A Successful Telescope Rebuild
The past two mornings, we have had clear skies and the moon has been in the sky until late in the morning. This has allowed me to test the little telescope that I recently finished rebuilding with better parts.
I had to make some adjustments to the tripod mount after yesterday morning's quick test because the mount was a bit gummed up. I disassembled it, cleaned it up, re-lubed it, and reassembled it. This morning, I was excited to head back outside to test this little cheap telescope again.
The primary advantage of this little telescope is that it is lightweight. My better telescope (which is far superior) needs to come outside in three parts... the tripod legs, the actual mount, and the telescope. Since this old cheap telescope (a Celestron 70az... converted to a 70eq) is so small and lightweight, I was able to set it up in a matter of minutes with minimal effort.
The disadvantage of this little telescope is that it has a small aperture (diameter of the telescope) and the mount (a Celestron CG-2) is still a bit puny (but lightweight) so capturing images with a scope such as this is a very difficult task. Everything in life is a balance of compromises and astronomy is no different. This telescope is a compromise which allows ease of portability.
Even though astrophotography is quite difficult to accomplish using this particular telescope (bordering on impossible), I did manage to capture a quick photo of the moon this morning... shot through the telescope and eyepiece... I had my camera with a lens attached directly to the end of the eyepiece... this type of imaging is called afocal imaging. As I had already suspected, afocal imaging with a camera attached to the eyepiece is far too heavy for this particular telescope! The weight of the camera causes the tripod mount to quickly sink on the heavy end no matter how tightly I tighten the locking bolts/knobs (and I can't slide the telescope any farther forward in the cradle rings because it is already as far forward as it will go). Actually, this telescope is not even close to being a viable tool for getting astro-images but, since the moon is such an incredibly bright object, I managed to hold the telescope up and steady enough to capture a halfway decent shot of the moon through the eyepiece this morning.
When viewing the moon while the sun is shining, the contrast is quite low. Regardless, I still managed to capture a fairly decent shot of the moon in these low contrast, bright conditions. This little telescope never before provided such crisp imagery so all my work over the past few weeks seems to have paid off. Before this rebuild, this telescope provided poor imagery and it was frustrating to use. Fortunately, it seems I have fixed all the major problems we had with this little scope.
(Incidentally, I am still waiting on delivery of some new eyepieces for this telescope... they are scheduled to arrive later today. This morning I used eyepieces from my better telescope. EDIT: The new eyepieces for this telescope arrived this afternoon so that is good news.)
And, here is this little telescope... and a little stool to rest my old, tired, weak and painful bu... uhhh... back while viewing...
The next test will be nighttime viewing whenever the sky is clear and my health is cooperating at the same time. I'm fairly confident that the grandkids will enjoy viewing the moon through this little telescope... and, if that goes well, then we can move on to other interesting celestial objects in the night sky...
UPDATE: June 7th, 2018 - I've used this telescope a few times since I wrote this blog entry and I have to say that I'm still feeling frustrated by it. Optically, it is pretty good... if you can get it in focus! That focuser is maddening even with the larger knobs on the focuser. It is still very difficult to finely adjust the focus because there is far too much slop in the focuser... it jiggles in every direction so it does move in multiple directions whenever you attempt to focus.
Because of this unrelenting focuser problem, I am now toying with the idea of putting this telescope in the trash with my Celestron 114eq which went into the trash bin a month ago. I won't ever buy another Celestron product after my experiences with these two telescopes and the crappy accessories that come with both of these scopes.
I may buy a Vixen refractor that is slightly larger than this Celestron 70mm. I can easily upgrade the focuser on that telescope and it gets great reviews regardless.
As far as all the new parts I bought for this Celestron 70mm... I can still use all of them on the new Vixen. I bought a high quality diagonal... I can use that on the Vixen. I bought far better eyepieces... I can use them on the Vixen. The other improvements I made on this scope were more about putting in time and labor rather than cost so not much is lost there.
I'm now thinking that it may be time to just toss out this piece of junk.
I had to make some adjustments to the tripod mount after yesterday morning's quick test because the mount was a bit gummed up. I disassembled it, cleaned it up, re-lubed it, and reassembled it. This morning, I was excited to head back outside to test this little cheap telescope again.
The primary advantage of this little telescope is that it is lightweight. My better telescope (which is far superior) needs to come outside in three parts... the tripod legs, the actual mount, and the telescope. Since this old cheap telescope (a Celestron 70az... converted to a 70eq) is so small and lightweight, I was able to set it up in a matter of minutes with minimal effort.
The disadvantage of this little telescope is that it has a small aperture (diameter of the telescope) and the mount (a Celestron CG-2) is still a bit puny (but lightweight) so capturing images with a scope such as this is a very difficult task. Everything in life is a balance of compromises and astronomy is no different. This telescope is a compromise which allows ease of portability.
Even though astrophotography is quite difficult to accomplish using this particular telescope (bordering on impossible), I did manage to capture a quick photo of the moon this morning... shot through the telescope and eyepiece... I had my camera with a lens attached directly to the end of the eyepiece... this type of imaging is called afocal imaging. As I had already suspected, afocal imaging with a camera attached to the eyepiece is far too heavy for this particular telescope! The weight of the camera causes the tripod mount to quickly sink on the heavy end no matter how tightly I tighten the locking bolts/knobs (and I can't slide the telescope any farther forward in the cradle rings because it is already as far forward as it will go). Actually, this telescope is not even close to being a viable tool for getting astro-images but, since the moon is such an incredibly bright object, I managed to hold the telescope up and steady enough to capture a halfway decent shot of the moon through the eyepiece this morning.
When viewing the moon while the sun is shining, the contrast is quite low. Regardless, I still managed to capture a fairly decent shot of the moon in these low contrast, bright conditions. This little telescope never before provided such crisp imagery so all my work over the past few weeks seems to have paid off. Before this rebuild, this telescope provided poor imagery and it was frustrating to use. Fortunately, it seems I have fixed all the major problems we had with this little scope.
(Incidentally, I am still waiting on delivery of some new eyepieces for this telescope... they are scheduled to arrive later today. This morning I used eyepieces from my better telescope. EDIT: The new eyepieces for this telescope arrived this afternoon so that is good news.)
And, here is this little telescope... and a little stool to rest my old, tired, weak and painful bu... uhhh... back while viewing...
The next test will be nighttime viewing whenever the sky is clear and my health is cooperating at the same time. I'm fairly confident that the grandkids will enjoy viewing the moon through this little telescope... and, if that goes well, then we can move on to other interesting celestial objects in the night sky...
UPDATE: June 7th, 2018 - I've used this telescope a few times since I wrote this blog entry and I have to say that I'm still feeling frustrated by it. Optically, it is pretty good... if you can get it in focus! That focuser is maddening even with the larger knobs on the focuser. It is still very difficult to finely adjust the focus because there is far too much slop in the focuser... it jiggles in every direction so it does move in multiple directions whenever you attempt to focus.
Because of this unrelenting focuser problem, I am now toying with the idea of putting this telescope in the trash with my Celestron 114eq which went into the trash bin a month ago. I won't ever buy another Celestron product after my experiences with these two telescopes and the crappy accessories that come with both of these scopes.
I may buy a Vixen refractor that is slightly larger than this Celestron 70mm. I can easily upgrade the focuser on that telescope and it gets great reviews regardless.
As far as all the new parts I bought for this Celestron 70mm... I can still use all of them on the new Vixen. I bought a high quality diagonal... I can use that on the Vixen. I bought far better eyepieces... I can use them on the Vixen. The other improvements I made on this scope were more about putting in time and labor rather than cost so not much is lost there.
I'm now thinking that it may be time to just toss out this piece of junk.
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