Keeping Jupiter in view

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northster1
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Joined: Wed Oct 24, 2007 9:01 pm
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Keeping Jupiter in view

Post by northster1 »

Hi all and all the best

Can I get a little advice as to how best keep objects in the fov whilst trying to image with a ccd, I have a celestron c8 on an eq5 mount
Will the tracking be sufficient from the goto or do I have to manually adjust with the handset ?

All advice is much appreciated

Not had chance to use yet with damn clouds but can't wait to get out and try to catch some pics
Thanks lee
Brian
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Re: Keeping Jupiter in view

Post by Brian »

Hi Lee.

Generally, it will be necessary to do some manual corrections using the handbox. For planets (long focal length with video sequences of maybe 2 minutes) you may find that corrections to recentre the target can be carried out prior to starting each new recording, and with luck any drift during recording will be small enough that the target doesn't leave the ccd during that time interval. It depends on how well your 'scope is polar aligned and how good the drives are.

For long-exposures (DSOs) you will probably want no drift over exposure times of maybe 1-2 minutes. Your EQ5 if well polar-aligned might track unguided for 20-30 secs (I'm guessing here, someone else may be able to give better info). For longer exposures it might be best to set up a guide system , with a small telescope and CCD camera to lock onto and closely track a guide star automatically.

In the past I've taken 5-minute exposures with a piggy-backed SLR (film) camera and 200mm FL lens, guiding manually using an 8-inch Cassegrain and an illuminated cross-hair eyepiece. 5 minutes manual guiding is certainly as much as I've wanted to do with watery eyes :lol:

HTH,
Brian
52.3N 0.6W
Wellingborough UK.

254mm LX90 on Superwedge, WO ZS66SD, Helios 102mm f5 on EQ1, Hunter 11x80, Pentax 10x50
ASI120MC Toucam Pros 740k/840k/900nc mono, Pentax K110D
Ro-Ro roof shed
northster1
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Joined: Wed Oct 24, 2007 9:01 pm
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Re: Keeping Jupiter in view

Post by northster1 »

Thanks for the advice Brian
Would it be possible to use the same ccd camera to both image and auto track or do you need another camera for the job ?
Brian
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Re: Keeping Jupiter in view

Post by Brian »

Hi Lee.

Just noticed your enquiry was about keeping Jupiter on the CCD. I should pay more attention, sorry about the Deepsky imaging waffle :oops:

You don't say which CCD you plan to use, but with my Toucams ( 640x480 pixels of 5um size) and 10inch SCT I find that Jupiter gives an image approx 110 pixels across at the native F10 focus and at F23 (x2 barlow) approx 230 pixels. This means that normally there is "plenty" of room on the CCD to allow for some wander of the image during recording. If your mounting is reasonablty well aligned you should be able to record 1-2 minutes of video (so up to 1000+ frames) without needing to make corrections. Your stacking software (I use registax) should be able to deal with the wanderings of the image. To make small pointing corrections between video sequences you should have a "guide" speed setting available on your handset.

To answer your last question, most imagers use a separate small refractor and CCD camera with guiding software (PhD, Metaguide etc) to pick up and follow a guide star for DSO imaging. You can get Off-axis guiders which place a small mirror into the edge of the 'scope field of view to track a star just outside of the imaging field of view, but you still need a second camera. I understand that some very expensive CCD cameras with big chips can use the imaging chip to act as an inbuilt guider, but the cost is more than I can afford :lol:

ATB,
Brian
52.3N 0.6W
Wellingborough UK.

254mm LX90 on Superwedge, WO ZS66SD, Helios 102mm f5 on EQ1, Hunter 11x80, Pentax 10x50
ASI120MC Toucam Pros 740k/840k/900nc mono, Pentax K110D
Ro-Ro roof shed
northster1
Posts: 43
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Re: Keeping Jupiter in view

Post by northster1 »

Thanks again Brian
Just need clear skies now
northster1
Posts: 43
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Re: Keeping Jupiter in view

Post by northster1 »

Hi again, OK well i have just recieved a celestron neximage 5, i have a long usb cable to plug into my pc from the mounted ccd in my garden (no laptop, tablet man) whats the best way to track jupiter for example. I'm thinking a desktop program which i could use to recentre the target whist the ccd is running in the background. Am i on the right track here or do i need a laptop and another ccd with another scope to track ?
whats the best pc program for controlling the telescope and could this do the tracking for me ?
sorry for all the questions just want to get going
thanks lee
Brian
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Re: Keeping Jupiter in view

Post by Brian »

Hi Lee.

The video capture software that came with your camera will give you a live-view screen showing what the camera sees. This liveview (preview) screen will allow you to locate, focus and keep track of your target.

Which software do you have with the neximage? It's best to save your video sequences as plain .avi, as this is compatible with most stacking programs. Don't save as mpeg or mov even if the option is given.

Once your telescope is set up and aligned, it should make a good job of tracking your target, and you should only need to make small corrections via the hand box (guide speed) to keep the target more or less central (a bit of drift across the preview screen during capture is will be handled by your stacking software).

As you will be sitting at your PC indoors while recording video, you may need to get and extention cable for your handbox, and probably an electric focuser with a long cable for the telescope. You need to be in control of operations from your control point, which is your PC. An electric focuser is useful on two counts - it allows remote control, and stops the image shake that hand focusing causes. Remember the camera, rather like a highpower eyepiece, has only a very small field of view and even a small vibration can send the image flying off on one side or other.

I haven't seen many images reported using the Neximage 5 , so I'll be really interested to hear how you get on.

Ask away! :D

ATB,
Brian
52.3N 0.6W
Wellingborough UK.

254mm LX90 on Superwedge, WO ZS66SD, Helios 102mm f5 on EQ1, Hunter 11x80, Pentax 10x50
ASI120MC Toucam Pros 740k/840k/900nc mono, Pentax K110D
Ro-Ro roof shed
northster1
Posts: 43
Joined: Wed Oct 24, 2007 9:01 pm
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Re: Keeping Jupiter in view

Post by northster1 »

Thanks Brian, will be ordering a hand controller ext cable soon, Just waiting for my ota back from Stockport telescopes as I made a hash out of collimating :(
The neximage5 capture software is called icap with registax for the processing
As soon as I'm up and running il try to post my progress

Thanks for the advice
Lee
The Bat
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Re: Keeping Jupiter in view

Post by The Bat »

I have an almost identical setup with a C8 on CG5 mount. Mine is not Go-To but I have managed to get some reasonable pics of the planets. You shouldn't need guide instruments with a webcam. I don't polar align exactly - usually I'm happy if I can sight Polaris up the polar axis - and I can normally get Jupiter to stay on screen for a couple of minutes even with a 2x Barlow in place. It will drift a bit, but I capture in batches of 1000 frames and then adjust manually if the target has moved off centre. Try to get the image central to start with - find it visually, centre it, then swap for the camera, refocus to find it at low power, centre it on screen and then switch to a Barlow if you're using one. I find if I go straight from visual to camera with Barlow I have trouble finding it, either because it is off centre, or just so far out of focus I can't even see the doughnut shape.

Good luck. :D

Rachel
Celestron C8-S XLT
CG5 mount, dual axis motor driven
Imaging Source DFK21AF04.AS camera
North Essex Astronomical Society
northster1
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Re: Keeping Jupiter in view

Post by northster1 »

Thanks Rachael
Can you put up a couple of your photos so I can see what to aspire to ?
Thanks lee
The Bat
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Re: Keeping Jupiter in view

Post by The Bat »

Most of my images are in the gallery somewhere, but I haven't posted any for quite some time, the last year being quite the worst as far as weather goes. Rather than trawl through trying to find them, here are a sample few.
My camera is different to yours. I have an Imaging Source camera and use different software to capture.

Cheers,

Rachel

Jupiter 2011
Image

Jupiter 2010
Image

Saturn 2011
Image
Celestron C8-S XLT
CG5 mount, dual axis motor driven
Imaging Source DFK21AF04.AS camera
North Essex Astronomical Society
northster1
Posts: 43
Joined: Wed Oct 24, 2007 9:01 pm
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Re: Keeping Jupiter in view

Post by northster1 »

Those photos are excellent, hope I can get something like them with my setup.
Did you use a Barlow lens

Thanks lee
The Bat
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Re: Keeping Jupiter in view

Post by The Bat »

Yes, all of those were using a 2x Barlow.

Rachel
Celestron C8-S XLT
CG5 mount, dual axis motor driven
Imaging Source DFK21AF04.AS camera
North Essex Astronomical Society
northster1
Posts: 43
Joined: Wed Oct 24, 2007 9:01 pm
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Re: Keeping Jupiter in view

Post by northster1 »

nebula orion1.jpg
nebula orion1.jpg (175.15 KiB) Viewed 7718 times
hi all, with my telescope being repaired last weekend i tried my hand at deep space for the first time with a cheap second hand modded cannon d1000, and a tripod and old lens borrowd from my dad
northster1
Posts: 43
Joined: Wed Oct 24, 2007 9:01 pm
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Re: Keeping Jupiter in view

Post by northster1 »

sorry dont know how to resize the image yet !!
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