M81's Elusive Twin

[Les Ewan]

Great seeing here tonight the M81 spiral galaxy is neck crickingly overhead and is easy with my 8X60's,however I've never managed to see its edge on companion M82 with binoculars. M82 is smaller and half the brightness but I would of thought that 60mm bins would of made it discernible.It would be good to know how others fare with this one.

[Knighty2112]

I see both when the seeing is good in my Celestron Skymaster 15x70 binoculars. Never seen them with my Strathspey 7x50's as I think I need darker skies to see them with these. Also, some form of mount/pole to assist when looking at them might enable the dimmer M82 to poke out, as arm wobble might make it less dicernable when holding just by arms on their own. Would have though with care you should just about see M82 with your binos. 

[andrew63]

Good point above about holding them steady - they are visible in a 9x50 finder, so i think the issue is keeping them more stable. It might be a bit easier when they are lower in the sky as your arms give more support.  Great sight though, when you think of what you are looking at through a pair of binoculars !

andrew

[BinocularSky]

Have seen M82 with averted vision in my 10x42; it requires excellent transparency and, of course, minimal light pollution. It's easier to see when its higher in the sky, as there is less atmospheric gunge in the way.

[Roy Challen]

I attempted these two last week from my heavily light polluted location. I got as dark adapted as possible ( not very, really), and spent quite some time star hopping. Eventually, M81 was spotted in averted vision, then later still, I'm almost certain that I got a very faint glimpse of M82, but whether it was a real spot or my brain playing tricks, I don't know.

This is in utter contrast to my viewing of this pair from Kazakhstan, where both galaxies were visible with ease in direct vision, even the dust lane in M82 could just be made out.

Dark skies and or patience are needed!

[Nyctimene]

You may believe it or not......

July 22,2015, 00h25min until 02h55min with average skies (NELM 5.5 mag,SQM-L 21,07) I was able to spot both galaxies with a really tiny, but excellent monocular, the foldable Docter 8x21!

(IIRC with averted vision). Of course, I had known exactly, where to look. The 21 mm aperture showed as well M 31, M 33, M 30, M 45, and the North America Nebula this night.

(When re-reading the notes I took that night, it seems almost incredible for me now - I'll have to repeat the observation during the next months.....)

Stephan

[Stu]

I've seen both of them quite frequently in binoculars both at dark sites and at home. Canon 15x50is gave me best results I think although I've seen them in others. Although M82 is much dimmer that M81, its surface brightness is still reasonably high at 21.4 mag/arcsec^2 because it is edge on rather than more spread out like M81.

[Nyctimene]

19 minutes ago, Stu said:

I've seen both of them quite frequently in binoculars both at dark sites and at home. Canon 15x50is gave me best results I think although I've seen them in others. Although M82 is much dimmer that M81, its surface brightness is still reasonably high at 21.4 mag/arcsec^2 because it is edge on rather than more spread out like M81.

Stu,

the "Night Sky Observer's Guide" shows the surface brightness of M 82 at 12.8 mag/arcsec, Stropek's Deep Sky Beobachteratlas at 12.5 mag/arcsec (--could 21.4 be a typo??)

Stephan

 

[Stu]

7 minutes ago, Nyctimene said:

Stu,

the "Night Sky Observer's Guide" shows the surface brightness of M 82 at 12.8 mag/arcsec, Stropek's Deep Sky Beobachteratlas at 12.5 mag/arcsec (--could 21.4 be a typo??)

Stephan

 

Could be I guess, what do those sources say for M81?

[Stu]

Putting the numbers into the unihedron site calculators gives a similar result so it can't be that far off....

[Stu]

I'm more confused now (not that this take too much  )

Cam someone explain the difference in these measurements? I see some quoting M81/82 at around 12 or 13, and some, including the calculator I used showing 22 ish. Is this a case of different units? Any ideas?

http://www.backyard-astro.com/deepsky/top100/10.html

I think my original point is valid i.e. The surface brightness of the two galaxies is much closer than their actual brightness making M82 relatively easier to see (although as it is small it is still a challenge in binos)

[YKSE]

4 hours ago, Stu said:

I'm more confused now (not that this take too much  )

Cam someone explain the difference in these measurements? I see some quoting M81/82 at around 12 or 13, and some, including the calculator I used showing 22 ish. Is this a case of different units? Any ideas?

http://www.backyard-astro.com/deepsky/top100/10.html

I think my original point is valid i.e. The surface brightness of the two galaxies is much closer than their actual brightness making M82 relatively easier to see (although as it is small it is still a challenge in binos)

I think the differences caused by the units for surface brightness, Magnitude per square arcsecond (MPSAS) or Magnitude per square arcminute(MPSAM),

MPSAS=MPSAM+8.89

as Glenn explained here

http://www.cloudynights.com/topic/473313-ngc-185-surface-brightness/?p=6172596

[Stu]

1 hour ago, YKSE said:

I think the differences caused by the units for surface brightness, Magnitude per square arcsecond (MPSAS) or Magnitude per square arcminute(MPSAM),

MPSAS=MPSAM+8.89

as Glenn explained here

http://www.cloudynights.com/topic/473313-ngc-185-surface-brightness/?p=6172596

Perfect, thanks Yong!! All is clear. MPSAS makes more sense to me as Glen says it is how sky brightness is measured.

[Stu]

Just didn't a couple of calculations on the bbastrodesigns site. Looks like it should be  visible from a suburban location, mag 18.5 to 19 with 50mm binoculars. Reading the graphs implies that a 10x50 with a 5mm exit pupil would be the best bet.

For info, readings of -0.25 to 0.25 are difficult but visible. Between 0.25 and 0.5 are visible, and above 0.5 they are easy.

http://www.bbastrodesigns.com/VisualDetectionCalculator.htm

[StarSapling]

On most night around here, I can see both M81 and M82 with my 8x42's.

[mikeDnight]

On 30/01/2017 at 01:18, Les Ewan said:

Great seeing here tonight the M81 spiral galaxy is neck crickingly overhead and is easy with my 8X60's,however I've never managed to see its edge on companion M82 with binoculars. M82 is smaller and half the brightness but I would of thought that 60mm bins would of made it discernible.It would be good to know how others fare with this one.

Hi Les,

I generally find M82 the easier of the two galaxies. It sounds like you might be a bit uncomfortable if viewing is giving you neck ache. Providing you can hold your binoculars steady enough, you could try lying back in a garden chair or inflatable mattress. Straining will definitely hinder your observing ability, so get comfortable. Just don't fall asleep! ?

Mike

[BinocularSky]

6 hours ago, mikeDnight said:

 you could try lying back in a garden chair or inflatable mattress.

I find a "zero gravity" chair to be ideal for binocular and naked-eye observing. Not the cheapest option, but well worth it, IMO.

[Nyctimene]

If you are looking for a cheap and effective image stabiliser for bins, here is a "low -tech" - solution:

Alan M. Mc Robert  from Sky and Telescope built a rectangular frame 1,5x0,25 m for his bins, which eliminates shakes almost completely; look at this:

www.skyandtelescope.com/astronomy-equipment/image-stabilize-your-binoculars/   (Feb. 6, 2007). I have built this device to use it with my 10x50 Zeiss Jenoptem bins, and it works really well! Cheap and simple to build, and you'll gain a full magnitude of star brightness, paired with much more freedom of movement, compared to a tripod.

Stephan

[trynda1701]

10 hours ago, BinocularSky said:

I find a "zero gravity" chair to be ideal for binocular and naked-eye observing. Not the cheapest option, but well worth it, IMO.

 I posted a thread about that type of chair a couple of years back. Now I've got my Helios Apollos, I must try and see about actually getting one of them to supplement my monopod setup. Any recommendations of makes, Steve?

 

Looking forward to the weather getting better to try out the Apollos on targets like M81/M82!

Mark

[BinocularSky]

20 hours ago, trynda1701 said:

 Any recommendations of makes, Steve?

No, sorry; ours are unbranded, picked up on special offer somewhere.

[PeterW]

Stu and I found them from a moderate suburban site using 8x40 and 7x35 bins, nice starhopping directions from Stu.

cheers

peter

[Stu]

46 minutes ago, PeterW said:

Stu and I found them from a moderate suburban site using 8x40 and 7x35 bins, nice starhopping directions from Stu.

cheers

peter

It's one of my best star hops Peter, works very well every time. Pretty well shown in these images.

[PeterW]

Works a dream! Skies were clear.

 

Peter

[Nyctimene]

Stu,

I'm using almost the same strategy, but I start from Upsilon UMa up to 23 UMa, because both are lined up almost parallel to Dubhe - Merak and point rather exactly at the "triangle". From there, the same way.

Stephan

[Stu]

7 minutes ago, Nyctimene said:

Stu,

I'm using almost the same strategy, but I start from Upsilon UMa up to 23 UMa, because both are lined up almost parallel to Dubhe - Merak and point rather exactly at the "triangle". From there, the same way.

Stephan

That's actually exactly what I do Stephan, I couldn't find an image that showed precisely this route though. It's such a great hop, so simple and works every time