#1  
Old 28-09-2019, 09:21 AM
poider (Peter)
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Better photos

SkyWatcher Star Adventurer + Nikon D7200 + Sigma 150-500mm É/6.3 500.0 mm 231seconds ISO 100
https://flic.kr/p/2hmMQ1R
What Can I do with this equipment to improve my photos, or do I need to Upgrade?
Peter
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Old 28-09-2019, 10:15 AM
Saturnine (Jeff)
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Others will hopefully add their knowledge of taking astro photos with that mount but in the meantime I would start by changing the camera ISO to 800 or 1600 and taking shorter subs of 30 or 60 seconds and taking lots of them and then stacking them with software like Deep Sky Stacker.
The focal length you were using may be a bit much for the mount but shorter exposure times will help and having good polar alignment cannot be overestimated. Hope this advice will be of some help.
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Old 28-09-2019, 11:10 AM
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billdan (Bill)
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The Star Adventurer is a bit limited with its 5Kg max payload.

But it does have a guide port for better tracking in RA, however a guide scope and guide camera may push you over the payload limit. Plus you would need to have a laptop close by with PHD2 installed for the guiding.
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Old 28-09-2019, 12:26 PM
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500 mm FL is rather pushing it I would think...I would try it shorter, higher iso, my Nikon D5500 does well at 1600 , shorter exposures but as many as you can...I often go for 30 seconds iso 1600 around 125mm and that seems a sweet spot...and even if polar is off you probably get clear shots but as the frames are moving you are in effect dithering which together with many short exposures I find helps reduce noise greatly.
And you can stack only a couple to have a core shot to merge in..
Mainly keep doing it, each time better focus slightly different approach...and with lots of shirt exposures you can drop a lot of bad ones...stacking with quality brings quality.
Alex
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Old 28-09-2019, 04:08 PM
Sunfish (Ray)
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I have used the SA with an 800mm f8 lense that weighs 3.5 kg plus camera On M42. The 400mm f4 too.

Worked ok if the polar alignment is good and the exposure time is limited to 40 sec or less. Good to travel with for wide angle. I use iso 400 as my noise is less at 400 but 800 works. The SW polar clock utility on your phone is helpful as you do not need to use the polar scope time settings.
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Old 28-09-2019, 06:34 PM
Sunfish (Ray)
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Here are two single 20 sec subs of M42 with some stretching and smoothing in PS on the SA . The first with an 800 F8 lense and the second with a 400 F4 lense and DSLR. Both iso400.

It is better if you can mean stack at least ten of these as mean smart object stacked layers aligned in PS or in DSS. So maybe 20sec is better for such a bright object.
Attached Thumbnails
Click for full-size image (IMGP4268Orion 800 400 20sec PS.jpg)
231.9 KB35 views
Click for full-size image (Orion 400 F4 20 sec astro PS.jpg)
201.5 KB35 views
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Old 28-09-2019, 07:46 PM
Mickoid (Michael)
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Peter, I'm not sure if your Flickr link goes to the correct page as when I look at your picture it seems like it's just a thumbnail of your shot. It's hard to establish the quality from this but the stars appear to be quite round so if that's the case, nearly 4 mins at 500mm focal length is pretty dam good. I can see some of the outer nebulosity appearing and the core is blown out. Maybe reduce your exposure to 120 seconds, increase your ISO to 800 and shoot about 40 or 50 of them. Also expose another 20 or so at 10 to 20 seconds to capture detail in the core. You can process these two exposure values separately in DSS and combine them in Photoshop to produce a dynamic range that reveals the dim and bright areas together that show equal detail.
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Old 29-09-2019, 02:23 AM
Ukastronomer (Jeremy)
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Practice practice practice........ simple

Only a poor workman blames their tools
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Old 29-09-2019, 01:48 PM
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Icearcher (Chris)
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Hi Peter

That's actually a really good shot for 231 seconds. I think you have a really good unit, mine doesn't perform close to that well.

If you can consistently get a good % of keepers with what you are currently doing then maybe drop the exposure time to something like 120 or 180 seconds and up the iso to around 800 and stack as many as possible.

If you had the funds, I would suggest a guiding setup. It helped me go from under 60sec @380mm to getting 100% keepers at 300secs now. It does make the whole setup less grab-and-go but I wouldn't be without it these days.

As an extra, a guide setup would also allow you to use sharpcap (or similar) for your polar aligning, I can get PA done in a couple of minutes these days and its an order of magnitude more accurate than eyeballing it or drift aligning.

Regards
Chris
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Old 29-09-2019, 07:23 PM
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Atmos (Colin)
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Having owned a Nikon D7200 I after some testing of the camera I found.
- The lowest native ISO 100? is great if you can do longer exposures.
- ISO 400 was the best all round and what I usually used myself.
- ISO 800 is the max that's worthwhile. There is very little change from ISO 400 to 800 and nothing after ISO 800 apart from a decrease in dynamic range.
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Old 30-09-2019, 06:52 AM
poider (Peter)
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Quote:
Originally Posted by Saturnine View Post
Others will hopefully add their knowledge of taking astro photos with that mount but in the meantime I would start by changing the camera ISO to 800 or 1600 and taking shorter subs of 30 or 60 seconds and taking lots of them and then stacking them with software like Deep Sky Stacker.
The focal length you were using may be a bit much for the mount but shorter exposure times will help and having good polar alignment cannot be overestimated. Hope this advice will be of some help.
I have tried stacking but seems to get less than the single exposure, will try shorter and see how i go
Thank you
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Old 30-09-2019, 06:53 AM
poider (Peter)
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Quote:
Originally Posted by billdan View Post
The Star Adventurer is a bit limited with its 5Kg max payload.

But it does have a guide port for better tracking in RA, however a guide scope and guide camera may push you over the payload limit. Plus you would need to have a laptop close by with PHD2 installed for the guiding.
Donít have a laptop for outdoor and funding for guidance, not yet anyway
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  #13  
Old 30-09-2019, 12:05 PM
poider (Peter)
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Quote:
Originally Posted by Atmos View Post
Having owned a Nikon D7200 I after some testing of the camera I found.
- The lowest native ISO 100? is great if you can do longer exposures.
- ISO 400 was the best all round and what I usually used myself.
- ISO 800 is the max that's worthwhile. There is very little change from ISO 400 to 800 and nothing after ISO 800 apart from a decrease in dynamic range.
Thank you Atmos
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  #14  
Old 30-09-2019, 12:11 PM
poider (Peter)
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Quote:
Originally Posted by Icearcher View Post
Hi Peter

That's actually a really good shot for 231 seconds. I think you have a really good unit, mine doesn't perform close to that well.

If you can consistently get a good % of keepers with what you are currently doing then maybe drop the exposure time to something like 120 or 180 seconds and up the iso to around 800 and stack as many as possible.

If you had the funds, I would suggest a guiding setup. It helped me go from under 60sec @380mm to getting 100% keepers at 300secs now. It does make the whole setup less grab-and-go but I wouldn't be without it these days.

As an extra, a guide setup would also allow you to use sharpcap (or similar) for your polar aligning, I can get PA done in a couple of minutes these days and its an order of magnitude more accurate than eyeballing it or drift aligning.

Regards
Chris
Ok thank you, auto guiding is out of reach now but maybe future purchase
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Old 30-09-2019, 12:15 PM
poider (Peter)
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Quote:
Originally Posted by Ukastronomer View Post
Practice practice practice........ simple

Only a poor workman blames their tools
Agreed, i am just curious if I am getting close to where i need to be before I upgrade or can i get much more form what i have.
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Old 30-09-2019, 12:20 PM
poider (Peter)
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Quote:
Originally Posted by Mickoid View Post
Peter, I'm not sure if your Flickr link goes to the correct page as when I look at your picture it seems like it's just a thumbnail of your shot. It's hard to establish the quality from this but the stars appear to be quite round so if that's the case, nearly 4 mins at 500mm focal length is pretty dam good. I can see some of the outer nebulosity appearing and the core is blown out. Maybe reduce your exposure to 120 seconds, increase your ISO to 800 and shoot about 40 or 50 of them. Also expose another 20 or so at 10 to 20 seconds to capture detail in the core. You can process these two exposure values separately in DSS and combine them in Photoshop to produce a dynamic range that reveals the dim and bright areas together that show equal detail.
Thank you, I am going to have to learn how to use DSSi think as all i have been doing is load in the darks, lights, flats and Bias frames and pressing process, there is obviously more to be done
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Old 30-09-2019, 12:22 PM
poider (Peter)
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Quote:
Originally Posted by Sunfish View Post
I have used the SA with an 800mm f8 lense that weighs 3.5 kg plus camera On M42. The 400mm f4 too.

Worked ok if the polar alignment is good and the exposure time is limited to 40 sec or less. Good to travel with for wide angle. I use iso 400 as my noise is less at 400 but 800 works. The SW polar clock utility on your phone is helpful as you do not need to use the polar scope time settings.
What is the SW polar lock utility? Please
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Old 30-09-2019, 12:25 PM
poider (Peter)
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Quote:
Originally Posted by xelasnave View Post
500 mm FL is rather pushing it I would think...I would try it shorter, higher iso, my Nikon D5500 does well at 1600 , shorter exposures but as many as you can...I often go for 30 seconds iso 1600 around 125mm and that seems a sweet spot...and even if polar is off you probably get clear shots but as the frames are moving you are in effect dithering which together with many short exposures I find helps reduce noise greatly.
And you can stack only a couple to have a core shot to merge in..
Mainly keep doing it, each time better focus slightly different approach...and with lots of shirt exposures you can drop a lot of bad ones...stacking with quality brings quality.
Alex
I will see what i can do when next i can.
Thank you
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Old 30-09-2019, 07:53 PM
Sunfish (Ray)
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The Star Adventurer Mini Console I think is the official title of the app which is available for Android here and there is an IOS version which I just checked on the App Store.

https://skywatcher.com/download/soft...ar-adventurer/

Designed to connect to the Star Adventurer Mini [SAM] but the useful thing for me is polar clock utility which shows an image of the Octans stars as they would appear in the polar scope at the current time on your phone with a reasonable dark mode.

As attached: So you can align by judging the correct location of the octans polar stars in the scope without having to have the time settings on the polar scope adjusted or see the diagram of the Star asterism markings which can be difficult.




Quote:
Originally Posted by poider View Post
What is the SW polar lock utility? Please
Attached Thumbnails
Click for full-size image (6DAD8D99-BD6B-4725-84BB-32C40B79B5C5.png)
107.4 KB14 views
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Old 01-10-2019, 06:54 PM
poider (Peter)
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Quote:
Originally Posted by Sunfish View Post
The Star Adventurer Mini Console I think is the official title of the app which is available for Android here and there is an IOS version which I just checked on the App Store.

https://skywatcher.com/download/soft...ar-adventurer/

Designed to connect to the Star Adventurer Mini [SAM] but the useful thing for me is polar clock utility which shows an image of the Octans stars as they would appear in the polar scope at the current time on your phone with a reasonable dark mode.

As attached: So you can align by judging the correct location of the octans polar stars in the scope without having to have the time settings on the polar scope adjusted or see the diagram of the Star asterism markings which can be difficult.
I don't have the mini so i don't think that the star adventurer pro can connect
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