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yong54321

How to see (maybe via imaging) the spiral arms of a galaxy?

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Hello

As I am a beginner in astronomy, I would like to ask for help before I spend more money on buying more ineffective equipments. My hope is to see the spiral arm of a galaxy, not just the core. I start with meade mini 114 but I cannot see any galaxy. But with my camera 30 sec exposure, I manage to see just the core of M83. So I go on and buy a Dob 8". It turns out I still cannot see the spiral arms, only the core is available. My next step could be

1. buy video cam like macllincam. I read they can see thru light pollution and see galaxy in a few second. I am located in Singapore. Do anyone has any success with similar setup?

2. buy manual meade polaris eq130 telescope and do imaging so that i can see the spiral arms? Use the eq motor drive? 

3. buy goto telescope alt/muz. Celestron SLT 130 or starnavigator NG 102. and do more stacking. Or need bigger aperture?

4. buy goto eq mount? This looks expensive.

5. Other solution that i am not aware of.

Thanks for any comments and help. I do not know which way to turn and it seems like a long way before i can enjoy a galaxy... M83 is shown as a "star" near the northwest of the cross hair in my attached photo.

 

regards

yong54321

 

 

m83 1x30sec full resolution 220219.png

Edited by yong54321

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I don;' think it is easy to see the spiral arms visually, though I could be wrong if you have a huge telescope.  Imaging is the best bet, but it is not a cheap hobby and you rightly say use an equatorial mount that tracks and preferably will guide as well.  

Not a video camera (you can use one for planets), but probably the cheapest option would be a DSLR camera.

Carole 

Edited by carastro

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The first thing you need is a very dark sky. I have that. Then you need very good eyesight. I don't have that. This means that to see spiral structure I need the object to be very high in the sky. (A low elevation kills it.) And I need a lot of aperture. When M51 is well placed, high in the sky,  it is easy for me in apertures above 14 inches. Below that it is, quite honestly, very subtle indeed. When expert visual observers describe spiral structure as easy they are speaking as expert visual observers. What they will call easy a beginner will call invisible.

With a tracking mount and a camera like the Mallincam you should see what you are looking for.

Olly

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hi Olly and Carole

Thank you very much for your advise.

Look like I will need a tracking mount. I will start with goto telescope slt 130 or starnavigator 102 (which is better?) since 14" is out of my budget and space at home. I might get a risingcam which look more affortable than macllincam.

Hopefully i will see a galaxy. And thanks again for your help.

Regards

Yong54321

 

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On 24/02/2019 at 07:05, yong54321 said:

hi Olly and Carole

Thank you very much for your advise.

Look like I will need a tracking mount. I will start with goto telescope slt 130 or starnavigator 102 (which is better?) since 14" is out of my budget and space at home. I might get a risingcam which look more affortable than macllincam.

Hopefully i will see a galaxy. And thanks again for your help.

Regards

Yong54321

 

If you wanna go pursue astrophotography and specifically deep sky imaging, you should go for a Equatorial Mount, not an Alt/Az as the Slt 130 is. When imaging on an Alt Az mount, you will get field rotation, which will make the stars blur and stretch after a certain exposure time. I made the mistake myself to start out with the Celestron 130 SLT. As good as a visual and beginner scope it is, it is really not suited at all for astrophotography.
Not only is the mount quite flimsy, so that you need tuberings. The OTA itself is not set up for imaging either, as a lot of cameras doesn't have enough inward travel to reach focus. I temporarily went around this problem by introducing a barlow. But that also introduces even more optical abberations than the coma of the telescope itself did from the start.
Only about half a year after I bought the SLT, I upgraded to a Celestron Advanced VX Mount and a Skywatcher 150PDS. A setup I've been very happy with. But less will do :)

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1 hour ago, The-MathMog said:

If you wanna go pursue astrophotography and specifically deep sky imaging, you should go for a Equatorial Mount, not an Alt/Az as the Slt 130 is. When imaging on an Alt Az mount, you will get field rotation, which will make the stars blur and stretch after a certain exposure time. I made the mistake myself to start out with the Celestron 130 SLT. As good as a visual and beginner scope it is, it is really not suited at all for astrophotography.
Not only is the mount quite flimsy, so that you need tuberings. The OTA itself is not set up for imaging either, as a lot of cameras doesn't have enough inward travel to reach focus. I temporarily went around this problem by introducing a barlow. But that also introduces even more optical abberations than the coma of the telescope itself did from the start.
Only about half a year after I bought the SLT, I upgraded to a Celestron Advanced VX Mount and a Skywatcher 150PDS. A setup I've been very happy with. But less will do :)

Hi thanks The-MathMog. 

It is good to hear from your experience with slt 130. It is very valuable. There seems to be people using it for imaging. And seem to have a lot more with 150P on the astrobin.

I have to go into imaging so that i can simply enjoy a galaxy at my location. I have not try a eq because i read about the alignment setup with polaris. How much time do you need to setup your Advance VX? i read newbie get frustrated with eq mount.

And what is the weight of your complete setup with 150PDS and mount? They are certainly a winning combination. I might be walking to a nearby park to use it beside my apartment balcony.

best

Yongchong

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To give a little historical context the first person to see the spiral arms of a galaxy was William Parsons, using this monster.

800px-Lossy-page1-6940px-Lord_Rosse's_Gr

Reflector coatings are better these days and a smaller scope is required, but it still makes for a very challenging observation.

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On 25/02/2019 at 10:41, yong54321 said:

Hi thanks The-MathMog. 

It is good to hear from your experience with slt 130. It is very valuable. There seems to be people using it for imaging. And seem to have a lot more with 150P on the astrobin.

I have to go into imaging so that i can simply enjoy a galaxy at my location. I have not try a eq because i read about the alignment setup with polaris. How much time do you need to setup your Advance VX? i read newbie get frustrated with eq mount.

And what is the weight of your complete setup with 150PDS and mount? They are certainly a winning combination. I might be walking to a nearby park to use it beside my apartment balcony.

best

Yongchong

And there indeed are people using it, but most of the time it is only the tube (OTA) that they are using. The Alt-Az mount is the main problem. I did so myself too in the beginning, but it was a lot of frustration, lack-luster results, and extra money spend, that could've been used a lot better, acquiring gear that was more suited for astrophotography in the beginning. In the beginning I didn't know that I wanted to go down the astrophotography road.
The longest exposures I ever got on it was like 30 seconds, and that was after a lot of practice and calibration. As said, this mount is very flimsy and the slightest breeze or someone walking close to it will ruin your images. The mount is the most important part, when acquiring gear for astrophotography, and where you want to spend most of your money.

Again, all in all, it is a very good telescope for beginners, or someone that wants something easy, light and user-friendly for exploring the night-sky visually. One that I would gladly recommend to people. Just not for astrophotography.

Remember, that when you see people refer to the 150PDS, 130PDS or similar, they are talking about the SCOPE (OTA), and not what mount it sits on. They will 95% of the time use a EQ mount. The SLT by default comes on the ALT-Az. Just wanted to make that clear.

Right now I have added quite a bit extra gear to my mount, with Filterwheel, Guidescope/camera, CMOS camera, Dew shield, extra counterweight to compensate for the extra weight etc. So the entire setup with tripod legs, mount, scope, all of it, weighs 35kg, so when I set it up I lift it out in two parts.
The Scope part of it with OTA (Skywatcher 150PDS), Camera, Filterwheel, guidescope/camera and OTA rings, weight about 9 kilos, so well within the limits of the mount, if it is properly balanced.

But all in all the setup is very quick for me to setup, compared to all the equipment I have, and I can be imaging in 30-45 minutes. If I were to only set up the telescope (OTA) and the mount, I would be up and running in way less than that. But everything is a learning curve and routines, and EQ might be harder to set up in the start, but once you get your head around it, and practice it, it is actually very intuitive and simple. 

A lot of people use the 130PDS with a similar mount as the AVX (Skywatcher HEQ5 or EQ5 for example), and get great results. You can see a lot of them in the thread "Imaging with the 130pds". The only difference with the 150PDS is the larger aperture (a slightly higher light-gathering cabability) and the slightly longer focal length, 750mm compared to 650mm. But the smaller size makes it more portable and "forgiving".

In short, my biggest advice would be, do a lot of research (as you seem to be doing), spend as much as you can on better gear now, so that you don't have to upgrade later, and prioritize spending the most on the mount. In astrophotography, the mount is the king.

Sorry for the long response, but I hope it can help you out somewhat :) 

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If you have any plans (And it looks like you do) to go into imaging, then get hold of This Book And read it thoroughly. I just hope it can be posted to Singapore.

Steve is a Mod on here, steppenwolf.

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Hi The-MathMog

Thanks very much for your reply. Your information is very valuable to me. I will avoid getting a slt 130. I read that it is require to enter time and date each time you want to use it. 

Since my current goal is to see the galaxy spiral arm (should be possible only by CCD camera), I might just get a Meade Polaris eq130 with motor drive and uses a "security camera". Then, I can expect to see the spiral arm within 2 minutes? Please correct me if I am wrong here.

The skywatcher 130pds seem be better and fits DSLR camera. Unfortunately, the telescope is not available in my country. Using an eq with DSLR will takes me a few hours to setup eq, capture long exposure, stack them in DSS and process them in photoshop. Don't think i can do it since I have small children. Base on what i see on youtube, learning to use eq alone will takes me months... sweat..

HI DaveS

Thanks for your recommendation. The book is available for shipping internationally on firstlightoptics.com It seems to be highly recommended on the forum. 

Hi Knight of Clear Skies

Thanks for the picture!

 

 

Edited by yong54321
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Posted (edited)

Hello

Just to update my struggle...

I manage to see the spiral arm with my 8" Dob and using iPhone as a camera. It is only a very subtle hint of the spiral arm of M83. So i wonder if i am seeing tge galaxy or just noise.  Could anyone verify?  It is at the lower left of the attached photo. Do note that I have use custom iOS app (my own programming) to do the tracking and stacking. It is a far cry from those beautiful DSLR images. 

 

Best regards

yong54321 

 

 

 

 

 

47508336011_8d6f868ebd_z.jpg

Edited by yong54321
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Posted (edited)

You might find the EEVA section of SGL quite useful; people there are doing what you are trying to. A post in the revamped Eeva discussion forum might get some details and discussion for you. There are people there doing what I think you’re interested in. It’s generally called EAA or video astronomy, the forums here are called EEVA to be more broad.

I regularly observe galaxies with my 150pds from central London and see detail using one of two cameras the asi290 mono and the Asi294 colour. If your just starting I would strongly recommend the zwo asi290 since it is very sensitive, not too expensive and easy to use with SharpCap software — however it is mono. 

These cameras are far more sensitive than a dslr (except maybe the Sony alpha 7s) and so they require only short exposures. I regularly use exposures in the range of 2-10s and live stack to see dso.

That means you don’t need a big mount. In fact I use an AZGTI which is a small alt-az mount (not with the 150 much it is a little heavy for that mount, but it still works). I don’t know what your light pollution is like but London is the worst I’ve seen — worse than New York or LA. 

You should be able to see detail in galaxies with the mini114 and a suitably sensitive camera - however you will still probably need a GoTo tracking mount of some sort. The AZGTI would be perfect for the Meade 114 if it can take a vixen mount - otherwise you might need to buy rings so you can add the vixen bar to attach to the AZGTI (or whatever other mount you get).

If you can add motor tracking to your 8” dob you will get great views with a camera like the asi290 when you live stack.

 

Edited by London_David

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It does appear that you've caught a hint of M83 which has a prominent hook-like arm. However, after checking the starfield in WWT I'm less convinced, I can't see an obvious match. Could be a different galaxy perhaps, or as you say some kind of artifact.

Nice bit of improvisation with the dob and phone camera anyway, are you tracking manually or is your dob motorized?

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Posted (edited)

Hi and thanks.

To David_London. Thanks for the great recommendations. I would certainly wish that you have reply earlier. It is very attractive to be able to see galaxy in 2-10s. If I know mini114 is able to see galaxy, I would have stop buying more telescope. :)

I spend so much time looking online for security camera such as LN300 which are hardly existing now. I opt for analog camera (analog camera) as I do not want to work with laptop and telescope in the dark. And prefer something easy and light. In the end, I give up searching for them. Just visit EAA section and did see some great images.

I did not order goto mount as I find them noisy (from youTube) and that would wake up my young children and neighbours (live in a tight apartment with small balcony). So I have actually order Polaris eq130 and will add on a motor drive later. Would consider again a goto if there is a quiet one being recommended. How is the ambient sound of AZGTI mount?

To Knight of Clear Skies. Thanks for your kind words! The M83s in WWT does not really match what I have. I have found a M83 with less detail in https://medium.com/hipster-color-science/imaging-the-m83-galaxy-7701408f3299 (last enlarged photo in the link, did not paste here as I do not have the author's permission). 

As for your question, I am tracking manually on an alt-azimuth mount. The iOS app (software) tracks the stars as they "float" across the eyepiece view for about 30-60 seconds. Then I move the telescope so that the stars return to view. The app finds the stars, tracks them and starts stacking again. 

 

Thank you very much. 

 

Best regards

Yong54321

 

 

 

 

Edited by yong54321
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Posted (edited)

I have good news, you have in fact managed to image M83 with a manual dob, iPhone and your own processing app. I fed your image into some plate-solving software and it matched it up (the easiest way to do this is upload it to nova.astrometry.net).

1518459487_M83PlateSolved.jpg.fbc35b4f099d42659b9a2deb9107477d.jpg

The label is hard to read but it says NGC 5236/M83 with another object designation superimposed over it. It's upside-down relative to the WWT link I posted above and only the inner part of the spiral arm is showing, which is why we had trouble finding a match.

A very impressive feat, congratulations. If you upload it to astrometry.net at the lower right of the results page it gives you a link to open your image in WWT. You can then use the crossfader control at the bottom to see how well your image matches up with the professional survey.

There is a sub-forum for smartphone imaging, it might be worth posting your image in there - I think people will be interested to see it.

Edited by Knight of Clear Skies

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Posted (edited)

That's amazing. Anyone can throw money and gadgetry at an imaging problem but your result is in the true spirit of amateur astronomy. Bravo!

There's just one problem: If you're anything at all like me, now you're thinking "OK, but maybe I could make this a little better". THAT WAY LIES MADNESS!

I kid. That way lies a rewarding, challenging, and very deep (no pun intended) hobby. There is no way to run out of "a little bit better" to pursue, and the chase itself is addictive. Enjoy!

Edited by rickwayne

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Posted (edited)

Hi

To Knight of Clear Skies: Thank you very much! It is very wonderful to have someone like you in the forum. I have tried your suggestions on uploading to astrometry.net and crossfader to WWT. It really match a M83 spiral arm in the crossfader. So happy that I do not know what to write. Many thanks for introducing me these great astronomy websites. :) I will post to smartphone imaging when I can capture more M83. 

I see you have done some great work on Milky way. Just to share, I have also used similar method to image the Milky Way with iPhone. If you are interested, you can google MilkyCam iOS. Its result is nothing spectacular but it lets me see the milky way over here. And wish you good luck clear sky! And thanks again for your help. 

 

To rickwayne: Thanks very much for your encouragement. To quote "That way lies a rewarding, challenging, and very deep (no pun intended) hobby." I have asked myself, now that I have see a galaxy spiral arm, what is next? There is still many bugs. I do not always see the galaxy each time I try to image. But I do find it "natural" to keep working on it.  You enjoy too! Thanks again. 

 

For anyone who is interested, here is a very recent short video of my setup running with a 114mm scope and iPhone 6.  https://youtu.be/oeMnA4v2Ejc

 

 

 

Edited by yong54321
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Posted (edited)

Here is an image of M83 using 114mm telescope (450mm focal length and 18mm eyepiece) and iPhone 6. The spiral arm starts showing after 5 min exposure. The second image is on a Dob 8". The spiral arm comes to sight in about a minute. Thanks everyone for your helps. 

 

 

m835.png

M83 DOB8.png

Edited by yong54321

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