Dark Sky- seeing for the first time

[markclaire50]

This thread is for stories you have about seeing something under dark skies that you were never able to see under more light polluted skies, maybe your back yard or from anywhere with light pollution. 

The story can be absolutely anything, as long as it relates to using the same scope or binoculars. So, I guess we're talking portable scopes here. 

I'd love to know what a difference going to a dark sky can really make? 

I look forward to your stories! 

Mark

[vlaiv]

Content does not relate well to title, or I'm missing something (maybe just a way to get peoples attention and get them involved into discussion )?

Ok, I planned to give this answer to previous thread you started, but since you opened another one, here it is here:

200mm F/6 scope (dob mounted) is equipment, usual LP observing site is around 18.5mag - dark site about 20.8mag.

Difference is unbelievable! From LP site I managed to observe total of 6 galaxies - M31/M32/M110 group, M81/M82 pair and M51 over my whole observing time in this site..

Last spring I went to dark site and in single observing evening I managed few dozen galaxies with ease.

M51 from LP site looks like two little dots of light and you think you see some nebulosity around them, but you are not sure. Sky just looks a bit brighter there. From dark site you can definitively tell what you are looking at - familiar shape of spirals around brighter core reaching toward nebulosity around dimmer one. No mistake there, its definitively M51.

When I looked in direction of Virgo cluster - galaxies just kept popping into view wherever I turned the scope. At some point I was just cruising the sky and honestly had no idea what I was looking at. I mistook Whale galaxy for C26 at some point, but noticed Crowbar next to it afterwards. I've also seen C26 at one point in the evening. M101 was probably the least impressive - it's very low surface brightness and no spiral structure was detected.

NGC6207 gave me real surprise - I was looking at M13 and without looking for that near by galaxy - it just popped into view - there it was, no effort needed to see it.

Markarian's chain was there of course, all surrounding galaxies as well. 4" F/5 short tube achromat showed only 4 galaxies of it, while 8" dob showed all. I also had trouble seeing Hamburger with 8", while other two members of Leo triplet were obvious.

Like I've said - difference is unbelievable! I wonder what it looks like from truly dark site, as this was from 20.8mag skies.

[markclaire50]

56 minutes ago, vlaiv said:

Content does not relate well to title, or I'm missing something (maybe just a way to get peoples attention and get them involved into discussion )?

Ok, I planned to give this answer to previous thread you started, but since you opened another one, here it is here:

200mm F/6 scope (dob mounted) is equipment, usual LP observing site is around 18.5mag - dark site about 20.8mag.

Difference is unbelievable! From LP site I managed to observe total of 6 galaxies - M31/M32/M110 group, M81/M82 pair and M51 over my whole observing time in this site..

Last spring I went to dark site and in single observing evening I managed few dozen galaxies with ease.

M51 from LP site looks like two little dots of light and you think you see some nebulosity around them, but you are not sure. Sky just looks a bit brighter there. From dark site you can definitively tell what you are looking at - familiar shape of spirals around brighter core reaching toward nebulosity around dimmer one. No mistake there, its definitively M51.

When I looked in direction of Virgo cluster - galaxies just kept popping into view wherever I turned the scope. At some point I was just cruising the sky and honestly had no idea what I was looking at. I mistook Whale galaxy for C26 at some point, but noticed Crowbar next to it afterwards. I've also seen C26 at one point in the evening. M101 was probably the least impressive - it's very low surface brightness and no spiral structure was detected.

NGC6207 gave me real surprise - I was looking at M13 and without looking for that near by galaxy - it just popped into view - there it was, no effort needed to see it.

Markarian's chain was there of course, all surrounding galaxies as well. 4" F/5 short tube achromat showed only 4 galaxies of it, while 8" dob showed all. I also had trouble seeing Hamburger with 8", while other two members of Leo triplet were obvious.

Like I've said - difference is unbelievable! I wonder what it looks like from truly dark site, as this was from 20.8mag skies.

Hi Vlaiv, 

Sorry. I managed to somehow mess up a new topic and replace title. There should be a separate topic relating to this title. However, your answer is still relevant to both! ? When you say 20.8 mag, do you mean this is absolute limit that any scope could see? 

Your report is very interesting. In my other question, I ask about portability of an 8" but also about using it on an heq5 mount. I note you have a dobsonian. I know from experience that I'm useless without goto and tracking! 

[markclaire50]

1 hour ago, vlaiv said:

Content does not relate well to title, or I'm missing something (maybe just a way to get peoples attention and get them involved into discussion )?

Ok, I planned to give this answer to previous thread you started, but since you opened another one, here it is here:

200mm F/6 scope (dob mounted) is equipment, usual LP observing site is around 18.5mag - dark site about 20.8mag.

Difference is unbelievable! From LP site I managed to observe total of 6 galaxies - M31/M32/M110 group, M81/M82 pair and M51 over my whole observing time in this site..

Last spring I went to dark site and in single observing evening I managed few dozen galaxies with ease.

M51 from LP site looks like two little dots of light and you think you see some nebulosity around them, but you are not sure. Sky just looks a bit brighter there. From dark site you can definitively tell what you are looking at - familiar shape of spirals around brighter core reaching toward nebulosity around dimmer one. No mistake there, its definitively M51.

When I looked in direction of Virgo cluster - galaxies just kept popping into view wherever I turned the scope. At some point I was just cruising the sky and honestly had no idea what I was looking at. I mistook Whale galaxy for C26 at some point, but noticed Crowbar next to it afterwards. I've also seen C26 at one point in the evening. M101 was probably the least impressive - it's very low surface brightness and no spiral structure was detected.

NGC6207 gave me real surprise - I was looking at M13 and without looking for that near by galaxy - it just popped into view - there it was, no effort needed to see it.

Markarian's chain was there of course, all surrounding galaxies as well. 4" F/5 short tube achromat showed only 4 galaxies of it, while 8" dob showed all. I also had trouble seeing Hamburger with 8", while other two members of Leo triplet were obvious.

Like I've said - difference is unbelievable! I wonder what it looks like from truly dark site, as this was from 20.8mag skies.

Title changed to correct one now. ?

[vlaiv]

3 minutes ago, markclaire50 said:

Hi Vlaiv, 

Sorry. I managed to somehow mess up a new topic and replace title. There should be a separate topic relating to this title. However, your answer is still relevant to both! ? When you say 20.8 mag, do you mean this is absolute limit that any scope could see? 

Your report is very interesting. In my other question, I ask about portability of an 8" but also about using it on an heq5 mount. I note you have a dobsonian. I know from experience that I'm useless without goto and tracking! 

Light pollution is sometimes expressed in these units, and 20.8mag should read as: 20.8 magnitude per arc second squared of sky. Which translates to - amount of light emitted from one arc second squared of the sky in relation to magnitude 0 star. It would be like taking magnitude 20.8 star and "smearing" it over one arc second squared of the sky.

Actually above unit is much more meaningful to astro photographers and people that measure things in astronomy - it represents background sky signal. For observing it's not straight forward to relate to sky brightness unless you've had chance to see what different sky quality looks like. There is one thing that can help you with understanding these units:

This is approximate comparison of different units. Bortle 1 sky is about 22 magnitude (above diagram places it at 21.75 but it needs to be darker for Bortle 1 site).

According to above diagram, two sites that I was referring to can be expressed as: Bortle 7/8 transition, or border of red and white zone, while dark one would be classified as Bortle 4 or yellow zone (close to green) - so by no means very dark skies. Darkest that I've got "easily" accessible would be green zone at 21.3, while best in my country would be Bortle 2, but I would need to travel 4-5 hours in one direction to get there, and I'm hoping to arrange short holiday once or twice on such location.

8" dob is small car portable with ease. On particular observing session described three of us went with two cars - one friend came straight after work so he did not carry any astronomical gear, just a chair if I recall correctly. We managed to pack 2 scopes 4" F/5 achro - ST102 with AZ4 mount and 8" SW dob.

I also have HEQ5 and I used 8" F/6 tube on it for a bit of AP (both planetary and DSO). I would not recommend this combination for general use - either AP nor observing. Newtonian on EQ mount gets eyepiece in very awkward positions, and you need easy way to rotate tube to put EP in right position when you change target. 12Kg OTA is not easily rotated in tube rings . I also wanted to continue using that OTA as dob mounted, so I never removed "ears" from it - this creates additional problem as you can't fully rotate OTA in rings - because "ears" get in the way.

There are few threads about mounting 8" F/6 ota on HEQ5 - people just remove those "ears" in the end. Bresser 8" dob might be better suited for this, as it already has rings for mounting on dob base, so no modding is necessary to put it on EQ mount. Here is what it looks like:

[markclaire50]

1 hour ago, vlaiv said:

Light pollution is sometimes expressed in these units, and 20.8mag should read as: 20.8 magnitude per arc second squared of sky. Which translates to - amount of light emitted from one arc second squared of the sky in relation to magnitude 0 star. It would be like taking magnitude 20.8 star and "smearing" it over one arc second squared of the sky.

Actually above unit is much more meaningful to astro photographers and people that measure things in astronomy - it represents background sky signal. For observing it's not straight forward to relate to sky brightness unless you've had chance to see what different sky quality looks like. There is one thing that can help you with understanding these units:

This is approximate comparison of different units. Bortle 1 sky is about 22 magnitude (above diagram places it at 21.75 but it needs to be darker for Bortle 1 site).

According to above diagram, two sites that I was referring to can be expressed as: Bortle 7/8 transition, or border of red and white zone, while dark one would be classified as Bortle 4 or yellow zone (close to green) - so by no means very dark skies. Darkest that I've got "easily" accessible would be green zone at 21.3, while best in my country would be Bortle 2, but I would need to travel 4-5 hours in one direction to get there, and I'm hoping to arrange short holiday once or twice on such location.

8" dob is small car portable with ease. On particular observing session described three of us went with two cars - one friend came straight after work so he did not carry any astronomical gear, just a chair if I recall correctly. We managed to pack 2 scopes 4" F/5 achro - ST102 with AZ4 mount and 8" SW dob.

I also have HEQ5 and I used 8" F/6 tube on it for a bit of AP (both planetary and DSO). I would not recommend this combination for general use - either AP nor observing. Newtonian on EQ mount gets eyepiece in very awkward positions, and you need easy way to rotate tube to put EP in right position when you change target. 12Kg OTA is not easily rotated in tube rings . I also wanted to continue using that OTA as dob mounted, so I never removed "ears" from it - this creates additional problem as you can't fully rotate OTA in rings - because "ears" get in the way.

There are few threads about mounting 8" F/6 ota on HEQ5 - people just remove those "ears" in the end. Bresser 8" dob might be better suited for this, as it already has rings for mounting on dob base, so no modding is necessary to put it on EQ mount. Here is what it looks like:

Sounds like a 6" f5 might be better on heq5? I probably need to watch a few YouTube videos on how much of a problem having to rotate tube would be, as well as seeing how high eyepiece would be for me. 

Thanks

Mark

[vlaiv]

27 minutes ago, markclaire50 said:

Sounds like a 6" f5 might be better on heq5? I probably need to watch a few YouTube videos on how much of a problem having to rotate tube would be, as well as seeing how high eyepiece would be for me. 

Thanks

Mark

Youtube videos is great idea. 8" F/6 on Heq5, even with tripod at minimum height, sometimes places EP at height that is unreachable for me, and I'm 6ft 1 (on a good day ).

If you are interested in visual only, why not go with Dob instead? If you worry about finding things - there is goto version, or version with electronic settings circles (that one does not move scope but it will tell you where it's pointing so you can check coordinates of object and move scope accordingly by hand).

[markclaire50]

14 minutes ago, vlaiv said:

Youtube videos is great idea. 8" F/6 on Heq5, even with tripod at minimum height, sometimes places EP at height that is unreachable for me, and I'm 6ft 1 (on a good day ).

If you are interested in visual only, why not go with Dob instead? If you worry about finding things - there is goto version, or version with electronic settings circles (that one does not move scope but it will tell you where it's pointing so you can check coordinates of object and move scope accordingly by hand).

Thank you. I think I must have tracking. Based on past adventures with manual! Pity there isn't a tracking version of dobs! 

[vlaiv]

3 minutes ago, markclaire50 said:

Thank you. I think I must have tracking. Based on past adventures with manual! Pity there isn't a tracking version of dobs! 

Yes there is!

Take a look a this one:

https://www.firstlightoptics.com/dobsonians/skywatcher-skyliner-200p-flextube-goto.html

It's goto and tracking dob mount - 8" F/6.

 

[markclaire50]

31 minutes ago, vlaiv said:

Yes there is!

Take a look a this one:

https://www.firstlightoptics.com/dobsonians/skywatcher-skyliner-200p-flextube-goto.html

It's goto and tracking dob mount - 8" F/6.

 

Mmm. How did I miss that one? I'm sure I researched enough, but clearly not! 

Now, you have given me more food for thought. ?? I bet it's pretty portable as well, being a truss design. 

Thank you. 

Mark

[markclaire50]

38 minutes ago, vlaiv said:

Yes there is!

Take a look a this one:

https://www.firstlightoptics.com/dobsonians/skywatcher-skyliner-200p-flextube-goto.html

It's goto and tracking dob mount - 8" F/6.

 

Of course, getting an heq5, 180mm mak, zwo imaging camera and a tracking Dob may be mutually exclusive from space and money point of view. I may have to make..... Ahhhhhhh..... choices! Nooooooo! 

I estimate cost of around £2300-2500, plus twice the storage space. 

I guess it will come down to can a 200mm f6 beat a 180mm mak on the Maks strong points of lunar, doubles and planets ( sharpness and contrast?). 

 

[vlaiv]

I have not tried many scopes, but so far 8" F/6 offered best planetary performance - it is indeed very versatile instrument. I've pushed mine 8" to powers past x300 and even x350 and it held it together (I did go ridiculously high as x533 - but just to see what would happen - it did not look good )

Cheapest planetary setup would be manual 8" dob + EQ platform. This will not provide goto, but you can image planets and Moon with that - it will "track"

I've read accounts of people not being satisfied with 6" Mak for lunar, but amazed with 6" newtonian in same role.

Check out these threads for example:

 

[markclaire50]

36 minutes ago, vlaiv said:

I have not tried many scopes, but so far 8" F/6 offered best planetary performance - it is indeed very versatile instrument. I've pushed mine 8" to powers past x300 and even x350 and it held it together (I did go ridiculously high as x533 - but just to see what would happen - it did not look good )

Cheapest planetary setup would be manual 8" dob + EQ platform. This will not provide goto, but you can image planets and Moon with that - it will "track"

I've read accounts of people not being satisfied with 6" Mak for lunar, but amazed with 6" newtonian in same role.

Check out these threads for example:

 

Wow. You have been very helpful! I will read these threads. Might take a while, but the more information I get, the more informed my decision(s). ? 

[markclaire50]

6 minutes ago, markclaire50 said:

Wow. You have been very helpful! I will read these threads. Might take a while, but the more information I get, the more informed my decision(s). ? 

 

44 minutes ago, vlaiv said:

I have not tried many scopes, but so far 8" F/6 offered best planetary performance - it is indeed very versatile instrument. I've pushed mine 8" to powers past x300 and even x350 and it held it together (I did go ridiculously high as x533 - but just to see what would happen - it did not look good )

Cheapest planetary setup would be manual 8" dob + EQ platform. This will not provide goto, but you can image planets and Moon with that - it will "track"

I've read accounts of people not being satisfied with 6" Mak for lunar, but amazed with 6" newtonian in same role.

Check out these threads for example:

 

Hi. I also have to take comments like this into account, from another post I made :

 

"I have owned both a 180mm Mak/Cass and an Orion VX8 Newt (great mirror). If your wish is to view the Moon, Planets and split tight doubles then the Mak/Cass, once cooled, will beat the 8" Newt everytime on these objects."

 

[vlaiv]

18 minutes ago, markclaire50 said:

 

Hi. I also have to take comments like this into account, from another post I made :

 

"I have owned both a 180mm Mak/Cass and an Orion VX8 Newt (great mirror). If your wish is to view the Moon, Planets and split tight doubles then the Mak/Cass, once cooled, will beat the 8" Newt everytime on these objects."

 

I would not consider 180mm Mak being superb planetary scope a surprise. I do however think that 8" F/6 dob with decent optics being able to match it (or get really close) at third of a price is a "surprise".

In theory, if both scopes have perfect figure and execution - 8" Newtonian will have very very slight edge - probably seen only by most experienced observer. In practice things are never equal. Each of those scopes has its strengths and weaknesses. You should choose between them based on your needs.

There is always just a bit better scope for particular purpose for a bit more money - so budget plays a part in it as well. Why stop at 180mm Mak, why not consider C11 - it will definitively out resolve 7" instrument.

For budget, 8" F/6 as all rounder is hard to beat, and it does give very good planetary image.

[markclaire50]

1 hour ago, vlaiv said:

I would not consider 180mm Mak being superb planetary scope a surprise. I do however think that 8" F/6 dob with decent optics being able to match it (or get really close) at third of a price is a "surprise".

In theory, if both scopes have perfect figure and execution - 8" Newtonian will have very very slight edge - probably seen only by most experienced observer. In practice things are never equal. Each of those scopes has its strengths and weaknesses. You should choose between them based on your needs.

There is always just a bit better scope for particular purpose for a bit more money - so budget plays a part in it as well. Why stop at 180mm Mak, why not consider C11 - it will definitively out resolve 7" instrument.

For budget, 8" F/6 as all rounder is hard to beat, and it does give very good planetary image.

Thank you. Sadly a C11 is well outside my price range. I have seen 180 mm maks for sale secondhand for £400. But C11 are over £1000 secondhand. 

I think that because I am planning to get a heq5 for imaging anyway, it just comes down to cost of ota. I've seen secondhand 200p explorer scopes around £150. So, you are correct, about a third of price of secondhand 180 mak. But, then this is where absolute cost is considered and for me, £450 would be worth paying for the mak on a heq5. 

However, I am going to read the threads you sent and think carefully. ? Thanks for your help. 

Mark

[John]

I replied to your other thread with this title yesterday (or maybe the day before) but I'm a bit confused what you are trying to get at with this new thread with the same title that you have started

Also much of the above discussion in this thread seems now to relate to high power planetary type performance which does now really relate to dark skies particularly.

 

[vlaiv]

2 minutes ago, John said:

Also much of the above discussion in this thread seems now to relate to high power planetary type performance which does now really relate to dark skies particularly.

That part is probably my fault

I noticed that I easily digress and venture off topic with ease. Title of this thread was actually 6" F/5 vs 8" F/6 or something like that, when I first replied, but initial post did not match the thread topic (as you can see from my initial reply), and OP changed that in the mean time. I guess original title was in relation to where discussion headed afterwards.

Maybe some post moving is in order to sort things out?

[markclaire50]

1 hour ago, John said:

I replied to your other thread with this title yesterday (or maybe the day before) but I'm a bit confused what you are trying to get at with this new thread with the same title that you have started

Also much of the above discussion in this thread seems now to relate to high power planetary type performance which does now really relate to dark skies particularly.

 

Hi John. Sorry for any confusion. At some point today I started a new topic a d somehow the title overwrote the dark sky thread, which vlaiv pointed out. I then edited the title back to the dark sky one.