Spiral Galaxy NGC 2841

I have looked at Mira Pro and do intend to purchase it at some future date. The only reason I haven't done so already is the amount of work still to do in positional astrometry and SN searching. I can fast see the day coming where my primary astronomical work will involve the 'serious' stuff and Mira looks like just the job for that. I have been smelling around some spectrographic equipment and may well consider that as my next purchase. Eamonn. have you any advice in that area?

I've spent quite a lot of money on software of late. My most recent purchase was ACP software for complete automated control of the observatory. I know Eamonn and DaveMc use this too.

Last night I kicked off a run to image 138 galaxies, and 2007 TU24. ACP did the following;

Slewed the scope to the first target.
Took a 30second test shot.
Determined the exact centre of the image.
Corrected the telescopes pointing to ensure the object was centred.
Started autoguiding automatically.
Took 2 x 2minutes shots and then aligned and stacked them!!
Added the pointing corrections to a model so that future pointing will be more accurate.
The moved on to the next object. Rinse and Repeat!! The only thing that can nobble it is the weather, which is exactly what happened last night!!

If I had my autofocuser ready it would look after that too. It also supports automatic opening and closing of the roof, weather detection and a whole host of other things besides. All it needs is Maxim DL to do all of this. Better still ACP is fully scriptable so you can have it do pretty much anything you want!

All of this wothout a single input from your truly. It's quite a sight to all of that happening automatically! It really is quite astonishing the amount of clever software out there.

Dave,

Regarding spectroscopy, it depends what targets you want to record eg. stars and nebulae and also the resolution you want to achieve. Here are some of my experiences in selecting and using different spectrographs.

I originally bought a single grating spectroscope some years ago from Rainbow Optics at around $200. This has a spectrum-widening lens with high-performance, glass, blazed diffraction grating. I got the fraunhofer lines of the Sun. It's probably the best one out of the low res gratings at 200 lines per mm. I have used it on first mag. bright stars and recorded spectra.

The limiting factor for me was resolution, because the Rainbow single element grating has no slit. The slit type version is important if you want significantly improve resolution.

I eventually went for a Czerny Turner design. This is heavy at about 2 kilos at the back of a telescope so I use a fibre optic feed. I use a one metre feed. The design has the bilateral slit and much higher resolution at 1200 lines per mm. The optical feed end is placed at the focuser. Results are very good. However, tracking is important in keeping the star in the centre. However, I am at presently improving the tracking by developing an off axis video system.

I designed and built a wide field spectral imager where the telescope is incorporated into the spectrograph. The field of view is 3d x 3d using a sensor of 2.5cm square. The grating I got specially made at 600 lines per mm. The results are also good on emission type objects, ie. Emission nebulae or comets. This instrument would be ideal for H alpha work on detecting wide field emissions.

Eamonn A

That is a super image Eamonn. It reminds me of M64, the Black Eye Galaxy. The dust lanes here are remarkable, and the gradient seems very well balanced.

Seanie.

Most of what you guys do with regard to astro photography is pure black magic to me. But your photo of NGC 2841 is utterly amazing I still marvel at my binocular view of M31 at 2.5 million Light years - while the light from your image travelled 46 million Light years. and shows incredible detail. "we are not worthy" :shock:

"Captain Slog star date 310108.20

You know, you can take all the long exposures you want, but you can really see the massive aperture of that scope in that image !

you and your fascination with humongous apature Dave. Anyone would think you were compensating for some...inadequacy