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Where On Earth Is M81?


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I looked out the window yesterday evening to discover that the sky had unexpectedly cleared.  This was an opportunity to try out the new Dob.  We had had a couple of earlier attempts that were hampered by cloud, so that all we really did before was look at Jupiter, the Moon and M42.  The forecast for yesterday evening had been so poor that we had done no preparation.  Other mistakes included taking the scope straight out from a warm house and immediately collimating it.  (We re-did the collimation about an hour in.)

Our previous experience had always been with GOTO SCTs and Refractors, and, other than one evening in France when Olly Penrice had showed us some objects through his 20", we have no experience of Dobs or trying to find stuff for ourselves.  I'm not sure that we did much 'star hopping' - most of our successes came when the target object was close to a naked eye visible star.    

So we started with easy to find stuff - Jupiter (and its 4 moons) followed by M42.  It was the best view of M42 we have had from our home site (the French view was sensational) even though it was still not quite dark.  

I then tried to find a couple of 'trickier' objects.  M35 was relatively easy to find and was terrific.  Then over to the Owl Cluster in Cassiopeia - this was one of the prettiest objects we have seen through a telescope and was unknown to us prior to getting the Dob.  From there it was not too far to the Double Cluster - which filled our 31mm Luminos eyepiece and was spectacular.  

M45 was easy to find but was probably too 'large' for our FOV.  M44 was also on the large side but still quite nice through the Dob.

We then had a go at the three Auriga clusters and were able to locate them all - we found M36 first (just a patch of haze in the finderscope) this was really impressive - then M37 and finally M38 (also very impressive).

Our final success was M51 and its companion.  This felt like a proper 'star hop' since (following the 'Turn Left At Orion' instructions) we had to locate 24CVn in the finderscope and then place it and Alkaid in a certain arrangement (a bit awkward since TLAO shows an uncorrected finderscope view and we have a RACI).  It took a couple of goes to find, but another success. 

It started getting quite hazy around 9:30 pm and we decided to pack in.

We were reasonably happy with the dozen or so objects we had found in the hour and a half.  But we had a number of 'fails' (in the parlance of our times, as Lebowski might say).

I couldn't find the Leo Triplet, but this was on me - I was trying to find it from 'memory' and was looking in completely the wrong place!  I went all over the left side of Orion several times but could not locate M78.  

The biggest disappointment was M81 and M82.  We kept going back to this several times without success.  I tried pointing our red dot finder at a patch of sky that seemed to be about the same distance and direction again as Phecda to Dubhe - nothing.  We then tried following the TLAO directions.  They talk about finding 'four dim stars' in a line just as Dubhe is slipping out of view of the finderscope.  I'm afraid we couldn't locate these at all and were, therefore, lost from the get go.    

Overall we were reasonably pleased for our first attempt, given our lack of preparation and the fact that we have very little idea of what we are doing.  Our inability to find M81/M82 was a bit disheartening, though.  Would some of the more experienced folks here be able to offer any hints, tips, tricks or even 'cheats' for locating these objects?  Some guidance on M78 would also be appreciated.  

Apologies for taking up your time with these ramblings.

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Here's how I do it, though people have their own methods.

finding M81.JPG

The classic 'pointer' stars of the Plough (looped in red), which point to Polaris, have a not-quite-parallel pair beside them marked 1 and 2. Continue the straight line between 1 and 2 to a third 'star' which, if you have great vision or are using a finder, is in fact a triangular asterism shown as such on the star chart above. (SkyMap Pro.) If you follow the baseline of this triangle back down towards the opposite end of the Plough you'll be within striking distance.

Do you have a Telrad? While star hopping is the right way to find very difficult things I think it's much easier to put a Telrad circle on the chart and estimate its position relative to naked eye stars nearby. I then just put the real Telrad circles into that same relative position. This is where a Telrad beats a red dot, because the big circle gives you a sense of scale. 

Olly

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Very nice report of a very good first session with your Dob. M81 is always tricky at first. Olly is spot on with the use of a Telrad or in my case a Rigel finder. And of course once you have found it a couple of times it becomes so simple you wonder why you had problems at first.

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As Olly typed, a Telrad will help a lot, i found 78 Messiers with mine once you use it your wonder why there not supplied out of the same box, you can download ready made Telrad maps and the circles are installed on Sky Safari, CdC, Stellrium the list just goes on....

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Or you could use my method...start with the bright pointer stars of the plough, follow the little arc of stars around with your finder next to my dotted line..then look for the crossbow shape of stars and then go where the arrow would go past the little group of three stars on the left and then turn right a bit..

Although I must say I like Ollies method.

m81.jpg

And to answer your question, where is M 81...It is 12 million light years away in a group of galaxies, many of which are visible in dark skies and a medium scope in that area of sky..The M 81 group of galaxies is part of the big disk like structure of galaxies that we are in that also includes the Virgo cluster and a number of other clusters in Ursa Major.

Mark

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Olly's star hop is the one I use. The only thing to add is that you follow the base of the triangle back towards the plough and come to a pair of stars with a dimmer one in between, the galaxies are just off the end of these.

If it's any comfort, I find these very easily in a refractor, but do often struggle with a dob! Something about the position of the eyepiece vs finder etc. TelRad makes it much easier though.

Great night.

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Got great views of M81 & M82 last night. I always find them dead easily with my 15x70 binoculars, and last night they really stood out due to the seeing and clearness. Takes me a while always to home in on them with my ST120 frac. I need to learn a good route to star hop to them better with the scope. Last night when I viewed them they were close to the zenith limit on my AZ3 stand, which made it hard to manovere around well. Was about to give up on using the scope to see them and just use the binos when in to the filed of view of the EP they popped in. Best views were through my 32mm, 20mm & 17mm (x18 to x40) were I could keep both of them in the same FOV. 

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Also, may invest in a Telrad also as an extra finder on my scope to find those things that are a little trickier to hunt down.

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Thanks to all who replied.  I do have a Telrad.  However, the scope came witha Baader red dot finder and a RACI (Skywatcher) 9 x 50.    I have though about getting the Telrad on there, but not sure where it would best fit.  My RACI has a FOV of 5.6 degrees and the Telrad circles go out to 4 degrees, which is not hugely different.  I thought I mght manage without - I guess not!

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35 minutes ago, gnomus said:

Thanks to all who replied.  I do have a Telrad.  However, the scope came witha Baader red dot finder and a RACI (Skywatcher) 9 x 50.    I have though about getting the Telrad on there, but not sure where it would best fit.  My RACI has a FOV of 5.6 degrees and the Telrad circles go out to 4 degrees, which is not hugely different.  I thought I mght manage without - I guess not!

The benefit of the TelRad is that you can very easily match up the different circles with apps or star maps which makes star hopping much easier eg place h Ursae Majoris in the top right of the 4 degree circle, then pan across by 4 degrees and Bode's should be in the RACI

image.png

image.png

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Nice report, I may invest in a telrad, as last night I actually found that using the flash shoe and the end of my camera lens worked surprisingly well for sighting, a telrad would have been even easier. Only thing is last night I had vastly more stars visible than usual!

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3 hours ago, Stu said:

The benefit of the TelRad is that you can very easily match up the different circles with apps or star maps which makes star hopping much easier eg place h Ursae Majoris in the top right of the 4 degree circle, then pan across by 4 degrees and Bode's should be in the RACI

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Looks great, and easy to use. One question though; why does this hobby always have me forking out more money? Hehe! ;) 

Edited by Knighty2112
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Some folks seem to like putting their Telrads on riser rails (up to 4" higher).  What are the advantages of doing that?  And the second question: is there an adapter that would allow me to fix the Telrad base onto something that I could screw into one of my Skywatcher finderscope brackets (I have 3 and think I would have to remove one to get the Telrad on)?

Edited by gnomus
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4 minutes ago, gnomus said:

Some folks seem to like putting their Telrads on riser rails (up to 4" higher).  What are the advantages of doing that?

It just means you don't have to get your head/eye so close to the OTA so it's a little easier to sight along the TelRad and see the circles.

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58 minutes ago, Knighty2112 said:

Looks great, and easy to use. One question though; why does this hobby always have me forking out more money? Here! ;) 

Motor racing is worse...

Olly

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I'm surprised no one else suggested the way I do it, which I assumed is the way everyone does it!

I just visualise a line drawn from Phad through Dubhe to the same distance the other side and aim a low powered field of view at that part of the sky. M81 usually takes a few seconds or maybe a minute of scanning around to find it. I have never used a finder on any scope. I just sight down the tube, rack-of-the-eye. The MD often questions how I get muddy knees from stargazing. 

Bit of a pain trying to slew round manually so close to the pole with an equatorial but I guess Dob's come into their own on these occasions. You might get muddy ears though, using my method! :)

 

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24 minutes ago, ollypenrice said:

Motor racing is worse...

Olly

That's one to avoid doing then! Leave that to the super-rich! ;) 

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On 29 March 2016 at 17:01, jrastro said:

For M78, centre on the westernmost star of Orion's belt and wait 15 minutes. It is slow, but works every time!:icon_biggrin:

Beautifully simple!!  Worth reminding people to switch off their drives if they have them, to avoid disappointment!!

Off to see what other elusive fuzzies this method can be used for.

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I also use Olly's method. Found clear instructions on the internet with the 2 search stars to the right of the big dipper, from there finding the triangle and from there the line. Since then it has become easy to find back. That triangle is easy to spot.

About the binoculars. With my handheld 10x50 under a dark sky, I can only see Bode's galaxy and not the sigar.

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I also find them as Paul M. On the line that goes through Phad and Dubhe and somewhere at about the same distance between Phad and Dubhe, in the direction of Dubhe, they should be on the left a little.

Alex

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I made myself a "road map" starting from Dubhe (see attachment).

In the 8x50 finderscope I follow the Phad-Dubhe diagonal line till reaching a sea-gull shaped group of stars.

Following the middle line between its wings, proceed onwards....if I reach a 90° right angle shaped group of stars it means I went too far !

Back a little and with a little chance M81 & M82 (I call them the Stan & Laurel galaxies :icon_biggrin:) they should both be in your widefield eyepiece...

M81 M82.pdf

Edited by PHIL53
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31 minutes ago, PHIL53 said:

I made myself a "road map" starting from Dubhe (see attachment).

In the 8x50 finderscope I follow the Phad-Dubhe diagonal line till reaching a sea-gull shaped group of stars.

Following the middle line between its wings, proceed onwards....if I reach a 90° right angle shaped group of stars it means I went too far !

Back a little and with a little chance M81 & M82 (I call them the Stan & Laurel galaxies :icon_biggrin:) they should both be in your widefield eyepiece...

M81 M82.pdf

Thanks Phil53 - I'll give that a try.

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