Getting Focus

[JohnP]

Carole - Have you got the webcam connected directly to the scope or are you connecting via the flipped mirror... this may be causing you the problem - John

[Carole]

I am using the ETX rear port for the webcam and using the right angled eyepice to view the object.  Once I have the object in the eyepiece I flip over to the rear port to get the image via the webcam onto the laptop screen.

This method was suggested to me by the shop that sold me the webcam (as recommended by Mike) forgotten the name.  Obviously when I am looking through the eyepiece (on top) I get no image at all on the laptop.

Carole

[Carole]

Just remembered the name of the shop that sold me the kit - (Modern Astronomy).

As you can imagine I am getting rather frustrated having spent around £250 and lots of nervous energy (not to mention all your nervous energy) and still not made any headway except I think I understand the mechanics of it all now, thanks to all your help.  However I am not going to be beaten yet.

Plan:
a) Try the focus out during the day on a distance object.
b) Check the rear port is showing the same as the eyepiece.

If that fails - nervous breakdown.
Recover from that and then I think I have to get together with some-one and go through the procedure and kit etc etc.

I've done everything I have been told to do and still not getting any result from it.

Carole

[JohnP]

If you can't focus in daylight try taking the flip mirror off & putting the webcam directly in the focusser tube.. John

[Ian]

I can sense your frustration Carole, and it's something we've all felt. Ask Mike about imaging with his Bresser scope on it's blancmange tripod...

I would say you are probably doing everything right, except one thing. You've got your head around the software, you've got all the equipment you need to image the moon and maybe a planet or two.

Like John, I'm wondering about that flip mirror. Because the size of the webcam chip is very small, it can be a challenge to get the target onto it and it wouldn't take much for the alignment of the mirror to be off. That's not a critism of the scope or Telescope house who I know have recently repaired it, just a statement of fact.

I would try a couple of things. Firstly, as John says, try putting the camera in the eyepiece hole, see if that's any better (obviously leaving the mirror where it is). Obviously you can't take it off, it's integral...

Or, or and, I'd take a piece of tracing paper, ground glass or something, and try to locate the focus plane of the scope through the rear port. All you need to do is point the scope at the moon and then hold the paper over the hole. Move it back and forth until it looks to be in focus. If that's close to where the CCD would be great, otherwise adjust the focus (probably by quite alot) and try again. it will also give you a clue as to whether the moon is centred in the rear port when it's centred in an eyepiece.

Don't give up, there's always a logical explanation. Somewhere.

[Carole]

Thanks every-one I'll give all these suggestions a try (except removing the flip mirror) and report back - weather permitting!!!

I haven't tried using the eye piece for the webcam as Mike said this was not an option, but anything is worth a try just to try to eliminate the problem.

Carole

[Carole]

The Results:

Imaging during the day has been a good exercise. 

I did not go to Norman park for 3 reasons:
a) It was an awful lot of kit to take and set up.
b) I would have felt a right nana doing this on my own in the middle of the day with all this equipment amongst jo public.
c) As some of you know my laptop battery has had it and I would have had to have taken the leisure battery, all the leads and the invertor, none of which I have tried out yet and I am not quite sure how to wire up the invertor and thought I should get some advice before blowing every thing up.

I looked through the bedroom window as I could get a more distant land-object view than in the garden.  Only managed to look at something in the next parallel street. 

I did however manage to confirm that the flip mirror is looking at the same as the eyepiece but upside down (I had forgotten that would happen because of the right angled lens in the eye piece).  It doesn't seem quite so central (vertically) which is not a problem on land items but I hope that is not going to be a problem with vast distances, and the focus knob needs to turn about 120 degrees clockwise when switching to the rear port and the Webcam.

I was able to play around with the controls and got an image.  Yippee!!!!!

What I have learnt from this is that the image on the screen is more granular than I had expected and that I could really do with a remote controller to change the focus as it is jumping around all the time, and this might be the reason I got the haze artifact.  Do they do such a thing?

Now what I need to do is see whether Focus at a more distant object requires the same amount of turning.  Incidentally I did all this without the Barlow.

With the Barlow:  It seems to need to turn through 360 degrees clockwise.
Interestingly this 2nd subject (waving palm leaves) needs 1/3 gamma 90% brightness 1/50 shutter speed and Maximum Gain for the best picture.  I am sure this is because it is a daylight object.

So I will now try again and maybe try it out in some-one else's house who has a distant view.  though I can't think where at the moment.  If only I could take it to work, there is a fabulous view of the London Eye from the Gynae Ward at Lewisham Hospital!!!!!

So apart from having a better opportunity to play with the controls and actually being able to see on the screen what I am doing, and finding the focal point, I can't really seeing what I am doing wrong at night time.  But I guess it is just a question of doing excercises like this and experimenting.  At least I know it should all work now and I am not being thick.

Back to the night sky.

Thanks for all your help.

Carole

[Daniel]

Hi Carol, I've been having nightmares focusing too, partly because the live view display of my camera is much darker than what i see with the naked eye, and partly because of the horrible amount of shake as i turn the focus knob.

The latter i think i may have fixed by fitting an auto focuser (well a motorized focuser anyway) to my scope. The one i got was the skywatcher auto focuser and only cost me £49   http://www.widescreen-centre.co.uk/Catalogue/Focusers.html  it will fit most rack and pinion focusers and takes a couple of minutes to install.

I Haven't had the chance to test it in the field yet, but from what i've seen from it indoors, it seems to have an incredible amount of accuracy when you slow the speed of the focus down and i've been told it produces no scope movement at all.

Anyway, I'll be able to give you a better idea if this is any good as soon as this bloody cloud lifts and i get to try it out properly!

Daniel
:O)

[Carole]

Thanks for that Daniel, although it doesn't fit my scope, I thought there must be something out there. 

Thanks to the very useful daylight exercise yesterday (as suggested by the boys) I have come to the conclusion now that all the controls need fine tuning to get a good image and knowing where focus is is a big step forward as even if I had the controls in the correct position I still would not get anything without the focus and of course with me not doing any tracking on the last occasional I did not get enough time to fiddle with everything because it disappeared off the screen, so I've learnt another lesson there.  I am feeling much more positive about it all now.

Doug has kindly suggested I go to his house as he has a distant landscape view to try out focus on a more distant object which I will try to do as soon as we can both fit it in.

I believe you will be coming on Thursday as a new member.  Look forward to seeing you there.

Carole

[Daniel]

Hi Carole, which scope do you have? the auto focuser fits a lot more scopes than mentioned on that page (mine is a Celestron C8n) Might have to try the daylight focusing myself, though i too have the same problem, I used to be able to see the thames out my back window, now all i see is flats, might see if i can take the scope down to the waterfront some time and see if i can focus on the thames barrier a little way up.

I'd like to come along on thursday, but right now it's looking unlikely i'll be getting away from my computer till the 30th, have a deadline for a job im working on looming and im pulling some crazy hours (hence posting at all hours of the morning)

Anyway, here's hoping for some break in the clouds!

Daniel
:O)

[Carole]

I have an ETX105EC.  If it does others than the ones mentioned it might be worth an enquiry but the ETX has quite a different focus knob to most telescopes so I don't hold out much hope.

If you can't make the meeting, see if you can make Deep sky camp end of February/beginningof March if you have a tent and mate to bring you.  Nice dark skies there, lots of us viewing and imaging and lots of fun.

Carole

[Daniel]

Ahhh, February would be perfect for me, Im not due back at work till mid February and that's just some evening classes im teaching, so it's only a couple of nights a week which i can get someone to fill in for if it clashes, plus I'll finally be able to get some more use of my tent that i bought for glastonbury 05 (still looks a little worse for wear)

I'll be talking to the place i got my focuser from tommorrow, so i'll ask em about your scope aswell, I've just had an idea to sort out my focusing without a barlow woes, I've seen some slightly shorter T-adapters than the celestron one im using right now, im hoping that the extra half inch closer I can get the camera to the barrel  might just give me enough to focus with

Daniel
:O)

[Rocket Pooch]

I could have a try with various positions of insertion, then if that works I'll try something like

Would someone like to explain to me what's going on here? 

[Rocket Pooch]

[Shouldn't be any moistrue inside there if Carole has stored the unit correctly, but it would be a bugger to get out once it got in !!

Whats!

[Rocket Pooch]

I did EXACTLY the same thing last night with Mars.  I moved the focus in and out, in and out, in and out but Mars remained a featureless white blob on the screen. I then realised the image was totally saturated because

No!!!!!!!!!!!!!!!