Modded Webcam for Polar Scope

While waiting for the weather to improve I was browsing youtube for more info on how to improve my polar alignment and came across a few videos from Astronomy shed.
His site is here and is worth a look when you have time:
 http://www.youtube.com/user/astronomyshed?feature=watch  
 I have since subscribed!

 One of his projects is to modify a webcam for the polar scope and I can tell you it was a breath of fresh air to know I am not the only one to suffer from wet knees trying to get my astrotrac properly aligned. In fact, I hope the webcam can be ported to my CGEM mount as well but I'll try that later.

This is the video I watched beforehand:
http://www.youtube.com/watch?v=5L6IvfievRE&feature=BFa&list=UUFK1huCp-0Y3COTfkoV6cVQ&lf=plcp

 Here's a summary of what I did. As I am over the inlaws for Christmas I was fortunate to convince my father in-law that he didn't need the logitech webcam lying in a draw since the new PC has an in built webcam. So, here's how I managed to disassemble and fit a cap the snuggly fits over the end of the polar scope.    


I'm happy with the focus and have the option to focus the scope when I'm in the field next.  On this polar scope I have illumination but the contrast was not ideal to show it. I'll add to this post with I have a chance to point it to the night sky. I'm a little concerned with how sensitive this webcam is to low light as it wasn't the preferred Phillips SPC900 but we will see.

Journal Entry 5 Dec 2011 - Just give me 1 clear shot of Jupiter, Pleeeeese!

Oh, the weather is horrible and I feel a little jilted because this morning the sky was so clear.

Anyway, the clouds have thinned out and I can see Jupiter and moon though still through cloud.

Let's see if I can get another pick of Jupiter's Satellites for the Jupiter mass determination experiment.

1) Jupiter mass determination

Equipment:
Astrotrac in lunar tracking mode
70/420mm APO ED Refractor
DBK41AU02AS Astronomy camera by ImagingSource
Baader Hyperion Zoom 8-24mm eyepiece
Laptop + RSpec

Setup:
70/420mm APO ED Refractor mounted on Astrotrac mount in sidereal tracking mode.
Diagonal added to Hyperion 8-24mm Zoom set to 20mm.
50 frames video avi captured with DBK41AU02 colour camera exposure time set to 1/ sec.







Jupiter at 600 px
Io at  539 px
Ganymede at 449 px
Europa at 376 px
Callisto at 37 px

Journal Entry 17 Oct 2011 - Back to my C11

Well my summer love affair with a 115mm refractor came to an end last night when I decided to go back to my first love, Celestron SCT C11 and have another look at Jupiter.

The APO 115 refractor has been a joy to use but in getting the detail of Jupiter while its in opposition just needed more aperture.

Here's my pictures while I prepare to explain the set up.

Journal Entry Nov 30th 2011 - Sun viewing

The clouds are clearing!

There was news of a huge CME erruption on Nov 26th inspired me to get a picture of the sun as soon as the clouds and fog clears. At last I got my chance.

Equipment:
Astrotrac in Sun tracking mode
70/420mm APO ED Refractor
Sun mask made from Baader Astrosolar filter foil
Astrodon Photometrics V filter
Astronomy camera DBK41AU02AS by ImagingSource



Weather:
8 degreesC
92% Humidity
1021 hPa
patches of cumulus cloud and some high level sirus cloud with patch of blue sky

 Images:



Pictures each stacked and processed with Registax6 from 200 frames. Left or top image has exposure time of 1/2500 sec and Right or bottom image has 1/2000 sec exposure time. Darks and Flats subtracted.

Here's a labelled image.



Ref:
Spaceweather Nov 30

Journal Entry 30 Nov 2011 - Eeek, the fog is rolling in....again!

Quick picture of moon before the fog really rolls in.
By 18:45, just 1 hr later I was covered in fog. Just made it!!!

Equipment:
Astrotrac in Sidereal tracking mode
70/420mm APO ED Refractor
Baader Moon & Skyglow Neodymium filter
DBK41AU02AS Astronomy camera by ImagingSource

Weather:
1 degree C
90% Humidity
1021 hPa
clear with fog increasing

Images
Pictures each stacked and processed with Registax6 from 200 frames.
exposure time of 1/625 sec per frame.
Time - 17:46 - 17:48 hr



 

 

 

 

Sidereal Time Experiment

The diagram above shows that there is a difference of approx 4 mins between a sidereal day and a solar day.

Here's a great app that shows the difference pictorially.
sidereal Solar Time



The following experiment is designed to test the hypothesis that a sidereal day is shorter than solar day.

Aim:
To show that a sidereal day is shorter than a solar day and to quantify the difference.

Method:
Regular observations of a reference star crossing a reference meridian noting times.
Reference star is Rigel with Alnitak used to verify results.
The process of capturing the times when Rigel and Alnitak crosses a point in space was automated using Canon EOS 1000D controlled by software known as Backyard EOS.
To ensure a consistent line of sight, 2 landmarks were kept in alignment.
Landmarks used to ensure consistency of the field of view were:
1. Power pole
2. Apex of neighbours roof.



















Results:

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Nov 7 2011












  Nov 14 2011














 Nov 22 2011

Dec 01 2011

Journal Entry 2 Dec 2011 - Start Jupiter mass determination exercise

Sky clearing, seeing good.
2DegC, 86% Humidity, 1011hPa
Session stopped at 23:15hr with poor seeing.
Temp 0.5 Deg C, 88% Humidity, 1011 hPa with fast approaching Sirus cloud and slight fog

Objectives for tonight:

1. Start Jupiter mass determination exercise
2. Moon pics with Astrotrac and eyepiece projection
3. Try out Helmut's eyepiece reducer

1) Jupiter mass determination

Equipment:

• Astrotrac in lunar tracking mode
• 70/420mm APO ED Refractor
• DBK41AU02AS Astronomy camera by ImagingSource
• Baader Hyperion Zoom 8-24mm eyepiece
• Laptop + RSpec  

Setup:
70/420mm APO ED Refractor mounted on Astrotrac mount in sidereal tracking mode because I couldn't get the damm thing to go into lunar tracking mode.
Diagonal added to Hyperion 8-24mm Zoom set to 20mm no reducer for this work.
50 frames video avi captured with DBK41AU02 colour camera exposure time set to 1/10 sec.





Results:
50 frames video avi captured by DBK41AUo2 camera, stacked and process by registax.

Satellites of Jupiter for Dec 2 at 19:43 hr

Neg image by Irfanview and labelled in Gimp

Analysis of image by RSpec.

Jupiter mean position = 154 px
Io  mean position = 50 px
Callisto mean position = 75 px
Ganymede mean position = 120 px
Europa mean position = 331 px



2) Moon pics taken through 24mm eyepiece projection, tracked by Astrotrac, 200 frames captured by DBK 41 AU02. 200 frames stacked and processed with Registax.

With 0.5x Focal Reducer



Discussion: (not finished)

1. Jupiter mass experiment went well. From the no. pixels from Jupiter's center I can track the motion of Io as it moves like a pendulum. I decided to leave the numbers as pixels and not try to measure the distance from Jupiter's center in mm's. 
2.  0.5 Focal Reducer improves field of view but with slight vignetting. Still when recording the moon at 24mm via eyepiece projection I prefer to get as much as possible of object in view.