First Light

[Morat_Gurgeh]

So after only waiting a week, I managed to have a clear evening. Thank goodness I'm on leave this week as I'm normally an early bird and 2.30am finishes don't suit me.

I reckon I had a really good first night seeing Saturn, Jupiter, some doubles, the ring nebula and a fuzzy M13, and thats the point of my post. I sort of expected to see some star detail but am I right in thinking that this is likely down to my bortle 6 skys or is it just poor seeing? For reference Saturn was much clearer in my 25mm than in my 10mm so I think the seeing wasn't great (although I could see Jupiters banding in the 25mm).

Obvs a newbie 

[Pixies]

Hi,

What scope do you have? The resolution of stars in a globular like M13 depends a lot on your aperture.

[wibblefish]

For reference I have a 90mm refactor and cannot resolve any stars in the globular M13 for example under Bortle 6 when I have tried, even with my highest power eyepieces,  I can just about make out the ring nebula's center on high power  

If the 25/10 came packaged with your scope which I am assuming it is usual for the 10 to not be a particularly good eye piece unfortunately.

Edited September 7, 2021 by wibblefish

[Morat_Gurgeh]

Thanks for the replies I have a 9.25 SCT and the 10mm is supposedly better than the 25mm kit lens. 

[Stu]

46 minutes ago, Morat_Gurgeh said:

Thanks for the replies I have a 9.25 SCT and the 10mm is supposedly better than the 25mm kit lens. 

A C9.25 should (will) resolve stars deep into the core of of M13 provided the seeing is good enough. M13 is pretty high up in the sky from the U.K. currently, not sure whereabouts you are but it is likely to be the case so the views should be pretty good.

The eyepiece may be the issue. I would have thought that the 25mm giving x94 would be showing resolution in M13, but getting an eyepiece giving around x150 may give good results.

If you were out until 2.30am, the scope would definitely have been cooled! Did you check the collimation as this really does impact planetary views and also the resolution in other objects. Also make sure that your focus is bang on using a nearby star, as even being slightly off focus will stop you resolving the stars.

[JeremyS]

I can confirm that I can resolve stars across M13 with my C9.25.

As an aside, I was amazed to resolve a few stars in M13 with my Tak  FOA 60Q at 100x

[Pixies]

Not meant to be a silly question, but how dark-adapted were your eyes?

[Morat_Gurgeh]

No question is silly - and thats a really good point - obviously I was in my back garden and whilst reasonably sheltered some kind neighbours do seem to leave a lot of lights on overnight with no curtains. I'll see what I can do about that.

@Stu am I right in thinking then that the gap from 25-10mm is too large? I'll maybe try the barlow and 25mm next time then. 

 

Thanks all.

[Orange Smartie]

Apologies if someone has already mentioned this, or if you know already, but you will probably see more if you use averted vision. I.E. don't look DIRECTLY at the cluster, look to one side or another. The centre part of your retina is sensitive to colour but less so to low light; you'll probably find more stars start to pop into view.

 

Pete

Edited September 11, 2021 by Orange Smartie
Typos

[Stu]

On 10/09/2021 at 08:10, Morat_Gurgeh said:

@Stu am I right in thinking then that the gap from 25-10mm is too large? I'll maybe try the barlow and 25mm next time then

Yes, it is really. x94 to x235 is a big gap, and between x100 and x200 are very useful magnifications for letting planetary, lunar and a lot else in between. I would think x150 would be a good mag for globulars in your scope.

[Sunshine]

As mentioned above your 9.25 will make short work of M13 assuming collimation and seeing are in check. By comparison, I can resolve a bunch of stars in M13 on a decent night with around 100x in a wee 4" refractor.

 

[John]

Collimation is key to resolving things, globular clusters included.

 

[Gonariu]

I quietly solved M13 in stars with a C8 and a 20cm Newtonian.

[paulastro]

In my view, globular clusters are fairly underwhelming in any scope below 5 inches/120mm. 

OK, a four inch will resolve some stars, but not totally resolved as some people claim. Anything less than 4 inches is really disappointing, making them like fuzz balls.

It's a matter of choice, but I  prefer a GC to look like it is, rather than having to strain to see its true nature.

 

[Voyager 3]

On 12/09/2021 at 00:24, John said:

Collimation is key to resolving things, globular clusters included ,  assuming that the seeing is good .  

 

 

[Morat_Gurgeh]

Thanks all for the advice. Appreciated.