Messier 5...

Click on image to enlarge.

Object: Messier 5 (NGC 5904)

Type: Globular Cluster
Distance: 24,500 light years

Constellation: Serpens

Date: 26 May 2009
Equipment: SXV-H9, Vixen ED 114mm aperture f5.3 refractor, ATIK manual filter wheel, Astronomix LRGB filters
Subframes: 20 x 60 seconds luminance (2x2 binned), 12 X 40 seconds each for red, green and blue channels, 16 flats/flat darks in luminance only, calibrated and stacked in AIP4Win, tweaked in AstroArt and PSP7.

From the same evening as the previous shot. As I started to image this at about 1.30 in the morning, M5 was already at only about 30° altitude and was starting to sink into the yellow fog of my western horizon.

Not surprisingly, it appeared a lot dimmer on the monitor screen than M3, even though in reality it's around half a magnitude brighter. This is definitely an object I need to revisit earlier in the evening to do it justice!

I was surprised at how blue this came up, even though it was processed in a pretty similar way to my earlier shot of M3. I don't know if that's just an effect of having to stretch the raws that much more to get rid of sky-glow.

With reference to my previous equipment glitch, David "Astroeyes" Moth (of galaxy imaging fame over on the UK SPA gallery site) has also had experience of SS2K crankiness. The connector between the handset and drives is definitely a piece of junk and lets the superb handset down. Both David and I have had the drive act randomly, and I have found I need to be careful not to have the connector under any sort of flexure. SS2K really is a wonderfully easy and powerful GoTo system and it's a shame that Vixen have superseded it with their SkyBook, which I don't care so much for. With SS2K, all the functionality is built in, without having to muck about with downloads, although I will admit things might have improved since I played with an early version.

As for my recent drive problem, I will have a look at the unit encoder - the behaviour does seem like the sort of thing that dust in an encoder might do.

Anyway.

Here's an earlier shot of M5 I took back in 2002:

This was a single afocal frame using a Casio QV-3500Ex and my Vixen VC200L, which actually gives a good impression of what it looks like visually with the same scope under a good dark sky (of the sort I might get once every year if I'm lucky). As with M3, it comes up greenish, although Rob Gendler's work gives a blue colour similar to the one I obtained with the SXV-H9.

Messier 3...

Click on image to enlarge.

Object: Messier 3 (NGC 5272)

Type: Globular Cluster
Distance: 34,000 light years

Constellation: Canes Venatici

Date: 26 May 2009
Equipment: SXV-H9, Vixen ED 114mm aperture f5.3 refractor, ATIK manual filter wheel, Astronomix LRGB filters
Subframes: 20 x 60 seconds luminance (2x2 binned), 20 X 40 seconds each for red, green and blue channels, 16 flats/flat darks in luminance only, calibrated and stacked in AIP4Win, tweaked in AstroArt and PSP7.

This session did not start particularly well. My venerable Skysensor 2000 GoTo unit has been getting increasingly cranky with age, rather like its owner. This time, when asked to point towards Regulus for initial alignment, the RA drive gave out a strange mewling noise and refused to move. Switching everything off and on again didn't help.

However, when I aimed at Vega as the initial alignment star, everything worked fine. Arcturus and Spica gave me my usual three star alignment in no time. Trying to return to Regulus prompted the drive to sulk again, however.

Regulus is a perfectly respectable star of course, and there was no need for this sort of behaviour. As the time was now around 11 pm though, and with clear and reasonably dark skies overhead, I really didn't want to spend any time fault-finding. Fortunately, when I aimed at M3, the image fell on the CCD chip first time. Tracking wasn't so good, though. The drive seemed a touch jittery and the best I could do was 60 second exposures, even with the PEC running.

Nevertheless this is plenty for a bright globular like M3, provided you don't want to image too deeply. I was interested in a wide field view and was reasonably satisfied with the final result as above, once I processed all of the images and layered them together.

It was certainly an improvement on my first attempt some five years earlier (see below).

I took this afocally with my (now sadly deceased) Casio QV-3500EX digital camera at the eyepiece of my VC200L. It's a single one-minute exposure at ISO400. It's interesting how the colour of this digital camera shot was reflected in the composite from the mono camera above - I have a routine I use for colour compositing in PSP7 and it does seem to match "reality" (subjective though that is when it comes to colours of deep sky objects) quite well.

Rob Gendler shows us what careful processing of top-class images of M3 can achieve here. He also gives us a stack of useful information about this object here.

Once I acquired the frames I wanted for M3, I thought I may as well stay up for another couple of hours and try and catch M5, possibly my favourite globular to look at visually. I don't know how those frames have turned out yet - rigor computoris is setting in and so they'll have to wait.