All up testing of DIY homemade telescope mount and first image!
Category: Homemade Telescope Mount
Posted by: Tom How
Following the successful mating of the large Newtonian to the homemade telescope mount, I decided to take things a step further.
In the UK we are running out of darkness. From now until mid-August the stars do not come out until late in the evening and don't stay out for very long. I'm hoping to start using the homemade telescope mount full time later this year, but this weekend, with clear skies and a few days holiday for Easter, is probably the last chance for an all up test of the system. So I decided to pop the new mount into the observatory for a complete test with camera and auto-guider and see what happened.
After nearly killing myself lifting the thing into the observatory and mating it to the pier (the mount weights 30Kg) I got everything setup and waited for the stars to come out.
This test was pretty important as it gave me a chance to find out all the niggles and snags in the homemade mount, and give me a chance to work on them over the next couple of months before I move the DIY mount into the observatory permanently.
First of all the mount seemed to slew around the sky quite well - no problems with the full load of the scope and cameras. Given that my polar alignment is abysmal (I've not polar aligned anything for 5 years - out of practise!) GOTO worked remarkably well. I was able to sync the GOTO to a Alkaid at the end of the Plough, and goto M51 and get it onto the sensor of the CCD camera.
So far so good, but what about guiding? Disappointingly I didn't have a good guidestar anywhere near M51 in the homemade OAG (who wants to image galaxies anyhow!), so I travelled a bit further to M63 and picked up a good guidestar with M63 just on the edge of the frame. Parts of the sky which contain galaxies do not, as a rule, contain many useful guidestars.
Guidedog started working on the guidestar and the Artemis 285 CCD camera started firing off 3 minute exposures. The RA guiding seemed ok - rarely recording errors much more than about 1.5 arc seconds, and the occasional glitch. Due to the dreadful polar alignment, the drift in DEC was huge in this part of the sky - something lie half an arc minute per minute, so the DEC guiding was working overtime. The resulting image has got the stars egging slightly in DEC - although this is hard to tell in the image below due to my esoteric camera angle. DEC runs roughly 10 o'clock to 4 o'clock on the image.
After tweaking around with the guiding parameters I decided this wasn't an entirely fair test due to the massive drift in DEC, however it highlighted that things could be tightened a little in the DEC axis of the mount so reduce sudden guiding jerks as the slack in the gears is taken up, but considering the drift I'm happy.
All the remained was to leave it running for a while. It behaved itself well - so I left it to gather 20 x 3min frames of the region.
Below you can see the image after processing - click here for the full sized one
Below M63 there are some photos of the mount in the observatory - I have to go and lift it back indoors now!
As an added bonus, whilst sitting in the observatory I watched the ISS float over!
In the UK we are running out of darkness. From now until mid-August the stars do not come out until late in the evening and don't stay out for very long. I'm hoping to start using the homemade telescope mount full time later this year, but this weekend, with clear skies and a few days holiday for Easter, is probably the last chance for an all up test of the system. So I decided to pop the new mount into the observatory for a complete test with camera and auto-guider and see what happened.
After nearly killing myself lifting the thing into the observatory and mating it to the pier (the mount weights 30Kg) I got everything setup and waited for the stars to come out.
This test was pretty important as it gave me a chance to find out all the niggles and snags in the homemade mount, and give me a chance to work on them over the next couple of months before I move the DIY mount into the observatory permanently.
First of all the mount seemed to slew around the sky quite well - no problems with the full load of the scope and cameras. Given that my polar alignment is abysmal (I've not polar aligned anything for 5 years - out of practise!) GOTO worked remarkably well. I was able to sync the GOTO to a Alkaid at the end of the Plough, and goto M51 and get it onto the sensor of the CCD camera.
So far so good, but what about guiding? Disappointingly I didn't have a good guidestar anywhere near M51 in the homemade OAG (who wants to image galaxies anyhow!), so I travelled a bit further to M63 and picked up a good guidestar with M63 just on the edge of the frame. Parts of the sky which contain galaxies do not, as a rule, contain many useful guidestars.
Guidedog started working on the guidestar and the Artemis 285 CCD camera started firing off 3 minute exposures. The RA guiding seemed ok - rarely recording errors much more than about 1.5 arc seconds, and the occasional glitch. Due to the dreadful polar alignment, the drift in DEC was huge in this part of the sky - something lie half an arc minute per minute, so the DEC guiding was working overtime. The resulting image has got the stars egging slightly in DEC - although this is hard to tell in the image below due to my esoteric camera angle. DEC runs roughly 10 o'clock to 4 o'clock on the image.
After tweaking around with the guiding parameters I decided this wasn't an entirely fair test due to the massive drift in DEC, however it highlighted that things could be tightened a little in the DEC axis of the mount so reduce sudden guiding jerks as the slack in the gears is taken up, but considering the drift I'm happy.
All the remained was to leave it running for a while. It behaved itself well - so I left it to gather 20 x 3min frames of the region.
Below you can see the image after processing - click here for the full sized one
Below M63 there are some photos of the mount in the observatory - I have to go and lift it back indoors now!
As an added bonus, whilst sitting in the observatory I watched the ISS float over!
