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M31, 32 and 110

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#1 Speedy1985

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Posted 20 October 2021 - 09:37 PM

During my session tonight, I wanted to see if I could get a look at M31. When I got to the location of them, I spotted two other fuzzies, both in the same FOV. Based on the roughly 2° of separation and the fact that they were both in the FOV of my 9mm(right at each edge with a 1.8° FOV) and 13mm(2.6° FOV) I assume these were M32 and 110. But I'm stumped because I could see no obvious signs of M31. The moon was full and bright, so is it possible that M31 was more affected by it due to its size?



#2 Napp

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Posted 20 October 2021 - 09:44 PM

Nope.  M31 is what will show in bright moonlight the biggest and brightest.  M32 will look like a fuzzy star.  M110 will be very faint and difficult.


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#3 Speedy1985

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Posted 20 October 2021 - 09:58 PM

Nope.  M31 is what will show in bright moonlight the biggest and brightest.  M32 will look like a fuzzy star.  M110 will be extremely difficult to impossible.

But wouldn’t M31 fill more of the FOV? Or was I just seeing the bright core due to the moonlight? M32 looked more like a globular to me than a fuzzy star though. 



#4 Napp

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Posted 20 October 2021 - 09:58 PM

I think your field of view calculations are off.  I think the apparent fields of view are well less than half what you quoted.


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#5 Napp

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Posted 20 October 2021 - 10:00 PM

But wouldn’t M31 fill more of the FOV? Or was I just seeing the bright core due to the moonlight? M32 looked more like a globular to me than a fuzzy star though. 

Yes M31 is way bigger than your field of view.  In bright moonlight you will be seeing the bright core which is big.  At the magnification you were using M32 probably would look more like a glob.


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#6 PJBilotta

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Posted 20 October 2021 - 10:57 PM

I'll second that M110 is very difficult. Depending on your sky conditions and light pollution level, M31 will often look much smaller than you expect because you are really only seeing the inner core, and M32 will look a bit like a bright globular in the same field. M110 is much more diffuse and farther from M31 than you anticipate because the image of the latter is smaller than you think it should be. As a result, observers often think they are seeing 31 and 110 in the same field, when what they are really seeing are 31 and 32, with 110 either outside the FOV or hardly visible.

Edited by PJBilotta, 20 October 2021 - 11:00 PM.

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#7 Speedy1985

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Posted 21 October 2021 - 08:05 AM

Yes M31 is way bigger than your field of view.  In bright moonlight you will be seeing the bright core which is big.  At the magnification you were using M32 probably would look more like a glob.

I'll second that M110 is very difficult. Depending on your sky conditions and light pollution level, M31 will often look much smaller than you expect because you are really only seeing the inner core, and M32 will look a bit like a bright globular in the same field. M110 is much more diffuse and farther from M31 than you anticipate because the image of the latter is smaller than you think it should be. As a result, observers often think they are seeing 31 and 110 in the same field, when what they are really seeing are 31 and 32, with 110 either outside the FOV or hardly visible.

Thank you both, this makes sense. I was pretty sure the moon and my location had some hand on what I was seeing, or thought I was seeing.



#8 Don H

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Posted 21 October 2021 - 02:49 PM

If you were using your 100 degree 9 and 13mm eps in your 12" f/5, your fov was only .6 and .87 degrees. Maybe even less if the Paracorr was in place, too. This would mean that M31 was completely filling your eps and extending way beyond the edges. So it's no wonder you were not really noticing M31. To figure your fov, take the ep fov and divide that by your mag, so 100 divided by 167 for the 9, and by 115 for the 13.


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#9 Speedy1985

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Posted 21 October 2021 - 02:55 PM

If you were using your 100 degree 9 and 13mm eps in your 12" f/5, your fov was only .6 and .87 degrees. Maybe even less if the Paracorr was in place, too. This would mean that M31 was completely filling your eps and extending way beyond the edges. So it's no wonder you were not really noticing M31. To figure your fov, take the ep fov and divide that by your mag, so 100 divided by 167 for the 9, and by 115 for the 13.

Yes, you're correct. I was using the eyepiece buyers guide that has all of the calcs built in and got the columns mixed up. What I posted was the exit pupil. I will have to try to observe them again on a moonless night to see how M31 differs. I'll also try my 20 and 30mm EP's then as well. 



#10 Napp

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Posted 21 October 2021 - 04:50 PM

Yes, you're correct. I was using the eyepiece buyers guide that has all of the calcs built in and got the columns mixed up. What I posted was the exit pupil. I will have to try to observe them again on a moonless night to see how M31 differs. I'll also try my 20 and 30mm EP's then as well. 

Start with your widest field ep for M31 and increase magnification as desired.  In fact, start with binoculars if you have them to get an idea of the scale.


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#11 lsm4691

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Posted 21 October 2021 - 05:29 PM

Yes, you're correct. I was using the eyepiece buyers guide that has all of the calcs built in and got the columns mixed up. What I posted was the exit pupil. I will have to try to observe them again on a moonless night to see how M31 differs. I'll also try my 20 and 30mm EP's then as well. 

Stick a 31 mm Nagler in that 12' dob and thank me later. grin.gif


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#12 Speedy1985

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Posted 21 October 2021 - 05:45 PM

Stick a 31 mm Nagler in that 12' dob and thank me later. grin.gif

As much as I'd love to do that, the EP budget went out the window with the upcoming night vision purchase. But I think that will be a good complement as well wink.gif


Edited by Speedy1985, 21 October 2021 - 05:45 PM.

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#13 Keith Rivich

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Posted 21 October 2021 - 09:16 PM

I'm sure you mistook the core of M31 as M32. In bright moonlight M31 looks more like a diffuse globular cluster. What you didn't see is M110. 


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#14 Tony Flanders

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Posted 22 October 2021 - 05:49 AM

During my session tonight, I wanted to see if I could get a look at M31. When I got to the location of them, I spotted two other fuzzies, both in the same FOV. Based on the roughly 2° of separation and the fact that they were both in the FOV of my 9mm(right at each edge with a 1.8° FOV) and 13mm(2.6° FOV) I assume these were M32 and 110. But I'm stumped because I could see no obvious signs of M31. The moon was full and bright, so is it possible that M31 was more affected by it due to its size?

The chances of anybody seeing M110 at full Moon are very small. The chances of a newbie seeing it at full Moon are precisely zero.

 

I have no doubt that the brightest of the objects that you saw was M31. At full Moon you would only see the core, which is very nearly circular and probably less than 10 arcminutes across. It is also certainly possible to see M32 at full Moon; it looks quite a bit like M31's core, but smaller and much fainter. I am baffled about the third object.


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#15 Speedy1985

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Posted 22 October 2021 - 06:31 AM

The chances of anybody seeing M110 at full Moon are very small. The chances of a newbie seeing it at full Moon are precisely zero.

 

I have no doubt that the brightest of the objects that you saw was M31. At full Moon you would only see the core, which is very nearly circular and probably less than 10 arcminutes across. It is also certainly possible to see M32 at full Moon; it looks quite a bit like M31's core, but smaller and much fainter. I am baffled about the third object.

What you described as far as M31 and M32 is exactly what I saw. I hadn’t realized at that time that M110 was so much dimmer. There was no third object, I was confused thinking I was seeing 32 and 110 in the area of 31.



#16 jayrome

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Posted 05 November 2021 - 12:46 PM

Great views last night for me of all three with my new Panoptic 35mm ep. Very clear night, no moon, so M31 was there in all her glory, dust lane and even detail to the left and right of the core. Even M110 (in the same fov) was very clearly visible without averted imagination - and all this from my Bortle 6 backyard. Need to try it out far from the city next time under similar atmospheric conditions!

OMG, and later in the night when M42 was up in the sky, wow! Amazing!

 

J


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#17 Astrojensen

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Posted 05 November 2021 - 02:15 PM

The chances of anybody seeing M110 at full Moon are very small. 

Now I want to try it. wink.gif  

 

 

Clear skies!

Thomas, Denmark


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#18 Redbetter

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Posted 05 November 2021 - 07:13 PM

Now I want to try it. wink.gif  

 

Yes, it makes a person wonder if it might be possible, and I suspect it is in the right conditions.    To make the attempt here, I would try it from one of my dark sites in August around 3 AM with the full Moon low in the southern sky--basically taking advantage of the ecliptic plane being low..  This would put about 70 degrees of separation between the Moon and Andromeda.   Of course, I don't take the 20" up to observe from a dark site during Full Moon...so I really don't have a feel as to what is possible in good skies.  Anything near the Moon will be trashed of course. 

 

It would also be subject to the whims of summer weather with dust/aerosol haze and smoke being primary bad actors locally.



#19 Tony Flanders

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Posted 06 November 2021 - 06:35 AM

I said:

The chances of anybody seeing M110 at full Moon are very small.


And Astrojensen replied:

Now I want to try it. wink.gif  
 
 
Clear skies!
Thomas, Denmark


Well, yes, of course the same though flashed through my head as I wrote that. The trick, of course, is defining exactly what you mean. No doubt M110 is quite easy to see when it's high in the sky and the full Moon is just 1 degree above the horizon. Does that count?

#20 Astrojensen

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Posted 06 November 2021 - 11:11 AM

No doubt M110 is quite easy to see when it's high in the sky and the full Moon is just 1 degree above the horizon. Does that count?

No, that wouldn't count. Besides, the sky is very, very bright, when the full Moon is just 1° above the horizon, because that means the Sun is just 1° below it! wink.gif

 

I was honestly thinking about attempting to spot M110, when the full Moon was high in the sky, no cheating there. Obviously, the sky needs to be very clear. 

 

 

Clear skies!

Thomas, Denmark


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#21 Rodgerraubach

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Posted 06 November 2021 - 11:25 AM

Several years ago, i spent quite a bit of my time viewing M31 looking for the Globular clusters that are in the arms of the galaxy. I was using a 12.5" Discovery Telescopes Dobsonian (with a Terry O mirror); I routinely started at a very low magnification to "take in the scenery" before getting down to details. There are also a number of Globular clusters in M110 that are possible with a 12.5" scope. 

 

My starting eyepiece was normally a Panoptic 27 or a William Optics UWAN 28, followed by a Nagler 17 T4 as I began to focus my attentions on a portion containing the "G" number I was hunting that evening. I looked for specific asterisms, and then went to a Pentax 10, then a Pentax 7, and finally a UWAN 4 for my highest magnification. 

 

M31 is a BIG galaxy, and fills the field of just about any telescope--even using a Nagler 31, or a Panoptic 35. But I was always able to see the 3 galaxies under dark sky conditions in all of my telescopes at that time. Smallest was a Takahashi TOA130.


Edited by Rodgerraubach, 06 November 2021 - 11:25 AM.

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#22 Redbetter

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Posted 07 November 2021 - 02:02 AM

 

I was honestly thinking about attempting to spot M110, when the full Moon was high in the sky, no cheating there. Obviously, the sky needs to be very clear. 

I don't see that a realistic goal, simply because separation and position in the sky are important.  You don't want the Moon to be near M110 at the time, and you don't want M110 to be low in the sky either.  Both will greatly reduce the contrast.  So I see this as finding the best balance, an optimization function.


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#23 Astrojensen

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Posted 07 November 2021 - 03:26 AM

I don't see that a realistic goal, simply because separation and position in the sky are important.  You don't want the Moon to be near M110 at the time, and you don't want M110 to be low in the sky either.  Both will greatly reduce the contrast.  So I see this as finding the best balance, an optimization function.

I know, but as there are so many variables, I'm simply waiting until the next full (or nearly full) Moon and see what I can see, and report accordingly. M31 is high in the sky all night this time of the year. 

 

 

Clear skies!

Thomas, Denmark



#24 Tony Flanders

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Posted 07 November 2021 - 07:09 AM

No, that wouldn't count. Besides, the sky is very, very bright, when the full Moon is just 1° above the horizon, because that means the Sun is just 1° below it! wink.gif


Doh! Why wasn't that fact obvious to me?


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#25 Astrojensen

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Posted 22 November 2021 - 01:42 PM

Had a go at NGC 205/M110 yesterday evening, around 9.00 P.M. local time, with my APM 152ED, with a not quite full moon in the sky. The Moon was 94% illuminated and around 45° away from the M31 trio, which was almost on the meridian. The Moon had an altitude of around 40°. The sky was clear, but not super exceptionally so. There was a very faint halo around the Moon. It was just below freezing and the grass was slowly being covered in hoarfrost. 

 

I took a peek at M110 before observing the Moon, to preserve what little dark adaption I had, but with the site I currently have, I'm not sure, it made much of a difference. I had the scope set up with a binoviewer, because I was about to observe the Moon, but I didn't want to change to a 2" diagonal. I had two 40mm plössls in the bino, giving just 30x. 

 

M31 and M32 were immediately and easily seen, the differences between their cores standing out strikingly. M110 was far more elusive, but it only took a few moments, before I had it in view. I had to cusp my hands around the eyepieces and my eyes, to shield me from stray light, but then I could hold it quite steadily with averted vision. It wasn't easy to see, but not particularly challenging either. The Moon wasn't quite full, though, so maybe it would have been more difficult to see M110, if it had been. 

 

My site was hardly ideal, though, as you can see from the photo below, so I guess M110 would be a lot easier, if I had been able to find a much darker location and shield myself from the direct glare from the Moon.

 

med_gallery_55742_4772_1986565.jpg

 

I later tried to see if M110 was easier to see in a single eyepiece and at the same (40mm ES68, 30x) or higher magnification (17mm ES92, 71x), but if anything, it was easier with the binoviewer at 30x! The picture is taken then, and the scope is pointing at M31. 

 

 

Clear skies!

Thomas, Denmark 


Edited by Astrojensen, 22 November 2021 - 01:43 PM.

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