Star Hopping

[Ed in UK]

Last night I tried my first unsuccessful attempt at Star Hopping to the Andromeda Galaxy.

I struggled on a few fronts really, but I was hoping that I may get some guidance here.

I understand that principal of how to star hop, start from a known star and locate another known star in the EP view and move across to that one etc......

However I do find my view very limited, I'm using a scope with 130mm aperture (Skywatcher) and my widest EP is the kit 25mm that came with it. I'm not sure what the FOV is with the EP but I can just about fit Pleiades in it to give you an idea of size/view.

The charts that I'm using are from the Cambridge Star Atlas by Wil Tirion (4th Edition) showing stars down to 6.5. However when I compare the size of Pleiades in the chart it's only 5mm wide. Thats about the same diameter as a Bic pen.

I've done a bit of research and I see that people use a piece of card with a hole cut in it to replicate what their EP FOV is, so they hold that over the chart to work out their path to the target. However all these pieces of card seem to have holes in that are at least a couple of centimeters in diameter.

So do I need an EP with a wider FOV or a better scaled chart or both?

Just to add to my complications my scope has a limit on how much it can be adjusted in Dec from the fine adjuster, so paths in RA are a preferred.

Many thanks in advance.

 

[iPeace]

Are you using a finder scope?

[Ed in UK]

Hi Ipeace,

Yes, I have a RDF to get me on to my required start.

Thanks

Ed

[iPeace]

OK Ed. I'll try to help - but I don't have any experience with an EQ mount, I just use alt-az, your basic left-right-up-down arrangement.

It reads like you're taking a good approach, but you might indeed need a chart on a different scale, one that shows more detail to hop by.

I use digital charts, programs like SkySafari and Stellarium, either on a smart phone, tablet computer or laptop computer. They are like an interactive sky atlas that shows you the night sky as it is visible from your location at the current time (or indeed any time). You can zoom in to get a closer view of a part of the sky, and see patterns of stars that you can recognize in your actual field of view and navigate by. Indeed, the programs allow you to configure a circle on the screen which has the exact(ish) diameter of your current field of view - this helps to see how many FOVs you need to move in any given direction. This gives you a continuous guide as to what you should be seeing whilst hopping from one clear target to the next. This works a charm for me.

So I use the RDF to point at and acquire a bright star, then use the view on my smart phone to help me nudge over to where I want to get.

An intermediate step is to add a so-called RACI (Right Angle, Correct Image) finder scope, a second finder scope which is just a small telescope with a wide FOV that you can use for finding your way around. There are brackets available which allow you to attach both an RDF and a RACI to the same main scope, side by side. I do this with my Newtonian, and use the RDF to get in the general area, then use the RACI to navigate and star hop, and then observe through the main scope. Indeed there are those who don't use an RDF at all, just the RACI (but I really like the convenience of the RDF as the first step).

Would using a program like SkySafari or Stellarium be an option for you?

[domstar]

I use stellarium at home and maybe draw what I see on overlapping circles on paper. My problem is always starting off on the wrong star (i.e. I'm not looking at the star I think I'm looking at). It takes a bit of practice so start with easy star hops to objects near bright stars. M 35 in Gemini is beautiful and near naked eye stars. 

I've never used a red dot finder or EQ mount so maybe things are slightly different for you. Apparently, though, once you've learnt a star hop on an eq mount, then it's the same hop no matter where in the sky your target has moved to. The eq grid on stellarium could be helpful too. Good luck.

[Stu]

Trying to learn star hopping on an EQ mount with a narrow ish field of view will be tricky. I suggest trying to get either a Telrad or an optical finder, say 6x30 or 9x50 and preferably a RACI (right angles, correct image) so things are more intuitive.

I would also consider getting the Sky & Telescope Pocket Star Atlas which is very handy. Personally I use SkySafari for reasons already given on the thread, it is so easy to fine tune the display to show the same magnitude of stars are are visible through your finder or eyepiece, as well as matching the fields of view and orientation.

To give you some more info, these diagrams may help. The first is, I believe, the field of view with your scope and the 25mm eyepiece. Next are the rings shown by a Telrad, then finally the field of view with your scope, compared with a 9x50 and 6x30 finder. The 6x30 gives around 7 degrees, the 9x50 around 5 degrees.

Finally, the last diagram shows how easy it is to locate something like the Eskimo from Wasat when using the larger field of view. Assume a RACI, you can place the starting star in the location shown and the Eskimo neb will be in the centre of your scope's fov. With targets further away from a bright star, you have to hop further, matching star patterns as you go, but the wider fov always helps.

[Moonshane]

try my star hopping guide. I do recommend both a red dot type finder and right angle correct image optical finder.

[Ed in UK]

Thanks to everyone for their responses.

I've got Stellarium on my laptop but not really taken outside during a session. I've also got the one with a french name (sorry can't recall the name) to print off star charts hopefully in more detail than the Cambridge Atlas gives me.

I'll have a look at SkySafari too and see if that would work on my tablet.

I'll keep trying and I'm sure I'll get there in the end.

Oh Moonshane downloaded and read your article a few weeks ago. Thank you for putting that together.

[Red Dwarfer]

2 hours ago, Stu said:

Assume a RACI, you can place the starting star in the location shown and the Eskimo neb will be in the centre of your scope's fov

I will have to try that method for the Eskimo neb ! To date that neb has been jinxed for me .

Note to OP : It might sound like a stupid question , and it`s a mistake a lot of people make , but you do remember that the reflector scope is reversed / upside down which makes hopping a bit more tricky ... The book Turn Left At Orion gives a lot pics that are right way up on the left and reversed on the right for this reason , for refractors on the left and reflectors on the right .

[iPeace]

1 hour ago, Ed in UK said:

I've got Stellarium on my laptop

You can configure 'ocular view' to give you a very good approximation of what you should be seeing at the eyepiece, including the rotated newtonian orientation.

[Stu]

34 minutes ago, Red Dwarfer said:

I will have to try that method for the Eskimo neb ! To date that neb has been jinxed for me .

Note to OP : It might sound like a stupid question , and it`s a mistake a lot of people make , but you do remember that the reflector scope is reversed / upside down which makes hopping a bit more tricky ... The book Turn Left At Orion gives a lot pics that are right way up on the left and reversed on the right for this reason , for refractors on the left and reflectors on the right .

Give it a go, but then as others have posted elsewhere, up the mag once on target and it should pop into view more clearly

[Littleguy80]

I went for a Telrad and it made a massive difference to me. Originally I was using Sky and Telescope Pocket Atlas. Now I tend to use SkySafari with the Telrad circles as Stu showed. I don’t have a finder beyond that. There are times when a RACI would definitely have helped. Doing it through the eyepiece takes a lot of getting used to with everything being reversed. It comes with practice though  

[Cosmic Geoff]

Ed - I sympathize with your difficulty as I have found manual telescopes fairly useless for finding faint and non-obvious objects and always use GoTo for this purpose.

I have also struggled to find M31 with a manual scope. IIRC it will show up in an optical finder if skies are dark (I saw it with binoculars once while on holiday). 

I never found M81 and M82 at all with my manual Newtonian and the experience prompted me to buy a much more expensive 8" SCT with GoTo.

Be aware that opinions diverge widely on this issue, with some people enjoying the search and extolling the virtues of star-hopping, while others (like me) think that life is too short to waste on this sort of thing when a box of modern tech can do the job far quicker.

[Nyctimene]

21 hours ago, Moonshane said:

try my star hopping guide. I do recommend both a red dot type finder and right angle correct image optical finder.

+1 for that. I'd add a 6x30 (TFOV=True Field of View of about 7°) or an 8x50 (TFOV appr. 5°) RACI finder to your 130 mm scope. Your RDF gets you roughly into the area; the finder will show you the region with the same orientation as the naked eye, very intuitive. The Pocket Sky Atlas will harmonize very well with the 130mm; you can then cut out a template, following Moonshane's suggestions, with the finderscope's field of view, for this atlas; or use SkySafari's or Stellarium's display options. No need for another long focus eyepiece.

Stephan

[Ed in UK]

Thanks guys for all your advice really appreciated.

I have a cunning plan (hopefully). I just need to double check that i can see M101, the Pinwheel Galaxy by the Big Dipper. Studying my charts and simulating the 'Hop' on Stellarium, I should be able to start at Mizar & Alcor and hop to M101 with each star just visible in the EP until i get there.

Waiting for a clear night now which should be Saturday.

[Ed in UK]

Cosmic Geoff, thank you for your support but unfortunately can't stretch to a Goto system but oddily enough really enjoying the challenge of trying to find stuff. Just not enough clear nights.

Walking the Dog at 10pm the other night I was looking up and realised how much I've learnt since the start of Dec last year. 

Still loads to learn and discover ?

[Stu]

On 17/02/2018 at 11:22, Cosmic Geoff said:

I never found M81 and M82 at all with my manual Newtonian and the experience prompted me to buy a much more expensive 8" SCT with GoTo.

I've often struggled to find these two when using a Newt, but find them quite easily with a refractor. Not sure why!  

[Littleguy80]

21 minutes ago, Ed in UK said:

Thanks guys for all your advice really appreciated.

I have a cunning plan (hopefully). I just need to double check that i can see M101, the Pinwheel Galaxy by the Big Dipper. Studying my charts and simulating the 'Hop' on Stellarium, I should be able to start at Mizar & Alcor and hop to M101 with each star just visible in the EP until i get there.

Waiting for a clear night now which should be Saturday.

Hi Ed. M101 is pretty faint (low surface brightness). It took a dark site trip for me to see it in my 130mm scope. I did manage M51 (Whirlpool galaxy) from home but it will depend on how good dark your skies are. If you haven’t seen them already M81/M82 are a nice bright pair of galaxies and show up pretty well even with a bit of light pollution. They’re all fairly straight forward star hops to get to them 

[Stu]

6 minutes ago, Littleguy80 said:

Hi Ed. M101 is pretty faint (low surface brightness). It took a dark site trip for me to see it in my 130mm scope. I did manage M51 (Whirlpool galaxy) from home but it will depend on how good dark your skies are. If you haven’t seen them already M81/M82 are a nice bright pair of galaxies and show up pretty well even with a bit of light pollution. They’re all fairly straight forward star hops to get to them 

It really is the skies that make the difference, they are all visible in binoculars if the skies are good enough. I saw M33 and M101 both first in 15x50 binos.

[Littleguy80]

7 minutes ago, Stu said:

It really is the skies that make the difference, they are all visible in binoculars if the skies are good enough. I saw M33 and M101 both first in 15x50 binos.

Very true. I saw M101 with my 10x50 bins recently under dark skies. M101 was the first target where I had that “why can’t see it?” moment. I’ve probably got it built up in my mind as a more challenging target as a result!

[Ed in UK]

Thanks guys. My research suggested that i should be able to see it with a small scope but i wanted to double check with stellarium & charts.

Actually having a secondary target may be wise so I'll have a look at M81& M82 as well.

Thanks again.

Ed

[Nyctimene]

Under moderate skies (naked eye limiting magnitude =NELM  of about 5.3), you will be able to make out only the core region of M 101, at the apex of an almost equilateral triangle with Mizar and Alkaid /Benetnasch. Follow, starting from Mizar, the star chain formed by 81, 83, 84 and 86 UMa; from the latter, at an almost right angle, you will find M 101. The use of averted vision will help (look slightly to the left or right side of it). Under really dark skies its a splendid sight, almost a full moon's diameter. Good luck with the hunt!

Stephan

[Red Dwarfer]

On 2/16/2018 at 18:34, Stu said:

Give it a go, but then as others have posted elsewhere, up the mag once on target and it should pop into view more clearly

Found it tonight ! Using that method you suggested above it was dead centre and looked a bit like a fuzzy star at 40mm then much better at 18mm 

[Ed in UK]

Well done Red Dwarfer, glad you had clear skies, sat under cloud and drizzle here. 

Just had a look at hopping to M88 or M81, struggling to see an easy starting point with a clear obvious path to both. I'll have a look on Stellarium later.

That was the attraction with M101, good clear starting point not too far way and then (hopefully) brighter, unmistakable stars to use for hopping.

If anyone else has any ideas of good targets for star hopping to for a complete beginner then I'm all ears...

Many thanks

Ed

[Stu]

1 hour ago, Ed in UK said:

 

Just had a look at hopping to M88 or M81, struggling to see an easy starting point with a clear obvious path to both. I'll have a look on Stellarium later.

 

Ed, there is a great star hop to M81/82. Once you get it, you will always be able to find them, I get there in a couple of seconds with binos, easy!

Ignore the lines in the first chart, I just put it in as it clearly identifies the triangle and line needed for the hop.

Follow a line from Upsilon Ursae Majorie through 23 UM about the same distance beyond and you find a small triangle of stars. Follow a line acros the bottom of this triangle and you come to a line of three stars, two brighter, one faint. Put these top right in a RACI and the galaxies will be in the centre of your finder.