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EAA with a manual Dobson... it´s working!

EAA
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#76 Ubuntu

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Posted 03 February 2019 - 07:29 AM

Here are some observations from yesterday laugh.gif

 

NGC 4565 needle galaxy: 58 frames, total 58s with NGC4562 of Mag14,6

Stack_58frames_58s_WithDisplayStretch V2.jpg

 

M51: 67 frames, total 67s

Stack_67frames_67s_WithDisplayStretch V2.jpg

 

M101: 76 frames, total 76s

Stack_76frames_76s_WithDisplayStretch V2.jpg

 

M63 sunflower galaxy: 57 frames, 57s

Stack_57frames_57s_WithDisplayStretch V2.jpg


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#77 Pcbessa

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Posted 03 February 2019 - 07:46 AM

Ubuntu, you are doing great work and I will join you!

I decided to buy the Orion XT10i as my scope will not have GoTo for a few reasons:

First and foremost I want to see deep sky objects and with a quiet environment, not the noise if a GoTo system yet.
So I realise I get the Intelliscope Dob now, allowing to go for the 10inch instead if the 8inch, plus extra money for eyepieces, and I can later get a second smaller scope with GoTo, for EAA.

I will be busy enough enjoying my Fob, and i can always try the stacking of small exposures as you have greatly shown us!

(I haven't bought the XT10i yet, just giving a couple more days to let this decision sink in)

Excellent job!

You can photograph almost all the Messier catalogue, no?

#78 Ubuntu

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Posted 10 February 2019 - 08:44 AM

M76: 34 frames, total 34s

Stack_34frames_34s_WithDisplayStretch V2.jpg

 

M65 & M66: 35 frames, total 18s

Stack_35frames_18s_WithDisplayStretch V2.jpg


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#79 DSO_Viewer

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Posted 10 February 2019 - 01:20 PM

M76: 34 frames, total 34s

attachicon.gif Stack_34frames_34s_WithDisplayStretch V2.jpg

 

M65 & M66: 35 frames, total 18s

attachicon.gif Stack_35frames_18s_WithDisplayStretch V2.jpg

Nice images considering the short exposure time. You would pickup even more detail if you could go longer with your subs but I know you are limited by using a Dob.

 

Steve


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#80 Ubuntu

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Posted 10 February 2019 - 03:19 PM

Nice images considering the short exposure time. You would pickup even more detail if you could go longer with your subs but I know you are limited by using a Dob.

 

Steve

Indeed steve... i think now I will try to do more then one run :)


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#81 SonDob

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Posted 13 February 2019 - 09:02 AM

Ubuntu, regarding the horsehead nebula, what was the Bortle scale on your sky, or where are you located?

Did you saw it visually with a H-beta  filter?

Do you use a focal reducer? And which EP?

 

How about you SonDob? Was your telescope a Orion XT8?

Do you use PushTo?

 

I am very excited as I am about to buy my first 8'' or 10'' Dob, possibly an Orion Intelliscope, but I am still unsure between them (as I want an easy grab and go scope). Its exciting to know that you can do simple EAA without any tracking!

 

I also considered the Skywatcher 200p which has GoTo (and the reason was doing simple EAA). But now I realize that probably there is no advantage to the GoTo system on a Dob, as you can do EAA without the GoTo. Am I correct thinking this way? Between PushTo and GoTO I probably would prefer PushTo as its cheaper, quieter and less hassle with power drain.

I am under Bortle 5 skies. Yes I saw the horsehead in 8" visually. Funny though, with Baader H-Beta an big AP i could not. I did the trick with a small AP and modest high magnification of 218x. Used Meade 5.5 82. Which is pretty contrary to all advise you'll get, otherwise. For me high magnification with dark adaption works pretty good for difficult objects as it darkens the background sky.

 

I am using a skywatcher 200/1200, manual, no pushto, no goto. I don't think pushto is worth it if you have Skysafari on mobile phone, which I highly recommend. I would consider goto a big improvement for EAA. Also make sure to get a flextube as Ubuntu pointed out. This way it is way easier to get into focus.



#82 Ubuntu

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Posted 26 February 2019 - 01:52 PM

I decided to shorten the exposure to try to get round stars... smile.gif

It means that I have to make several passes to get a total of one or 2 minutes exposure...

 

NGC2903: 87 frames, total 44s

Stack_87frames_44s_WithDisplayStretch V2.jpg

 

M81: 128 frames, total 128s

Stack_128frames_128s_WithDisplayStretch V2.jpg

 

And my prefered galaxy laugh.gif :

M104, Sombrero galaxy: 95 frames, total 48s

Stack_95frames_48s_WithDisplayStretch V2.jpg


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#83 Pcbessa

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Posted 26 February 2019 - 02:11 PM

I got my 10inch Dob and have been blown away by some of the views!

It's actually easy to transport with the Orion bag. And the Intelliscope is just what I needed. Got to see so many unknown galaxies but couldn't see the Horsehead yet (I have no nebula filters yet and my first one might be a UHC)

Yesterday I tried to take photos with a normal digital camera, in typical primitive style. Nothing to hold the camera, nothing to prevent the movement caused by my finger pressing the shutter, and even short 5' exposures cause blurry pics. Yes I know this is as bad as o e can get!!

But I realised that it captured the targets quite easily (I choose m81 as a first target and m36 as second target).

I can see how addictive EAA or AP can become!!! I will try stacking to see What happens.

And I agree. High magnifications yield dark skies. I use them to see Abell clusters which are quite faint under the 25mm eyepiece. Under the 10mm they are much easier to spot!
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#84 Ubuntu

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Posted 26 February 2019 - 04:10 PM

Yesterday I tried to take photos with a normal digital camera, in typical primitive style. Nothing to hold the camera, nothing to prevent the movement caused by my finger pressing the shutter, and even short 5' exposures cause blurry pics. Yes I know this is as bad as o e can get!!
 

Congratulations for your acquisition... I'm sure you will enjoy it a lot :)

Now you have to post the pictures laugh.gif


Edited by Ubuntu, 26 February 2019 - 04:11 PM.


#85 SonDob

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Posted 27 February 2019 - 06:41 AM

Hi Ubuntu,

 

finally..... i got some time under moonless nights. Here are my first shots with the manual skywatcher 200/1200 and 0.5x. Sorry, only mobile phone snapshots of the notebook screen. It's the flame, owl, Horsehead :-) and M108. The bigger M108 and Owl are shown with the focal reducer varied to ~0.5x to gain more magnification. , all other shots are at ~0.35x or f/2.1. All single shots are 1.28 seconds. I used 2-3 passes of the objects to gain enough data. Keep in mind I used my heavily grinded low cost analogue cctv camera for 30$. Looks promising to me :-)

Thank you for the inspiration to try that out. I'll post more pics as I progress

 

 

 

Attached Thumbnails

  • flame_8inch_resized.jpg
  • horsehead_8inch_resized.jpg
  • horsehead_8inch_2_resized.jpg
  • m108_8inch_resized.jpg
  • m108_closer_8inch_resized.jpg
  • owl_close_8inch_resized.jpg

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#86 SonDob

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Posted 27 February 2019 - 07:06 AM

I got my 10inch Dob and have been blown away by some of the views!

It's actually easy to transport with the Orion bag. And the Intelliscope is just what I needed. Got to see so many unknown galaxies but couldn't see the Horsehead yet (I have no nebula filters yet and my first one might be a UHC)

Yesterday I tried to take photos with a normal digital camera, in typical primitive style. Nothing to hold the camera, nothing to prevent the movement caused by my finger pressing the shutter, and even short 5' exposures cause blurry pics. Yes I know this is as bad as o e can get!!

But I realised that it captured the targets quite easily (I choose m81 as a first target and m36 as second target).

I can see how addictive EAA or AP can become!!! I will try stacking to see What happens.

And I agree. High magnifications yield dark skies. I use them to see Abell clusters which are quite faint under the 25mm eyepiece. Under the 10mm they are much easier to spot!

Hi Pcbessa,

 

congratulations, you will be stunned what you will be able to see visually. For the horsehead. It took me three years to see it, but now it is quite obvious without filter. There are two things going on. 1st you need to know what to look for, 2nd you need to gain observing skills. If this is your first scope you will be able to see much more in a few month when you observer quite regularly. There are some tricks you need to use like averted vision, etc and your brain just needs to train observing faint things.

Regarding the Horsehead. I attach a little helper. This is my eaa shot from above modified to what I see in 8" and also in 12" visually and what you can expect. Just one dark roundish blob, no snout. Actually the shape of a ink finger print. The stars in the red boxes are your navigating aid. The upper two stars are the most important. You may need high mgnification to see them. The horsehead is just under it. You can only see it with averted vision and dark adaption.

 

Good luck and have fun.

Attached Thumbnails

  • hh_map.jpg


#87 Howie1

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Posted 27 February 2019 - 07:28 PM

Very cool to see you folk pushing the boundaries! Congrats


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#88 descott12

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Posted 27 February 2019 - 09:05 PM

Have you considered using a longer exposure? It looks like alot of yours are 1 second.



#89 SonDob

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Posted 28 February 2019 - 04:34 AM

Have you considered using a longer exposure? It looks like alot of yours are 1 second.

Hi Dave,

at maximum i can use 1.25s per single frame. Even that is pushing it regarding startrails. Remember, these pictures are all done with a full manual dobson. Bare minimum tech. No tracking, no eq platform, nothing. Just letting stars drift through the camera then pushing the scope back, recapture and stack. Most pictures were done with pushing the scope back for 2-3 runs.


Edited by SonDob, 28 February 2019 - 05:49 AM.


#90 SonDob

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Posted 28 February 2019 - 05:40 AM

got another clear night without Moon. Went GX hunting, mostly. Incredible. :-)

 

Attached Thumbnails

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  • hockeystick_resized.jpg
  • whale_resized.jpg
  • cocoon_resized.jpg
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  • runningman_resized.jpg

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#91 SonDob

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Posted 28 February 2019 - 05:46 AM

a few more and this time really pushing it. Last picture is cone nebula NGC 2264 in the christmas tree cluster at ~f/2. Very faint but it is there :-)

Attached Thumbnails

  • m42_resized.jpg
  • hh_resized.jpg
  • cone_nebula_resized.jpg

Edited by SonDob, 28 February 2019 - 05:52 AM.

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#92 descott12

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Posted 28 February 2019 - 07:31 AM

Remember, these pictures are all done with a full manual dobson. Bare minimum tech. No tracking, no eq platform, nothing. 

Oh yes, I remember seeing that way back on page 1!

Very cool!



#93 SonDob

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Posted 28 February 2019 - 09:19 AM

Oh yes, I remember seeing that way back on page 1!

Very cool!

But you are right. There is lots of unused space in the telescope drawtube and the not grinded part of the camera case still sticks out a bit of the focusser.  I need to rethink the camera case. The space could be used for additional focal reduction leading to longer exposure options.



#94 Ubuntu

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Posted 28 February 2019 - 01:54 PM

got another clear night without Moon. Went GX hunting, mostly. Incredible. :-)

Amazinnnnnnnnnnnggggggg.... bravoooooo :D

 I see that you managed very well :) you even got the horse head!!!

 

You use sharpcap pro to save your results... :)

 

Are you happy with the result ?? :D


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#95 descott12

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Posted 28 February 2019 - 02:09 PM

I noticed you have some pretty severe vignetting. I recently learned how to use flats in SharpCap and they pretty much eliminated the problem. You should check it out. It turns out they are pretty easy to create, they work wonderfully AND you can in fact use old flats.  They don't work as well but you don't have to re-create them for each session.



#96 SonDob

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Posted 01 March 2019 - 04:48 AM

Amazinnnnnnnnnnnggggggg.... bravoooooo laugh.gif

 I see that you managed very well smile.gif you even got the horse head!!!

 

You use sharpcap pro to save your results... smile.gif

 

Are you happy with the result ?? laugh.gif

yes,I am very happy with the results. especially for the first try out. Way to learn and enhance, but it let me see things I could not with the 12" under my skies.

Next challenge will be NGC 1555 "Hinds variable nebula". Was never able to see it visually. But it is small and will probably call for less strong focal reduction and higher magnification because of my low camera resolution of 720x576, only. Lets push the limits :-)


Edited by SonDob, 01 March 2019 - 06:13 AM.


#97 SonDob

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Posted 01 March 2019 - 05:02 AM

I noticed you have some pretty severe vignetting. I recently learned how to use flats in SharpCap and they pretty much eliminated the problem. You should check it out. It turns out they are pretty easy to create, they work wonderfully AND you can in fact use old flats.  They don't work as well but you don't have to re-create them for each session.

are you referring to the black almost frames around the objects? This is an alignment or stacking artifact. I think it is not vignetting. If you look at this https://www.cloudyni...-1551267524.jpg previous picture you can see even different levels of stacking as shades.

 

the problem is that almost all of my captures are done with several passes. In between passes I push the dobson back to the start. If the obect to capture ist not at the same starting point like in the previous run then the frames sharpcap needs to align are only partial overlapping. Instead of just stacking the intersecting area, i guess sharpcap only stacks full frame. Thus the not overlapping parts receive a full black frame for the stacking. During the stacking you can see those frames getting created and running towards your object. I experimented a bit. If I continue to stack longer and pay attention where to push back the object you can also reverse it.

In a way i see this also with my little refractor on a tracking mount. if the tracking is not stable enough then i got little black border frames around the picture. You can try it yourself just let your object run out of the fov and continue tracking. Same effect.

 

So the problem is the manual push accuracy. I think it will improve by just increasing push frequency. A second window showing the single frame camera signal in in parallel to the live stacking would be useful for this . This way i would not need to stop stacking, push dob, press continue stacking and so on. I do not see a option for this in sharpcap. I guess manual driven telescopes where never in the scope.

 

Hmm, maybe I split my analogue video signal and feed it into a hardware screen. Then I do a rough manual "guiding" every 5 seconds, keeping the objects drift area in closer boundaries. Lets try.


Edited by SonDob, 01 March 2019 - 05:03 AM.


#98 descott12

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Posted 01 March 2019 - 08:32 AM

are you referring to the black almost frames around the objects? This is an alignment or stacking artifact. I think it is not vignetting. If you look at this https://www.cloudyni...-1551267524.jpg previous picture you can see even different levels of stacking as shades.

 

Yes, it looks very bright in the center and gradually darker towards the edges and corners.  That is exactly what vignetting looks like on my setup and the flats corrected it.

 

I have seen the stacking artifact with SC but that is normally a completely black stair-step pattern with sharp margins around the edges and results from areas of the image being cropped to correct for rotational differences between frames. That doesn't look like what you have here...but I could be wrong.


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#99 SonDob

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Posted 01 March 2019 - 01:24 PM

Ok I see now what you mean. Indeed it looks like a circular darkening. Ill try the suggested darkframe. Thank you, I missed that one!

#100 descott12

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Posted 01 March 2019 - 01:29 PM

Ok I see now what you mean. Indeed it looks like a circular darkening. Ill try the suggested darkframe. Thank you, I missed that one!

Actually it is a master flat frame. Not a dark.  Yes, give it a try. They are really great.




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