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bobro

Hello - and here goes!

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Hi all,

Quick into - recently moved house in the Isle of Wight and now have a south facing garden. The view upwards rekindled an old (though never progressed) interest in the sky. A good number of years ago I used to spend time in the south of France and enjoyed lying on a big table at night looking to the sky. The sky was so full of stars that it seemed to press down on me and finding the Milky Way didn't need any skill. I purchased a Celestron 114 (I think) and, to be frank, was a bit disappointed in what I could see with my limited time and knowledge. The big surprise though was, on a whim, holding my first digital camera to the telescope eyepiece and taking a surprisingly good image of the moon. Good enough to print at 8" x 6" and produce an acceptable photo.

Now, with the interest (rapidly!) rekindled, I couldn't resist a Meade Polaris 130MD at a very good price, a 2nd hand Canon 1000D DSLR body and a Microsoft LifeCam Cinema webcam. With the webcam modified and a bit chopped off the end of the telescope to allow the DSLR camera to focus, I'm off on this long considered journey of imaging. Entry level of course, but the fun is in the learning for me.

In these early days I'm pleased with the image of Jupiter with the webcam, plus a couple of check images of starfields taken with the DSLR and shortened Meade 130. Of course, I can see that alignment and tracking using the simple motor drive will be a great challenge, plus getting Registax to work with individual images on my PC - seems to be OK though for AVI video files from the webcam. Hopefully the wide field of view of the Meade will be forgiving of poor tracking!

Lots of questions (e.g. does the tracking motor speed vary depending on declination?), though this seems to be the right place to find answers.

So a 'hello' from the IOW!

Bob

Polaris and starfield.jpg

Jupiter3.jpg

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Hi Bob,and welcome to SGL.I`m sure you will get all the answers to all those questions, as they are very knowledgeable here.the images are good,just a bit of trailing.Des

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Hi Bob and welcome to SGL - Glad that you found us and that your interest has been rekindled! I hope you enjoy your time here.

Look forward to seeing you around :)

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Quote:   "Lots of questions (e.g. does the tracking motor speed vary depending on declination?"

Hi Bob,

Using an equatorial mount, the motor speed should be constant to adjust position for the speed the earth is rotating, regardless of declination (keeping it simple, without bringing guide-scopes and atmospheric distortion into it).  Here' my way of explaining it:  

In the diagram, Telescope T1 is closer to the north pole than Telescope T2. Both have their polar axis aligned to the celestial pole.  Looking at View B, and assuming that at 0 hrs, both telescopes are on the same longitude and are viewing a star, then 3 hours later you can see that the change in angle to view the same star is the same for both telescopes.  The star is effectively at infinity, so the light from it will always be travelling parallel whichever part of the earth it falls upon.  

Hope that makes sense.  

John

 

EffectOfDeclination.jpg

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Hi Bob and welcome from another new member of Stargazers. I live in a rather wet & cloudy West Yorkshire – sounds like you have good sky's in IOW – enjoy. I have a Meade LX200 12” but it's not in good shape – hope to get new kit soon and “restart” my hobby.

Will :hello:

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Thanks for the welcomes and to John (Starwiz) for the explanation on declination. My question on motor speed relative to declination came about after a quick polar alignment and viewing a star close to the celestial equator that showed motor tracking was achieving something as the star remained relatively static in the eyepiece view for a few minutes when the RA motor was on, compared to it relatively quickly moving out of view with the motor off.

So, having thought the telescope was reasonably aligned, I had a peek around the sky (exciting as very new), took a few images and then decided to (as originally planned) take some starfield photos to see how well the camera/telescope combination was working. The sky around Polaris seemed a good place for these images, but I was surprised to see star trails indicating an alignment error. After a couple of images showing the same error, I switched the motor off and was even more surprised to see that the star trails all but disappeared!

Now with a bit more time, I can see that Polaris also had a trail and the trails were not circular, so the alignment must have been well off. Perhaps something moved that shouldn't have.

Often we learn more by the mistakes we make than the things we get right.......(old Chinese proverb?).

 

Polaris badly aligned.jpg

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Hi Bob & Welcome to SGL.

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Hello and welcome to SGL. You live in a good spot for stargazing!

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