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Old 29-08-2020, 01:07 PM
Cliff (Clifford)
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Helix Nebula NGC7293 very faint poor result ?

Over the last couple of nights I have tried imaging the Helix Nebula NGC7293 with poor results.
Only using a Tak 76mm so 3" or so scope on a AZEQ6 mount and a QHY163C OSC camera and a IR/UV filter. Also tried a UHC-S filter.
I did manage to coax an image out but needed extreme stretching to see it.

I am only using about 30sec max exposure (actually 22 last night ) at around 150 gain tried higher but seemed more noisy.

Capturing in Sharpcap Pro so I can see a live stack and also save the images for later processing. Stacked for about 20minutes

Larger aperture or more sensitive camera ? Longer exposure a problem as I can't see the south celestial pole to accurate polar align due to a tree.

My image is here
https://telescopius.com/pictures/vie...ebula/by-cliff

No flats or darks in this.

Also seemed i got no colour I used Siril for stacking and Startools to process.

Moon light could also be a factor. Bortel zone suppose to be 6 I think higher.

Appreciate any help, imaging from my Villa in Picnic Point Sydney a real problem!
I have a bit more sky as a large tree was just cut down but still can't see a lot.

Cliff
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Old 29-08-2020, 01:36 PM
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LewisM
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Longer exposure sorry to say. When I did helix with my Tak FSQ-85 and OSC I had almost zero south view but was still doing 5 minute subs.

Sharp cap polar align doesn’t need to see the actual SCP but uses stars a few degrees away. If you are so restricted you may need to try going somewhere to image.
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Old 29-08-2020, 04:35 PM
jahnpahwa (JP)
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Cliff, if you have the handpiece for the mount, you can just polar align using your handset, no sighting the SCP, no worries. It might take some time to get below an arc-minute, but at the focal length of your 76 it will be good enough for longer exposures than 30seconds. (unless you are in F12 mode with 1.7x extender?). I was using the handset PA routine at 1000mm FL and able to get 45 to 60 second subs unguided on a good night, perhaps 90seconds or so with a 500 or 600mm FL?



I've been taking some subs on the helix too, at 80mm F5 ish and 5min subs at gain 139 (unity on zwo) narrowband has been getting it done.



Good luck!
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Old 30-08-2020, 01:12 PM
Cliff (Clifford)
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Thanks Lewis,

Seems exposure time is the key thanks , Polar alignment is a problem here.
Tried Sharpcap with my iPolar and yesit is recognised but all I can see is tree branches.
Maybe I need to talk to my rear neighbour to cut down the tree but is a home to birds and possums.

Tried two nights and similar results so guess I might have to go somewhere else or try a different position not much room in a Villa. Pergola takes up 3/4 of the back.

Cheers
Cliff
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Old 30-08-2020, 01:21 PM
Cliff (Clifford)
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Thanks,

Only using the native focal length at 570mm .

How do I polar align using the handset ? Not using the Synscan at the moment
Oh by the way I am using the Celestron Starsense and Celestron Handset and GPS.
I am remoting it from inside using a INtelNUC at the scope. Remote desktop on my Mac.
More trial and error I guess
Appreciate the feedback good luck on your Helix. I was going to try some Ha with my OSC but it was even less defined.
Cliff
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Old 31-08-2020, 12:51 PM
Cliff (Clifford)
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Well a bit better last night actually got colour 60sec exposure polar aligned with a compass using the offset for true south mostly round stars.

Also got reasonable NGC 253 Sculptor Galaxy also 60sec

Still learning, i guess you never stop learning thats what I like about technical hobbies

Cliff
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Old 31-08-2020, 06:24 PM
etill (Elliot)
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There's a number of software options to assist with polar alignment. Sharpcap and PHD2 both have tools to help which dont require visibility of the SCP.

I also used a manual method with my DSLR intially which worked quite well but could be a little time consuming. Search for DARV polar alignment.

Even if you're not guiding with PHD2 you may be able to use some of the alignment tools to help out since that option is free.
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Old 31-08-2020, 06:33 PM
raymo
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DARV is actually pretty good once you are up to speed with it. It is especially good if you are able to leave your rig in place between sessions, and only need a confirmatory check.
raymo
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Old 31-08-2020, 09:36 PM
Cliff (Clifford)
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Thanks Elliot haven't tried guiding yet next thing to try, I did use a app on my old iphone called Polar Scope Align Pro works ok if I am away from the metal fence and Pergola. I have it on a dovetail bar with a phone holder .
I tried the polar alignment in Sharpcap but there is a tree right in line.Not tried PHD will take a look.
I have APT so could try DARV as well.
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Old 31-08-2020, 09:39 PM
Cliff (Clifford)
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Thanks Raymo

Well I tend to leave the rig in place a few nights if the weather allows so DARV might be worth a try.
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Old 26-07-2021, 05:11 PM
Cliff (Clifford)
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I know this is an old thread not sure anyone is monitoring it

But about 1 year later , learnt a lot ! Starting to understand guiding.

6 x 5min Subs UHC-S filter

So not a half bad image I think for 30min

Used a ASI533mc Pro camera and a F5 scope .

Cliff
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Old 26-07-2021, 05:15 PM
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Sunfish (Ray)
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Looks good for 30 min.

The Helix is fairly faint and difficult to extract the full range of colour and detail over that time so you are doing well.
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Old 26-07-2021, 07:16 PM
Cliff (Clifford)
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Thanks Ray, a big improvement on my original a year back. No calibration frames used either ! A lot of that is down to the 533 camera no amp glow.
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Old 26-07-2021, 10:06 PM
AdamJL
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That doesn't look good for 30mins, it looks incredible. I shot it a week ago for 6 hours. It was a noisy mess (3min subs).
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Old 26-07-2021, 10:15 PM
raymo
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Good job Clifford, onward and upward.

By the way, did you ever try DARV?
raymo
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Old 27-07-2021, 08:07 AM
Cliff (Clifford)
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Thanks Adam,

Maybe the 533 and the 106 are a good combo. I can't really do extra long exposure runs due extremely limited sky back of the Villa.
Started trying Mono with a 163M same sensor as a 1600mm but early days.
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Old 27-07-2021, 08:12 AM
Cliff (Clifford)
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Quote:
Originally Posted by raymo View Post
Good job Clifford, onward and upward.

Thanks raymo

By the way, did you ever try DARV?
raymo
You have a good memeory
I had a go but the best thing I did was change mounts from a AZEQ6GT to a Vixen SXD2 , I worked out a way with a compass and some string to get pretty close to Polar Alignment. A spirit level for the AZ set.

Cliff
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Old 27-07-2021, 09:13 AM
Startrek (Martin)
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Cliff,
You have a great image there for a very difficult target. The Helix does require a few hours to expose good depth and detail. Also best to image it in the dark with no moon around
As far as polar alignment goes , Iíve been using the Synscan polar alignment routine which comes with all Skywatcher EQ and EQAZ mounts using the handset and my DSLR with BYEOS on the laptop for over 4 years now and get below an arc minute every time, takes me 5 or 10 minutes.( I donít use the DSLR for imaging, I just use it for polar alignment as BYEOS has a really good live view , and the DSLR has no lag like an astronomy camera ) You can use any software with ďlive viewĒ on the screen with a cross hair feature or target reticle to make star alignment and polar alignment easy.
You donít need a view of the South Celestial Pole just a view of the East to South from 35 degrees to 65 degrees in Alt with 2 bright stars within 40 or 50 degrees in Azimuth apart ( closer to the south meridian line will produce quicker and better PA results )
The Synscan method is an often forgotten method as folk go for recent Polemaster or other similar methods that require a view of the Pole area. Not everyone has a view of the Pole , me included. Synscan is just as accurate and itís free , itís on your handset ( if your mount has a Synscan version older than V3 you may have do an update, just check the handset for the polar alignment routine )

Anyway Iíll attach the procedure if your interested. When first using it ovr 4 years ago it took me 20 of 30 minutes to get the error down below 1 arc minute and now after years of using this method it only takes 5 or 10 minutes to get down below an arc minute

Hope the above and attached help in some way

Cheers
Martin
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Old 27-07-2021, 11:07 PM
Cliff (Clifford)
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Thanks Martin,

Appreciate the encouragement, my pics are here full size if you care to have a look https://telescopius.com/profile/cliff

I basically do EAA with Sharpcap and capture the Raw frames to process later sought of like the live stacking amazing what the camera sees when I can see but a few stars.
Especially like to leave the scope outside and come back inside from the cold or mosquitoes , I use an intel Nuc with Win10 at the mount and remote desktop on my Macbook pro.

I actually have BYEOS but never tried it with the AZEQ6 when i had it.

Well just sold my Skywatcher mount so no Synscan polar alignment for me.
Don' think the Vixen has anything like that.

Having fun and games with the QHY163M Mono camera think I need flat frames , a new learning experience !

Cliff
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