So, Monday night just past we finally had a short break in the weather so, out with my newly acquired CG5 Adv GT EQ mount to have a go at my first Polar Alignment & snap some simple pics from my piggy back mounted camera to see what the tracking was like...
It was a good learning experience; some silly mistakes, some impatience, some 'couldn't be bothered' but all in all a good learning experience.
Stupid stuff I did & shouldn't have done:
1. Noticed my azimuth peg was loose when I set the tripod up & didn't fix it up before putting the mount on.... azimuth adjustment was more difficult than it needed to be.
2. Used a handset with a suspect RJ connector; had just finished alignments & was halfway through calibration stars when the handset pulled out.. had to start from scratch... This made me frustrated & impatient which led to more issues.
3. After point two, I became sloppy with my alignments & calibration stars.. this obviously had a detrimental effect on my later processes.
4. Probably wasn't as precise with my polar alignment as I should have been.. I was sweating profusely (temp up here was about 32* at night with 87% humidity) & I'd just about had enough... more patience grasshopper.
The good stuff:
1. I did achieve a polar alignment & on spec, the results weren't horrid. Will require more precision & patience if I'm to get it to a decent standard.
2. Did manage to get some simple test snaps with my piggy back mounted DSLR; there are trails but, I was pushing exposure times a fair bit to see what would happen so, still got something out of it.
What will I do next:
1. Make sure I pay more attention to some of the little stuff. When I began taking more care with my alignments on my Alt/Az mounted LX90, the nights viewing became way better as gotos were more precise & I spent more time viewing & less time searching.
2. Be more precise with alignments, calibrations & PA; use a more suitable eyepiece for centreing stars. Then rinse & repeat to refine the pool of errors before settling in for test images.
3. Stop messing around trying to push the exposure lengths & ISO settings... I've already been told 1600 is the sweet spot for this camera so, pay attention Carlton!!
4. Limit my exposure times to sub 60 seconds & see what works
5. Maybe try a smaller focal length lense on the camera; they way it's mounted it's a bit prone to vibration with a 55 - 250mm zoom hanging of the front.
6. Work on my focusing...
Pics attached, focus is not spot on & there are definitely star trails but, they are consistent & seem to be in the RA tracking which, was where my largest number was after the PA.. Shots range from about 40 sec to 120 sec, ISO's between 800 & 1600, targets were Sirius (to the west at about 58* alt, M42 & Canopus to the South at about 48* alt). I took more shots but, there is some obvious vibration artefacts in some & the others don't really show any more or any less than these ones do...
Fix one thing at a time, so that that thing works every time, and soon becomes second nature.
Start with focus; tight stars and sharp features look good, and encourage
you to persevere.
Polar alignment, needs to be as good as you can get it without being
obsessive about it. Obsession with any part of AP robs you of enjoyment
and your sense of achievement, and just ends up with frustration.
Add bells and whistles one at a time, and get used to them before adding
more.
Don't try to walk before you can run[unless you are a genius].
Don't expect the road to fine images to be easy[unless you are a genius].
Don't get tunnel vision regarding techniques/ hardware/software. If you
are really happy with something, by all means stick with it, but keep your eyes open, technology is moving forward quickly.
Decide whether you are going to aim high and eventually produce high
quality results, or aim for mid level quality, or perhaps not much more than stick your toes in the water, and produce mediocre results which never the less satisfy you.
This decision is important, because it will guide your equipment purchases,
and it will make you think about your budget. To produce very fine images
is a costly exercise.
Tell us what method of focusing you are using, and ditto with PA, and
somebody will help you with those things if necessary.
raymo
My main focus at present is mastering my EQ mount & getting my Alignment & PA as tight as I can without becoming totally obsessed; I agree, obsession ruins enjoyment.
I use the all star polar align that is part of the Celestron options in the handset. Once I have that as good as I can get it, I may move on to the Sharpcap application to further refine. I have the software, I haven't used it as yet.
At present, I just want to see improvement.. I don't really have and end state in mind but, I don't plan to go overboard on expenditure either. I will probably purchase a reasonable (Read: TS Optics or similar doublet) 80 - 100mm APO within the next 12 months as I know the little Orion will produce false colour that I probably won't want to deal with. I know a triplet would be better but, the price becomes too much of a factor. I want to go the refractor path largely because it is compact, easy to transport & if I'm modest in my aperture then when we do travel I can pack it easily along with a bigger scope for visual work.. dependant on mode of travel.
I still intend to continue imaging with my SCT; it has limits being a fork mounted AZ/Alt but, as long as I work within those limits I can produce acceptable results & benefit from larger aperture, just shorter exposure times.
Camera wise; having seen your results, I will probably stick with my unmodded 1100d; the results you have produced & displayed here would satisfy me no end to be honest.
Definitely not a genius.. that's why I have paired back my approach & am just trying to take small steps & identify errors in one part of the process & correct before moving on.
My first goal is to produce some sharp images, short exposure with no trails; when I can achieve that, I will examine what my next step will be & probably seek further advice here.
On this note, is it worthwhile trying to find a 'bhatinov mask' for my dslr lens; I have seen them available on ebay fairly cheaply.. I already have one for my SCT & when I decide on what size APO, I will definitely get one for it. I have already learned that trying to focus by eye without a focus mask is pretty much a recipe for failure.
As always, thankyou for your input.. You are keeping me grounded & I really appreciate that..
Cheers
Quote:
Originally Posted by raymo
My suggestions gleaned from many years of AP.
Fix one thing at a time, so that that thing works every time, and soon becomes second nature.
Start with focus; tight stars and sharp features look good, and encourage
you to persevere.
Polar alignment, needs to be as good as you can get it without being
obsessive about it. Obsession with any part of AP robs you of enjoyment
and your sense of achievement, and just ends up with frustration.
Add bells and whistles one at a time, and get used to them before adding
more.
Don't try to walk before you can run[unless you are a genius].
Don't expect the road to fine images to be easy[unless you are a genius].
Don't get tunnel vision regarding techniques/ hardware/software. If you
are really happy with something, by all means stick with it, but keep your eyes open, technology is moving forward quickly.
Decide whether you are going to aim high and eventually produce high
quality results, or aim for mid level quality, or perhaps not much more than stick your toes in the water, and produce mediocre results which never the less satisfy you.
This decision is important, because it will guide your equipment purchases,
and it will make you think about your budget. To produce very fine images
is a costly exercise.
Tell us what method of focusing you are using, and ditto with PA, and
somebody will help you with those things if necessary.
raymo
Firstly, by all means keep using your SCT, but you won't get shorter exposure times, at f/10 it is very slow photographically. Being alt/az you are limited to 15-20 second subs before star rotation rears its ugly head. An f/6.3 reducer
would help things immensely, but are not cheap.[assuming that you don't already have one.]
It would appear that your polar alignment is not good[judging by your pics],
or something is slipping during the exposures.
Using the 55-250mm lens the stars should be round using 40-120sec subs.
raymo
I know I was sloppy with my alignment stars, calibration stars & to be honest with my PA... I was getting frustrated with my earlier dramas & I let it get to me & then got sloppy..
Interestingly, the numbers in the handset looked pretty reasonable but, the pictures tell a very different story.. that's why I took them because I knew they would show the actual results rather than just theoretical numbers.
I have an f6.3 & an f3.3 reducer for the meade, picked them up secondhand quite cheaply. The f3.3 is no good for the DSLR, spacing is around 35mm which is shallower than the sensor depth but, it does come to focus with my ZWO.
Next time out, I will apply the lessons I have learned & be more critical & precise with my alignment, calibration stars & PA & then probably do a second routine to refine the errors down. As stated in my first post, I should know better.. when I got the SCT I was sloppy with setup & alignment which ended up in a frustrating night of missing gotos, when I focussed on the little things & got them right, the nights viewing was much more enjoyable as I was hitting gotos in a 12mm EP....
It's all in the initial setup; a lesson I really should have etched in my brain by now...
I did notice when mucking around with my camera setup today that it wasn't as 'tightly mounted' as it should have been & it was rotating a little, that might account for some of the movement but, I suspect it has more to do with the PA.. I have since rejigged the camera mount & inserted a thin washer which was just enough to tighten it all up & still have the camera pointed forward...
Cheers
Quote:
Originally Posted by raymo
Firstly, by all means keep using your SCT, but you won't get shorter exposure times, at f/10 it is very slow photographically. Being alt/az you are limited to 15-20 second subs before star rotation rears its ugly head. An f/6.3 reducer
would help things immensely, but are not cheap.[assuming that you don't already have one.]
It would appear that your polar alignment is not good[judging by your pics],
or something is slipping during the exposures.
Using the 55-250mm lens the stars should be round using 40-120sec subs.
raymo
The star elongation was far in excess of what would have been experienced with poor alignment, much more likely that the camera was rotating very
slowly; this is often encountered when using ball joints, as I do with my nano
tracker.
raymo
In that case I might stick a camera in the back of the Orion to test my PA & tracking then.. might be more beneficial & certainly takes out any camera rotation out of the equation.
Your the second one to mention that might be the issue; came up in an offline discussion with another member earlier in the evening. He suggested using my ZWO in the 80mm ST to remove that possibility from the equation...
Thanks for that Raymo, I believe I might have a slightly amended plan for moving forward..
Quote:
Originally Posted by raymo
The star elongation was far in excess of what would have been experienced with poor alignment, much more likely that the camera was rotating very
slowly; this is often encountered when using ball joints, as I do with my nano
tracker.
raymo
Hi Carlton,
Like Raymo and Peter say.....Patience grasshopper.....
PA is vital. I was pretty rough with my PA for a while and also my scope wasnt quite square with my mount so my alignment was always a bit out. I'd do a visual and then a drift and it was out so I'd go back to a visual alignment not realizing it was out a bit so I'd start to get stretched stars.
Then it dawned on me it's not the scope that needs alignment it's the mount!!
It helps if the scope is spot on with the mount and that's why a drift alignment works because it picks up errors with the mount.
Also a bahtinov is a must. The screen on my 450d is tiny and without a mask there's no way I could get focus. I also got an app on my phone that I can conect my camera to my phone and with a bigger screen focus is easier.
At the moment im getting 2 minute unguided subs and only getting coma so I must be doing somthing right. http://www.iceinspace.com.au/forum/s...d.php?t=174169
Is was getting frustrated for a while until I went back to basics and stated learning from the Masters....
Now im trying to learn processing and thats another hurdle but with the years of expertise on this site and people willing to help it makes it so much easier
PS Have you tried nightscapes yet.
They're pretty easy and you get not too bad results.
They kept me going when all i was getting was washed out stripey stars!! http://www.iceinspace.com.au/forum/s...d.php?t=167819
Cheers
Andy
Hi Calton
May I suggest for starters do this.
Mount your camera direct to the mount...take away your counter weigths add jury rig something small ..tape on something☺
During the day line the cameramm up with the polar axis by looking to see that what is centered in your polar scope is what is centered in your camera with the mount in home position. At night have the mount pointing South as best you can.
At night dont switch on your mount as we dont want any tracking. Set iso to 100 choose bulb. We want a shot off the CSP☺
Take a long exposure of say 10 minutes (sit and catch your breath).
At the end look at your photo and you will have many arcs of star trails. Adjust the mount to get the trails centered.
Repeat until the center of your trails is in the center of your photo.
This should be pretty close to get you started. I do this for my widefields and is all I did until I got the pole master and even with pole master I do this to bring the stars into frame needed to use polemaster (I cant see squat thru the polar scope and so this gets me there).
I notice that even before I use pole master I have gotten pretty close.
For starters dont worry about your goto if you want to get something...
I dont use it cause I dont have trouble finding objects with just the guide scope.
Anyways I think this will get you a decent polar alignment for a wide field.
Next and most important remember to reset ISO☺ so easy to forget.
Now start the mount tracking and select a region to photograph.
Focus as best you can and take a test shot of say 10 seconds and ask if focus could be better. This will horrify camera lovers but I stick some blue tac on the lens body to hold it from moving..check focus again to make sure nothing moved..blow up your test shot and check focus is as good as it can be...take say a 60 second capture and check it blown up..if trails reduce it to 30 seconds..check again..reduce exposure until trails are negligable.
When happy take as many subs as you can...20 minutes worth at least maybe do an hours worth...put the lens cap on and take darks while you pack up or have a coffee...as many as you can but at least 20 ..whatever.
Do another batch at a little higher exposur maybe but dont overstep your limit.
This way you will get a decent result and get a handle on the overall process.
Look at your results and delete anything that does not look ok..no need to be to harse but drop the ones that had a cloud or a plane.
Stack in Deep Sky Stacker and get to know your way around it..select the opion to stack say 85% or 90% and play with the various settings on your final result...if that is the only software you have else dont play with the settings and process in Startools...have a play with whatever result in Gimp. It has a levels feature and a brightness contrast feature which is handy for starting out.
If you have photo shop even better as it has a dodge and burnbfeature that enables broghtning or darkening specific areas which I find really handy.
Both Deepsky Stacker and Gimp are free downloads and not trial versions.
Startools provide a trial version but I would not bother first up.
The polar may be off but if you can get decent stars with 30 seconds the mount not being absolutely perfect in PA you have a built in dither☺ and together with many subs and darks should manage noise and hot pixels.
This proceedure is the very basic but it will get you there...if you notice drift in a particular direction you can do a small adjustment on the mount mid stream...at least think to yourself..now the stars are drifting North so what should I do..do it a quarter turn and note the result in the next ten frames...I think doing this helps to get a feel for how to polar align...I have found even using pole master my stars drift a little North which I think is a refraction of atmosphere factor..my point is you think about what is going on...also balance of counter weights is often an issue...the mount can be perfectly balanced but the thing travels too fast West or hangs East until you move the counter weights to destroy your perfect balance.
Also I cant recall what camera lens you have but start with the lowest F/L in your kit..18 if you have it and take a batch and progressively increase your focal length...that way you get a feel for where the lens works well..an 70/200 may have a sweet spot at 100 for example...so in the future you know that your 70/200 lens really for your astro purposes a 100 mm lens☺.
And a good wide field is very satisfying but not as easy as it seems.
Now if you can get that down after you have got something to process introduce the goto but after you have your first batch...
Avoid your long fl scope in my view until you really know what you are doing and able to understand drift and balance etc...
Like the bass start simple...a solid simple beat is better than a complex beat that is not in time☺ do it good slow and slowly increase pace with practice and repetition.
Also I suspect you may need something in the way of dew hoods...there is a material like a wet suit or mouse mats which work really well for a camera lens even a small refractor...dew can sneek up on you so always keep an eye on your lens.
So that my 2 cents worth...hope you can use something there...and the star trail circle thing is a nice photo to have in ones collection even if you dont like the idea of finding PA that way.
All great information & advice thankyou Gentlemen...
I'll probably go for some shots through the refractor next time out, just to see if it was the camera rotating or not...
Just have to wait for the next clear night.. which could be a while according to current forecasts
Slowly, slowly I will get there... especially with the assistance of all the experience found on this forum.
Cheers
Quote:
Originally Posted by raymo
Make sure that your R.A. and Dec clutches on the mount are securely tightened.
raymo
Quote:
Originally Posted by mynameiscd
Hi Carlton,
Like Raymo and Peter say.....Patience grasshopper.....
PA is vital. I was pretty rough with my PA for a while and also my scope wasnt quite square with my mount so my alignment was always a bit out. I'd do a visual and then a drift and it was out so I'd go back to a visual alignment not realizing it was out a bit so I'd start to get stretched stars.
Then it dawned on me it's not the scope that needs alignment it's the mount!!
It helps if the scope is spot on with the mount and that's why a drift alignment works because it picks up errors with the mount.
Also a bahtinov is a must. The screen on my 450d is tiny and without a mask there's no way I could get focus. I also got an app on my phone that I can conect my camera to my phone and with a bigger screen focus is easier.
At the moment im getting 2 minute unguided subs and only getting coma so I must be doing somthing right. http://www.iceinspace.com.au/forum/s...d.php?t=174169
Is was getting frustrated for a while until I went back to basics and stated learning from the Masters....
Now im trying to learn processing and thats another hurdle but with the years of expertise on this site and people willing to help it makes it so much easier
PS Have you tried nightscapes yet.
They're pretty easy and you get not too bad results.
They kept me going when all i was getting was washed out stripey stars!! http://www.iceinspace.com.au/forum/s...d.php?t=167819
Cheers
Andy
Quote:
Originally Posted by xelasnave
Hi Calton
May I suggest for starters do this.
Mount your camera direct to the mount...take away your counter weigths add jury rig something small ..tape on something☺
During the day line the cameramm up with the polar axis by looking to see that what is centered in your polar scope is what is centered in your camera with the mount in home position. At night have the mount pointing South as best you can.
At night dont switch on your mount as we dont want any tracking. Set iso to 100 choose bulb. We want a shot off the CSP☺
Take a long exposure of say 10 minutes (sit and catch your breath).
At the end look at your photo and you will have many arcs of star trails. Adjust the mount to get the trails centered.
Repeat until the center of your trails is in the center of your photo.
This should be pretty close to get you started. I do this for my widefields and is all I did until I got the pole master and even with pole master I do this to bring the stars into frame needed to use polemaster (I cant see squat thru the polar scope and so this gets me there).
I notice that even before I use pole master I have gotten pretty close.
For starters dont worry about your goto if you want to get something...
I dont use it cause I dont have trouble finding objects with just the guide scope.
Anyways I think this will get you a decent polar alignment for a wide field.
Next and most important remember to reset ISO☺ so easy to forget.
Now start the mount tracking and select a region to photograph.
Focus as best you can and take a test shot of say 10 seconds and ask if focus could be better. This will horrify camera lovers but I stick some blue tac on the lens body to hold it from moving..check focus again to make sure nothing moved..blow up your test shot and check focus is as good as it can be...take say a 60 second capture and check it blown up..if trails reduce it to 30 seconds..check again..reduce exposure until trails are negligable.
When happy take as many subs as you can...20 minutes worth at least maybe do an hours worth...put the lens cap on and take darks while you pack up or have a coffee...as many as you can but at least 20 ..whatever.
Do another batch at a little higher exposur maybe but dont overstep your limit.
This way you will get a decent result and get a handle on the overall process.
Look at your results and delete anything that does not look ok..no need to be to harse but drop the ones that had a cloud or a plane.
Stack in Deep Sky Stacker and get to know your way around it..select the opion to stack say 85% or 90% and play with the various settings on your final result...if that is the only software you have else dont play with the settings and process in Startools...have a play with whatever result in Gimp. It has a levels feature and a brightness contrast feature which is handy for starting out.
If you have photo shop even better as it has a dodge and burnbfeature that enables broghtning or darkening specific areas which I find really handy.
Both Deepsky Stacker and Gimp are free downloads and not trial versions.
Startools provide a trial version but I would not bother first up.
The polar may be off but if you can get decent stars with 30 seconds the mount not being absolutely perfect in PA you have a built in dither☺ and together with many subs and darks should manage noise and hot pixels.
This proceedure is the very basic but it will get you there...if you notice drift in a particular direction you can do a small adjustment on the mount mid stream...at least think to yourself..now the stars are drifting North so what should I do..do it a quarter turn and note the result in the next ten frames...I think doing this helps to get a feel for how to polar align...I have found even using pole master my stars drift a little North which I think is a refraction of atmosphere factor..my point is you think about what is going on...also balance of counter weights is often an issue...the mount can be perfectly balanced but the thing travels too fast West or hangs East until you move the counter weights to destroy your perfect balance.
Also I cant recall what camera lens you have but start with the lowest F/L in your kit..18 if you have it and take a batch and progressively increase your focal length...that way you get a feel for where the lens works well..an 70/200 may have a sweet spot at 100 for example...so in the future you know that your 70/200 lens really for your astro purposes a 100 mm lens☺.
And a good wide field is very satisfying but not as easy as it seems.
Now if you can get that down after you have got something to process introduce the goto but after you have your first batch...
Avoid your long fl scope in my view until you really know what you are doing and able to understand drift and balance etc...
Like the bass start simple...a solid simple beat is better than a complex beat that is not in time☺ do it good slow and slowly increase pace with practice and repetition.
Also I suspect you may need something in the way of dew hoods...there is a material like a wet suit or mouse mats which work really well for a camera lens even a small refractor...dew can sneek up on you so always keep an eye on your lens.
So that my 2 cents worth...hope you can use something there...and the star trail circle thing is a nice photo to have in ones collection even if you dont like the idea of finding PA that way.
Alex
Quote:
Originally Posted by xelasnave
If you want to use a scope you can still go the star trail way and it will be better of course.
Alex
