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winniewsp

Unable to locate the star on finder scope

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Hiya, 

Please can anyone help me to locate star on finder scope. i am having a difficulty of unable to locate the star I want to see in the finder scope to do the three stars alignment last night. it was a clear night. I am using Celestron Astro Wifi 90cm to do 3 stars alignment. when the sky is clear and full of stars i am having difficulty of locating the star i want because they are all appear to be similar brightness and size. Any recommendations what i should do ? Many thanks. 

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On my scope I would take the scope outside during the day and focus onto a distant target, the further away the better. Once I have sighted a target using the telescope,  I then look through the finder scope and use the finder scope adjusters to correct the image through the finder so that it matches to that, that I  see through the telescope.

You would then need to follow the setup instructions for your own particular scope especially where auto alignment is possible.

Learning the Stars takes time, and many do look the same, but its my belief that the telescope knows where it is after the user completes and programs in the location co-ordinates.

Edited by Charic
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You sound as though you need a map of the sky so that you can find the stars that the finding device names.  Many free applications exist.  Stellarium is available on a PC and there is a mobile phone version which I use, and lots of other planetarium apps are available on the mobile phone - if you have GPS some even try to track the sky and show on the screen what the the phone is being held up in front of, you can even buy a hand-held cardboard planetarium for your location and that will show the sky at different times in the year.  It is difficult to know whether the system has found the correct star (esp. the first one unless you know what it is and, like me, you will need a guide until you learn your way around.  It is also worth closely following your instructions to see if you need to start off the process with your telescope facing celestial North and horizontal - I find this helps on the system that I use.

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You need to learn the night sky. 

Try downloading " Stellarium." on your PC.

There is also star hopping which is like using the stars you do know as a route to the star you are looking for.

As already suggested get the finder and telescope aligned.

When looking through the finder keep both eyes open and use the eye not looking through the finder to look at the star you are lining up on. It seems a bit strange doing this at first but makes alignment much easier once you get used to it.

Good luck

 

Pat

 

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a phone app like StarWalk, makes it possible to see the stars realtime and at the same time on a lay-over 'map'

That makes it realy easy to determine what you are looking at.

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It is often difficult to pick out a star once it gets dark, I sometimes even miss finding Polaris when looking through a finder, the bright stars needed for initial alignment are often easier to spot during dusk where the sky brightness blots out the fainter ones.

Alan

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Mind you even when you know which star you are after it can still be difficult to find it by waving about with the finder-scope - this was as much my problem as knowing which star I needed to aim at in the first place.  My cheap solution was to add to the existing finding scope.  A RACI finder rather than my supplied straight through one, a dual mount (cheaply 3D printed from the popular auction site from a guy in Poland!) and a el cheapo Celestron RDF soon sorted me out - I have the two finders more or less aligned with the RACI spot on with the EP.  I land on the star with the RDF - that puts it into the RACI - which I then and therefore into the EP view.  This is my set-up

Finders2.jpg

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No problem on finder and main scope alignment. I have got all those apps to locate the stars. I can find them and see them with my eyes. But when I point the scope on that star and I can see more stars. I do need to learn the sky mapping. Just see if any one got a better ideas. I even have two similar guiderscopes can be fit together but is that help ??? Means I have two findscopes and get more confuse ??? 

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I had similar problems even looking through 2 eyes using the RACI ( which is good advice) , I switched to using a Telrad, so much easier for alignment, your finder must be aligned with the Scope ( as mentioned do it on a distant object during the day or early evening before darkness falls)

Telrad wins hands down though, easy peasy

eric    

ps: Download Stellarium as suggested on your laptop or iphone its free, but cost about £3 to download on a Ipad !!

Edited by 2STAR
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With most of the GoTo systems, (e.g. the Nexstar) the 3-star align does not require you to know what three bright star-like objects you have picked to align on. It will figure that out for itself.

Assuming that your finder is aligned with the telescope to start with, if you make sensible choices of alignment star, e.g. first magnitude stars like Vega, once you get the star in the finder field it should be obvious which is the one you want as it will be the only really bright star there.  You will soon get to know what a bright star looks like with the extra light gathering power of the finder, or the main scope. 

I hope that helps.

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Hiya Winnie. As mentioned above align your finder with a fairly distant object during daytime and the fine tune it suring darker hours. Start with a low power eyepiece and work your way up to as high power as you can, each time making sure you centre the star in both the finder and at the eyepiece. This method helps to make sure the target you want will be the one in the centre of the eyepiece, thus less confusion when there are lots of stars in your field of view ?

Edited by Pig
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Hm, not sure what the problem is, but if I got it right, you point a scope to a certain star, you look at the finder and there is a bunch of stars and you can't distinguish which one is the star you are interested in?

Two techniques can help here - first is to "learn" how certain star brightness looks in your finder - there is no definite method here, just practice and looking at the stars of known brightness (once you know that it is the proper one) - usually order of magnitude is more than enough for this (and honestly being more precise by eye is next to impossible).

Second and more important technique is not to look at stars individually, but rather at groups of stars, or to be more precise - patterns. Our brain works well with patterns (sort of connect the dots kind of thing) - this is why we are able to spot and learn constellations - they present certain patterns. So take a sky map (or planetarium program), identify what sort of field of view your finder gives you and look up what sort of image you should see in your finder. Now looking at the star map spot your target star and surrounding stars and try to make up some pattern - triangle with particular angles, or square / rectangle. It can sometimes be more stars than this, like 5 or 6 in particular arrangement - notice which star is of the interest and where it sits within a pattern and then observe thru the finder and try to match the pattern - once you find your pattern - you will be able to tell your star depending on its position within a pattern.

This is how we often find particular stars in the night sky with plain eyesight - Polaris for example - we look at Ursa Minor (Little dipper) and locate star that is on the end of the "handle".

image.png.708d5c62dd649cf65a94cc2aa4e0faaf.png

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Another tip is to choose red or yellow target alignment stars if you can. Eg Antares, Arcturus.

Use stellarium to find others.

Since most stars are blue/white a bright red or yellow target will be very distinctive in the finder.

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Learning a bright star with naked eye is easy. For example I can see very clearly the Big Dipper, Orion, Summer Triangle, Cassiopeia etc on the sky but when I point to them with the finder scope there appears a lot more stars than our naked eyes. Hence I lost which is which ?‍♀️ I agree I need to learn to look at each stars. Forget about 3 stars alignment. Perhaps just an exercise to find the bright stars first ? LoL 

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I often use binoculars ( just cheap 10 X 50's ) to find an unfamiliar target, since aiming bino's is so intuitive.

The FOV is about the same size as a typical finder so you can see what to expect when you point the scope.

This is particularly helpful if you have a RACI finder, otherwise you have to mentally flip the image.

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3 hours ago, winniewsp said:

Learning a bright star with naked eye is easy. For example I can see very clearly the Big Dipper, Orion, Summer Triangle, Cassiopeia etc on the sky but when I point to them with the finder scope there appears a lot more stars than our naked eyes. Hence I lost which is which ?‍♀️ I agree I need to learn to look at each stars. Forget about 3 stars alignment. Perhaps just an exercise to find the bright stars first ? LoL 

Depending where you are located and the condition of the sky, 3 bright star alignment is sometimes difficult as there are not always 3 bright stars !!

Polaris is not a bright Star ! but is easy to find re diagram above, I do 2 star auto with the Nexstar and always use Polaris as my first star, the mount slews to a second star and this is nearly always distinguishable from those Stars near to it.

Just learn a couple of Stars at the time of year and night where you are , the weather in the UK does not give you enough clear nights to faff about , this comes with time and patience and I found is best learnt when actually looking for or viewing objects over a period of time patterns develop and Stars become more familiar.

Stellarium is good, study the present night sky and time you will be going out to observe,  also as mentioned previous with your initial problem, purchase a Telrad !!!

ps: avoid using Stars above 70 deg or below 20 deg, select 2 stars with a separation of between 90 deg & 135 deg apart. 

eric

Edited by 2STAR
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5 hours ago, winniewsp said:

but when I point to them with the finder scope there appears a lot more stars than our naked eyes

This sounds like an issue if the finder is a magnified one.  If you use a non-magnified finder like my Celestron RDF or something like a Telrad which seem very popular on SGL then you should not be able to see more stars through the finder than you can see with your eye.  My RACI is a magnified finder and I've some idea of what you are describing - I've had that problem too - often with Polaris of all things - it is not a particularly bright star, but it does have one quality that you can see on a decently clear night with a high enough magnification EP - it is a double star.  As noted above if you can pick from the offered list on the goto list something with a specific quality to it - maybe a particular  colour or the fact that it is a double star then this will make it more obvious when you land on the right place. 

Some folks above are assuming that the automatic device will actually turn to the correct place straight away if the system is started correctly and therefore you can assume that the star selected is correct.  However, my own experience with my goto system is that there are a myriad of reasons why it doesn't find the stars first time and I frequently have to manually correct the selected star location before proceeding.  Thus, I agree with the OP you DO need to be able to spot where you should be.  @winniewsp you will find in many cases that, if you are going for the brightest star configuration, in many cases, even in a magnified finderscope, the multiple stars presented will still all look a bit different and it should still be the brightest one that you are aiming for, but the best advice might be to try a non-magnified finder like a Celestron RDF or Telrad and make sure it is spot-on aligned with the EP centre during the daytime, then when your selection is selected in the centre of the RDF or Telrad (which is a form of RDF) it WILL be the star in the centre of the EP.  Don't forget to check the alignment each time you use it too.

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What about aligning just as it's getting dark and there are fewer stars out? Is that a brilliant idea or totally stupid? I'm not sure but worth a try.

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On 06/09/2018 at 00:21, valleyman said:

When looking through the finder keep both eyes open and use the eye not looking through the finder to look at the star you are lining up on. It seems a bit strange doing this at first but makes alignment much easier once you get used to it.

Good luck

 

Pat

 

I need to try this technique.

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When looking through the finder keep both eyes open and use the eye not looking through the finder to look at the star you are lining up on. It seems a bit strange doing this at first but makes alignment much easier once you get used to it.

Good luck

===========

This is it, efficient technique.

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