Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_supernovae_remnants.thumb.jpg.0a6deb4bf0886533629e2bdc08293bc9.jpg

Nerf_Caching

M80 brighter than M4?

Recommended Posts

Managed to see M80 and M4 with 100mm reflector last night. Just wondering whether M80 is brighter and more concentrated than M4? It seems as though M4 was larger and more diffuse through the eyepiece. M80 was more concentrated and compact.

  • Like 2

Share this post


Link to post
Share on other sites
Posted (edited)
On 15.5.2018 at 08:16, Nerf_Caching said:

Managed to see M80 and M4 with 100mm reflector last night. Just wondering whether M80 is brighter and more concentrated than M4? It seems as though M4 was larger and more diffuse through the eyepiece. M80 was more concentrated and compact.

Your observation is quite correct. M 4, probably the nearest globular (6.5 KLy) is rated with a density of 9 on the Shapley-Sawyer concentration class scale (1 for the densest, 12 for the lowest concentrated globulars), whereas M 80 (28 KLy away) reaches just the value 2. Thus, M 80, with a total visual brightness of just 7.3 mag, has a surface brightness of 11.0 mag per square arc second and appears "brighter" than M 4 (brightness 5.8 mag, surface brightness 12.0 mag). It's always nice to compare these two globulars of a very different appearance. Strangely, none of them both fulfills the criterion of an aesthetically pleasing globular - "the cores of class 1 to 3 resist resolution, and classes 9 to 12 are hardly more than glorified open clusters" (to quote the "Night Sky Observer's Guide", pg. XXX).

Have fun when observing them, and try higher magnifications.

Stephan

Edited by Nyctimene
  • Like 6

Share this post


Link to post
Share on other sites

I agree with Stephan . I use to could see M80 from the city a few years ago and it was always much brighter than M4 . Might say M4 is a challenge . Have you seen M22 in comparison to any other GC ? M22 is a very nice one to observe as well as M3, M5 , M13 and M92 . One I have not seen yet is M15 which from images looks exciting to view . Maybe someday , not sure I can see it from the city anymore :(

Share this post


Link to post
Share on other sites
8 hours ago, celestron8g8 said:

I agree with Stephan . I use to could see M80 from the city a few years ago and it was always much brighter than M4 . Might say M4 is a challenge . Have you seen M22 in comparison to any other GC ? M22 is a very nice one to observe as well as M3, M5 , M13 and M92 . One I have not seen yet is M15 which from images looks exciting to view . Maybe someday , not sure I can see it from the city anymore :(

I've tried to observe M107 and M68, but to no avail. Too diffuse and dim maybe?

  • Like 1

Share this post


Link to post
Share on other sites
12 hours ago, Nerf_Caching said:

I've tried to observe M107 and M68, but to no avail. Too diffuse and dim maybe?

With your 100mm reflector it would be very hard to see either of the M107 or M68 . I've not seen M68 myself but I have seen M107 in my C8 with a 2x barlow and a 32mm Plossi . It's very small and barely able to stars in the main cluster but I can see the outer stars fairly well . I did try a 25mm Plossi also and somewhat bigger but not as defined as with the 32mm . Sometimes overpower does not look as good as a lower power EP . WHat EP you using and are you using a barlow ? Keep looking , those small jewels are nice to observe ! 

Share this post


Link to post
Share on other sites
Posted (edited)
12 hours ago, celestron8g8 said:

With your 100mm reflector it would be very hard to see either of the M107 or M68 . I've not seen M68 myself but I have seen M107 in my C8 with a 2x barlow and a 32mm Plossi . It's very small and barely able to stars in the main cluster but I can see the outer stars fairly well . I did try a 25mm Plossi also and somewhat bigger but not as defined as with the 32mm . Sometimes overpower does not look as good as a lower power EP . WHat EP you using and are you using a barlow ? Keep looking , those small jewels are nice to observe ! 

My scope's FL is f/4, so using a 9mm Plossl, I'm using about 44x. Don't want the images to be too dim and blurry. That's the shortest FL eyepiece I have.

Edited by Nerf_Caching
  • Like 1

Share this post


Link to post
Share on other sites
Posted (edited)

In my 8" dobs M4 was diffuse, whilst M80 was very bright with stars sometimes being resolved.

In my 4.5" Newtonian M4 was not visible in the light pollution found at 53° latitude. M80 was clearly visible.

Edited by Arcturus D

Share this post


Link to post
Share on other sites
On 23/05/2018 at 07:12, Arcturus D said:

In my 8" dobs M4 was diffuse, whilst M80 was very bright with stars sometimes being resolved.

In my 4.5" Newtonian M4 was not visible in the light pollution found at 53° latitude. M80 was clearly visible.

I could see M4 with my 3 inch reflector under some light pollution.

Share this post


Link to post
Share on other sites
Posted (edited)
On 17/05/2018 at 02:10, Nerf_Caching said:

I've tried to observe M107 and M68, but to no avail. Too diffuse and dim maybe?

Both need moonless nights.

Edited by Arcturus D

Share this post


Link to post
Share on other sites

In Gran Canaria M4 and M80 are easy binocular objects. I saw them in a 10x50.

On my best night there they were averted vision naked eye objects.

 

  • Like 1

Share this post


Link to post
Share on other sites

In the UK due to their low position, I had to use an 8" dobs. M80 is fairly bright, M4 much fainter.

Share this post


Link to post
Share on other sites
Posted (edited)

M4 is a tough cookie. I once observed it from Tenerife on a dark night with an ED80 and it didn’t grab me enough to stick with it. As mentioned it is very loose at a IX but is also three times the diameter of M80 as viewed from earth. That spreads out the surface brightness, and in fact M4 is the largest globular from our vantage point in the northern hemisphere. Perhaps there is a sweet spot in distance to view globs and we are too close...!!   Think we are very fortunate to have the class V M13 in the northern hemisphere. It really is ideal to observe!

Edited by Special K
  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×

Important Information

By using this site, you agree to our Terms of Use.