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_lunar_landings.thumb.jpg.b50378d0845690d8a03305a49923eb40.jpg

Piero

Preparing a target list for a 60mm under dark sky

Recommended Posts

In the next two weeks I have the opportunity to observe from a very dark location for three, maybe four nights, weather permitting. It is on the Dolomites at about 800 mt above the sea level at 46 degrees North Latitude. I do not have a precise measure for the apparent magnitude visible at naked eye, but it is at least 6. I also remember that the Milky Way was clearly visible side by side. 

The telescope I will observe with is my TV60, combined with eyepieces of focal lengths: 24mm, 13mm, 7mm, 5mm, and 3.5mm.


I don't generally prepare observation lists before a session, but this time things are a bit different. For this event, I would like to observe targets that I cannot see easily under the moderate light polluted location where I currently live. Therefore, I will skip planets and double stars. I will also skip small open clusters that I have recently spotted (e.g. in Cassiopeia). Instead, I would like to create a list of medium-large size DSO targets, some of these findable with a 60mm but difficult to appreciate from a moderate light polluted location. 


So here is my current list:


M5 Glob CL Ser (?)


M13/M92 Glob CL Her


M51 Galaxy CnV


M81/M82 Galaxy UMa

M97 PL Neb UMa

M101 Galaxy UMa

M108 Galaxy UMa


NGC6888 Neb Cyg

NGC 6960/6992 SN Rem Cyg

M57 Pl Neb Lyr


M27 Pl Neb Vul


M10 Glob CL Oph

M12 Glob CL Oph

NGC6633 Opn CL Oph

IC4665 Opn CL Oph


M31/M32/M110 Galaxy And

NGC7662 Pl Neb in And (maybe not)

M15 Glob CL Peg


M33 Galaxy Tri (if high enough)


M2 Glob CL Aqr (if high enough)



The sessions (if any due to the weather) will start at 9pm. Let's say that it is not possible to see up to about 30-40 degrees above the horizon due to the surrounding mountains, could you let me know which other interesting targets (max 11mag) you would add, please? 


Thanks in advance for your help,


Piero



p.s. 

Beside these targets, I also plan to simply get lost in pure wide field observation in the Milky Way :)

  • Like 1

Share this post


Link to post
Share on other sites

Dude, happy hunting!

I would consider adding M4, M7 in Scorpio and M8 M20 in Saggitarius. I don't know if you can get these there though. M72/73 in Aqr clusters open and glob. NGC 6760 in Aql a glob. The saturn nebula in Aqr again NGC 7009 and Helix Nebula NGC 7293. M30 in Cap and maybe you could even get a glimpse of Neptune and Uranus (moon permitting)

Anyway you have a nice list but it might need more targets as 2-3 days will be enough for your list I suppose.

Anyway, have a great time no matter what!

Cheers from Greece

Tzitzis

  • Like 2

Share this post


Link to post
Share on other sites

Thanks Tzitzis for your suggestion. I don't really know whether they will be accessible, but it is worth having them anyway. 
The moon won't be there as I decided this holiday when it is new moon intentionally :)

I will check magnification, sizes and surface brightness for some the targets you listed. 

Thanks again, Piero

Share this post


Link to post
Share on other sites

All the Messiers are worth trying imo. After all they are Messier objects :p

Share this post


Link to post
Share on other sites

Sure, but there are also other targets, some of them prettier than certain messier objects (e.g. Veil nebula). I was just wondering which of these objects shows up nicely and therefore could be worth looking at with a 60mm under dark sky. 

For instance, I doubt that a 60mm will show the Elephant's trunk nebula even under dark sky. Therefore, I would not give priority to such a target if there are others which are easier to see. 

The fact is that I haven't ever observed with a telescope from a very dark sky, and therefore don't really know the limits :)

Forgot to add: NGC7000. 

For instance, will the Wizard Nebula (NGC7380), Iris nebula (NGC7023), or Cocoon nebula (IC5146) be accessible with just 60mm?

Edited by Piero
  • Like 1

Share this post


Link to post
Share on other sites

Don't forget the North America Nebula NGC7000 Piero. Needs dark and transparent skies plus a UHC or OIII but should be good in the wide field of view you have

  • Like 2

Share this post


Link to post
Share on other sites

Don't forget the North America Nebula NGC7000 Piero. Needs dark and transparent skies plus a UHC or OIII but should be good in the wide field of view you have

Thanks Stu, that is surely worth looking at!  :rolleyes:

Can I ask you a totally naive point, please?

How do you work out which objects are visible using the surface brightness measure?

When I observe here under normal sky, I don't bother too much but just select open clusters >8-9mag or bright nebulae of modest size. However, I suspect that having a indication of the SB is actually mandatory if the sky is sufficiently transparent and dark. 

Therefore, if an deep sky object has, let's say, mag:9 and sb:12, does it mean that I have to consider that dso as an object of mag 12 globally? If so, assuming that my telescope can reach 11 mag under such a sky, if I understood correctly, large part of that object will be invisible to my telescope because it requires 12 mag to be seen entirely..  

So, for these objects, what is the magnitude useful for? ..indicating the brightness of the brightest part? 

mm.. getting confused!  :confused:  :confused:

Share this post


Link to post
Share on other sites

Give this a go Piero, should be right up your street :)

http://www.bbastrodesigns.com/VisualDetectionCalculator.htm

My understanding is that the magnitude of diffuse objects is pretty irrelevant when it comes to establishing visibility or otherwise. Surface brightness is the key thing, plus of course the SQM reading of the sky background as this determines whether there is any contrast in order to make the object visible. As you mention, SB varies within larger objects so it's hard to get an exact measure on it.

This link is also useful for calculating SB if you can't find the figure:

http://www.users.on.net/~dbenn/ECMAScript/surface_brightness.html

Acey is the real expert on this, hopefully he will be along soon :)

Stu

  • Like 4

Share this post


Link to post
Share on other sites

Thanks again, Stu! Your first link is really interesting! I never heard about that measure before, but the idea seems good to me.

Tricky subject though.

If I think of the veil nebula, its surface brightness is expected to be very low, basically unreachable for small or medium telescopes. However, the main branches are brighter and therefore visible (with OIII filter) with a small / medium telescope under medium/good sky condition.

It seems to me that while SB, Mag, and size are valid tools to provide us with an indication, eventually the way is a trial and error.

  • Like 1

Share this post


Link to post
Share on other sites

It's true that trial and error has its place, but if you put the details in for the Eastern Veil, NGC6995 at mag 5 and 60 x 30 arc minutes you get some interesting results which do seem accurate.

With a 2.5" scope under mag 18.5 skies, the visibility is very tricky, but under mag 21 skies it is pretty easy.

c0aa20ce12f921eda85214e7e78eb23d.jpg

2589abbef503bcc9dba8a4d85d30d10d.jpg

  • Like 1

Share this post


Link to post
Share on other sites

Wow, it is incredible how much a very low power ep is expected to make such a difference on this target! 

Okay Stu, you convinced me! :) 

Just hope to be able to make a good list of objects which are non trivial under average skies, pleasant, but also accessible for my little Kiddo :) !

  • Like 2

Share this post


Link to post
Share on other sites

Piero, the listing information below includes Messier objects, NGC wonders, and Double Star gems which I think are well worth taking a shot at even if the possibility of success isn't always going to be 100%. I apologise if I've repeated much of what you're already aiming for but I figured I'd give a possible Summer List that's easy to cut, paste and print :smiley:

Unless directed otherwise the listing will be set out as follows:

  • Target Name; Constellation; Type of Object; Level of Subjective Difficulty 1 (relatively easy) to 4 (very difficult).

The Messier List



M 13: Hercules Globular Cluster 1

M 92: Hercules Globular Cluster 2 - 3


M 29: Cygnus Open Cluster 2

M 39: Cygnus Open Cluster 3 - 4


M 5: Serpens Globular Cluster 2

M 16: Serpens Open Cluster 1


M 10: Ophiuchus Globular Cluster 2

M 12: Ophiuchus Globular Cluster 2

M 19: Ophiuchus Globular Cluster 2

M 62: Ophiuchus Globular Cluster 2 - 3

M 107: Ophiuchus Globular Cluster 2 - 3


M 57: Lyra Planetary Nebula 1

M 56: Lyra Globular Cluster 3 - 4


M 27: Vulpecula Planetary Nebula 2 - 3


M 71: Sagitta Globular Cluster 4


M 8: Sagittarius Galactic Nebula 1

M 17: Sagittarius Galactic Nebula 1

M 20: Sagittarius Galactic Nebula 3

M 21: Sagittarius Open Cluster 3

M 23: Sagittarius Open Cluster 2 - 3

M 22: Sagittarius Globular Cluster 3 - 4

M 25: Sagittarius Open Cluster 2 - 3

M 28: Sagittarius Globular Cluster 3 - 4

M 54: Sagittarius Globular Cluster 4

M 55: Sagittarius Globular Cluster 3 - 4


M 11: Scutum Open Cluster 1


M 4: Scorpius Globular Cluster 2

M 80: Scorpius Globular Cluster 3

M 6: Scorpius Open Cluster 1 - 2

M 7: Scorpius Open Cluster 1 - 2


A Few New General Catalogue (NGC) Wonders

NGC 6235: Orphiuchus Globular Cluster 4
NGC 6572: Orphiuchus Planetary Nebula 2 - 3

NGC 6910: Cygnus Open Cluster 2
NGC 6866: Cygnus Open Cluster 3 - 4
NGC 6819 Cygnus Open Cluster 2 - 3
NGC 6826 Cygnus Planetary Nebula 1 - 2
NGC 6834 Cygnus Open Cluster 3 - 4

NGC 6830 Vulpecula Open Cluster 3 - 4
NGC 6823 Vulpecula Open Cluster 2 - 3

NGC 6302 Scorpius Planetary Nebular 1 - 2

NGC 6543 Draco Planetary Nebular 3 - 4

Pretty Double Stars

I guess these doubles won't all be possible with a 60mm. I really don't know but it would be interesting to see how you get along  :smiley: 

Kappa Herculis (k Her)  Hercules
Alpha Herculis (α Her)   Hercules

Alpha Scorpii (α Sco) Scorpius
Beta Scorpii (β Sco)  Scorpius

Beta Cygni (β Cyg) Cygnus
61 Cygni Cygnus

Epsilon Lyrae (ε Lyr) Lyra

Zeta Ursae Majoris (ζ UMa) Ursa Major
Alpha Ursae Minoris (α UMi) Ursa Major

Alpha Canis Venaticorum (α CVn) Canes Venatici

Epsilon Boötis (ε Boo)  Bootes
Mu Boötis (μ Boo) Bootes

Gamma Delphini (γ Del) Delphinus

Good luck :icon_salut:

  • Like 3

Share this post


Link to post
Share on other sites

Rob, thanks so much for your help! I will include your targets in my current list.

I don't really know whether I'll be able to see the targets on Scorpius because of the mountains. However, I agree it is worth having them in a list and see whether they are visible over there.

I've also added heart, soul, and cocoon nebulae.

Looking forward to it!! :)

Thanks everyone for your help!

Hope this thread is useful to everyone having a small telescope!

  • Like 2

Share this post


Link to post
Share on other sites

Hope this thread is useful to everyone having a small telescope!

Very helpful, many thanks to you and everyone adding to the list!

I think it's all been said but getting the North American in the whole EP should be grand. You could also try for the entire Veil depending on the TFOV of your widest EP. should be able to do it with 4 degrees I think. I reckon you'll get much of Scorpio in view. There's some absolute gold in that region!!! Enjoy and looking forward to the reports.

  • Like 3

Share this post


Link to post
Share on other sites

Also look for 'nothing' ;)

Dark Nebulae!

Barnard's 'E' in Aquila

The dust around the Scutum Star Cloud and 2 small patches in Small Sagittarius Star Cloud.

Good hunting

Paul

  • Like 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

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