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arshia1_987

Help me with observing nebulas

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arshia1_987    1

Hi everyone. First im sorry that my english in not good. I'm from iran persia. Me and my friend had a skywatcher az 3 inch neowtonian and one month ago we get a new gso 10 in dobsonian. So we can observe deep sky objects.two times we get this huge instruments out of city where the light pollution is low. Its quite hard project to travel with 10 inch tube! All we succeeded to see is a wery low light and wery weak orion nebula. That previously we observed this with 3inch and now with 10 inch it's just a little biger and the difference in not so obvious. The andromeda is a low low low weak point of light that hardly can see it and the crab nebula better say that its nothing!! Just a point of fade light. If anyone else come in and see in the eyepiece he or she would say what? There's nothing here. Also the mars is just a star that maybe its red but it's like a star and not a planet. My questions is that is this we observe is right? The observing is this that wee saw? In this is true what's the difference between 3inch and 10 inch or 16 inch and bigger? Why we bother? If all the nebulas is just a fade point of light so what's the difference between them? When we saw all the nebulas one shape and all a point light. What difference it makes if it's spirall or rounded or etc?? 

Is the eyepiece affect the observing? How much difference it makes? Our eyepiece is amateur eyepiece in the telescope box. Gso superplosoll 25 mm 

 

Thanks alot and again sorry about the terrible english i speak 

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Knighty2112    2,759
Posted (edited)

You should see a very pronounced difference between both scopes, with the 7 inches extra of light gathering your getting on the new dob. First thing I would check is make sure your scope is colimated OK.  I’m not an expert on collimation, so others can tell you better in this regard, but if collimation is bad then than this will affect your seeing with the new scope. The stock 25mm is probably not helping, but try the scope on the moon if you can at some point and seee how the views go viewing that.

Edited by Knighty2112
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pipnina    538

+1 for trying the moon. It is possible light pollution or bad visibility is ruining your deep sky views as well. What are weather conditions like? Misty or hazy is a bad sign.

Mars is a very small planet, very hard to observe as anything but a star even in a 10". It also isn't at opposition yet (Best time to view mars this year is in late July, when it is closest.) which makes it harder.

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Peter Drew    6,243

Hello Arshia, welcome to this forum  :icon_biggrin:  As already said, there should be a big difference using a 10" compared to a 3" so something is not quite right.

First of all, make sure that you remove the full 10" front cover cap, not just the small cover. If you had already done this, the next thing to do is to look through the focuser without an eyepiece to make sure that the small mirror hasn't rotated in its holder, you should be able to see the reflection of the whole 10" mirror.

The 25mm eyepiece should be good for viewing nebulae as low power should give the brighter views. The eyepiece will not be powerful enough to show Mars as much more than a star size, it is still very far away in its orbit, you will need something like a 5mm or 6mm eyepiece for a better size.

If this doesn't help, get back to us for further advice.  Good luck !

 

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arshia1_987    1
15 hours ago, Peter Drew said:

Hello Arshia, welcome to this forum  :icon_biggrin:  As already said, there should be a big difference using a 10" compared to a 3" so something is not quite right.

First of all, make sure that you remove the full 10" front cover cap, not just the small cover. If you had already done this, the next thing to do is to look through the focuser without an eyepiece to make sure that the small mirror hasn't rotated in its holder, you should be able to see the reflection of the whole 10" mirror.

The 25mm eyepiece should be good for viewing nebulae as low power should give the brighter views. The eyepiece will not be powerful enough to show Mars as much more than a star size, it is still very far away in its orbit, you will need something like a 5mm or 6mm eyepiece for a better size.

If this doesn't help, get back to us for further advice.  Good luck !

 

Thanks a lot my friends. What do you mean front cap? In only have a big cap in the front of tube that should be removed. I will test one more time and let you know what happened. I just aks one question. Can i see the shape of nebulas with this scope or not? I mean if i can see the andromeda shape and the spiral shape of pinwheel or whirlpool? Or just very dim light? I want to know what should i expect with my device. As i said i saw crab nebula a very dim light that hardly can see it

 

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pipnina    538
Just now, arshia1_987 said:

Thanks a lot my friends. What do you mean front cap? In only have a big cap in the front of tube that should be removed. I will test one more time and let you know what happened. I just aks one question. Can i see the shape of nebulas with this scope or not? I mean if i can see the andromeda shape and the spiral shape of pinwheel or whirlpool? Or just very dim light? I want to know what should i expect with my device. As i said i saw crab nebula a very dim light that hardly can see it

 

It depends, with a properly collimated 10" with dark skies and good weather I would expect a fair bit from Andromeda. My own 10" can only see the faint fuzz of the core from home, but 20 minutes drive away I can see the first dust vein split the core from the outer disc. When I saw the triangulum galaxy from the same dark place in the 10" I could see a bright "cone" shape of light for the core and faint, slightly shaped smudge for the rest of the galaxy.

I've also seen M1 which doesn't have a lot of definition but is still relatively easy. M57 (the ring nebula) is also fairly easy (and can bee seen as a ring in my 10").

M42 however should be very good in a 10". You should be seeing the core of the nebula as a bright mottled cloud, under darker skies the arc over the top should be visible, under very good skies you should even be able to see the "bottom lip" faintly. My best bet is that either your secondary is misaligned, you have too much light pollution or the sky transparency isn't good where you are if M42 doesn't look good.

Another test you can try is to look at mizar. Use the 10mm eyepiece with your telescope if mizar A and mizar B are easy seen apart things are good. Now find Algieba, again with 10mm eyepiece. This is a more difficult double star and will only be visible as two under both good sky conditions and good collimation. Report what you see.

 

Hope you figure out what's wrong :)

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Moonshane    10,783

are you using a mobile phone to locate objects? This can destroy your dark adaptation (ability to see in the dark) and every time you look at your phone this happens again for maybe another 20 minutes. you will be best not using any lights for around 15 minutes or more and you should start to see things more clearly. This will have a bigger effect than any new eyepieces.

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Hungrymark    79

I have nothing to add about the astronomy but can I just say there's absolutely no need to apologise for your English language skills, which are excellent. Especially given that you are writing about a technical subject. All the best.

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wok    36

Maybe your expectations are a bit too high. A lot of people think they will be able to see NASA quality images when they get their first telescope. I am just starting and only saw a few nebulas so far, orion nebula, lagoon nebula and a few others I can't identify yet (found them pointing the scope at random places). The orion nebula, I see it very bright, a lot of detail and I can even see some color, the lagoon nebula wasn't so defined at first, but after about 20 minutes of being in the dark, I started seeing a lot more.

I found that quality sketches are a pretty good representation of what I see thru my telescope, you can see some good ones here http://www.deepskywatch.com/messier-dso-sketches.html

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arshia1_987    1
19 hours ago, Hungrymark said:

I have nothing to add about the astronomy but can I just say there's absolutely no need to apologise for your English language skills, which are excellent. Especially given that you are writing about a technical subject. All the best.

Thanks dear hungrymark. I hope it will be better and better everyday 

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arshia1_987    1

In the reply off moonshane asked i should say yes i use mobile phone to track sky objects. 

I will test the mizar and algieba stars and report here. Thanks for your help

https://pasteboard.co/HdgKaZA.jpg

Please look this picture my friends. I saw the andromeda like this.i saw only the weak light in the red circle. Its same as the top red circle. 

Is this sketches really what should i see?? I can tell you i saw nothing like this pictures. Not even close to them!! 

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arshia1_987    1

In the reply off moonshane asked i should say yes i use mobile phone to track sky objects. 

I will test the mizar and algieba stars and report here. Thanks for your help

https://pasteboard.co/HdgKaZA.jpg

Please look this picture my friends. I saw the andromeda like this.i saw only the weak light in the red circle. Its same as the top red circle. 

Is this sketches really what should i see?? I can tell you i saw nothing like this pictures. Not even close to them!! 

 

One more question. Im really sorry. I add this for observing the sky and finding dark place is hard for me. Every time we go out we should drive at least 3 hours or more to reach a dark place. Because of that i should get enough details for the next time

The question is how i find that the telescope is not colimated and how i colimate it? Can i colimate whit a green laser? Is the mizar and algieba double stars test for finding out the colimation? 

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Stu    17,496

Hi,

Just a few thoughts.

Can you be more precise about how dark your skies ar? Are you able to see the Milky Way or things like M31 and the Double cluster with the naked eye (ie without scope or binoculars?)

Collimation can be checked by defocusing on a moderately brighter star, Polaris is good because it doesn’t move! The pattern should appear concentric, if not then collimation is likely to be necessary although it is less important for lower power views.

Don’t forget that M31 is huge! With your scope you will only get a small portion of it in view at a time which might explain what you are seeing. These three diagrams show the field of view circles for your 25 and 10mm eyepieces (assuming that is what you have). As you see, much of the Galaxy is out of the view

9FB6CC96-550F-4B13-BF85-DB9B6FF676CB.png

A57BCBCD-CB67-4777-A9BC-5A64A45BD71D.png

E96BCD1E-260D-4E24-A89D-D986B4AF9B06.png

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arshia1_987    1
On 3/27/2018 at 17:59, Stu said:

Hi,

Just a few thoughts.

Can you be more precise about how dark your skies ar? Are you able to see the Milky Way or things like M31 and the Double cluster with the naked eye (ie without scope or binoculars?)

Collimation can be checked by defocusing on a moderately brighter star, Polaris is good because it doesn’t move! The pattern should appear concentric, if not then collimation is likely to be necessary although it is less important for lower power views.

Don’t forget that M31 is huge! With your scope you will only get a small portion of it in view at a time which might explain what you are seeing. These three diagrams show the field of view circles for your 25 and 10mm eyepieces (assuming that is what you have). As you see, much of the Galaxy is out of the view

9FB6CC96-550F-4B13-BF85-DB9B6FF676CB.png

A57BCBCD-CB67-4777-A9BC-5A64A45BD71D.png

E96BCD1E-260D-4E24-A89D-D986B4AF9B06.png

The sky was so dark in the middle of desert in about 20 kms out of a small city. But it was not bright. It has some clouds and some clear. Another time i went somewhere else the sky with no clouds but near to the road and more light pollution than the first time

Thanks. I will try again this time i have the new information. Then i report here. 

Did you see the image i upload? Do you think what i saw i not andromeda? 

 

 

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pipnina    538
32 minutes ago, arshia1_987 said:

The sky was so dark in the middle of desert in about 20 kms out of a small city. But it was not bright. It has some clouds and some clear. Another time i went somewhere else the sky with no clouds but near to the road and more light pollution than the first time

Thanks. I will try again this time i have the new information. Then i report here. 

Did you see the image i upload? Do you think what i saw i not andromeda?

Andromeda is very hard to observe this time of year because it is very close to the horizon. I could not see Andromeda with my telescope recently but I could see M51 faintly. The height of the object matters.

Try objects like M51 and M101, they might be easier than M31 at the moment.

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Stu    17,496
1 hour ago, pipnina said:

Andromeda is very hard to observe this time of year because it is very close to the horizon. I could not see Andromeda with my telescope recently but I could see M51 faintly. The height of the object matters.

Try objects like M51 and M101, they might be easier than M31 at the moment.

That’s a very good point! M31 is close to the sun currently and is not easy to observe against a dark sky. As pipnina says, try some other galaxies nearer the zenith, M81 and 82 are always good.

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arshia1_987    1

I tested the algieba and mizar. I saw both with 10 mm eyepiece. That's ok. But the sky is always cloudy these day and i cant test other things but i realized my scope is fine. 

I want some help buying an eyepiece for deep sky objects. I know that the less focal length is better for deep sky objects. Like 8 or 10 mm. Is that true?? I have an sky watcher stock 10 mm but its quality so bad. Is the zoom eyepieces work good? The 8-24 mm vixen eyepiece. Any idea? 

The other options is night sky 2inch 20 mm ultra wide - skywatcher sky panorama 2inch 23 mm 82 degree wide - skywatcher 15 mm 1.25 inch 82 degree - skywatcher 7 mm 1.25 inch 82 deegre - skywatcher swa 70 deegre 13 mm 1.25/2 inch 

My focuser is 2 inch. Now with the options i mentioned, 1.25 is better or 2?surely 2 inch is better but i want to know the difference is great or what? And is the zoom eyepiece like 8-24 works like three 8-15-24 separate eyepieces?? 

Finally whats the 1.25/2 inch means? Is it both? How? 

Thanks alot and much moreeeeee 

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wok    36
2 hours ago, arshia1_987 said:

I tested the algieba and mizar. I saw both with 10 mm eyepiece. That's ok. But the sky is always cloudy these day and i cant test other things but i realized my scope is fine. 

I want some help buying an eyepiece for deep sky objects. I know that the less focal length is better for deep sky objects. Like 8 or 10 mm. Is that true?? I have an sky watcher stock 10 mm but its quality so bad. Is the zoom eyepieces work good? The 8-24 mm vixen eyepiece. Any idea? 

The other options is night sky 2inch 20 mm ultra wide - skywatcher sky panorama 2inch 23 mm 82 degree wide - skywatcher 15 mm 1.25 inch 82 degree - skywatcher 7 mm 1.25 inch 82 deegre - skywatcher swa 70 deegre 13 mm 1.25/2 inch 

My focuser is 2 inch. Now with the options i mentioned, 1.25 is better or 2?surely 2 inch is better but i want to know the difference is great or what? And is the zoom eyepiece like 8-24 works like three 8-15-24 separate eyepieces?? 

Finally whats the 1.25/2 inch means? Is it both? How? 

Thanks alot and much moreeeeee 

I get better views from long focal lenght eyepieces for deep sky objects, the shorter I go the darker the image and less details I am able to see. I don't own one myself, but from what I read the TeleVue wide angle eps are great for dsos.

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pipnina    538
10 hours ago, arshia1_987 said:

I tested the algieba and mizar. I saw both with 10 mm eyepiece. That's ok. But the sky is always cloudy these day and i cant test other things but i realized my scope is fine. 

I want some help buying an eyepiece for deep sky objects. I know that the less focal length is better for deep sky objects. Like 8 or 10 mm. Is that true?? I have an sky watcher stock 10 mm but its quality so bad. Is the zoom eyepieces work good? The 8-24 mm vixen eyepiece. Any idea?

There is much debate as to whether zoom eyepieces are worth the cost. Personally I would prefer to get different eyepieces with the properties you desire for different tasks.

An important factor when buying an eyepiece is the "exit pupil" which is the size of the beam of light that comes out of the eyepiece. You can work out by taking your aperture (250mm for your telescope) and your magnification (focal length divided by eye piece focal length) and dividing the aperture by magnification. This means if your telescope has 1200mm focal length and 250mm aperture, and your eyepiece has 24mm focal length, you get an exit pupil 5mm wide.

The exit pupil is important because it determines the brightness of the image. Bigger exit pupils are brighter and smaller exit pupils are dimmer. The maximum exit pupil you want might be somewhere between 5.5mm and 7mm. This is largely dependent on how large your pupils can dilate to. 5mm-6mm is usually a safe bet, but the maximum dilation decreases slightly as you age.

Usually the minimum exit pupil you want will be somewhere in the region of 1mm and 1.25mm I find.

10 hours ago, arshia1_987 said:

The other options is night sky 2inch 20 mm ultra wide - skywatcher sky panorama 2inch 23 mm 82 degree wide - skywatcher 15 mm 1.25 inch 82 degree - skywatcher 7 mm 1.25 inch 82 deegre - skywatcher swa 70 deegre 13 mm 1.25/2 inch 

My focuser is 2 inch. Now with the options i mentioned, 1.25 is better or 2?surely 2 inch is better but i want to know the difference is great or what? And is the zoom eyepiece like 8-24 works like three 8-15-24 separate eyepieces?? 

Finally whats the 1.25/2 inch means? Is it both? How?

I think a 2" eyepiece with a big apparent field of view like the 82 degrees from those skywatcher eyepieces would be ideal for nebula and galaxy viewing. I use a 24mm maxvision 82 for this purpose and the large field of view is always stunning.

A 2" focuser is better, however a 1.25" eyepiece can work just the same in a 2" focuser as in a 1.25" focuser. The need for a larger focuser comes from the eyepieces properties. An eyepiece with 24mm of focal length and 82 degrees afov needs the extra size of the 2", as the light cannot fit inside a 1.25" focuser.

IMG_20180416_110839384.thumb.jpg.0528788ec9387d4ae108892f562435d3.jpg

This is the bottom of my 24mm 82deg maxvision. It is a 2" eyepiece and the bottom lens is almost as big as the 2" space it sits in, this is because of the large field of view it covers. A 12mm 164 degree eyepiece would need the same size glass. Ultimately a 1.25" eyepiece is not necessarily lower quality, but manufacturers do not make eyepieces with 2" size unless it is needed for the eyepiece design to function.

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