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Seven Ways To Find Things In The Sky - Are there others?

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#26 aeajr

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Posted 28 August 2020 - 03:50 PM

I really like doing this, but when I find an object, I'm often unsuccessful in trying to identify it.  Like many, I don't  have setting circles on my mounts, or any other useable substitute.  I usually use Sky Safari, but find that it is not precise enough, or shows nothing in the location of the object.  I'm in the process of getting a Nexus with digital encoders set up for my APM big binocular fork mount.  This should solve the problem.

 

Rick

Pick up a digital Angle Gauge - $30.  Will give you precise Alt which will help you identify the object.

 

I ran a workshop on the AltAz method recently for two clubs.  One of the exercises was to have the group center a bright star, read the angle gauge and then check it on Stellarium or whatever program they were using.  Matched perfectly. 

 

So, if you find something at 36.5 degrees altitude, a little right of Arcturus, you can check your app and identify it.  If you can estimate the Azimuth you can be even more precise.  You can get the AZ by using Arcturus and using FOV of eyepieces, Telrad circles to estimate.  Or you can use a compass or AZ circle on the mount. (see post 24)

 

A newbie who attended the workshop emailemed the next day. He had his scope only a few weeks.  He got up at 3 AM and found Uranus by pegging Mars, then setting the altitude, then sweeping left till he found the blue ball.  I was impressed that he had done that on his own.   He can now find anything in the sky. 

 

Using an angle gauge to help find targets – AltAz coordinates
https://www.cloudyni...y/#entry8120838


Edited by aeajr, 28 August 2020 - 03:59 PM.

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#27 kfiscus

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Posted 28 August 2020 - 07:25 PM

Here is a pair of techniques that use green laser pointers.  One uses carbon-based guidance systems and the other a computerized go-to.

 

The first one is when my observing buddy or I find the target's location in a star atlas (usually the Jumbo PSA) and then manually point at the spot with a GLP while the other person steers the scope up the beam to the correct spot.

 

The other method, not yet used by us but used by others, has a GLP mounted on a small go-to scope that slews to the target and guides the human on a manual dob toward the target.


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#28 Dave Mitsky

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Posted 28 August 2020 - 09:09 PM

I believe that it was during the 2013 Stellafane that I helped to guide Kevin Frederick's 17" Chiefspiegler to a number of targets using my binoculars while he used his mounted GLP.

https://stellafane.o...013-scopes.html (bottom of page)


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#29 sg6

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Posted 29 August 2020 - 02:32 AM

Have you removed one?

I only see 6 listed ?

 

I use goto or rather basic aim scope at right bit of sky and use a high percentage of hope, and the widest FoV I can manage.


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#30 Mark9473

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Posted 29 August 2020 - 07:37 AM

When I put up the first post I was thinking more in terms of a deterministic desire to find a particular object.   Where is M13 or NGC????.

I find M13 by two methods not on your list :

Either point the instrument to where I know M13 is going to be, or else use a finderscope. 


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#31 Voyager 3

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Posted 29 August 2020 - 09:28 AM

I've got an idea but dono whether it works or not . Can v attach our phone to a phone holder and use a sky Safari or such as finder scope ? Using an adjustable holder , v can fine tune the holder . But v have to use a adjustable holder which can go both ways - alt and azimuth . Then zoom in on sky saf and fine tune it . Dono whether this works or not , never tried but I'm just thinkin ....
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#32 Chris K

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Posted 29 August 2020 - 09:32 AM

Have Ed or John point the scope for you, does that count?

 

wink.gif


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#33 aeajr

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Posted 29 August 2020 - 09:37 AM

Have you removed one?

I only see 6 listed ?

 

I use goto or rather basic aim scope at right bit of sky and use a high percentage of hope, and the widest FoV I can manage.

There are two under Setting Circles.  For some reason only one got bullited.



#34 aeajr

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Posted 29 August 2020 - 09:43 AM

I've got an idea but dono whether it works or not . Can v attach our phone to a phone holder and use a sky Safari or such as finder scope ? Using an adjustable holder , v can fine tune the holder . But v have to use a adjustable holder which can go both ways - alt and azimuth . Then zoom in on sky saf and fine tune it . Dono whether this works or not , never tried but I'm just thinkin ....

I don't know if Sky Safari has that feature.  SkEye does but I don't find it at all accurate.   In either case it would be a form of computer assisted  PushTo, based on magnetic fields and accelerometers.   It could get you into the right general area but not likely to be accurate enough to put you on the target. 


Edited by aeajr, 29 August 2020 - 09:44 AM.


#35 Jon Isaacs

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Posted 29 August 2020 - 10:09 AM

I really like doing this, but when I find an object, I'm often unsuccessful in trying to identify it.  Like many, I don't  have setting circles on my mounts, or any other useable substitute.  I usually use Sky Safari, but find that it is not precise enough, or shows nothing in the location of the object.  I'm in the process of getting a Nexus with digital encoders set up for my APM big binocular fork mount.  This should solve the problem.

 

Rick

 

I have not had that issue. I'm using Sky Safari 6 Pro with all the added databases.  I'm using a Telrad plus a 50 mm RACI finder to "reverse star hop" and identify the object.

 

I find Sky Safari to be plenty accurate, it's just a question of how accurate my technique is. 

 

Identifying an object is a bit tricky, I essentially learn the area and develop at star hop from the object to a identifiable bright star.  Sometimes it's easy but sometimes I lose the object and have to find it again. There's always a moment when I decide I've got it and do the star hop start to finish.. 

 

Jon


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#36 rowdy388

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Posted 29 August 2020 - 11:08 AM

I find that a Telrad with its concentric degree circles works really well for finding stuff.  For M13 I 

put the 4 degree circle on Eta with the center oriented towards Zeta. That simple move puts M13

in the main eyepiece. I use a QuInsight finder mostly these days which has even more and larger

concentric measuring circles which makes measuring greater distances easy.

 

Could be filed under the star hopping category I suppose.


Edited by rowdy388, 29 August 2020 - 11:19 AM.


#37 aeajr

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Posted 29 August 2020 - 12:49 PM

I find M13 by two methods not on your list :

Either point the instrument to where I know M13 is going to be, or else use a finderscope. 

What method would you use to find NGC6946, assuming you don't have its location memorized. 



#38 Mark9473

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Posted 29 August 2020 - 01:50 PM

I don't know anything about that object, but normally I'd look on a chart where it is, then aim a red dot finder at its position relative to recognisable stars. I almost never do starhopping.

So that's a third visual method you hadn't captured.

Edited by Mark9473, 29 August 2020 - 01:51 PM.


#39 brentknight

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Posted 29 August 2020 - 02:05 PM

I'm working my way through the Messier objects and my method is pretty pedestrian. I find the object in my sky atlas and compare it's location to what I see in the sky. I then point my laser to that approximate location and check where I'm at with my finder eyepiece. Most of the time what I'm looking for is usually somewhere in the FOV. Very simple but works good for me so far.

I would call this star-hopping with a zero power finder...


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#40 aeajr

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Posted 29 August 2020 - 02:06 PM

I don't know anything about that object, but normally I'd look on a chart where it is, then aim a red dot finder at its position relative to recognisable stars. I almost never do starhopping.

So that's a third visual method you hadn't captured.

As I define it, that is star hopping.  

 

You are using one or more visual stars as a starting point and then positioning the scope (hopping) relative to the visual stars.  Whether you use a laser, Telrad rings, eyepiece FOV or just estimate the distance visually, that is classic star hopping.

 

I do that myself with my Telrad and RACI finder or low power/wide view eyepiece, depending on scope.  I used to use a laser but I am in the center of three major airports so I took that off and put the telrad on my Dob.   On the ST refractors it is RDF and 32 Plossl.  On my 5" Mak I use a 6X25 RACI finder.    

 

But it doesn't matter what it is called as long as it works for you. 


Edited by aeajr, 29 August 2020 - 02:21 PM.

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#41 Jon Isaacs

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Posted 29 August 2020 - 02:07 PM

What method would you use to find NGC6946, assuming you don't have its location memorized. 

 

Depends on the scope.

 

First I'd look it up in Sky Safari.

 

Then I'd star hop to the object.

 

NGC 6946 is often called the Fireworks galaxy. It's magnitude 8.8 and about 2.0° from magntude 3.5 Eta Cephei, 4.3° from magnitude 4.5, 33 Cygni and the three more or less form a line.

 

I'd identify ETA Cephei by naked eye star hopping. From there, that's plenty doable with a Telrad and a 12.5 inch though I'd use my 50 mm RACI with it's 6.8° field.

 

I'm with Tony, star hopping is a collection of techniques that indentifying stars and their relationships and positioning the scope relative to those stars.

 

With M13, I first identify the Keystone in Hercules and point the scope based on that.

 

 

Jon


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#42 brentknight

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Posted 29 August 2020 - 02:10 PM

Have Ed or John point the scope for you, does that count?

 

wink.gif

If either of them had "laser beams" coming out their eyes, that would work really well...


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#43 hcf

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Posted 29 August 2020 - 02:15 PM

I use the PSWAI which is platesolving camera based. Its best application is not entirely as a pushto, although it could be used as one.

I use it more as an accurate e-finder.

 

Once you set it up, you connect Sky Safari Pro (maybe Plus will work too) to it. You click on Align in Sky Safari, and it takes about 10 seconds to show you on sky safari where the scope is pointed to. It works in regions of the sky where you cannot see any naked eye stars. I use it to get close to the target to about 5-7 degrees, and from there I star hop using the RACI/eyepiece. I can even use the PSWAI to get within 1-2 degrees and then use a wide FOV EP. This needs a good alignment between the camera, and the OTA.

It also helps if you are just star hopping, and you get lost on  a long hop.

 

For fainter DSOs, once I have the target DSO centered, I hit "Align" on sky safari again to look where I am , to confirm that I am centered on the target. It works very well in my Bortle 7 skies.

 

The action camera and lens cost about $80, and I use a $30-$40 Orion Precision Slow-Motion adapter to accurately align the camera to the scope accurately. The rest of the gear is a linux laptop/raspberry pi. The camera connects wirelessly to the laptop/pi, and so does my tablet with sky safari. 

 

I mount the slow motion adapter on a finder bracket, and so it can be used on any scope. I have tried it both on my Dob and a small refractor on an EQ mount. No surgery is needed on the mounts.

 

The code is free on github (see link below).

 

https://www.cloudyni...sual-astronomy/


Edited by hcf, 29 August 2020 - 02:17 PM.


#44 brentknight

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Posted 29 August 2020 - 02:17 PM

Something that should be done for any object identified with any of these methods is to check the general area for any other objects that might be nearby.  Especially useful around galaxies, but could work for interesting double-stars, etc.  Discovering something in this way is pretty neat...



#45 aeajr

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Posted 29 August 2020 - 02:25 PM

If either of them had "laser beams" coming out their eyes, that would work really well...

When helping others find a target, I get my scope on it then fire my laser pointer through the eyepiece or the RACI. The beam marks the spot in the sky so others can find it. 


Edited by aeajr, 29 August 2020 - 02:25 PM.

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#46 Jon Isaacs

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Posted 29 August 2020 - 02:30 PM

When helping others find a target, I get my scope on it then fire my laser pointer through the eyepiece or the RACI. The beam marks the spot in the sky so others can find it. 

 

Lasers are not permitted at my primary observing site. They disturb the visual silence.

 

Jon


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#47 aeajr

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Posted 29 August 2020 - 03:13 PM

Lasers are not permitted at my primary observing site. They disturb the visual silence.

Jon


Should I ever have the opportunity to observe with you Jon, please remind me.
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#48 Sketcher

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Posted 30 August 2020 - 05:27 PM

What method would you use to find NGC6946, assuming you don't have its location memorized. 

OK, so this question was directed toward Mark9473; but I like the question, since answers by different people might better explain some of the methods that different people use.

 

I would look up the object's coordinates, followed by looking up the object on an atlas chart.  Then, seeing its location relative to nearby, naked-eye, "landmarks" I would (naked-eye) look at Eta and Theta Cephei, mentally drawing a line segment from Theta, to Eta, followed by making a (slightly greater than) 90 degree counterclockwise turn and continuing an almost equal distance away from Eta; and that's where I will find NGC 6946.

 

So I center that location in my finder and look through the primary telescope using a relatively low-powered eyepiece.

 

I would also check out the nearby open cluster, NGC 6939, northwest of NGC 6946 in the same low-powered field of view.

 

Opinions will differ as to what star-hopping is.  In my opinion, this method is not star-hopping.  It's more of a point and shoot method -- point the telescope directly at the object or at the known location of the object, and commence your observation -- with no intermediary pointing or stopping.

 

It's better to have different names for different methods; and hopping from star to star with a finder or with the primary telescope is not the same method as shifting one's eye from star to star followed by pointing the telescope at one and only one location -- the known position occupied by the targeted object.

 

Now if one is using a "large" telescope with a "narrow" field of view, or if one is beneath a light-polluted sky, some refinements may be necessary; but with the telescopes I normally use, under my dark sky, the point-and-shoot method is very effective-- most of the time, for most of my targets.


Edited by Sketcher, 30 August 2020 - 05:32 PM.

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#49 aeajr

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Posted 30 August 2020 - 06:29 PM

Thanks Sketcher.   I would call any method that uses visible stars as reference points to be star hopping.   But the name is irrelevant.

 

To find NGC6946 I would go to Stellarium. 

  • Punch in the name in the search field. 
  • Once Stellarium has it I tap on it and the information screen comes up. 
  • I find the AltAz coordinates.   
  • Set my AZ circle to the AZ coordinate
  • Set my angle gauge to the altitude given by Stellarium. 

That usually puts me on it with my low power wide view eyepiece or my RACI finder.  If my initial set-up of my AZ scale is off a touch, a little sweep left or right of a degree or so will usually have it.

 

My 8X50 RACI gives me about 5.5 degree FOV.  My 38 mm eye piece gives me about 1.75 degree FOV in my 12" Dob.  A 32 mm Plossl gives me about .85 degrees in my 5" Mak .  Same 32 mm Plossl gives me about 4 degrees in my 80 mm refractors.  

 

Finding things is usually quick. 



#50 Tony Flanders

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Posted 31 August 2020 - 06:40 AM

To find NGC6946 I would go to Stellarium.

  • Punch in the name in the search field. 
  • Once Stellarium has it I tap on it and the information screen comes up. 
  • I find the AltAz coordinates.   
  • Set my AZ circle to the AZ coordinate
  • Set my angle gauge to the altitude given by Stellarium. 
That usually puts me on it with my low power wide view eyepiece or my RACI finder.  If my initial set-up of my AZ scale is off a touch, a little sweep left or right of a degree or so will usually have it.

 


And what would you do if you still failed to find NGC 6946? That seems like a very likely outcome, given that it is a face-on spiral with fairly low surface brightness, and you are observing from light-polluted skies. Would you then:

 

Conclude you were in the wrong place, and try over using the same technique?

Conclude that NGC 6946 is invisible from your location?

Try again using the same technique but higher magnification?

Try again using a completely different technique?

 

The great virtue of star-hopping in the narrow sense of the word is that you know that it lands you on precisely the correct spot. So if the object remains invisible at all magnifications, you know that you really can't see it (at least then and there) instead of wondering if you were in the wrong place.


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