My First Attempt Imaging with the EQ5 - M57

[acharris77]

Hi all, after all the trial and error with the EQ5, I managed to get it setup and do some imaging. So I thought I would try M57 Ring Nebula. I know this is a hard target, and through a 130P DS with a Canon 1000D it appears small, but I did a crop and this is the result.

I don't think the light pollution filter worked very well, as I still got the same amount of orange in the original image as I do without so was a little bit disappointed with the filter. Anyway here is a quick edit and I got the same issue with a M51 that I can't get any detail out of.

This was taken using 60 sec subs and I only managed to add 20 darks to the stacking process. The background is a bit light after using GradientXtreme filter, but I shall work on them and try and learn more techniques to remove light pollution from the images.

Thanks for looking and any advice is appreciated.

[Freddie]

That's a nice start though there are some issues with star shape. This could be because the cam in not sitting square/flat in the light path or could be tracking. Do you know if the elongation is aligned with RA, DEC or at an angle to both? That would help you pin down the problem.

[xtreemchaos]

great first image of M57,well done,you have jumped in at the deep end,  try and get a bit more data to improve detail,thanks for sharing. charl.

[acharris77]

Hi thanks for the comments.

@Freddie To be honest I am new to imaging with a EQ mount, so to be honest I am not sure how to know. It might be the SLR is was not right, as when the shots were taken they were taken in portrait mode, so don't know if that would make a difference.

I will have to take a look at that when I get out next with the scope and see if I can find which is causing it, or if it was tracking. Maybe I might try a 2 star alignment to see if that helps tracking. Thanks again.

[Chris]

Nice start but you can improve it by getting better focus using a focus mask. Also you have some tracking error (all the stars are elongated in the same direction), tis will smear the photons across your sensor. M57 is quite bright so you're probably better off using even shorter subs of 45 seconds to help prevent tracking errors, or you can work on polar allignment and backlash in the mounts gearing.

Good start, keep up the good work

[Chris]

I will have to take a look at that when I get out next with the scope and see if I can find which is causing it, or if it was tracking. Maybe I might try a 2 star alignment to see if that helps tracking. Thanks again.

goto allignment and polar allignment are two different things. Getting a better polar alligment will help with the tracking. Getting a better goto alligment will help with how accurately your goto places objects in the field of view prior to tracking the object.

[Knight of Clear Skies]

Congratulations for getting up and running, imaging is quite a learning curve and you've made some good progress to produce the image above. The issue above seems to be tracking as all the stars are elongated in the same direction by the same amount, but it would be easier to check this if you posted the full frame.

A few tips:

- Portrait or landscape mode on the camera doesn't make any difference, the stacking software will ignore this. For convenience there is a setting somewhere in the camera menus to turn off auto-orientation.

- A 2 star alignment won't improve tracking, only goto accuracy. Tracking accuracy is determined by polar alignment accuracy (drift alignment may help) and periodic error from the mount (checking the balance carefully and making sure cables aren't dragging may help).

- Unguided imaging is quite tough at a focal length of 650mm, 1 minute subs may be difficult to achieve. It might be worth checking with other 130PDS users what sub lengths they can manage, the "Getting Started with Imaging" sub-forum is a good place for questions like this.

- Personally I wouldn't worry too much about darks at this point, my understanding is that dark current only becomes significant with longer subs. If conditions are good you're probably better off taking more lights. Dark bias frames on the other hand are quick and easy to take, so don't cost much precious imaging time.

- Fitting a camera lens and putting the camera directly on the mount makes for an easier introduction to unguided imaging, everything is more forgiving at short focal lengths.

Hope that's some help.

[Freddie]

Hi thanks for the comments.

@Freddie To be honest I am new to imaging with a EQ mount, so to be honest I am not sure how to know. It might be the SLR is was not right, as when the shots were taken they were taken in portrait mode, so don't know if that would make a difference.

I will have to take a look at that when I get out next with the scope and see if I can find which is causing it, or if it was tracking. Maybe I might try a 2 star alignment to see if that helps tracking. Thanks again.

To determine how the cam is aligned, set for a 20 sec exposure, set the rate on the hand set to 1 and then move the mount north or south (up or down arrow) during the exposure. Have a look at the resulting image and the line the star has taken will indicate north/south i.e which direction on the image related to Dec. Once you have done that it will help you determine how to resolve tracking errors if it is that or camera tilt if that is the cause of the elongated stars on your posted image. 

[acharris77]

Thanks all for the advice.

Here is the full frame image without any crops after I stacked them in DSS. I used a Bahitov mask and didn't realise the focus was out that bad until I cropped it.

Thanks again.

[Freddie]

It's difficult to tell if focus is out on a longish exposure as you have the effects of tracking and seeing impacting on the image. You can only really be certain it is focus and none of these other things on a short 3-5 sec exposure. If you used a mask, I doubt focus is far out if at all. Resolving the issue causing the elongation I would say is your priority.

[Alien 13]

The uncropped image looks much better and a good start for your 1st attempt, some of the star shapes in the cropped image could be due to tracking errors or as mentioned some slight out of squareness in the imaging train.

The main thing is that you got your image which is much better than my 1st attempt and things will get easier with practice.

Alan

[laudropb]

Good first attempt. Work on your polar alignment will bring its rewards.

[acharris77]

Thanks all, some really great advice. After 4 failed attempts at setting up the EQ5, last night was the first time I got it polar aligned and the goto working OK. So probably I am out somewhere with regards to the tracking. It could be balancing as I didn't balance the scope with the camera on, so maybe that could be one issue, another is probably my Polar Alignment as for the first time last night I understood the engravings in the polar scope.

I have plenty to work with above and now the next clear night I will know how to set it up, so I can work on what has been above to see where the stars are elongating and improve my tracking.

Thanks again, much appreciated.

[JohnnyD333]

M57 is so so small, even in my 1000mm, but you got it nicely with 650mm.  As someone mentioned earlier, polar alignment will do wonders.  You should be able to pull off a minute exposure without auto guiding if you have good polar alignment.  My CG5 has a polar alignment feature in the handset, which works surprisingly well.  You should check if your mount has the same.  Good luck on the future photos.