Andrew’s Astronomy Blog

I got an email to say that Gyulbudagian’s nebula was brightening again so grabbed ten 3 minute exposures just before dawn on Monday. Taking advantage of the 7 hour time difference between the UK and New Mexico made this a much more reasonable 11am.

While it’s possible to distinguish the nebula as a small fan shape this is still a very faint object. The brightest star in this image is Magnitude 10.1 and some of the faintest, 19.4

The telescope used was GRAS-1, a Takahashi Mewlon 300mm with FLI IMG1024 Dream Machine camera. I’ve written before about this camera with it’s 24 micron pixels. It’s very sensitive, but this system suffers from pronounced vignetting which isn’t entirely compensated for by the flat frames when the images are stretched as much as this one.

Got back from my first Spring star party on Sunday afternoon having arrived Friday evening. The event was wonderfully cloud free with a lack of aircraft contrails as well; something to do with a volcano in Iceland!

While the skies were clear there was more sky glow than I remember from the autumn event. On the first night there was a lot of moisture in the air with dew dripping off every surface pretty much from nightfall but on the second  this didn’t start being a problem until after 2am, by which time I was thinking about bed.

On Friday I had problems getting the AstroTrac to track at all well but this had resolved itself by Saturday and I concentrated on Mars in M44 and M13 in Hercules. 24x 2 minute exposures at ISO400 through the ZenithStar 70.

M13 to follow.

While the Leo Triplet is well known, there is a fourth member of this group a little further away and it’s depicted here in this 2.5 degree field.

All three galaxies in the main triplet show signs of interaction and the group as a whole is listed in Arp’s Atlas of Peculiar galaxies as ARP 317. M66 is also listed separately as ARP 16 (Spiral with detached segments). Distance to the group is about 33 million light years and measuring this picture shows that the nuclei of M65 & M66 could be as close together as 192,000 light years. By comparison, our nearest galactic neighbour is M31, Andromeda at 2.5 million light years.

The image is a stack of 15x 3 minute exposures at ISO400 using the WO Zenithstar  70 with a Sky Watcher field flattener.  Some trailing is apparent and the individual frames could use rather more exposure time and/or a higher ISO setting.

This being a Bank holiday weekend, and the skies being cloudy I’ve had some time to review the DVD presentations from the 2009 Mid West Astro Imaging Conference that I bought from Astro Photo Insight some time ago. Two were of particular interest; “The Hows and Why of Image Calibration” by Kevin Nelson of QSI and “Choosing a camera for astrophotography” by Craig Stark. After watching these I decided to evaluate some flats produced by pointing the telescope with Canon 350D at a blank illuminated laptop screen (I used an empty Notepad window). Analysing these images in Maxim, the results were nothing like I expected; less an even grey frame, more a technicolour nightmare!

After that shock I went back to look at my images of the Double cluster and reprocessed them with the new flat frames. Compared to my original efforts there’s much more colour evident in the stars and the overall blueish tint is much reduced. How much of the improvement is down to the flat frames and how much to improved technique is up for debate.  That’s all part of the fun; there’s always something new to learn!