15 replies to this topic

[Smurf]

Hi.
Does it exist a list of DSO Rising? Just ordering object from left to right.

 

I want to have listed DSO from left to right, because sometimes after observing, I remind that I want some other target, and see that target gone for tonight (goes too right, behind my house).

 

I can get data from Telescopius app and write it,  but it is a long process. I am sure that exists somewhere, but I can't find it.

 

And I suppose that all DSO objects move "together" in the sky, from our view, because of their long distance. And they never overtake each other? (talking in our time, and not for next million years).

Edited by Smurf, 01 February 2025 - 11:31 AM.

[Martinbruce]

DSO’ won’t overtake each other, planets will with their differing orbits. They (planets) in turn will overtake DSO’s. Application such as sky safari will give rise and setting times for most DSO’ listed in catalogues. I typically will go out with a pre-planned target list for the night. I don’t know of the type list you’re asking about, perhaps others will. Good thought shared. 

[nitsky]

Hey  Smurf!

The perfect time of the year for that very question with March and early April coming up before too long.....and the Messier marathons popping up.

Here's a good source I came across to help PLAN an evening's viewing, even if it doesn't include participating in one of these gruelling all nighters.

 

astronomy.com/messier-marathon.php

 

All the best,

Nitsky

 

*Just in vase that LINK doesn't work...just search for (Messier marathon sequence)

 

Edited by nitsky, 01 February 2025 - 12:11 PM.

[Starman1]

Hi.
Does it exist a list of DSO Rising? Just ordering object from left to right.

 

I want to have listed DSO from left to right, because sometimes after observing, I remind that I want some other target, and see that target gone for tonight (goes too right, behind my house).

 

I can get data from Telescopius app and write it, but it is a long process. I am sure that exists somewhere, but I can't find it.

 

And I suppose that all DSO objects move "together" in the sky, from our view, because of their long distance. And they never overtake each other? (talking in our time, and not for next million years).

You can download the list I link.  It is in Excel Format.

https://www.saguaroa.../sac-downloads/

Simply sort by RA and you have the West to east arrangement.

Since that will include objects at various declinations, inconvenient for observing, then sort by constellation and you will have each constellation in the order in which objects transit.

Note: the computer program SkyTools4 will arrange any list of DSOs in the order in which they should be observed.

[sevenofnine]

You can also visually see what stars and DSO's are rising by keeping a large planisphere up to date. I hang this one on my bedroom wall as an astro decoration   it's that nice. The back has excellent info on DSO's RAh, Dec, Mag & Constellation.

Very well done 

 

https://www.abebooks...-069250334X/plp.

Edited by sevenofnine, 01 February 2025 - 05:42 PM.

[Tony Flanders]

Most lists of deep-sky objects are sorted by right ascension (RA), which indicates the sidereal time when the object transits (is highest in the sky), and therefore best to observe. So when in doubt, do your observing in RA order.

 

The order in which objects rise depends on your latitude, so it's impossible to order such a list so that it will work for observers at different latitudes. In general, all objects rise very nearly six hours before they transit for observers on Earth's equator. Moreover, all objects on the celestial equator (declination zero) rise very nearly six hours before they transit for observers at all latitudes.

 

For observers in Earth's northern hemisphere, objects north of the celestial equator (positive declinations) rise more than 6 hours before they transit, and the higher the declination and the observer's latitude, the longer they stay in the sky. Objects south of the celestial equator (negative declinations) rise less than 6 hours before they transit. For an observer at latitude L, objects north of declination 90-L are circumpolar, meaning that they're always above the horizon, and never rise or set. Conversely, objects south of declination L-90 are permanently below the horizon.

 

Consider, for instance, an observer at latitude 40N. Objects north of Dec 50 are circumpolar, and objects south of Dec -50 are never visible. And just to give one example, objects at Dec 20 rise and set 7.2 hours before and after they transit.

 

For observers in Earth's southern hemisphere, everything is just as above, except reversed -- i.e. objects at southerly declinations are above the horizon more than 12 hours at a stretch, and objects at northerly declinations for less than 12 hours at a stretch.

 

In practice, it's more useful to know when an object reaches a reasonable observing altitude than when it rises. Ideally, you should never observe anything less than 30 degrees above the horizon, and 45 or 60 degrees is significantly better. That complicates the situation even more.

 

Back in the days when I observed massive lists of objects, I would first divide them into classes by declination, and then sort each class by RA. On any given night, my highest priority would be to observe objects south of Dec -15, which are only reasonably high for very short periods of time. Then, when I had exhausted those for any given night, I would attack the ones between Dec -15 and +15, then the ones between Dec +15 and +45, and finally the ones north of Dec +45, which remain high in the sky for very long periods at a stretch.

[Smurf]

For mobile app I'm using Stellarium, about 1 year. I started recording DSO at half of last season.

 

Thanks guys for many lists! That is exactly what I am looking for.

 

At page astronomy.com/messier-marathon.php at short check I found that not all objects good align, i.e. that exist a big "jump" or not ordering in the right way. E.g., on the page are M64-M3-M98, but in Stellarium are M3-M64-M98.

 

Also on page https://www.saguaroa.../sac-downloads I Sorted by RA, A-Z. There is existed that "jumps". NGC 2645 and NGC 2632 are to far away! Even we here can't see 2645, because it is close to the horizon, and in Excel shows only 1 degree difference! Why?

That is maybe because of that?:

The order in which objects rise depends on your latitude, so it's impossible to order such a list so that it will work for observers at different latitudes.

That's what I was going to ask next.

Thanks @Tony Flanders for such a detailed answer.

 

In meantime, I made a test in Stellarium compare my Croatia and Pennsylvania, USA, and sky objects are seems on the same place, and that is because similar latitude. Then I try to compare with  Sao Paulo, Brasil, and sky objects are messed up. Also learned that they have LMC and SMC objects, which I never heard before

 

At the end, maybe my own created list would be better choice and precise?

 

EDIT: Sky Tools3 Start Edition it seems working good and have aligned by Country/City. All neatly arranged (Sky Tools 4 seems to exist only payware version).

Edited by Smurf, 02 February 2025 - 07:16 AM.

[Starman1]

Well, SkyTools is the answer for the sort, but if you sort the SAC list by RA first, then by constellation, it pretty much will tell you the sequence to follow in a given constellation.

I don't know about you, but I tend to observe in one constellation at a time anyway.

 

Tony's idea of starting south and then heading north has merit, but only if you only observe for 2-3 hours at a time.

If you observe all night, the sky rotates quite a bit and new constellations cross the meridian.

So going back and forth from south to north to south and north again would be a decent modification of his plan.

 

The issue with Sky Tools, I found, is that it gives me a few thousand objects to observe each night and I can only see maybe 50 to 70 over a night (depending on the season),

and it's impossible to pick out which objects I want to observe in advance.  Though perhaps it doesn't seem very adventurous, I tend to stick to my list of 2500 favorites or the 5500 objects in the Night Sky Observer's Guides

or "follow the herd" if there are other deep-sky observers there at the site.  One of the nice things about group observing is that you may all select the same object and you can go from scope to scope to get different views

of the same object.  One of the bad things about doing that is that you may enjoy using an eyepiece you don't own, and you know where that leads!

 

An 8" scope in dark skies can see up to about 15000 deep sky objects (estimate).  Even being systematic about it, it would take many years to see all those objects even once.

And many objects you will want to revisit.  Even though you won't see all those objects in bright skies, you might travel to dark skies or to the southern hemisphere, so, over the years, if you keep track of the objects you observe,

you will learn which ones to revisit and which ones not to revisit, and which ones you need dark skies to see and which ones you don't.

 

Sometimes just pushing yourself can be a reward.  I observed 45 galaxies one night in the small constellation of Corona Borealis.  Other nights I won't observe any objects in that constellation.

There is nothing wrong in using a variety of observing interests as they ebb and flow.  You might look only at open clusters one night, and only planetary nebulae on another.

If you do it that way, the list size in Sky Tools gets more manageable.  Don't forget to record which objects you want to revisit and which you don't.  You might be able to see 15000 DSOs, but you may only ever want to revisit 1000 of them.

I guess the point is that there are a lot more than the brightest 500 objects in the sky to observe.  Every night I think I've seen all the objects I want to see (and my log has about 13000 DSOs in it), I run across a new one I've never seen

that quickly gets added to my Favorites list.

 

I attach a small list of about 500 favorites I have seen in my 4" refractor.  Your list might include other objects not on my list.  I did not put objects larger than about 1° on the list so that people with SCTs and MCTs would still be able to see every object.

Remember to have fun!

 

Attached Files

•  Best 500 Deep Sky Objects.xlsx   333.38KB   5 downloads

[mrflibbles]

This isn't 100% what you were asking but it is somewhat relevant: https://theskylive.com/ is a resourse I use when I'm out observing. There is a link to "what's visible right now" which lists everything currently and gives you current altitude. You unfortunately cant move time ahead or backwards but it's still a good tool. You can however narrow the field.

 

Edited by mrflibbles, 02 February 2025 - 04:32 PM.

[daveb2022]

Tonight's sky can be set up to show objects rise and set times. Puts it a kind of an orderly fashion.

 

 

Lets you pick what types of targets, and you can use different categories... I prefer the rise/set times. You can go by constellations or difficulty.

Edited by daveb2022, 05 February 2025 - 02:24 AM.

[Mike Q]

Sky Safari gives you several different options on the sorting of objects.  

[Smurf]

Thanks.

 

This question has been bothering me for a long time. I understand the opposition of the planets. The sun is opposite the planet while the earth is between them. Then the planet is at its highest point in our the sky.

 

But as a beginner, I don't understand why we're looking the "opposition" in DSO? Can it really be called the "opposition" of DSO? (although there is no sun there, only the object on the highest point).

 

And another question, let's say that at 30° we start observing DSO, isn't the same observation around 60°, instead of waiting for DSO opposition (90°)? I.e., are DSO objects better seen when they are directly above us? (90°).

 

I know that at lower angles we can find more clouds which accumulate in a pile and blocked observing, if is that reason.

 

But our observing position are not closest to that object in any time, no matter how the earth turns, because we are talking in Light Year distance here.

[Starman1]

Thanks.

 

This question has been bothering me for a long time. I understand the opposition of the planets. The sun is opposite the planet while the earth is between them. Then the planet is at its highest point in our the sky.

 

But as a beginner, I don't understand why we're looking the "opposition" in DSO? Can it really be called the "opposition" of DSO? (although there is no sun there, only the object on the highest point).

 

And another question, let's say that at 30° we start observing DSO, isn't the same observation around 60°, instead of waiting for DSO opposition (90°)? I.e., are DSO objects better seen when they are directly above us? (90°).

 

I know that at lower angles we can find more clouds which accumulate in a pile and blocked observing, if is that reason.

 

But our observing position are not closest to that object in any time, no matter how the earth turns, because we are talking in Light Year distance here.

Opposition does occur with DSOs, but it has nothing to do with closeness, so there isn't just one time of the year when they will be closest to the Earth.

Hence, we usually talk about opposition in relation to planets.

The only important factor for DSOs is transit time, i.e. the time the object culminates, or crosses the N-S meridian.  It is at that time the object is highest in the sky, and we see it through the least amount of atmosphere.

 

At the zenith, the atmosphere is 1 atmosphere thick.  At 30° altitude, the atmosphere is 2 atmospheres thick.  And at the horizon, about 10 atmospheres thick.

And in that atmosphere is haze, particles, smog, fog, clouds, and light pollution.  You may have noticed what is called "horizon lightening" which is a gradual brightening of the atmosphere as you go low.

This is also called "extinction", and is measured in magnitudes of loss per atmosphere.  At high altitude, it can be as little as 0.125 magnitude per atmosphere, and at sea level about 0.3 magnitudes per atmosphere.

Add in a little haze or a wet atmosphere and it can be as high as 0.5 magnitudes per atmosphere.

This is why, for DSOs, observing them at or near the meridian is essential to seeing them at their best.

 

There is one advantage for an object being far from the sun in the sky--it will be closer to the center of the Earth's shadow, that time of night when the sky is typically the darkest overall, i.e. the horizons will be the darkest.

People who don't observe all night, who typically observe only for a couple hours in the evening, talk about how certain constellations are in a "season".  What they mean is that that constellation is transiting at the hours they are observing.

 

Constellations don't really have a season, since they advance westward about 30° a month at the same time each night.  There is only about 36° of sky blocked from view by the sun, and it advances eastward as the months pass.

If you stay up all night, you can pretty much see the entire sky in 2-3 months.  It takes a little longer if you observe objects near the meridian.

Edited by Starman1, 17 February 2025 - 06:18 PM.

[Dave Mitsky]

https://www.space.fm...ulmination.html

[Starman1]

https://www.space.fm...ulmination.html

Excellent graphics.  Reminds me of the old Edmund's stuff.

"All About Telescopes":

https://www.edmundop...elescopes 2.pdf

[WillR]

Excellent advice here all around. Observing lists can be  sorted by right ascension if they are in an excel format and have the coordinates. By the way, the New General Catalogue (NGC) objects are numbered in order of right ascension as well.

 

Another way, which I actually prefer, to sort a list is by constellation. While not strictly by order from west to east, it has the advantage of also sorting them by declination to the extent they are in the same area of the sky. One NGC number can be far north and the next one in the southern hemisphere. This is because they are strictly ordered by RA.

 

Here is where a planisphere is very useful to show the progression of the stars in the sky. Most of us can’t look up and see what right ascension is overhead, but we can see which stars and constellations are.

 

Experienced observers know to observe targets from west to east. They also tend to concentrate on a particular constellation since many guide books like the “Night Sky Observer’s Guide” are organized by constellation.