Struggling With Ccd

[brrttpaul]

set up last nightusing HEQ5 mount equinox ed 80 and a nikon DSLR ( the plan was I could see everything on my laptop).  everything worked great  focused using BYN  and took some shots of various stars etc , even slewed to Jupiter and had a go in planetry mode everything was good untill I switched over to CCD, using maxim I done continuos and began the focusing using the subframe and large stats I tweaked the stars the lowest I got it was about 15 on the HWHM (sure I spelt that wrong but its the half thing for focusing).  I took a load of shots of the pinwheel but they look terrible stars like doughnuts which I dont understand as 15 was the lowest I could get to ( would that be about the norm? when I used BYN I was down to 3. Seriously thinking of selling the CCD im not getting on with it at all .

[Thalestris24]

set up last nightusing HEQ5 mount equinox ed 80 and a nikon DSLR ( the plan was I could see everything on my laptop).  everything worked great  focused using BYN  and took some shots of various stars etc , even slewed to Jupiter and had a go in planetry mode everything was good untill I switched over to CCD, using maxim I done continuos and began the focusing using the subframe and large stats I tweaked the stars the lowest I got it was about 15 on the HWHM (sure I spelt that wrong but its the half thing for focusing).  I took a load of shots of the pinwheel but they look terrible stars like doughnuts which I dont understand as 15 was the lowest I could get to ( would that be about the norm? when I used BYN I was down to 3. Seriously thinking of selling the CCD im not getting on with it at all .

Hi

It's fwhm and/or hfd But 15 sounds way too big. What ccd are you using? Most (probably all) don't have the backfocus of a dslr. So you may need an extension tube to make up the difference in order to achieve focus. I find setting up such things is best done during the day.

Louise

[blinky]

Get it outside during the day and get it focussed on as far away an object as you can, as Louise has said you might need an extension tube to reach focus but try during daytime and you should get a pretty good idea what the problem is.

[brrttpaul]

I got the focus spacer and have had it focused in the day its that step up from being able to view through a dslr to not seeing that catches me out TBH, so many things like how many secs exp when im doing continuous  to use fwhm then and this is the biggest one for me, i acctually went to 5 mins exposures and had the stas perfectly round and no trailing (unguided) but when im using the ccd how do you know whats the best length of time exp as you cannot alter the iso  on a ccd , my camera is the starlight sxv osc (2nd hnd). I will give it a few more gos guess im just a bit gutted that a perfect clear sky last night and a mucked up

[Thalestris24]

I got the focus spacer and have had it focused in the day its that step up from being able to view through a dslr to not seeing that catches me out TBH, so many things like how many secs exp when im doing continuous  to use fwhm then and this is the biggest one for me, i acctually went to 5 mins exposures and had the stas perfectly round and no trailing (unguided) but when im using the ccd how do you know whats the best length of time exp as you cannot alter the iso  on a ccd , my camera is the starlight sxv osc (2nd hnd). I will give it a few more gos guess im just a bit gutted that a perfect clear sky last night and a mucked up

Hi

I'm  confused  - you said above that  you 'switched over' from dslr to ccd? It's probably better to set up the ccd, get  it focussed and leave it.  I use APT to  acquire images as it works with Canon eos and ccd's. In any case, whatever you use should allow you to set up a focus plan (I don't know Maxim). It is a little more awkward with a ccd as you usually need to take longer exposures. Once you get used to it, it's not so bad. There are probably instructions with your ccd to set up its optimum dynamic  range (offset and gain) which you need to do before properly imaging.

Louise

ps I find a SW autofocuser invaluable for fine adjustments and for holding focus

[brrttpaul]

Dont mean to confuse you, I set up using the dslr because the chances are my star alignment will be off so when i come to do it i can sync the alignment far easier using a laptop, just watching the screen and using the up/down left/right to centre the stars (in this case  capella). once done i usually slew somewhere to see im on the target  and i stayed using the dslr untill the battery went, after that i took the camera off and put the CCD on (knowing i wouldnt be far off I slewed again to Dubhe I think it was, but i dont think i focused tidy as i said 

[Pompey Monkey]

Focussing a CCD is, as you have found out, a completely different kettle of fish to focussing a DSLR. Persevere and you will find it a lot easier. Have you considered using a Bahtinov mask?

I will also second Louise's shout out for APT (Astrophotography Tool), but I use live view rather than a plan for my focussing.

FWIW, I have wasted many clear sky hours learning to do new astrophotography related things and it was very frustrating at the time. However the day will come where you suddenly realise that it's all up and running with no hassle at all!

[blinky]

During the day focus the CCD on as distant an object as you can, if you want to then use your DSLR to frame a target then take a note of the focuser position so you can get reasonably close when you stick the CCD back in.  

The way I focus my CCD is set it roughly during the day if possible, then get  the brightest star there is on the CCD at night and take short exposures to focus the star - I also use a Baht mask, makes it so much easier!  I find focusing a CCD easier than a DSLR as I can take sub frames round a bright star and quickly get it focussed.

[brrttpaul]

Well I will persevere with it for now and see how it goes, using that fwhm from what I seen in the tutorials all i need do is keep it on continuos and alter the focus untill i get the smallest number possible, i might try astro tool and see how that is, there are so many diferent programes out there  it can be daunting

[ncjunk]

I think the best bet is to do what Blinky says. I'd put the dslr on during the day and focus it, making a note or marking the focus position. I'd then mount and focus the ccd noting the new position and which way i had to change the focus.

When i moved to ccd i stuck with the ccd and didn't try to use them both in one night. I aligned the finder scope with the ccd on a far away object and then at night found a very bright star and used the finder scope to get roughly on the ccd and focused with half a second subs.

Get it right during the day first though otherwise you could be fighting with two errors or problems at the same time and not realise it.

Good luck for the next try!

[ncjunk]

Btw my ed80 at 600mm fl gets hfd of 1.5 - 2.5 and my c11 at 1680fl gets a hfd of around 6.5

[brrttpaul]

thanks very much for the replies its much appreciated, I agree I messed up big time with the focusing but i will know next time . I might try the software that came with the camera (SXVOSC) as maxim does seem a steep learning curve i have also downloaded astrophotography tool and will look at that

[carastro]

What is the CCD camera you are using?  

Unless it has a very small chip it should be easier to align with it than the DSLR as it will see more, unless it is a OSC CCD camera.

I know it's difficult to wean yourself off what you are used to, but I think you are really making life too complicated for yourself by switching cameras.  

I remember when I first started imaging, I used to do an alignment with an eyepiece and then stick the camera in as it was what i was used to, but I soon realised it was better to align with the camera in place.  

The tip above about finding the point of focus during the day time is a good idea, it will be approximate but will give you a good guide.  Once you have found the point of focus, either mark the tube or take a photo on your phone for future reference.

Do you guide, and if so what guidescope and camera are you using.  I use a finderguider and normally use that to get my alignment star in the "ball park" as my CCD camera has a smaller FOV, so if I can't see it on the CCD at least I have a rough idea where it is on the wider FOV of the finderguider.  

If you are struggling with FWHM the Bahtinov mask also works fine with a CCD camera.

Carole 

[brrttpaul]

Its a starlight SXV OSC camera. the plan was to get guiding up and running, but what happenend was a nightmare TBH with the weather etc so when the camera arrived back in Oct i played with the settings etc ( using a distant pylon to focus on etc) , once I done all that I connected the HEQ5 mount to use CDC but for whatever reason (im guessing the lead) I can not run CDC, ( tried everything drivers unistalling reinstalling. I give up on it in the end and went back to the synscan handset just to get something under my belt. The biggest trouble is working during the week and the lack of clear skies, im also in the process of mounting a permanent pier out the garden so been up to my neck busy wise. I suppose thats why I was peeved off Friday was clear nights and probably too excited and went wrong  lol

[ncjunk]

Sounds like my life story!

I've got used to doing things over months where others manage to improve in weeks. I get so much cloud during the winter i'll only really get 6 or 7 decent nights over 4 or 5 months. Then if a night coincides with a busy bit at work i won't be able to get the scope out at all.

I started with a lxd75 small mount, then went to dragging an eq6 out of the garage each time i wanted to use it, then to a pier and finally a roll off roof.

Each step up made it slightly easier and less setup time. You really are at the most difficult stage of it all and if you can get a pier build it will help (if you have a couple of clear nights you can leave the mount on it saving on setup time)

It amuses me when someone with an observatory and expensive gear gets praised for their wonderful pictures and someone starting out produces something not as pretty but technically more difficult (having to set up each night etc) and recieves criticism.

Not that i'd go back! It takes me 10 mins to set up and i can control it from the house it's great fun, my images are worse though i think ;-D

I understand what you're going through though.

[carastro]

Its a starlight SXV OSC camera. 

OK, that won't be as sensitive as a Mono camera, but should be as sensitive as a DSLR.  Does the camera software allow for binning as this vastly improves the download time and makes for easier "live view" (or looping as it is really called), and will give a better image to be able to align and focus with.  But don;t forget to switch back to non binning before you start to capture.  

I'd take baby steps and get one thing right at a time, but not so good when you have to set up every time of course.  Getting good focus is crucial though.  

I am sure once you get through this stage you'll be fine. 

Carole 

[brrttpaul]

I have never used binning but I can see it on the software panel 2x2 3x3 etc. I think I am going to try out the software that came with it I have been reading it through again today. I will get there (to a point lol), while this topic is fresh then maybe someone can answer another question which puzzles me. With a dslr I can say do an exposure of 3 mins and if its blown out reduce the ISO but with a CCD there is no ISO so I would have to reduce the exposure time,  ok i understand that  and with it being a CCD and more sensitive than a DSLR I would expect shorter exposure times anyway, so how come with it being more sensitive people keep saying you need to guide so you can have 20 min exposures wouldnt it be blown out by then?

[carastro]

I can't see the camera getting "blown out" on long subs.  I used to own a OSC camera and did 600secs subs no problem and regularly do 20min (even 30min) subs with my mono camera though that is narrowband.   I defintely know some-one with a OSC who did 15mins subs regularly.   Depends on the target really and your LP.  

Regardless you'll still need to guide to get anything more than 2 - 3 minutes and that's even if your PA is spot on, which is unlikely in the situation of having to set up every time.  

Conquer your getting focus and getting an image with your OSC camera, and then try to get a guide system sorted out, longer subs means more data and better images.

Carp;e 

[brrttpaul]

thx for taking the time to respond carastro its much appreciated. 

[ollypenrice]

I would never, ever, swap cameras in the evening. I try not to touch them for whole months at a time. Not pulling the kit about is, for me, a golden rule of imaging. 

I would work entirely from the CCD. You can get a deeper image in less time using that when it comes to aligning your GoTo and finding your target.

Do an initial focus on your first alignment star. Firstly just look at the star during looping mode and focus till it is about as small as you can get it but don't spend ages on that. I would then use a Bahtinov Mask. Don't try to use Full Width Half Max on a bright star because it will be saturated (the while middle of the star will have filled the pixel wells completely.)

Go to your target and frame it as you wish. Then pick a small star in Bin 1 and try your full width half max routine on that. The white point (maximum brightness) should not reach 65000. If it does your star is saturated and the FWHM cannot work. Some UK imagers find that the FWHM method is a pain because of turbulence which causes the numbers to jump around too much. Using focus subs of three seconds can calm things down but it you don't get a reasonably steady stream of FWHM values ditch it and use the B mask again.

It's always best to understand what it is you're working with in imaging so here's a bit of graphics I use to explain FWHM on courses. In both cases we see the same star but on the right the exposures are too long so the centre of the star has saturated the pixels. Above each star we have a graph showing its brightness from the faint outer edge, across to the bright middle and on to the opposite faint edge. Because it is so hard to define where a star actually begins it is best to measure its diameter half way between its outer edge and its brightest centre. We measure the star's Full Width at  Half its Maximum brightness. The brightness curve of the saturated star goes off the scale and distorts the measurement.

Olly

[brrttpaul]

Thanks very much you have all been a great help, hopefully tomorrow night looks like it will be clear so may give it another go, I suppose once I get into a routine of it it will get easier

[brrttpaul]

Ok just got in from work and set everything up in record time I think, polar aligned and done a one star alignment on capella, looked through the telrad and wernt far off (inner circle so I used the directional controls to put it dead centre. I then took a quick 4 sec shot to see if the scope was nice with the telrad and all ok. I have just gone for something simple now (orion nebula) and in the middle of taking 60 sec subs. (yes I know the moon is out) but its more practise than anything. I would like to try and get Catalina but even though I know the rough whereabouts  (near NGC 5308) I dont know how to get on there using the synscan. Still onwards and upwards

[ollypenrice]

Ok just got in from work and set everything up in record time I think, polar aligned and done a one star alignment on capella, looked through the telrad and wernt far off (inner circle so I used the directional controls to put it dead centre. I then took a quick 4 sec shot to see if the scope was nice with the telrad and all ok. I have just gone for something simple now (orion nebula) and in the middle of taking 60 sec subs. (yes I know the moon is out) but its more practise than anything. I would like to try and get Catalina but even though I know the rough whereabouts  (near NGC 5308) I dont know how to get on there using the synscan. Still onwards and upwards

Just look up the RA and Dec estimates for the night on the internet and either enter them as a user defined object or use the 'Show RA and Dec' feature so you can drive the mount to those positions while watching the current positions change.

Olly

[brrttpaul]

Do you have a link where i can get them from? I keep getting for november for some reason

EDIT worked it out and taken my first sub of it at 300 secs (unguided) wohoo, just having a go at 10 mins now for the hell of it, then I will prob go and try an hours worth of subs around the 3 min mark  ( im guessing my 10 min sub is going to be a disaster  but never know lol

[Owmuchonomy]

Catalina right now:

RA 13h 35m 9s

Dec +61deg 39' 45"

Don't forget it is fast moving so this is only good for tonight