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Trying to hop - which way to move?

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#1 randallpatrickc

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Posted 24 November 2021 - 11:30 AM

Blundering around last night with an old C8 on forks. The setting circles work really well, getting me to a star mentioned in "Go Left at Orion" But, peering through the 9x30 RACI, I can't easily match what I see against the finder pic in the book. Is there a simple way to determine which way to start moving? I'm confused.



#2 brentknight

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Posted 24 November 2021 - 12:03 PM

I use an app called SkySafari.  In the app, you can define the field of view for your eyepieces and the finder scope.  You can also define the orientation of the view to match your telescope/eyepiece/finder combination (they are often different).

 

Screenshot_20211124-105744_SkySafari 6 Pro.jpg

 

It takes a little practice but this method will allow you to see your surroundings and to give you a clue which direction to move the telescope.

 

What local sky conditions are you in?  Is it fairly dark or is it pretty light polluted?

 

And ... welcome to Cloudy Nights!


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#3 Noto

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Posted 24 November 2021 - 12:03 PM

Two things:

  1. My 9x50 RACI has a 5° AFoV. This aligns with the finder pics in the book almost exactly to scale. I don't know the AFoV of your 9x30, but I would assume it would be smaller, and therefore, the pics in the book would be larger than what you would actually be seeing.
  2. The finder pics in the book are "upside down". If you have a RACI, you'll need to flip the book.

I'm using a Dob with a 45° mounted focuser, with RACI that's mounted at 0°. Definitely takes practice slewing while viewing through either the RACI or an eyepiece, while keeping your perspective of North or South.

 

I think both above are correct smile.gif


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#4 havasman

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Posted 24 November 2021 - 12:20 PM

Blundering around confused is where we all started. That goes on and then one night it starts making sense and gets easier. It helped me a lot to remember that rises in the east, sets in the west holds at night too. Spend a bit looking at the sky and seeing the directions well so your base is sure when you start in with the finder. Start with some visible, clear star hop. I encourage folks to hop along Orion's belt to start and then expand the hop to Rigel and the many other bright stars in the area. Using the sky instead of trying to match an illustration has worked better for me. When you move from a belt star to Rigel to Aldebaran (bright red Alpha star in Taurus, the blazing fiery red eye of The Bull) instead of matching an illustration you will see the piece of sky across which you are moving and that should give you a useful frame of reference. Be sure to swing from a southerly pointing to a northerly pointing direction for your site and use another easily visible set of bright stars. From that you will realize east-to-west in the sky is sometimes left to right, sometimes right to left and sometimes up to down depending on where your objects lie in the sky that night.

 

Being sure to look around and past the RACI to see the sky you're moving across can be very helpful with orienting your pointing to the sky's organization and movement.

 

I hope this or something someone else offers helps. Come back for more as you like and then when it starts working out, let us know.


Edited by havasman, 24 November 2021 - 10:51 PM.

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#5 Dave Mitsky

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Posted 24 November 2021 - 12:32 PM

Star-Hopping for Backyard Astronomers by Alan M. MacRobert is an excellent book on learning the technique of star-hopping.  It's long out of print but used copies are available.

https://www.amazon.c...t/dp/0933346689


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#6 sevenofnine

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Posted 24 November 2021 - 03:20 PM

A Telrad in combination with a RACI finder helps keep me oriented when using a manual scope. Do the hop with the Telrad then check the RACI. With a wide field eyepiece I usually find my target. Best of luck to you! waytogo.gif  


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#7 Spile

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Posted 24 November 2021 - 05:19 PM

The Telrad and RACI combination works for me. Getting the right asterism makes all the difference https://astro.catshi...ng-dim-objects/


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#8 clearwaterdave

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Posted 24 November 2021 - 08:25 PM

I taught myself to hop using bino's first.,I was looking at my tablet and comparing the stars naked eye and with the bino.,I was looking at UMa.,Lots of stars naked eye for me here. Starting matching the chart with the view in 7x35 bino kinda one or two stars at a time.,going slow.,moving the bino, and looking at the chart.,back and forth.,. back and forth.,.I think teaching yourself to match the chart and the view FIRST is an easier way to learn to hop.,as opposed too spending time trying to find a target without knowing how to starhop.,At first I tried looking through the finder and figure it out while trying to "find" a target .,not fun.,.Sitting here in my recliner with the tablet and bino.,going back and forth.,back and forth.,and being able to see the same stars in the bino.,as on the chart.,moving a little after looking at the chart and seeing what you know you will see.,that was fun.,

 If you don’t know how to read the map you're going to get lost.,lol.,Starhopping is fun to learn.,I used a correct image diagonal in my refractors at first and that helped me.,  I guess I'm saying that I found matching the views was an enjoyable way for me to get the hang of it.,no target.,just matching the view.,move a little and match it again.,

 Good luck.,It takes some practice but it's time well spent.,


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#9 S.Boerner

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Posted 25 November 2021 - 12:15 PM

If you are using your C8 Alt/Az and not EQ on a wedge you may have to rotate your book. 

 

Books generally show north at the top of the page.  In astronomy north is towards the celestial north pole near Polaris.  If you are looking due south no problem, but if your object  is in the east or west you'll need to rotate the book such that the top of the page is towards Polaris for the view to match the book.

 

I get a headache when I try to explain this with something between Polaris and the northern horizon.lol.gif


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#10 Dave Mitsky

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Posted 25 November 2021 - 02:33 PM

Using binoculars to preview a star-hop, as clearwaterdave mentioned, is a good idea.


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#11 Dave Mitsky

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Posted 25 November 2021 - 02:41 PM

There's a section on star-hopping in my post (#22) at https://www.cloudyni...mers/?p=5184287


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#12 randallpatrickc

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Posted Yesterday, 10:12 AM

Thankyou all for help :-)

 

I’m on all the suggestions. Bought the book, downloaded the apps.

 

Was sat out there for the longest time. My biggest prob is still knowing which way to move. I substituted a Celestron RACI 9x50 finder for the original 6x30 and I think that gives 6 deg. I also have a Telrad and have made up the little wire circles. I do quite well with these as they relate to the sky exactly (If the stars are bright enough anyway). I quickly get lost however. Any more tips apart from starting over?

 

The RACI has that red reticule - and I’ve noticed that if it is oriented ok, the C8 knob twiddles (wedged fork) match up and down along each axis. (Is that the right way to use it?) My eyesight isn’t too good though and I then try to use the EP to help but am having trouble. I have a new Celestron 6.3 reducer and an old 40mm EP (make unknown, came with the old C8 scope says K 40mm). Much better but finding it *so* hard to move the scope in the right direction…

 

I struggled for a couple of hours then gave up and went back to using the setting circles. 
 

I now have the Pocket Sky Atlas, Star Hopping for Backyard (just arrived), Turn Left at Orion, Stellarium and Sky Safari. Someone on CN suggested using the angle tool in Stellarium to show a line to hop along. I liked that but couldn’t do it in Sky Safari.

 

Blunder, blunder!


Edited by randallpatrickc, Yesterday, 10:19 AM.


#13 Paul Sweeney

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Posted Yesterday, 01:11 PM

Here are a few tips that might help a bit.

Remember that in your finder, the image is correct, ie if looking South, North is up and East is left. Assuming you are using a diagonal, then the image in the telescope will be upright but reversed: North is up and East is right. You have to make the change from finder to scope in your mind. Seems difficult at first, but you will get it.

Make sure you hold your star chart to match the constellations orientation in the sky. Sometimes I hold it up and try to get the image scale to match the constellation's size. That makes it easier to pick the place in the sky I want to move to.

Try making geometric shapes that are easy to remember: lines triangles, curves, etc. Let's say you are looking for M31, the Andromeda galaxy. Start at the lower left corner of Pegasus (the big square). Andromeda extends down and to the left, so sweep that way until you see two brighter stars, which form a triangle with the beginning star. If you continue further, extending the triangle's sides, you will come to three brighter stars in a row. The top "star" is M31. Easy.

Your finder scope has a huge field of view. Your scope with a standard 40mm eyepiece will only show about half a degree ( the full moon fills the eyepiece). Therefore, you have to align the finder well and you have to aim well. That increases your chance of getting the target in the eyepiece first try.

If you are off, no problem. Time to do a search pattern. Think of a checker board three squares by three squares, nine in total. You are looking at the middle square. You want to search the 8 squares around the middle. Pick a bright star near the center. This is your "home" star that you will return to after each search. Go up, down, left and right until the star disappears. Always return to "home" before going off in another direction. To cover the diagonal positions, go left until the home star disappears. Pick another bright star as a reference, and now go up and down, coming back to the reference star. Now right to the home star, and repeat for the right side. Normally, your target should show up somewhere in the searched area.

Lastly, keep to bright targets at the beginning. Once you get the hang of star hopping, you can go for faint fuzzies. Until then, keep it simple.

Edited by Paul Sweeney, Yesterday, 01:16 PM.

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#14 brentknight

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Posted Yesterday, 01:17 PM

On my C8, it came with a star diagonal right angle 9x50 finder.  It isn't correct image like your RACI, but it exactly matches the orientation in the C8 through it's diagonal.  This makes it significantly easier to star hop as you don't have to reorient your inner view to make it work...

 

Having a good, wide-angle finder eyepiece helps a lot too.  At some point you might want to consider upgrading that 40mm to something with a wider apparent field of view.  I've heard good things about the APM UWA 30mm if you can find any in stock - or maybe the 24mm in the same series if you have a 1.25" diagonal.

 

If you are sticking with charts for now, the best way to move around in the eyepiece is to find the general field of your target in the RACI (the Telrad will work as well if you can see the faint stars and you can leave the chart oriented for your naked eye - I like green laser pointers even better though).  All of these finders need to be aligned with the main telescope, so I make sure the finder telescope is aligned with the main telescope (maybe easier during the daytime) and then at night, align the laser to the finder scope or the Telrad to the sky).

 

With SkySafari, you can have 3 FOV indicators on the screen for the Telrad, finder scope and the finder eyepiece.  Look at the field of the finder scope on your chart and try to identify any little patterns of stars that appear within the ring of the finder eyepiece and then look for those in the telescope (remember that the orientation will change but the size of the field will be the same as the chart).  That should help you orient and move in more or less the correct direction (I try to think of the field as a clock face with 2 o'clock meaning I need to move the telescope to the upper right).  Continue doing that until you know you are in the right place.

 

Most of these faint fuzzies are really faint and they might not just show up in the eyepiece.  If you can nail down positively where the target is in the eyepiece, then start trying higher powers, filters and averted vision.

 

Do not give up though.  Star hopping is a skill that must be learned and practiced, and one night it will just "click" and then you'll be on your way...


Edited by brentknight, Yesterday, 01:48 PM.

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#15 randallpatrickc

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Posted Today, 11:39 AM

Just spent some time with SkySafari on iPad.

 

Is it possible to set it so when I switch to EP view (C8 with star diag), the view auto flips horizontally? 
Then when I go back to the RACI finder the view unflips?

 

Supplementary; in Stellarium, I was able to use the angle tool to “draw a line” that would show in all the views. Helped me keep track of where I was - Is it possible to do this in SkySafari?
 

And… a popup is offering me SkySafari 7 at half price black Friday price. Worth it for a beginner?

 

(last nights blundering now explained - the Star-hopping for Backyard Astonomers #14 Cassiopeia chart was upside down - doh - mixed up the points on the W alpha and delta, that meant that my setting the RA circle on what I thought was alpha, screwed my backup plan…)


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#16 brentknight

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Posted Today, 02:55 PM

Go back up to post #2.  I don't know of any "eyepiece view" in SkySafari (I think that's a Stellarium feature).  It always shows the full sky with the screen zoomed in on the FOV circles.  Use those buttons to flip to the finder orientation, then pick the button that switches to the eyepiece orientation.  You get to these settings by clicking on the FOV size in the top right corner (2.2° x  4.0° in the screenshot).

 

I'm not sure what you are looking at in Stellarium.  Any chance you can post a screen shot?  (If you don't know how to post a picture, click on "More Reply Options").

 

If you stick with the hobby, SS7 (Plus or Pro) is definitely worth it - especially when it's half-off.  If you have enough storage space on your device, I'd go with the Pro, but it will gobble up over 1.2GB with stars down to 17th magnitude.


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#17 randallpatrickc

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Posted Today, 04:25 PM

Here's a screen shot of Stellarium's angle tool showing the path to M31. You move the finder or EP view along the line with arrow keys (not mouse)

Attached Thumbnails

  • Angle tool.png


#18 radiofm74

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Posted Today, 06:06 PM

Just spent some time with SkySafari on iPad.

 

Is it possible to set it so when I switch to EP view (C8 with star diag), the view auto flips horizontally? 
Then when I go back to the RACI finder the view unflips?

 

Supplementary; in Stellarium, I was able to use the angle tool to “draw a line” that would show in all the views. Helped me keep track of where I was - Is it possible to do this in SkySafari?
 

And… a popup is offering me SkySafari 7 at half price black Friday price. Worth it for a beginner?

 

(last nights blundering now explained - the Star-hopping for Backyard Astonomers #14 Cassiopeia chart was upside down - doh - mixed up the points on the W alpha and delta, that meant that my setting the RA circle on what I thought was alpha, screwed my backup plan…)

As a user of a C6 with red dot and finder:

1. Get a 0.63 reducer … yes one more gadget but it will make life a lot easier for you! And give you a wider FoV for bigger objects

2. With a scope like yours, you do most or all of your finding in the red dot (gets you in the ballpark) and in your RACI (gets you there. The eyepiece is normally for observing. so for finding your Atlas and the finder and dob charts in Turn Left at Orion – turned upside down if needed – work just fine. Needless to say, Turn Left at Orion also have charts that are flipped horizontally for your eyepiece view. 

3. There may be tough objects without a clear reference point nearby that you must find in the eyepiece still. For that, unless you have a handy flipped chart, the easiest solution is to use Sky Safari (6 does it) > Coordinates > "flip horizontally". Even if it's not automatic, and not the eyepiece view, it will give you the reference points you need to bag that pesky object. 

 

Don't be discouraged. It's all pretty confusing at first!

 

Clear skies!




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