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

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#1 aeajr

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Posted 28 August 2020 - 07:49 AM

I have learned of seven ways to find specific targets in the sky with my telescope and was wondering if there are others that I have not come across.
 
Visual

  • What you can see with your eyes alone when you look up 
  • Star Hopping – Naked eye and optically assisted but still visual

Computer Assisted

  • PushTo - encoders
  • GoTo - encoders
  • Plate Solving - camera based

Setting Circles

  • Equatorial Alignment - Right Ascension/Declination
    Altitude Azimuth Alignment

Each has its advantages and its challenges, so I have learned to use 5 of them.
 
I have not tried RA/DEC setting circles because I don't have an equatorial mount but I could polar align my ETX scopes.   And I have not used plate solving because I am not using a camera at this time.
 
But are there others?   Another approach?
 
What's your favorite?
 
Edit:  I was not thinking of scanning for discovery, but I guess that would apply.  It just isn't a way to find specific targets.


Edited by aeajr, 28 August 2020 - 10:52 AM.

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#2 DHEB

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Posted 28 August 2020 - 07:56 AM

Perhaps there could be a variant of your second type, one in which one would connect a camera to the finder and search by what is shown in a screen, kind of eea finder. I do not know if it exists.
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#3 Jon Isaacs

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Posted 28 August 2020 - 08:00 AM

There is another side to finding things in the sky. 

 

Just looking around to see what you can see with the telescope. It can be casual or it can be quite organized.  Herschel did not have charts to use to find all his discoveries.  As an amateur, I can find objects unknown to me in a similar manner. 

 

Jon


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#4 clearwaterdave

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Posted 28 August 2020 - 08:00 AM

I do what I call trianglutating.,this is done by making the target part of a triangle with two naked eye stars.,I aim my laser at the estimated area and scan from there if it's not in the fov.,

  I have also had "some" success with just using the dec. dial on an eq mount.,knowing about where to point I go a little to one side of the target then sweep towards it.,cheers.,


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#5 wrnchhead

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Posted 28 August 2020 - 08:13 AM

Perhaps there could be a variant of your second type, one in which one would connect a camera to the finder and search by what is shown in a screen, kind of eea finder. I do not know if it exists.

I have my first gen AsiAir in it's box, and I am considering using it to make something like this. 

 

There is another side to finding things in the sky. 

 

Just looking around to see what you can see with the telescope. It can be casual or it can be quite organized.  Herschel did not have charts to use to find all his discoveries.  As an amateur, I can find objects unknown to me in a similar manner. 

 

Jon

I love doing this. Discovered a few planetary nebula and globular clusters this way, very exciting. 


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#6 MOwen

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Posted 28 August 2020 - 08:18 AM

Are apps such as Sky Safari, Stellarium, etc., in the running??


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#7 John Carlini

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Posted 28 August 2020 - 08:32 AM

There are times when I'm looking for a dim comet, I will set a starting point then take a series of images with my DSLR sweeping incrementally in RA or DEC. It's not plate solving since I'm not using the laptop. However, the technique takes advantage of the camera sensitivity through the telescope to let me "see" objects dimmer or less colorful to the naked eye. It's useful in finding the green carbon glow of weak comets (like comet Lemmon currently). I typically cover a 2-degree swath on each image.


Edited by John Carlini, 28 August 2020 - 08:51 AM.

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#8 aeajr

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Posted 28 August 2020 - 08:46 AM

Are apps such as Sky Safari, Stellarium, etc., in the running??

That depends on how you would suggest using them. 

 

They provide RA/DEC or AltAz coordinates for the setting circle methods.   

 

You can use them on a phone/table/computer to replace the handset on a GoTo/PushTo scope but it is still the same approach using encoders and electronics star charts. 

 

Did you have something else in mind?



#9 aeajr

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Posted 28 August 2020 - 08:48 AM

There are times when I'm looking for a dim comet, I will set a starting point then take a series of images with my DSLR sweeping incrementally in Right Ascension. It's not plate solving since I'm not using the laptop. However, the technique takes advantage of the camera sensitivity through the telescope to let me "see" objects dimmer or less colorful to the naked eye. It's useful in finding the green carbon glow of weak comets (like comet Lemmon currently). I typically cover a 2-degree swath on each image.

Interesting, but it sounds like visual, but instead of using an eyepiece you are using a camera and a screen.  But that doesn't make it any less valid, just feels like visual to me. 



#10 aeajr

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Posted 28 August 2020 - 08:52 AM

There is another side to finding things in the sky. 

 

Just looking around to see what you can see with the telescope. It can be casual or it can be quite organized.  Herschel did not have charts to use to find all his discoveries.  As an amateur, I can find objects unknown to me in a similar manner. 

 

Jon

Good point Jon.  I guess I would call this visual sky scanning.

 

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 think you are talking more in terms of discovery rather than finding a specific target.  But it is all good.  I added an edit at the bottom of the first post to address this.

 

Thanks!


Edited by aeajr, 28 August 2020 - 08:55 AM.

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#11 John Carlini

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Posted 28 August 2020 - 08:54 AM

Interesting, but it sounds like visual, but instead of using an eyepiece you are using a camera and a screen.  But that doesn't make it any less valid, just feels like visual to me. 

Yes, I agree. It's mostly visual to take advantage of the extra sensitivity of the camera and compensate for aging eyes... :)


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#12 MOwen

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Posted 28 August 2020 - 09:01 AM

That depends on how you would suggest using them. 

 

They provide RA/DEC or AltAz coordinates for the setting circle methods.   

 

You can use them on a phone/table/computer to replace the handset on a GoTo/PushTo scope but it is still the same approach using encoders and electronics star charts. 

 

Did you have something else in mind?

 

I guess I was thinking of folks who simply use an app to help them identify stars or planets.  Good example is if I am doing a 2 star alignment and I'm not entirely sure of the name of my target, I could identify it quickly with an app. If that fits your definition of 'a deterministic desire to find a particular object' (as you just replied to Jon), then you might want to add it to your list.  You seem to be restricting the app to only those functions that are connected to finding something with a scope.  If that is your definition, I would suggest you amend your original requirement to '...finding things in the sky with a telescope'.


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#13 Cames

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Posted 28 August 2020 - 09:23 AM

I could break the Go-To into two categories.

 

First the objects stored in the memory of the hand-controller itself.  Kind of cumbersome for most controllers. Most of the hundreds of thousands of objects stored in there are not really useful.  Too much button pushing in order for me to get where I want to go - YMMV.

 

The second and better way, in my estimation, is via a graphical application on a phone, tablet or laptop.  That application is then set to communicate with the hand-controller and instructs the hand-controller remotely.  This combination is far more complicated to get set up initially.  But once reliable functionality is mastered, I've found no method that is more productive for locating celestial targets. Especially those applications that are capable of updating coordinates for interlopers like comets, minor planets, asteroids, supernovae, etc.

-------------

C


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#14 Migwan

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Posted 28 August 2020 - 09:27 AM

Or any combination thereof? 

 

I've used RA/Dec, Alt Az coordinates and go to to get to close and then scan.   Usually on comets or asteroids where I didn't have current coordinates and not on go to.  (Don't like to look at my phone.)

 

jd


Edited by Migwan, 28 August 2020 - 09:28 AM.

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#15 chrysalis

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Posted 28 August 2020 - 09:49 AM

The method I used as a teenager in the late 60s-early70s was to find a star I could see, and, having already measured the angular distance N-S and E-W from it to the object, use the GEM to count fields N-S or E-W based on the TFOV of the eyepiece so that the object would (theoretically) be in the FOV. This is how I found the majority of the Messier objects I located prior to restrating the hobby in 2005 with the Intelliscope and COL.

 

Yet another way is to set the telescope on a star and allow the Earth to rotate under the sky such that at the appropriate period in minutes later, the object will be in the field. Probably most familiar of these is to set on Almach and, 17 minutes later, NGC 891 will be in the field.

 

And maybe a subset of what you already posted: dead reckoning, which works well for objects like M57, M13, some NGC objects, etc.


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#16 aeajr

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Posted 28 August 2020 - 09:50 AM

I guess I was thinking of folks who simply use an app to help them identify stars or planets.  Good example is if I am doing a 2 star alignment and I'm not entirely sure of the name of my target, I could identify it quickly with an app. If that fits your definition of 'a deterministic desire to find a particular object' (as you just replied to Jon), then you might want to add it to your list.  You seem to be restricting the app to only those functions that are connected to finding something with a scope.  If that is your definition, I would suggest you amend your original requirement to '...finding things in the sky with a telescope'.


You make a good point.  Yes, I was thinking in terms of the telescope.  Certainly the apps can point you to a target and, if it is visible naked eye,  then you found it.

 

One app I know of, SkEye has a feature that tries to provide PushTo capabilities on your scope.  I have tried it and don't find it accurate enough to be useful, but it will get you into the general area so you can search around. 

 

As you suggested, I amended the first sentence in the first post to make it specific to telescopes.  

 

Thanks for the feedback. 



#17 chrysalis

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Posted 28 August 2020 - 09:53 AM

Oh, and for planets - when the moon is nearby and visible in daylight, it's easy to find Venus in relation to the moon even in the middle of the day.

 

I actually did this shortly after sunrise for Jupiter on 10-27-88 based on proximity to the moon - I think the only time I can lay claim to observing Jupiter in the daytime.

 

And by the way, that same day, I located Venus near greatest elongation at the same time that morning, and also spotted Mars rising in the east shortly before sunset - three planets naked eye while the sun was up in one day!


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#18 kklei940

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Posted 28 August 2020 - 10:48 AM

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.


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#19 Hesiod

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Posted 28 August 2020 - 11:00 AM

That depends on how you would suggest using them.

They provide RA/DEC or AltAz coordinates for the setting circle methods.

You can use them on a phone/table/computer to replace the handset on a GoTo/PushTo scope but it is still the same approach using encoders and electronics star charts.

Did you have something else in mind?

I have seen that some entry-level telescopes come with a way to fix a phone to them, enabling a sort if "push to" but without encoders as relies upon the phone's accelerometer.

Some years ago Celestron had in their catalogue a gizmo devised along this very same concept: it was pretty expensive and bundled with really awful telescopes.

EDIT: to visual methods I would add also when you aim at a given spot in the sky even if can not see the object, and do not have to hop from star to star but rely on loose geometric figures or proportions (e.g. m27 as the fourth angle of a rectangle made up by Cygnus' stars or a triangle with stars from Sagitta; or ngc6934 by "prosecuting" the Dolphin's arched back)

Edited by Hesiod, 28 August 2020 - 11:09 AM.

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#20 Tony Flanders

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Posted 28 August 2020 - 11:01 AM

I would say that star-hopping is actually a grab-bag of techniques, and sighting on a naked-eye target is one of those. Yet another is sighting on the spot in the sky where you know from past experience your target will be. Then there's a plethora of tricks involving patterns among the naked-eye stars and measuring distances with a red-circle finder. Then getting into the right general neck of the woods and sweeping around at low power until your target appears. All the way down to working your way eyepiece field by eyepiece field from a known star to your target. Normally, I use some combination of all of the above in the course of a night, and even in the course of finding one target.

 

Star-hopping proper (going field to field) is profoundly different when using a finderscope vs. using your main scope.

A common technique that may or may not fit into one of your categories is the right-ascension sweep, where you start at a bright star with the same declination as your target and sweep with the RA knob of an equatorial mount until the target appears in the eyepiece. Or in your finderscope. Can also be done in declination. And can be done with an alt-az mount for objects that are transiting the meridian, or nearly so.

A related technique, which I use routinely to find Venus and Mercury when they're low in bright twilight, is to scan above the horizon at the altitude where my app (or whatever) tells me they will appear. Alternatively, estimate the azimuth based off where the Sun set and then sweep up from the horizon.


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#21 tommm

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Posted 28 August 2020 - 11:13 AM

Are you including an inclinometer for alt and setting circle for az in your "setting circles" item? If not, that is a variant that a number of people use.


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#22 MOwen

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Posted 28 August 2020 - 11:22 AM

You make a good point.  Yes, I was thinking in terms of the telescope.  Certainly the apps can point you to a target and, if it is visible naked eye,  then you found it.

 

One app I know of, SkEye has a feature that tries to provide PushTo capabilities on your scope.  I have tried it and don't find it accurate enough to be useful, but it will get you into the general area so you can search around. 

 

As you suggested, I amended the first sentence in the first post to make it specific to telescopes.  

 

Thanks for the feedback. 

Certainly.  That is why I framed it as a question initially.  By your (amended) definition, my suggested 'stand-alone' use of the phone app doesn't qualify for the list.


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#23 Dave Mitsky

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Posted 28 August 2020 - 11:30 AM

I do what I call trianglutating.,this is done by making the target part of a triangle with two naked eye stars.,I aim my laser at the estimated area and scan from there if it's not in the fov.,

  I have also had "some" success with just using the dec. dial on an eq mount.,knowing about where to point I go a little to one side of the target then sweep towards it.,cheers.,

Some time ago someone discussed an elaborate system of triangulation with charts, IIRC.  I thought that there might have been a web page on the technique but I haven't found anything yet.


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#24 aeajr

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Posted 28 August 2020 - 11:36 AM

Are you including an inclinometer for alt and setting circle for az in your "setting circles" item? If not, that is a variant that a number of people use.

Absolutely - The idea is you are using AltAz coordinates.

 

The inclinometer/angle gauge is my primary method for finding things with my manual scopes.   Angle gauge on the tube and AZ circle on the mount.   I consider the angle gauge to fall into the "setting circle" category.  Performs the same function as an actual circle but less sensitive to the mount being level. 

 

 

Attached Thumbnails

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Edited by aeajr, 28 August 2020 - 11:39 AM.

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#25 oldmanrick

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Posted 28 August 2020 - 01:32 PM

There is another side to finding things in the sky. 

 

Just looking around to see what you can see with the telescope. It can be casual or it can be quite organized.  Herschel did not have charts to use to find all his discoveries.  As an amateur, I can find objects unknown to me in a similar manner. 

 

Jon

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




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