The whole affair was a struggle - getting the new HEQ5 aligned (via the 3-star setup on the hand controller) took forever. Even after multiple attempts (and parking the scope in between each attempt) I had an error that was measured in arc-minutes.
Given the moon was due to rise, I slewed to M8 and fired off a long sequence of frames.
Reviewing them, the tracking was way off and I could see that the stars walked halfway across the camera sensor over a 45 minute period. (More learning on setup and alignment required!)
They stacked OK with Sequator (Siril stacked them well but totally over-exposed the stars - although that's probable me not knowing what I was doing when doing the stretching. More learning required!)
So here you go - my first attempt at M8.
Comments, feedback, etc gratefully received.
Cheers,
V
Martin - I have d/loaded your alignment guides from a different thread and will go over them (again) before dragging the mount out next time.
Steve,
The mounts probably tracking ok at sidereal rate but your polar alignment is way off causing drift and elongated Stars
Apart from PA at least you found M8 , framed it up and captured a respectable image
Just need to tighten up your PA and you should be off and running ....
I’ll send a bunch of procedures from setting up the tripod and mount to polar alignment again
Well I really think you have done an excellent job.
My tip and this is general and not prompted by anything that has worried me that I could see in your image...is to always look at your first couple of exposures just to check they are "still" in focus and how the trailing is going..sometimes you need to just give up on getting polar perfect and just reduce your exposure time so the trailing becomes less or un noticable. Now me having the stars walk across the screen is a good thing and I call it auto dithering..strictly its not good dithering but I say that to remind you that it really is suposed to be fun and we both know that is very easy to forget.. I am known to break the rules with gain for example but my short cuts are usually prompted by finding something is not really working as it should tracking seeing or what ever so I just bang out something and have fun taking the results thru the process and making the best out of the mess that I can ...
And you know when that perfect night is happening so the time spent on "funny" nights becomes worth it...and much the same with processing..dont necessarily expect a "good" result as Most important is each time you build your skill..the result even if crook builds skill..and temper that with you learn by mistakes you can keep it as a fun experience...look at what goes wrong and laugh.
Now all my mistakes and high gain tom foolery has me expert in correcting stuff in photo shop..not good for the Marlins but a useful skill and just so much fun.
Thanks for posting .
I really like your image and frankly hope I can do as well if this rain ever stops,
Alex
Great M8.
Lots of depth and colour.
Polar alignment is hard if you do not have good dark sky to the south but that is ok on shorter shots.
Have you tried Deep Sky Stacker which can stack camera raw , fits or other files accurately with some dark files.?
Better perhaps for stacking.
Which camera / lense / scope combination is that?
Thanks for the words of support and encouragement. I look at the images presented by other forum members and am always impressed with how stunning they are. You all give me inspiration to work harder at this and to get better.
For this image of M8, I had:
EvoStar 72ED + Reducer
HEQ5-Pro
Nikon D7100
Unknown Bortle level, but lots of light pollution
200 subs at ISO 800, 13 seconds exposure
50 darks
Ray - I have a Mac machine for my editing & processing, so that counts Deep Sky Stacker out. (I have Sequator running inside 'CrossOver', a sort-of Windows emulator / runtime and it works well. DSS refuses to play with CrossOver.)
As someone else mentioned - getting flat frames and bias frames will help a lot with calibration. I'll try to get them next time, too.
Polar alignment in the polar scope is the main thing and getting ready at dusk to go as soon as octans is visible.
You could trial Astro Pixel Processor which runs in Mac and which will stack and add dark, bias frames etc. takes a little longer but is a complete package cheaper than PI.
Quote:
Originally Posted by AstroViking
Hello all,
Thanks for the words of support and encouragement. I look at the images presented by other forum members and am always impressed with how stunning they are. You all give me inspiration to work harder at this and to get better.
For this image of M8, I had:
EvoStar 72ED + Reducer
HEQ5-Pro
Nikon D7100
Unknown Bortle level, but lots of light pollution
200 subs at ISO 800, 13 seconds exposure
50 darks
Ray - I have a Mac machine for my editing & processing, so that counts Deep Sky Stacker out. (I have Sequator running inside 'CrossOver', a sort-of Windows emulator / runtime and it works well. DSS refuses to play with CrossOver.)
As someone else mentioned - getting flat frames and bias frames will help a lot with calibration. I'll try to get them next time, too.
Steve,
Just to point out that the Synscan PA routine doesn’t require a view of the Pole, just 2 stars either on the east side or 2 stars on the western side of the meridian ( closer to the Pole the better ) that meet the requirements in my attached procedure
Not sure if you have clear line of sight of the pole, if you do you can choose other methods to polar align using the polar scope for visual alignment or a device called Polemaster which replaces the polar scope for a camera ( $450 ) or Nina which is similar to Synscan or just stick with Synscan as it’s installed in your hand controller.
All methods require different levels of skill during iterations with fine adjustments
Cheers
Martin
I was out again tonight, trying to get things working. I managed to get out and set everything up before dusk - had a compass to get the mount aligned to within 1 degree of south, and levelled as well.
But could I get the thing aligned? Nope. I have visibility of Octans on a clear night, so that should be the go. Right? Tried the polar scope, but couldn't see a single star through it. (Yes, I did turn the Dec by 90 degrees, and shining a light down the hole showed I had a clear line of sight.) The light pollution was worse tonight, so that probably stopped me seeing anything.
Tried 2-star alignments via the SynScan controller, tried a couple of 3-star alignments, and consistently had errors in the arc-minutes, and even degrees at one stage. Eventually I got something that appeared to be reasonable. I had those stars dead-set in the centre of the field of view.
I tried imaging NGC3532 (The Wishing Well Cluster) but the stars were egg-shaped and walked off the edge of the camera sensor.
For fun, I tried slewing to various random 'Named Stars' via the controller. Some were exactly in the middle of the camera, some weren't within my field of view, and some were sort-of there.
I thought this thing was supposed to work out where it was pointed and track accordingly?
I have a PoleMaster, but need to get my hands on a laptop to run it.
Right now I'm just frustrated and annoyed. (I tried channeling Alex and seeing it as a learning experience, but it didn't go so well...)
Hi Steve- hang in there mate! Your images are already coming along quite nicely and you should be very proud of the results so far! I find that I go a bit crazy if I spend more than a clear night or 2 in a row trouble-shooting so I make sure to try and pick just one area to improve on each month, and wherever that gets me, enjoy the time under the stars when I can get it.
Getting your PA right is a big hurdle, and I can also recall my own initial frustrations and failed attempts at first- but it is a worthwhile endeavour and I’m certain it’ll click for you soon. Once you work it out, it’ll be much much easier each setup. I’ve also found that poor sky conditions can make manual alignment very difficult, so definitely take advantage of the technology you have. Polemaster runs on Mac so perhaps that might be a good option for you to consider.
Regarding other processing software for Mac:, Astro Pixel Processor (APP) provides stacking and basic processing, and Startools and PI both operate on Mac too. APP has a free one month trial that gives unlimited use, while Startools has an unlimited trial with restricted exports. I would absolutely recommend APP on Mac for stacking.
Steve,
Firstly eye balling polar alignment Star centering on a DSLR flip screen or eye piece is a waist of time
You really need a laptop screen and a program that has polar alignment feature like ( in your case ) “Backyard Nikon”. I use Backyard EOS and my Canon 600D with a 5m cable to my Laptop ( even though I image with a $3500 camera , the ZWO 2600MC , I still use my old Canon 600D to polar align, never lets me down and DSLR’s have a much better live view than dedicated Astro cameras. Astro camera have too much delay or buffer etc..,
The live view on BYEOS is unbelievable and there a zoom function for super close in accurate Star centering using the polar alignment reticle crosshair. Sometimes when conditions are average I defocus a bit so my stars are a donut which also helps centering.
Backyard Nikon supports your Nikon 7100
Secondly aligning your mounts tripod to magnetic south will inevitably take you a long way from the pole , maybe 1 to 3 degrees ( 1 degree is a long way )
I use the solar moon shadow method ( attached in my previous post ) and after setting up the tripod and rig , generally I’m usually 10 to 12 arc minutes off after my first iteration. Second iteration I’m around 1 to 2 arc mins and third iteration sub arc min depending on sky conditions
I don’t know why your using 2 and 3 star alignments , just use a 2 star alignment followed by your PA routine
At the moment between 7pm and 9pm I’d use the following Stars ( Atria as your first alignment Star and also your PA star and Hadar as your second alignment Star )
Atria is fairly close to the Pole so a good choice as your PA Star
After you complete a 2 star alignment using firstly Atria then Hadar , choose Polar Alignment from the menu and scroll through and select Atria. After the mount slewed to nearby Atria you will have to centre Atria then press enter. ( you may have to find Atria in your finder scope as it may be out of normal camera view) The mount will slew away from Atria ( how far is dependent on how much your PA is off ) , it will then ask you to use the Altitude bolt to re centre Atria. Get it centred as close as you can using the Altitude bolts and remember that position ( I usually take a photo with my iPhone ) Press enter and it slew away again and then ask you to adjust the Azimuth bolts to centre Atria again as close as possible to the previous Alt position and press enter. Now go back to Star Alignment in the menu and perform another 2 star alignment on same Stars Atria then Hadar, once completed press enter and it will show your PA error in degrees, min , sec ( 000:00:00 ) This is one complete iteration. It may take 2 , 3 , 4 or even sometimes 5 iterations to get below and arc min ( it all depends on conditions) The closer your PA becomes the more accurate your alignments become and the quicker Star centering becomes.
Backyard EOS and Backyard Nikon were specifically designed for DSLR astrophotography and I think have the best “polar alignment” target window , so accurate and easy to use ( the zoom box is fantastic)
Yeah, apologies about the venting when I posted that. Was really, really frustrated that nothing went right last night.
Thanks very much for the instructions Martin. I'll give them a try next time I'm outside. My biggest issue is knowing which star is where in the sky and then trying to find them. As they say, "Space is big."
I'll check out BackYardNikon and see how it goes. I've heard the name kicked around on other forums, so it's not totally unknown to me.
With regards to my using a compass to align the mount, it's an app on my phone. I know it gives me a true South reading, as I was using it with my Star Adventurer to get the polar scope lined up with Octans.
Thanks again for all the support - it's much appreciated.
Yeah, apologies about the venting when I posted that. Was really, really frustrated that nothing went right last night.
Thanks very much for the instructions Martin. I'll give them a try next time I'm outside. My biggest issue is knowing which star is where in the sky and then trying to find them. As they say, "Space is big."
I'll check out BackYardNikon and see how it goes. I've heard the name kicked around on other forums, so it's not totally unknown to me.
With regards to my using a compass to align the mount, it's an app on my phone. I know it gives me a true South reading, as I was using it with my Star Adventurer to get the polar scope lined up with Octans.
Thanks again for all the support - it's much appreciated.
Cheers,
V
Hi Steve, in regards to finding where stuff is download Stellarium to your phone, tablet or pc and this will be a big help (I'm sure Martin will recommend the same as I know he is an avid user). This is an excellent application free to pc and cheap for phone or tablet.
Cheers, Richard
Yeah, apologies about the venting when I posted that. Was really, really frustrated that nothing went right last night.
Thanks very much for the instructions Martin. I'll give them a try next time I'm outside. My biggest issue is knowing which star is where in the sky and then trying to find them. As they say, "Space is big."
I'll check out BackYardNikon and see how it goes. I've heard the name kicked around on other forums, so it's not totally unknown to me.
With regards to my using a compass to align the mount, it's an app on my phone. I know it gives me a true South reading, as I was using it with my Star Adventurer to get the polar scope lined up with Octans.
Thanks again for all the support - it's much appreciated.
Cheers,
V
Glad to help
I needed a lot help too back in 2017 but eventually got there
If you choose those 2 stars Atria (1st alignment Star and polar alignment Star ) and Hadar ( 2nd alignment Star ) it should make a huge difference in getting your PA error down after each iteration
Also phone apps do not indicate True South ( only magnetic South) they are entirely different. Some apps give you the magnetic declination Offset for True South but again they are not correct. Magnetic South is a moving target. True South doesn’t change , only after a few thousand years
I placed my iPhone compass app on the ground where I have my permanently scored “True South” line along the pavers and its way out every time and gets worse as you project your line further along due to the angular difference.
If you have a permanent position you will use each time , I strongly recommend you use the solar noon shadow method and score a permanent thin line on the ground or if on grass some marker stakes etc.. it’s going to safe so much time when you set up and polar align, believe me , it’s worth the effort , takes 10 mins to set up and then pick a sunny day to wait for solar noon. I used the same method at both my imaging sites , Sydney and South Coast NSW in my Dome, the more accurate you are with doing it the more accurate your first slew will be. All my first star alignment slews are well within the FOV of my cameras ( I never need a finderscope.
Glad to help
I needed a lot help too back in 2017 but eventually got there
If you choose those 2 stars Atria (1st alignment Star and polar alignment Star ) and Hadar ( 2nd alignment Star ) it should make a huge difference in getting your PA error down after each iteration
Also phone apps do not indicate True South ( only magnetic South) they are entirely different. Some apps give you the magnetic declination Offset for True South but again they are not correct. Magnetic South is a moving target. True South doesn’t change , only after a few thousand years
I placed my iPhone compass app on the ground where I have my permanently scored “True South” line along the pavers and its way out every time and gets worse as you project your line further along due to the angular difference.
If you have a permanent position you will use each time , I strongly recommend you use the solar noon shadow method and score a permanent thin line on the ground or if on grass some marker stakes etc.. it’s going to safe so much time when you set up and polar align, believe me , it’s worth the effort , takes 10 mins to set up and then pick a sunny day to wait for solar noon. I used the same method at both my imaging sites , Sydney and South Coast NSW in my Dome, the more accurate you are with doing it the more accurate your first slew will be. All my first star alignment slews are well within the FOV of my cameras ( I never need a finderscope.
Cheers
Martin
Oh forgot to mention
Skywatcher mounts like the HEQ5 can use EQMOD and Stellarium ( both free downloads ) to control the mount from your Laptop ( I use it on both my EQ6-R mounts and soon on my EQ8-R pro mount ) I also have procedures for these ( not sure about a Mac though ?? )
In any case Stellarium is a free download and it’s your road map to the night sky 24/7 year after year. Very intuitive and teaches you the layout of the night sky very quickly
I use it with EQMOD for Goto and navigation for imaging and also by itself for visual observing with my big 12” goto dob
I second that. Hard to know what you are looking at sometimes when the obvious ones are out of reach.
True that when the I have had trouble with octans being so faint , I have used the Polar alignment feature of Sharpcap . Any polar alignment feature you have access to will improve the result in regard to tracking.
If you are aligning a permanent set up drift align works but too time consuming for tripod work.
Quote:
Originally Posted by croweater
Hi Steve, in regards to finding where stuff is download Stellarium to your phone, tablet or pc and this will be a big help (I'm sure Martin will recommend the same as I know he is an avid user). This is an excellent application free to pc and cheap for phone or tablet.
Cheers, Richard
Thanks again for all the advice. I have some time off coming up, so will try that "Solar noon" alignment trick, Martin. I can't make anything too permanent in the concrete but I think discrete drill holes or globs of spray paint might be OK...
