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I'm a complete noob with imaging but am really methodical in approaching any hobby I pick up so I'm hoping that with a little practice I can someday take some amazing images for my own enjoyment.  Currently I'm having no end of trouble with my scope setup and was hoping someone could shed some light on what MIGHT be going on here.  I have a Nexstar 6se which uses spur gears I realize, but it's what I have.  I'm using a celestron 6/8se wedge on a cpc 1100 tripod which makes for a rock solid platform for this modest scope.  Movement calms down with this setup in under a second so I'm confident it's not the mount.  The problem though, when I get my camera on the scope, get things focused as well as I can without a mask (i'm working on getting one 3d printed), I'm getting trails no matter what I do!  I'm polar aligned, making very sure to use a high power eyepiece and really spend the time to line up my mount.  Any image longer than about 20 seconds however exhibit trails!  I've adjusted the backlash controls from 0 to 50 in 5 unit increments with no discernible results.  I've used A/C power as well as a 12 volt 20amp/hr battery so I don't believe it to be power related. 

This setup, with the heavy tripod, the wedge, a decent computerized mount should allow me to image for a couple of minutes at least in my mind, but I cannot get it to work properly for even super short exposures!  I'm wondering if this is something that can be adjusted with the mounts clutch or some other trick to get things working how they should.  The images I've attached show an extreme amount of error in tracking and I'm beginning to wonder if my particular mount is just not going to work no matter what!  The "trailing 3" image is of Albireo and you can see that the stars below this double are doubled themselves, meaning to me that the mount is skipping or jumping partway through the exposure (45 seconds in this case) Any help would be awesome.  

TRAILING 2.jpg

TRAILING 3.jpg

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The 6SE has too long a focal length and so any errors will display as trailing. Your focal length is something like 1500mm, a fast 500mm focal length scope is a better option. A scope I have that is suited to imaging is just under 500mm and that is without a reducer/flattener.

If there is not a polar scope on the wedge, never seen one with one but never looked, then accurate polar alignment is not easy and that adds to the errors. If you aimed the scope and viewed Polaris then you are 1 degree out, and so trailing at 1500mm focal length will occur.

The bottom line is the scope is not well suited to long exposure astro imaging. It can be done but the setup I have seen using an SCT has been on somewhet professional systems, and everyone has been on a permantent pier not a tripod. I guess the reason for that is to get the repeated accuracy.

Unless you get equipment specifically for imaging I would say to ignore the statements about taking photographs. Manufacturers have realised that people like images and so if a camera can be attached they "mention" this. Some say "to attach a DSLR", without mentioning that the optics forbid getting an image. But they did not mention getting an image just attaching a DSLR. If you look round someones imaging rig it is build up from individually purchased items, not a "package".

Not sure what to suggest, very accurate polar alignment is the first, very accurate location data, focal reducer, accurate setup (get it all level - reduce the errors that the scope needs to compensate for). Even then I would say that you are only going to get 30-60 second exposures. It is that focal length that is the problem. So do the setup bit very well and at this time go for 30 second exposures, likely a better option as it mean you can have a 30 second exposure then a 20 second cool down for the sensor. Take say 20 exposures then practise stacking. Even with a EQ and a short scope I tend to limit myself to 60 seconds, and often 40 second exposure and 20 second cooling.

One other often forgotten aspect is the 6SE was out several years before DSLR's were available. It was not designed to have close to 1Kg of weight hanging off one end.

How would you feel if I said keep the 6SE for visual. Buy a nice equitorial mount, and a short fast 70 to 80mm ED refractor with flattener and t-ring then use that to image with? Reason to keep the 6SE is to use it to view through when the imaging rig is getting multiple exposures. I know it seems a bit stupid but is likely to be the best solution. Forty exposures of forty second will take close to an hour to collect. 40 seconds for the exposure, 20 seconds for sensor cool down and a little extra, that comes to close on an hour.

What are the skies like in Utah, guessing both clear and dark. Any clubs near you that you find welcoming? Clubs have peole that may have done all this before you and can offer a solution in 5 minutes.

 

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I believe the Nexstar SE range are "Faststar" compatible which allows very short exposure times. This maybe an option for you if you do not want to change your set up.

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Ronin, you make some excellent suggestions!  I did forget to mention that I have a focal reducer on it so I'm closer to F 6.3 on my scope.  Ihave thought about getting a short refractor like the William Optics GT but you know, money. :)  Its interesting though what you say about sub 60 second exposures, I've been working under the misapprehension that I had to expose for 5-10 minutes at a stretch which I base off of what others have done with this scope, I'll try those shorter exposures and work on my stacking to see if there are any improvements in the quality of my fledgling images.  I also did not realize that the sensor needed to cool down, though I have been taking "dark frames" as I see it mentioned wherever people are talking about imaging.  Thank you very much!

The weather in Utah has gone cloudy and rainy, normally we enjoy brilliant clear skies and great views even from areas close to salt lake city (I'm north of SLC) but of course as soon as a guy wants to get his scope out and take a few looks at the heavens....I was a member of the Ogden astronomical society years ago but have let that lapse.  I've thought about signing back up again to lean on that wealth of knowledge, looks like I'll be paying dues again!  

Thanks for you help Ronin!

Edited by Graptharshammer

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5 hours ago, Pig said:

I believe the Nexstar SE range are "Faststar" compatible which allows very short exposure times. This maybe an option for you if you do not want to change your set up.

Unfortunately, the fastar is now only on the evolution series.  I was hoping that mine would be as I see you can get down to F2 with that setup but alas it is not. I have to compensate with an f6.3 focal reducer/flattener.  Pig, do you take shorter exposures and stack them as Ronin suggests?  It seems a very logical alternative to what I pictured (pun intended) as "Long exposures" being 4-5 minutes in length. 

 

 

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47 minutes ago, Graptharshammer said:

Unfortunately, the fastar is now only on the evolution series.  I was hoping that mine would be as I see you can get down to F2 with that setup but alas it is not. I have to compensate with an f6.3 focal reducer/flattener.  Pig, do you take shorter exposures and stack them as Ronin suggests?  It seems a very logical alternative to what I pictured (pun intended) as "Long exposures" being 4-5 minutes in length. 

 

 

I don't do any AP at all as I do not have the patience for it, but one of my friends is a very keen astrophotographer and he used to use an SCT. He never got much above 20-30 seconds so you will not have much choice to stack them I'm afraid. ..... That is most annoying that fastar is not compatible with your mount as that was one of the main parts of the marketing material. They do annoy me at times !!!!!

Edited by Pig

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There are two members with this mount and no wedge imaging though using a fast short small refractor. See the no eq challenge thread.

Take the wedge off, align mount, use your camera with a camera lens, see what you get, then add the wedge point at same area of sky and compare results. Rule out that the wedge might not be accurate adding to issues. 

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1 hour ago, happy-kat said:

There are two members with this mount and no wedge imaging though using a fast short small refractor. See the no eq challenge thread.

Take the wedge off, align mount, use your camera with a camera lens, see what you get, then add the wedge point at same area of sky and compare results. Rule out that the wedge might not be accurate adding to issues. 

Happy-kat, when you say to use my camera with a lens, do you just mean to piggyback the camera to the scope and use it separate of the SCT optical train entirely?  I get removing the wedge, I hadn't thought of that, then just using the scope in alt/az mode like they are doing in the thread you pointed out to maybe rule out my trailing issue.  I'll give that a shot as soon as the (bleeping) clouds move out of Utah :)

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Are you guiding ? If not then you should be at this focal length . With guiding and a decent polar alignment on the wedge I'd say 2 min exposures are achievable on this mount . You may get bloated stars though but that's OK to start with before you move to a refractor . 

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Yes I do mean use the camera and a camera lens and not image through the SCT. The camera lens will be more forgiving as it wont have a focal length anywhere near your SCT.

Ideally take the SCT off and mount the camera direct to the mount if you already have an adaptor to do that.

Edited by happy-kat

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3 hours ago, happy-kat said:

I did actually see a platform adaptor on thingiverse that I wanted to print with my 3-d printer, It replaces the scope and provides a mount for a DSLR.  It looks like I'm going to get that going and see what results I can get with just the camera on the drive.  I would not have thought of that but it makes perfect sense with the camera lens being so much shorter focal length wise.  

I'm intrigued also by the auto guiding Ken82 suggests, I do have a right angle viewfinder and spc900 webcam I was hoping to try planetary imaging with one of these nights, is that suitable for guiding if I use sharp cap or some other program that would allow me guide on a bright star?

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For planets I think the inbuilt tracking will be good enough with your sct. Planets is about video like using your webcam rather than stills with a dslr. The webcam will be a bigger planet image the dslr will be diddy, got a good barlow might help there.

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On 10/30/2016 at 14:41, happy-kat said:

I did actually see a platform adaptor on thingiverse that I wanted to print with my 3-d printer, It replaces the scope and provides a mount for a DSLR.  It looks like I'm going to get that going and see what results I can get with just the camera on the drive.  I would not have thought of that but it makes perfect sense with the camera lens being so much shorter focal length wise.  

I'm intrigued also by the auto guiding Ken82 suggests, I do have a right angle viewfinder and spc900 webcam I was hoping to try planetary imaging with one of these nights, is that suitable for guiding if I use sharp cap or some other program that would allow me guide on a bright star?

I ended up conversing with Celestron for a couple of weeks about the mounts tracking issues and they think it is an problem with the gears getting hung up so I've sent my mount back for adjustment/repair under the 2 year warranty.  They have been great through the whole process, patiently working with me on what I've done, what can be done, asking me to test this and that.  I have to say that I've been greatly impressed with Celestron's customer service.  I had horrible experiences with Meade back in the day with my classic 12" LX200 which soured me on them as a brand.  When I decided to get back into astronomy I made the move to Celestron and will be a Celestron customer going forward because they have treated my so well with this issue.  

I did end up getting a William Optics GT-81 which I put on the Nexstar SE mount for some test shots and I have to say that it made a great difference in the quality of image I was getting.  Being F4.72 with the reducer/adaptor that came with it has given me some confidence that I can be successful at this hobby some day!  Despite still being limited to very short exposures, I was able to to get 4 good shots of Andromeda (out of about 30) which I stacked in DSS with primitive but pleasing results.  I'm still going to keep trying with the Nexstar mount and 6SE when it gets back but the difference by switching to a fast refractor was amazing!  

I do have a 50mm guide scope and QHY5L-II cam that I'm going to mount on the Nexstar to see if guiding out some of these star trails is possible. I can't not meet a challenge!  

M31 11092016.jpg

William Optics GT81 with .8 focal reducer, mounted on the Nexstar 6SE mount in EQ north mode then polar aligned.  Canon T5 DSLR, 4 images of 20 seconds each at ISO 3200, stacked in DSS and processed in Photoshop afterward.

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That's great news about your mount, hope it works out.

Just four images, wow satisfying capture. I think this thread might interest, take a browse back through it but note they are using altaz mounts like your mount but with no wedge. Some flats will help with vignetting.

link here

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Thanks!  I was wondering what i could do about that vignetting, A series of flats would help you think? I had to make this black and white to pull any detail out, color looked horrible  with the minimal amount of light i was able to capture with only 4 images  

I have been following the other thread with great interest, its captivayed me with what people are doing with non-traditional equipment .   thank you so much for your help on here, it makes learning so much more enjoyable when you can get experienced opinions!

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Gosh thank you, I'm an avid reader not experienced as don't get hands on enough but I try and like to help people to have a go with what they already have. Too much cloud!

Yes flats definitely help with evening stuff out, you can use gradient exterminator plugin if using phtoshop or paintshop pro and I think CSC as well it works with.

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Hi @Graptharshammer

I'm jumping in on this thread a bit late, and I'm only skim read.  I too use a long focal length scope - I've got a Meade 8" LX-90 which is 2000mm native focal length.  Just like you I also have access to an F6.3 focal reducer.  I've also managed to get hold of an F3.3 focal reducer too! ;)    I'm saying this because alot of people will immediately say that the 8" F/10 scopes are too slow for imaging.  I say otherwise.    It seems to be a symtom of people that I come in to the hobby recently and have read Making every photon count, and taken it as a bit of a bible.  (That's just my opinion, disagree if you want, diversity makes for a colourful and enjoyable world)   My point is that you can do some great things with a larger scope.  However, I do agree that as others have pointed out they are much more tempremental scopes than an f5 80mm refractor.  So yes, any issue will be greatly magnified in the resulting image attempt.

 

Using my scope as a comparision, unguided I would expect to be able to take a 30 second exposure without any star trailing, indeed this is what I was able to get last time I tried it.

IMG_1239[1].jpg

 

I'm fairly sure that any issues with trailing that you see in this image are due to imperfect alignment rather than the scope not tracking.  Enough with the "it should work" stuff.

Here's some things to check out to see if it makes any difference.

 

Firstly, setup your scope, and try to take a picture with with the power turned off.   This way, you will get to see what the star trails will look like when the scope is not tracking at all.  You can then compare it with your image above and see if the scope is tracking at all.

I'm not familiar with the Celestron hand controller firmware, so I'll talk about this in terms of my Meade Autostar.  They should be fairly similar.

If you discover that your scope is not tracking, it's worthwhile checking out the settings in for the mount.  On the autostar there is a setting to set the scope to "terrestrial targets" this mode turns off the tracking completely.   This might be the first issue.

Next step, again this is meade specific.  There are some settings that I can run through to calibrate the motors.   This involves setting the scope up in the daytime, and pointing to an object in the distance (I use a flagpole that is about 5 miles away)  Then the scope slews off target and asked me to fix it using the hand box. I do this a both in RA both ways and Dec both ways.   After this, the scope tracks alot better than before.  I don't know if Celestron has that routine build into the firmware.   It's worth checking out to be sure.

 

Hope this is useful for you.

 

btw, something to watch out for is the spacing between the Focal Reducer and the camera, if you look carefully in that image, there is a ring around each of the bright stars, this is caused by a reflection because my camera was too far away from the focual reducer.  It's a problem that I'm going to try solving soon.  (my solution is to remove the flip mirror system that I'm using and drive the camera by software rather than using eyepieces like I have for the last 16 years)

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On 30/10/2016 at 05:18, Graptharshammer said:

I'm a complete noob with imaging but am really methodical in approaching any hobby I pick up so I'm hoping that with a little practice I can someday take some amazing images for my own enjoyment.  Currently I'm having no end of trouble with my scope setup and was hoping someone could shed some light on what MIGHT be going on here.  I have a Nexstar 6se which uses spur gears I realize, but it's what I have.  I'm using a celestron 6/8se wedge on a cpc 1100 tripod which makes for a rock solid platform for this modest scope.  Movement calms down with this setup in under a second so I'm confident it's not the mount.  The problem though, when I get my camera on the scope, get things focused as well as I can without a mask (i'm working on getting one 3d printed), I'm getting trails no matter what I do!  I'm polar aligned, making very sure to use a high power eyepiece and really spend the time to line up my mount.  Any image longer than about 20 seconds however exhibit trails!  I've adjusted the backlash controls from 0 to 50 in 5 unit increments with no discernible results.  I've used A/C power as well as a 12 volt 20amp/hr battery so I don't believe it to be power related. 

This setup, with the heavy tripod, the wedge, a decent computerized mount should allow me to image for a couple of minutes at least in my mind, but I cannot get it to work properly for even super short exposures!  I'm wondering if this is something that can be adjusted with the mounts clutch or some other trick to get things working how they should.  The images I've attached show an extreme amount of error in tracking and I'm beginning to wonder if my particular mount is just not going to work no matter what!  The "trailing 3" image is of Albireo and you can see that the stars below this double are doubled themselves, meaning to me that the mount is skipping or jumping partway through the exposure (45 seconds in this case) Any help would be awesome.  

TRAILING 2.jpg

TRAILING 3.jpg

I use a avx 8 sct for imaging..it has a longer focal length than the above scope.. id suggest that the polar alignment isnt quite bang on and there maybe a problem with power..i had the same issue with mine a few months back and it was a conection problem to the mount from the power tank..also i was told from my friendly local telescope shop(F1) of a polar assist on the handset...has made a huge difference...

FB_IMG_1478601134319.jpg

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