What can I hope to see?

[Stuu]

Hi all. Most cloudy this weekend so no telescope fun :( But I was wondering if there is anything that I can use on a clear night to tell me what DSOs would be within reach that takes my location/Bortle rating and equipment into account. 

[Tiny Clanger]

You don't say where you are,  what bortle rating or what telescope you are using, but assuming it is not wonderful dark skies or huge 'scope, there is a wealth of free info out there for us.

There's the much recommended (but not free) book 'Turn left at Orion' which is aimed at use with small 'scopes in less than ideal (from a light pollution point of view) skies,  also plenty of freely available lists , including one by Don Pensack who says they are ' the 500 best DSOs, as seen in a 4" refractor and 5" Maksutov in modestly dark skies over a couple of years.' , the Loughton list , the Moore Winter Marathon (not for now, obviously !) and the Caldwell list ... 

Jasonb and I attempted to provide a list based o Don Pensack's , excluding those not visible from the UK, and cross referencing the Loughton , Caldwell, and MWM numbers and the page references in Turn Left at Orion. All you need to do is check with stellarium (other programs are available, as are analogue planispheres) to see what constellations will be visible on a given night , look down the 'constellation 'column in our list (which is initially sorted first by alphabetical order of constellations, second by Messier number) and see what may be good targets, then look them up on the free lists.

 

[Pixies]

If you are in the UK, the bright summer nights just now, mean that a lot of DSOs are not easily seen.

Once proper astronomical darkness returns, try some of the brighter objects:

Globular cluster: M13

Planetary nebula: M57

Galaxies: M81 & M82

 

Do you know what your 'Bortle' rating is?

[Tiny Clanger]

Here's a link to the Loughton List : it's a UK home counties based list, they grade objects bronze, silver & gold, with bronze the easiest to see, it is a really nice free resource  https://las-astro.org.uk/docs/Loughton_List_v2_0.pdf

Heather

[Stuu]

Thank you, that's plenty of information to be getting stuck into! The Bortle rating is 5 and I'm using a 6" Newtonian. As I'm using a manual alt-azimuth mount until I can save up for something more advanced, it'll be good to have an idea what's going to be visible while I'm learning my way round the night sky. 

[Jiggy 67]

Bortle 5 isn’t great but a lot better than my Bortle 8 and I can see quite a bit in my 8” scope. I don’t really trust the Bortle scale anyway, especially the online sources that tell you where you are on the scale. 
At this time of year, don’t expect too much from DSO’s, it just isn’t dark enough, open clusters, globular clusters and multiple star systems should be your targets at this time of year.

Come the winter you will be able to see hundreds of nebulae, planetary nebulae,  fainter star clusters and the brighter galaxies. As an example, in my skies, galaxies are my nemesis, they have very low surface brightness and require dark skies but even I can see quite a few.

There are aids to viewing….dark adaption is crucial. You can try light pollution filters or other types of filters for nebulae, OIII and UHC…..but a level of patience is the biggest assist you can have

[Stuu]

If i set the Bortle to 5 on Stellarium it's fairly accurate at the moment but on a moonless winter night I set it to 4 which seems about right. I've only just got the 6" scope after using a 90mm refractor so can't wait for winter to roll round again! I do have a neodymium and UHC filter but haven't had much opportunity to use them yet. I was amazed what a difference dark adaption makes, I just need to work out a way to stop my neighbor's security light coming on every time a moth gets within range of it!

Edited June 27, 2021 by Stuu

[Spile]

Turn Left at Orion is my default list but I use others too and Tiny Clangers link to the Loughton List looks great. In addition, you'll see posts on here or Cloudy Nights recommending a target and sometimes ,I'll just give it a go! As for the planning away from the eyepiece, the downloadable version of Stellarium is indispensable for me especially for creating screen shots.

Edited July 5, 2021 by Spile

[Tiny Clanger]

37 minutes ago, Stuu said:

Thank you, that's plenty of information to be getting stuck into! The Bortle rating is 5 and I'm using a 6" Newtonian. As I'm using a manual alt-azimuth mount until I can save up for something more advanced, it'll be good to have an idea what's going to be visible while I'm learning my way round the night sky. 

Bortle 5 is what clear outside reckons I'm dealing with too, and I have a 150mm heritage dob. , so very  similar circumstances.

The key criteria for observing DSOs for me are :

Is the Moon up ? If yes don't bother, look at the Moon instead. 

Is the target in a 'good' bit of sky from my back garden ( there's a patch to the south west where light pollution is far worse) , if not, wait until it is.

Is the target above at least 30 degrees altitude ? If not wait ...

Also, my neighbours stop lighting up their conservatories like flippin' lighthouses around 11:30 pm, and the local council turns off every other street light at midnight, so after that's when it is a bit darker and better.

This time of year isn't great, it is never truly, properly dark , but at least it's relatively warm for faffing about outside , and you can still see some good stuff : on the last clear night I got my first ever sight of the Dumbell Nebula with the little dob and a UHC filter.

A weird looking but quite effective trick is to drape a towel or similar (preferably dark coloured ) over your head and the eyepiece to cut out some ambient light, like a photographer in a historical drama ... also worth having a dew shield on the newtonian, not so much for dew as to reduce that ambient light a bit more , just like a lens hood on a camera.

Worth finding out about exit pupil and eyepiece selection too. In my f5 dob, an 18mm eyepiece turned out from experience to be the ideal one for me to use to see faint fuzzies against my not very dark suburban sky . The discussion on here about choosing eyepieces by exit pupil showed me why ! 🙂

Heather

[Stuu]

9 minutes ago, Spile said:

Turn Left at Orion is my default list but I use others too and Tiny Clangers link to the Loughton List looks great. In addition, you'll see pots on here or Cloudy Nights recommending a target and sometimes ,I'll just give it a go! As for the planning away from the eyepiece, the downloadable version of Stellarium is indispensable for me especially for creating screen shots.

Up to now I haven't really been doing much planning, just seeing what's about while I'm in the garden. I'll definitely start being a bit more organized before I start, I don't know why I didn't think of doing screen shots! 

[Stuu]

11 minutes ago, Tiny Clanger said:

Bortle 5 is what clear outside reckons I'm dealing with too, and I have a 150mm heritage dob. , so very  similar circumstances.

The key criteria for observing DSOs for me are :

Is the Moon up ? If yes don't bother, look at the Moon instead. 

Is the target in a 'good' bit of sky from my back garden ( there's a patch to the south west where light pollution is far worse) , if not, wait until it is.

Is the target above at least 30 degrees altitude ? If not wait ...

Also, my neighbours stop lighting up their conservatories like flippin' lighthouses around 11:30 pm, and the local council turns off every other street light at midnight, so after that's when it is a bit darker and better.

This time of year isn't great, it is never truly, properly dark , but at least it's relatively warm for faffing about outside , and you can still see some good stuff : on the last clear night I got my first ever sight of the Dumbell Nebula with the little dob and a UHC filter.

A weird looking but quite effective trick is to drape a towel or similar (preferably dark coloured ) over your head and the eyepiece to cut out some ambient light, like a photographer in a historical drama ... also worth having a dew shield on the newtonian, not so much for dew as to reduce that ambient light a bit more , just like a lens hood on a camera.

Worth finding out about exit pupil and eyepiece selection too. In my f5 dob, an 18mm eyepiece turned out from experience to be the ideal one for me to use to see faint fuzzies against my not very dark suburban sky . The discussion on here about choosing eyepieces by exit pupil showed me why ! 🙂

Heather

I have a fairly decent patch of sky from South to West with less light pollution than the rest of it so that's usually where I look for lower altitude objects. The towel and dew shield sound like a good idea, I'll give them a go. My main eyepieces are 68° 16mm and 24mm. I don't really know anything about exit pupil so I'll investigate further. 

[Pixies]

Re the  exit pupil. What's the focal ratio of your scope? You calculate the exit pupil as eyepiece focal length / scope focal ratio.

For example, in my F6 dob, a 12mm eyepiece gives a (12/6) 2mm exit pupil. Some say that perceived contrast is best with an exit pupil around 1mm-2mm. I tend to agree. 8mm - 12mm eyepieces seem best for a lot of faint DSOs in this scope for me.

Here's a good thread if you have a couple of spare hours:

 

[Stuu]

On 27/06/2021 at 18:44, Pixies said:

Re the  exit pupil. What's the focal ratio of your scope? You calculate the exit pupil as eyepiece focal length / scope focal ratio.

For example, in my F6 dob, a 12mm eyepiece gives a (12/6) 2mm exit pupil. Some say that perceived contrast is best with an exit pupil around 1mm-2mm. I tend to agree. 8mm - 12mm eyepieces seem best for a lot of faint DSOs in this scope for me.

Here's a good thread if you have a couple of spare hours:

 

It's an F5 (150/750). I currently have 3.2mm, 16mm and 24mm. I've been considering a 10mm to give me a nice range , so that would give me 2mm exit pupil.

Edited June 29, 2021 by Stuu

[mikemarotta]

On 27/06/2021 at 07:07, Stuu said:

Hi all. Most cloudy this weekend so no telescope fun But I was wondering if there is anything that I can use on a clear night to tell me what DSOs would be within reach that takes my location/Bortle rating and equipment into account. 

First off, the thing about telescopes is that they gather light. So, despite nominally poor seeing conditions, you will be able to cut through some of the problem. For example, I live in an urban area where the Milky Way is often not visible or just parts of it some times of the year. Even so, my instruments will  show me the Milky Way. I was surprised, but there it is.

So, the easy answer is that if you look in your average "Friendly Stars in Your Sky" book or a magazine, you will probably be able to chase most of the targets labeled "easy for beginnners." (Myself, I chase binaries.) There's a lot to see. Let us know if you run out of things to look at.

Everyone recommends Stellarium or similar software. I find them overly complicated for just telling me what I can see tonight. I use this Sky & Telescope online application:

https://skyandtelescope.org/interactive-sky-chart/

Click on Deep Sky Objects. Click off the annoying stuff.

On 27/06/2021 at 13:31, Stuu said:

It's an F5 (150/750). I currently have 3.2mm, 16mm and 24mm. I've been considering a 10mm to give me a nice range , so that would give me 2mm exit pupil.

You have a nice telescope and a nice range of occulars. (I assume you mean 32 mm, not 3.2.) You could achieve the same results for a 10mm by using a Barlow with your 24 and 16 which would give you effective 12 and 8 mm but at a more comfortable eye relief.  Also, for yourself as an experiment, you could compare the 32mm with 2X Barlow against the 16 mm and let us know how they look to you. You might find differing results with different targets. Let us know. (Just a suggestion.)

I suppose that I should have made this my "zeroth" suggestion before the first, but do you keep a log book of some kind? I use bound graph paper notebooks. Other people use their computers, phones, or tablets, but whatever, keeping track of your work is an important part of the science.

Edited July 5, 2021 by mikemarotta

[mikemarotta]

On 27/06/2021 at 08:13, Tiny Clanger said:

There's the much recommended (but not free) book 'Turn left at Orion' which is aimed at use with small 'scopes in less than ideal (from a light pollution point of view) skies, 

 

Yes, in the Introduction, Dr. Consolmagno tells of being shown the stunning binary Albireo within the glare of New York City (from Fort Lee, New Jersey). He already had his doctorate, already had taught at MIT, already worked for the Harvard Observatory, and had never seen it. His friend showed it to him with a small refractor. 

In the words of New York Yankees catcher, Yogi Berra, "You can observe a lot just by watching."

One word of warning about TLAO: while any copy might be better than no copy (if the price is right), the current second printing of the fourth edition corrected errors from previous editions. It happens. There's a Cambridge University book for amateurs, Anthology of Visual Double Stars by Argyle, Swan, and James, that is missing the constellation Capricorn. Dang it all anyway...

 

[Stuu]

13 hours ago, mikemarotta said:

First off, the thing about telescopes is that they gather light. So, despite nominally poor seeing conditions, you will be able to cut through some of the problem. For example, I live in an urban area where the Milky Way is often not visible or just parts of it some times of the year. Even so, my instruments will  show me the Milky Way. I was surprised, but there it is.

So, the easy answer is that if you look in your average "Friendly Stars in Your Sky" book or a magazine, you will probably be able to chase most of the targets labeled "easy for beginnners." (Myself, I chase binaries.) There's a lot to see. Let us know if you run out of things to look at.

Everyone recommends Stellarium or similar software. I find them overly complicated for just telling me what I can see tonight. I use this Sky & Telescope online application:

https://skyandtelescope.org/interactive-sky-chart/

Click on Deep Sky Objects. Click off the annoying stuff.

You have a nice telescope and a nice range of occulars. (I assume you mean 32 mm, not 3.2.) You could achieve the same results for a 10mm by using a Barlow with your 24 and 16 which would give you effective 12 and 8 mm but at a more comfortable eye relief.  Also, for yourself as an experiment, you could compare the 32mm with 2X Barlow against the 16 mm and let us know how they look to you. You might find differing results with different targets. Let us know. (Just a suggestion.)

I suppose that I should have made this my "zeroth" suggestion before the first, but do you keep a log book of some kind? I use bound graph paper notebooks. Other people use their computers, phones, or tablets, but whatever, keeping track of your work is an important part of the science.

I've been getting on pretty well with Stellarium, but I will checkout the link you posted. 

It is a 3.2mm. A BST Starguider. To keep cost down I'm trying to keep everything in 1.25", mainly because all my filters are that size. So the 24mm is my longest focal length EP at the moment. I had some excellent views of Jupiter and Saturn with the 16mm and a x2.5 powermate. First time seeing Jupiter's cloud belts so very happy!

I've been keeping an occasional log over the last year, but this year I'm trying to be more organized before I start each session so it will be getting a lot more entries. If I ever run out of things to look at I must be doing it wrong

Do you get plenty of clear nights in Texas?

[mikemarotta]

9 hours ago, Stuu said:

IDo you get plenty of clear nights in Texas?

We used to. I moved here in 2011. This year has been especially cloudy and wet. Looking back over my logs, A week of cloud cover was unusual, maybe a couple of times in the winter and spring. This year, I have not had a cloudless week since early April. Realize, though that Texas is a big place. We can have a snowstorm in the north and a tropical storm in the south on the same day in March or November. The west is high desert. The east is coastal marshes. The distance from the University of Texas Austin to the University of Texas McDonald Observatory in Fort Davis is the same as Paris to Prague. or just short of Edinburgh to London.