De-Forking a Meade 8″ SCT OTA

This sound a bit obscene but I promise that no animals, people or telescopes were harmed in the process.

The Meade SCT in question is an 8″  2080 model that I purchased around 1992. I used it quite a bit for a number of years until my interest turned to astrophotography. The specific model do not have a dec motor and the RA motor is running off 240VAC.

img_2775Over time I build an invertor that could work from AC or 12VDC and allowed me to vary the frequency  around the nominal 50Hz and I could therefore do some manual guiding in RA with a set of buttons and with the existing fine controls on the DEC. It worked a treat for a while but anybody that has guided long exposures manually will know that its a very tedious exercise with unpredictable results.

Well, now everything has changed. The new Skywatcher EQ6-R can easily carry the 8″ OTA (Optical Tube Assembly) as well as my ED 80mm and new opportunities becomes available.

I had to de-fork the OTA out of the Meade fork mount to allow me to fit a Losmandy plate to allow for the OTA to be fitted to the EQ6-R. There are a lot of guidance on the web for how to do this but I used the following site:

http://uncle-rods.blogspot.com.au/search?q=getting+deforked

Its remarkable easy and took no time at all.

Loosen two bolts on one of the arms first.

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Then remove three small bolts from each side of the tube. Take care to work on a soft surface and have someone assist you to make sure you don’t scratch the tube surface.img_2779

And its off!img_2780

Now to mount the Losmandy DM8 kit into the existing holes on the OTA.img_2783

10 minutes later…img_2784 img_2785 img_2786

And now the amazing Meade 8″ OTA can be used on a very capable and accurate mount. A big change for me and there should be some new images soon.

img_2788With my luck it will probably be cloudy and rainy for a month now ….

Unpacking the SkyWatcher EQ6-R mount

The EQ6-R has arrived on Thursday and I unpacked it that night. No surprises there….

Here are some photos of the process:

img_2751 img_2753 img_2754 img_2755img_2756 img_2757 img_2758The handle makes it easy to lift the mount head with one hand.img_2759 img_2762The adjustments bolts look quite solid, at least 15mm on the main altitude bolt and 12mm on the other three.img_2766 img_2767Saddle takes Vixen and Losmandy.img_2768 Probably not many changes visible here on the cable panel except for the power connector that is now a solid screw on type.img_2769 img_2770Synscan loaded with version 04.37.03.

img_2772 img_2773 img_2774Waiting for the weekend now and a mounting plate for my Orion ED 80mm EON and also a Losmandy DM8  dovetail plate for my Meade 8″ SCT.

SkyWatcher EQ6-R mount

Well, I have finally surrendered to the temptation of getting myself a heavy mount.

Initially I was looking at the Skywatcher NEQ6 Pro but then discovered that the brand new Skywatcher EQ6-R mount is available on a limited product release from an Aussie supplier. Major changes are the belt driven system with zero backlash, PPEC support, newer motor drive with lower periodic error, improved tracking accuracy, 20kg payload capacity and a carrying handle!

skywatcher_eq6r

Basic specs are as follows:

eq6-r-specs

Will be delivered next week so expect more feedback here soon ……

Worm Wheel and Worm for anyone?

I am thinking of making some more worm wheels soon. My new lathe will be set up soon and it will allow me to make the worm wheels much quicker and hopefully more accurate.

If anybody is interested in ordering a specific worm wheel, please let me know and I will see what I can do. Send me your requirements ( starsinphotos@gmail.com ) with the size of the wheel (or the number of teeth. I suggest that you use an ACME thread as it does not bind as easily as a metric thread. I could also make the worm from an ACME threaded rod  (10mm diameter with a 2mm pitch) as shown in my blog.

I will look at your requirements and let you know if I can make it and then we can discuss a price that suits us both.

Updated 19 June 2016:  I have found that nothing is easy. The lathe is not quicker, if anything its harder to get it right. I will have to fine tune the production process before I can go into the business of selling worm gears. 🙂

Tracker 5 April 15-1149 Tracker 5 April 15-1148 Worm detail Jan15-1 2 x 130mm Al disks Tracker progress Jan15-1 IMG_1726

Canon EOS 600D IR filter Replacement Results

A couple of weekends ago, late on a Sunday afternoon I decided that the time was right to open up my 600D. I suppose I was in a hurry and couldn’t wait any longer. The clear glass replacement filter has just been sitting there and I was already prepared with all my tools and silicon, etc.

So I did it.

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Opening the camera up was pretty easy. I used the following websites to guide me along:

http://dslrmodifications.com/rebelmod450d1.html

http://www.lifepixel.com/tutorials/infrared-diy-tutorials/canon-t3i

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A large number of very small and delicate connectors have to be disconnected.

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Eventually the CCD assembly can be removed.

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This is the complete filter and imaging chip assembly, before I took it apart (and almost broke it…)

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The piezoelectric element is removed here..

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And here I was too impatient and broke the IR cut filter. The crack line can be seen from top left to bottom right. I should have ready the instructions in more detail! Take it from me, don’t be in a hurry when you do this. Fortunately there was no damage to the imager chip and after I cleaned all the filter glass fragments off the CCD surface I could start the assembly process again.

The clearglass filter replaced both the IR cut filter and the piezoelectric filter element. I have now modified the camera to a full spectrum camera.

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Pieces of the IR cut filter. This is not the way to do it!

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Inside of camera, looking at the back of the shutter.

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Putting it all together was reasonably easy. The most difficult part was to get the imaging assembly in the correct position to allow the auto focus to work properly.  I will have to make some more adjustments to get the auto focus to be more accurate. It can wait as I mostly use manual focus for astrophotography anyway.

A big sigh of relief when the camera fires up and still works !

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A weekend later and I was testing the camera under an almost dark sky. Nothing spectacular but just confirming that it all works as it should.

Orion Nebula (M42 / M43)

Picture saved with settings embedded.

 

Large Magelanic Cloud (LMC)

Autosave

Coalsack with the Southern Cross and two pointers

Coalsack

And, the evening would not have been complete without a image of Carina.

Carina

Added a declination axis to the tracker

This project is never going to end…..

I have been very busy at work over the last 10 months and have done very little with my projects or even observing under the night skies. Over the Christmas break I started a little project to add a declination axis on the tracker to be able to install my Orion 80ED. It looks a bit weird but it works a treat.

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The new dec axis is based on another 20mm mild steel rod that is clamped in a 40 x 40 x 80mm aluminium block that is mounted on the RA axis. This dec arm is currently locked in place by tightening the split block with two allen key screws. Not very elegant but rock solid. The dec axis is long enough to handle a counter weight but when I used it, I did not have any counter weight on and the system handled it without any worries. I think that it may be able to take my Meade 8″ SCT telescope if I add a counter weight as well.

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When I tested the new setup I was battling like crazy to get a guide star in view and in keep it in focus. It would really be a good idea to buy a proper guide camera to do the job properly. The webcam is ok to start with but it’s frustrating when you are trying to change to a new target quickly. The sensitivity of the webcam is not great. In a dark sky it works reasonably well but in a polluted sky it’s no good. Hopefully I can afford to spend a few hundred dollars on a dedicated autoguider camera with a ST-4 port, it would make the guiding experience much easier.  Does anybody have any recommendations for a good camera?

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I almost forgot, I have now effectively locked down the RA axis and I don’t have a clutch on the RA axis. I have to drive RA with the motor to point in any particular direction. I have added a switch and some new code on the stepper driver box to allow me to change the stepper motor speed to slew the RA axis faster or slower. It works well but I wont be able to handle a crowd at a star party with this setup!

Carina Nebula from under a streetlamp

I had to test my new tracker with autoguiding and could not get away to a dark site so I decided to test it in the front garden where I could reach further south towards Carina Nebula. Unfortunately I have a bright streetlamp in front of my house. I tried to shield the light from falling on the camera and lens to avoid the worst effects of the light conditions. I use a modified Canon 350D and got 29 light frames of 30 seconds each, 7 dark frames and 18 bias frames at f/5.6, ISO 800 with a 250mm focal length.  Ideally you would try to get longer exposures than 30 seconds but the sky was so bright that I had to limit the exposure time for each frame.

Picture saved with settings applied.