labtech1122

1 hour ago, newbie alert said:

That T adapter would work with a Celestron reducer but it's a Antares one, which I'm sure that I've seen 85mm thrown about rather than the 105mm that Celestron spec... Have a little search on Mr google

would this one work better do you think?

6 minutes ago, Elp said:

I'm assuming your scope (SLT) is just a model number variation of the Celestron C6 SCT design (SE, nexstar, edge etc). Out of curiosity, are you using the supplied mount or an EQ one?

If the former, add in the reduced focal length you're trying to image at (1000mm+) that mount won't be sufficient to prevent star trailing. You ideally need equatorial for deep sky, more so for long exposure, even more so for long focal length.

Having tried imaging recently with my C6 SCT at F6.3, it isn't easy getting bang on focus, or getting good guiding. The bloated stars and confirmed by failure to stack is indicative of out of focus stars with poor FWHM values. The software doesn't see them as points of light so can't register the pictures. You can sometimes brute force the registration by choosing different registration algorithms (I use Siril more because of being able to customise such things), but usually any stacking program won't like the data.

You mentioned you're using a guidescope, unless it's a similar imaging scale to your SCT your guiding won't be good at all. Long focal length really needs a matching guidescope (usually an actual refractor telescope being used for guiding duties) or an off axis guider (what I use). Even then, any poor seeing may result in bad guiding which short focal length imaging can usually get away with.

With my F6.3 Celestron reducer I work to 105mm back focus from the rear of the reducer lens to the camera sensor, so maybe find out what your reducer BF distance is, it might be similar. You mentioned the visual back, you don't need this, the reducer screws directly to the back of the scope and then your spacers, adaptors etc follow. Work on this until you can get the stars round. Also confirm via visual observation with your diagonal and an eyepiece when you look at stars or planets, are they completely round with no edge shadowing, if not your scope collimation could be off.

The good thing about an SCT is backfocus isn't so critical as it is with a refractor due to how the scope is designed so a few mm off won't cause an issue. I think your edge stars will be a problem due to the sensor size, larger the sensor, the more precise to perfect your backfocus needs to be to get a completely flat field, in such instances its much less hassle to crop the final image.

As for the artifacts, if they're rotating when you're rotating the camera, the camera is the likely culprit as there's a lot of internal surfaces for light to reflect off unlike in an astro camera where the sensor is closer to the mounting face.

I wouldn't get discouraged, part of the "fun" in AP is problem solving and looking for ways to improve. If it were easy, more people would be doing it.

hi yes its a celestron nexstar 6slt, the mount im using is a skywatcher eqm-35pro, guide scope is the svbony 60mm and guiding with PHD2. i have had a look around on loads of forums and some people say its 85mm but are then corrected by many others that its 105mm so not really sure what is correct

"You mentioned the visual back, you don't need this, the reducer screws directly to the back of the scope" i dont remeber mentioning that as i have got the reducer screwed directly to the back of the scope, i shared an image of it saying i could use this instead of the celestron adapter as i can put my 1 1/4" t piece into it and make the BF adjustable.

"are they completely round with no edge shadowing, if not your scope collimation could be off" yes i have done this and the collumation is just right

"part of the "fun" in AP is problem solving and looking for ways to improve" yes i do definately like the reserching and working out differnt things and how to fix the problems i just need to do a trail and error because a minority say 85mmBF and the others say 105mmBF so im going to try both

do you know of any adapters that i can use that come wiith differnt size spacers? the on i have is the celestron #93633-A and is a fixed length

the thing i was worried aout with the 1 1/4" before when i was using it all the time was it once being screwed down with the two tightening screw that it wasnt properly central and you would a little bit of tilt

Do you think swapping to this (see image) would help, i would be able to move the back focus around on this set up (the celestron adapter is a fixed length) as you can see i can use a multitude or focal lengths with the 1 1/4" tpiece

The thing about it is this way will be 1 1/4" instead of the 2" that the celestron one is, will this make any negative or positive impact on the images taken, i may be wrong ut thought that the 2" would let more light in?

22 minutes ago, labtech1122 said:

 

does this set up look ok? telescope, FR screwed strait onto scope, t adapter, t ring then camera?

4 minutes ago, wesdon1 said:

definitely out of focus, imo. Try getting your stars as tiny and "dense" as possible when focusing mate. There's tons of people on here who know the hobby inside out, who will give you amazing advice, so keep coming back here, and try YouTube vids aswell. In time, things you find difficult today, will feel second nature, you just have to stick with it mate. Best of luck!

thanks  ive been trying the same thing over and over for over a year now and am finding it really hard to get to grips with, ive got a pretty good understanding of a few things but since getting the FR i get the blue rings and the trail shapes in the corners. im agreeing with people its probably back focus but ive got the same things ive seen other people have but not getting any results

10 minutes ago, AstroNebulee said:

Just seen this post, sorry. 

The shape of your stars in that radial position indicates your sensor is to far away from the scope. Try moving it in a bit. 

Can you take a picture of your optical train please. 

Lee

3 minutes ago, AstroNebulee said:

Hopefully someone else will chip in soon with better advice than I. 

If you went from 200 secs to 100 secs the trailing would probably still be there. Maybe next time try experimenting with shorter exposures, starting with 20 secs and upwards to see if the trailing is still there. What software are you using to guide? 

I don't know a lot about internal reflections but could be caused by anything in the optical train from your scope down to your dslr. 

 

Lee 

oh ok, i did that reduction because i thought 100s more would show up any issues. i took a photo of orion with 20s and the stars on the outer edges trailed in the same rotaional way (i dont have these images anymore i accidently deleted them 

17 minutes ago, AstroNebulee said:

As newbie above says up your iso on your dslr to view a brighter star and focus s with your bat mask. 

I've never trued my bat mask on Jupiter so cannot comment but would of thought ok, though best to use a bright star. 

What are your individual subs like are they all bad? The blue rings as said above are internal reflections most probably. 

How is your guiding in reference to the subs, looks a bit of trailing. 

Lee 

i was wondering if the tracking was ok when i first did the evening so went from 200s to 100s but the trils didnt get longer or worse so i out it down to an optics problem eith either focus, back focus, the FR or the camera.

how do i get rid of internal reflections?

10 minutes ago, AstroNebulee said:

As newbie above says up your iso on your dslr to view a brighter star and focus s with your bat mask. 

I've never trued my bat mask on Jupiter so cannot comment but would of thought ok, though best to use a bright star. 

What are your individual subs like are they all bad? The blue rings as said above are internal reflections most probably. 

How is your guiding in reference to the subs, looks a bit of trailing. 

Lee 

ok i will try that on the next clear night, each sub looks kind of ok in the center but alot of trailing on the stars on the edges in a radial fashion. the guiding seemed to be doing ok while i was doing it although im not sure it was up up right, i was advised to use a tracking rate of 0.9x but have since seen people saying not to have it that hight, i used sharpcap for the plar align and got the tracking going and looked ok, some over corrections but seemed ok

49 minutes ago, newbie alert said:

Use a big bright star and up the iso on your camera .. longer exposure length also helps

ok thanks, how should i do the longer exposure lengths with my dslr, meaning shall i do it sharpcap or backyeard EOS.

i tried using the screen on the camera and zoomed 10x but that didnt work. maybe i need to keep trying until its compleaty clear.

i went to devon at the weekend and it was so clear and yould see the stars sparkle but its extreamly rare to get that here

Just now, labtech1122 said:

i live in peterborough but noth is of it so when i photo graph the flame or orion or anything all the light pollusion from the city glares everything. the image i uploaded was meant to be of the flame lol. i focused on jupiter because it was the clearest to see at the time but still didnt show the spikes like you see in all the batinov photos or videos. is it ok to focus on jupiter?

attached is the stretched image 

as you can see its stacked the images ontop of echother but not aligned. my main problem is the rings though

38 minutes ago, AstroNebulee said:

Yes stretch it first the upload your jpeg. Looking at your image focus is off and maybe as said backfocus is slightly off. 

Whereabouts are you in the UK with your light pollution. There must be a bright star in your view to focus on eg Capella, Betelguise, Castor, Rigel, Regulus at the moment etc. They should provide you with a nice star to see the spikes. 

I would say DSS is struggling with aligning due to the stars shapes, are all your subs off focus. Try stacking some of the data available from tutorials online maybe, just my thoughts. 

Lee

i live in peterborough but noth is of it so when i photo graph the flame or orion or anything all the light pollusion from the city glares everything. the image i uploaded was meant to be of the flame lol. i focused on jupiter because it was the clearest to see at the time but still didnt show the spikes like you see in all the batinov photos or videos. is it ok to focus on jupiter?

attached is the stretched image 

4 minutes ago, AstroNebulee said:

If you use a batinov mask you can get focus spot on. Could you upload the stack in jpeg format please 😊. 

Lee 

because the star detection (im assuming due to the focus) is so bad its not alighing the images either its just placing one image ontop of the other (or i have a setting wrong in DSS, ive tried for about a year now to work out DSS but ive never seemed to be able to work it out

2 minutes ago, AstroNebulee said:

If you use a batinov mask you can get focus spot on. Could you upload the stack in jpeg format please 😊. 

Lee 

yes sure, shall i stretch it first? ive very hard to see anything on it, ive used a batinov mask to focus on the stars but you cant see the spikes off the star because of the light pollution, i zoomed in on the star with my dslr and tried my best but it was extreamly dificult to see the spikes from the batinov

Hi, does anyone know the correct back focus for the antares x0.63 FR, ive got this focal reducer and the #93633-A celestron t adapter sc, the t ring and a canon 650d

10 minutes ago, Cornelius Varley said:

What image processing software do you have ? (other than DSS)

ive been trying to learn how to use pixinsight recently and have gimp. ive managed to turn them to jpeg now

ive stacked 6 images just to show the rings more clearly

(ive tried getting the focus spot on but very hard to do with the light pollution i have here, any tips on advancing it?)

Autosave001.tif

4 minutes ago, Aramcheck said:

@labtech1122 - The stars are a bit out of focus & I think the elongation at the edge is due to the camera back focus being too large (i.e. camera sensor is too far from the field flattener). The blue rings look to me like internal reflections from the bright star.

Just my 2p!
Cheers
Ivor

 

ok thanks alot, i was worried about the back focus but everywhere i read it says it is right, ive got the antares x0.63 focal reducar and the #93633-A celestron tpiece

hi thanks for your reply, whats the best way to convert it to JPG?

Hi, I'm wondering if any one can help me,

I've just started imaging through my telescope and keep getting a very strange set of rings on my images with bright stars, the rings move around and change position depending what angle the camera is at.

also the stars at the edges look like they are trailing or out of collimation or out of focus or something. 

im using a celestron nexstar 6slt with antares x0.63 focual reducer, sc -tpiece and canon 650D. 60mm guide scope with svbony sv305pro to guide

I've been racking my brain a lot about this and really need help. DSS wont stack them because it cant see stars and when I got it to stack a couple of images it didnt actually align the images it just put them one on top of the other.

blue ring (2).CR2 blue ring (3).CR2 blue ring (4).CR2 blue ring.CR2