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.

Pickers84

Observing Nerbula

Recommended Posts

Hi Guys,

 

I got a 10" Dobsonian for the purpose of view Nebula Primarily. Short version is that even in the darkest skies I can't seem to see the nebula itself, only the stars that are located within said Nebula.

 

They are there obviously but do I need a special filter to view them?

 

Cheers in advance

 

Adam 

  • Like 1

Share this post


Link to post
Share on other sites

Most people can see some things but it takes practice and experience to really appreciate what is being observered.

Takes at least a few minutes of study to tune your eye, take your time, relax, deep breath, and then start again.

Think in terms of taking 5 minutes or so per observation. The more you look the more you will see.

 

  • Like 6

Share this post


Link to post
Share on other sites

Which one are you trying to observe?...Are you using a type of filter?, different nebula require different filters.

Share this post


Link to post
Share on other sites

I know that i had difficulty with a scope looking at nebula. yet 15x70 binoculars had an EXTRAORDINARY view of them (especially that good lookin' lagoon nebula). Try getting your F/ratio as low as you can. Using a .5x focal reducer and low magnifying eyepiece will help a whole ton. also remember to wait 1/2 hr for your eyes to adjust. 

 

Edited by TheMan
  • Like 1

Share this post


Link to post
Share on other sites

Which nebula are you looking at?

The Ring and Dumbbell Nebula should be easily visible in your 10" as they are in my 8"

  • Like 1

Share this post


Link to post
Share on other sites

Yes, dark adaptation, experience and knowing what to expect are key to sucessfully observing nebulae: the Veil Nebula for example is huge but very dim, the Ring Nebula is bright but very small. Filters may help, but not all filters are suitable for all nebulae. But it'll help a lot if you're telling us which nebula you'd like to see, maybe we can give you some specific advice.

  • Like 1

Share this post


Link to post
Share on other sites

Hi Adam,

It takes about half an hour for rhodopsin (visual purple) to become effective in our eyes. It's a hormone that increases sensitivity to light when its dark. If there are any bright light sources around and you catch sight of them, it will immediately prevent the release of rhodopsin, so shield yourself from any stray light.

Next, many nebulae are much larger than you might think, so things like the North American and Pelican nebula can more than fill the field of view of some scopes and eyepieces. It's important to use a wide enough field eyepiece while still maintaining a good level of contrast. Very low powers can sometimes wash out the nebula you're looking for. Also, if there is any mist or haze you will have difficulties, so the sky needs to be transparent.

I tend to play around for the first half hour or so, waiting for my dark adaption to build up while I look at star clusters and simple low power views of star fields. Then I'd begin looking for more nebulous targets while all the time keeping my head and focuser covered with a black out blanket to block stray light. I often get some quite pleasing views of nebulae and even galaxies despite my scope only being 100mm aperture. You might like to try using a UHC nebula filter as they can really help if you're still finding nebulous targets difficult.

  • Like 4

Share this post


Link to post
Share on other sites

Thanks everyone for the responses,  some really good information!

 

I should have mentioned I am in Western Australia, I don't have any filters except for an IR/UV cut out filter. I  should give my eyes more time to adjust to the dark then I would say. 

I have tried many times to view the Lagoon Nebula and the Tarantula nebula  but to no avail at this stage. I am heading out to Dark Skies on the 27th and would like to get some viewing in on some nebula.

Some of you have said some nebula require certain filters, which filters would be recommended for viewing nebula in general I see MikeDnight mentions the UHC filter

I am using a 2 x Barlow with a 40mm Celestron eye piece (which I love) I also have:

the 2 eye pieces that came with the scope:

basic 10mm and 25mm

an 8mm 68 degree Saxon EP

5mm "UWA" EP

Celestron 40mm EP

Saxon 2 x Barlow

 

Share this post


Link to post
Share on other sites

The Lagoon Nebula and similar emission nebulae will look really great with a narrow-band filter like UHC. Lots of detail and contrast. I've read reports that these kind of filters perform well on the Tarantula Nebula too, but I never observed this one myself. That said, the Lagoon should be readily visible with your scope without filters if the conditions are good, so I guess other factors mentioned in this thread may play a role here - like dark adaptation. Also, don't use too much magnification: these nebulae are quite large!

In general: a good narrow-band filter is a great all-round supplement for your setup that will enhance your views of many nebulae. Be sure to pick out one with a narrow pass-band - like the Lumicon UHC, the Orion Ultrablock or the DGM NPB.

Edit: this link compares different filter types for some common nebulae. A great resource to get an idea of what to expect.

Edited by Waddensky
  • Like 3

Share this post


Link to post
Share on other sites

Dark skies are paramount for observing nebula and under them objects like the Swan and Lagoon are bright with no filter, however a good UHC and OIII will give much flexibility to your observing. It might be good to observe these objects with a filter and with an eyepiece that gives a 4.5mm-5mmish exit pupil in your scope.

My current pick for the needed OIII and UHC would be the Astronomik.

Gerry

  • Like 6

Share this post


Link to post
Share on other sites

I don't understand. You live in Australia. You mention 'under the darkest skies'. You cannot see nebulae. You are either looking in the wrong places, you have a serious problem with your eyesight, or (I doubt that possibility), your skies aren't half as 'dark' as you say they are.

With a 10" telescope and whatever eyepieces, unfiltered, even in light-polluted skies, you should be able to get a glimpse of the Tarantula, the Lagoon etc...
You say you're heading out to dark skies, yet you mentioned before you could not see the nebulae under the darkest of skies. Could you be more specific under what kind of skies you are NOT seeing nebulae?

In the case you're trying to see them within minutes after leaving a pc monitor or brightly lit room, then you should indeed take more time to adapt.
Most of all I think you may be looking in the wrong places. You should see a dim patch in a (well-aligned) finder first, before attempting viewing through the scope. Or take some time scanning the area with low power.

If you are using goto, you might be quite sure you're looking in the right place, and therefore thinking you can't see it. Yet the goto might be malfunctioning.

 

Edited by Sagitta
  • Like 1

Share this post


Link to post
Share on other sites
9 hours ago, Sagitta said:

I don't understand. You live in Australia. You mention 'under the darkest skies'. You cannot see nebulae. You are either looking in the wrong places, you have a serious problem with your eyesight, or (I doubt that possibility), your skies aren't half as 'dark' as you say they are.

With a 10" telescope and whatever eyepieces, unfiltered, even in light-polluted skies, you should be able to get a glimpse of the Tarantula, the Lagoon etc...
You say you're heading out to dark skies, yet you mentioned before you could not see the nebulae under the darkest of skies. Could you be more specific under what kind of skies you are NOT seeing nebulae?

In the case you're trying to see them within minutes after leaving a pc monitor or brightly lit room, then you should indeed take more time to adapt.
Most of all I think you may be looking in the wrong places. You should see a dim patch in a (well-aligned) finder first, before attempting viewing through the scope. Or take some time scanning the area with low power.

If you are using goto, you might be quite sure you're looking in the right place, and therefore thinking you can't see it. Yet the goto might be malfunctioning.

 

I do a lot of star hopping and probably don't linger enough on the "nebula" to let them adjust to make out Nebula. I saw some the weekend just gone which I'm pretty stoked about. 

I got to see the Tarantula and lagoon but will pick up some filters to help out. I don't have the best eyesight adjustment period and need to learn a bit more patience evidently. 

  • Like 1

Share this post


Link to post
Share on other sites
On ‎26‎/‎10‎/‎2018 at 21:44, jetstream said:

Dark skies are paramount for observing nebula and under them objects like the Swan and Lagoon are bright with no filter, however a good UHC and OIII will give much flexibility to your observing. It might be good to observe these objects with a filter and with an eyepiece that gives a 4.5mm-5mmish exit pupil in your scope.

My current pick for the needed OIII and UHC would be the Astronomik.

Gerry

Cheers Gerry,

I'll look into some for Christmas with any luck haha.

  • Like 1

Share this post


Link to post
Share on other sites
9 hours ago, Sagitta said:

I don't understand. You live in Australia. You mention 'under the darkest skies'. You cannot see nebulae. You are either looking in the wrong places, you have a serious problem with your eyesight, or (I doubt that possibility), your skies aren't half as 'dark' as you say they are.

With a 10" telescope and whatever eyepieces, unfiltered, even in light-polluted skies, you should be able to get a glimpse of the Tarantula, the Lagoon etc...
You say you're heading out to dark skies, yet you mentioned before you could not see the nebulae under the darkest of skies. Could you be more specific under what kind of skies you are NOT seeing nebulae?

In the case you're trying to see them within minutes after leaving a pc monitor or brightly lit room, then you should indeed take more time to adapt.
Most of all I think you may be looking in the wrong places. You should see a dim patch in a (well-aligned) finder first, before attempting viewing through the scope. Or take some time scanning the area with low power.

If you are using goto, you might be quite sure you're looking in the right place, and therefore thinking you can't see it. Yet the goto might be malfunctioning.

 

No goto mount for me, I like the idea of learning where everything is.

Share this post


Link to post
Share on other sites

Me too. It's nice to know your way 'around'. With some patience, I'm sure you'll see more yes. Also, think dark skies, no local interfering light sources (especially mobile phone screens), low power wide field eyepiece(s), UHC and OIII filters, and maybe some dark hood also to pull over your head and focuser.

Share this post


Link to post
Share on other sites

Manually searching out the DSOs is a great part of the fun for visual. My HEQ5 Pro is only for imaging. When I'm out for visual, I always choose one the manual Alt-AZ mount.

My guess is that the sky in your area might not be as dark as you think. I've done some quick comparisons between light polluted areas (my backyard) and dark skies (still only semi-dark) on one of the easiest to find DSOs, M42. For clarification, my backyard isn't as badly light polluted as big cities since I can still easily see M57 (Ring), M81/82 and M40 (Winneck 4). However even under this condition I could only see a few bright stars with small fuzzy patches of lights around M42 through a 4" frac. Once I moved to dark sky, the basic structure of the nebula could easily be seen. Your 10" dob must be able to do a lot better than this (larger newts are more susceptible to LP).

I suggest you give it another try at a different dark sky site. If you could then see the nebula, that would prove your current area isn't truely dark. In this case get yourself a narrowband filter like UHC or O-III.

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.

×
×
  • Create New...

Important Information

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