The image below is a 15-framer, stitched together perfectly by CS3. 

This upgrade to Photoshop is going to be a great help in stitching together deep-sky images, and high resolution Moon shots!  If you produce mosaic images and you use Photoshop, you really should consider this upgrade.

When I originally bought the Celestron Nexstar 11 GPS Schmidt-Cassegrain reflector way back in April-May 2002, I did so because it could use the highly innovative Hyperstar lens, and at that time there was no Meade equivalent.

The Hyperstar is in my opinion a totally brilliant Celestron concept and an extremely brave move on their part as they would have known about the considerable problems with properly aligning the lens assembly, and the potential customer dissatisfaction with the product.

The Hyperstar is basically a 1x field-flattener lens assembly that takes the place of the secondary mirror in a standard Schmidt-Cassegrain telescope.  Your CCD imager sits on the end of the Hyperstar and this creates a very strange looking beast indeed.  I must admit, I fell in love with this thing before I even started Hyperstar imaging; this looked so extreme and really piqued my curiosity.

Since you now have your imager at the secondary mirror position, it is clear that the focal length you are working at is very much reduced, the light does not now go all the way up to the secondary mirror, and then all the way back down the telescope again to come out at the normal eyepiece position.  So the Hyperstar basically turns a very slow f#10 optical system into an unbelievably fast f#1.85 astrograph – an incredibly good idea.  Read the rest of this entry »