The Hercules Great Globular Cluster - M13

[Graeme]

This is The Great Globular Cluster in Hercules, Messier 13. Captured last night and made from 60ish x 70 second sub frames. The mount that steers my telescope appears to be having a problem with guiding. So it can track a target but it is not responding to the guide pulses in one direction. I probably need to take it apart and blow the dust out.

M13-01.jpg

It's nice to see some background galaxies and I could probably get a bit more detail in the core if I had another go, but I'm off now to take my mount apart.


Graeme

[HansV]

I like it!

[ChrisGreaves]

I probably need to take it apart and blow the dust out.

There is something sickeningly poetic about making an image that is essentially, an image of dust and then complaining about dust.
How did/would dust get into the guidance system? I imagined that the precision required would call for a sealed unit, with electrical wires passing through the case in a flexible epoxy-resin channel.

M13-01a.jpg

It's nice to see some background galaxies and I could probably get a bit more detail in the core if I had another go, but I'm off now to take my mount apart.

I can see only one galaxy (outlined above). How many others are visible in your image, and how do you spot them?
Thanks, Chris

[Graeme]

How did/would dust get into the guidance system? I imagined that the precision required would call for a sealed unit, with electrical wires passing through the case in a flexible epoxy-resin channel.

Yes, you would like to think so wouldn't you! But it's a motorised belt driven system so there's lots of opportunity for dust ingress unfortunately.

I can see only one galaxy (outlined above). How many others are visible in your image, and how do you spot them?

You upload it to Astrometry.org! And they produce a plate solved annotated version. Having said that, the haven't caught them all, there's at least one more that can be seen in the top right corner. And I've heard talk of more!

8670404.jpg

Graeme

[ChrisGreaves]

I can see only one galaxy (outlined above). How many others are visible in your image, and how do you spot them?

Thanks Graeme. So I did score the top-left corner - because it looked elliptical
The other circled galaxies I took to be stars in our galaxy.
Cheers, Chris

[Graeme]

The other circled galaxies I took to be stars in our galaxy.

They are. The IC designation is for deep space objects. The HD designation is for stars.

Graeme

[ChrisGreaves]

They are. The IC designation is for deep space objects. The HD designation is for stars.

Thanks Graeme. That's a load off!
So I found one of the two distant galaxies. That second one was too small (for my eyes/your image) to spot.
I have a general rule that says "If it can be seen by these 77-year-old naked eyes, then it is most probably a sun within our own galaxy"!
Cheers, chris