mental4astro
09-03-2011, 09:04 PM
After a week of anticipation of clear skies after taking delivery of this beautiful Old Girl, I finally had a fang of this 30 year old icon of amateur scopes.
This is the C8 that Leonard Nimoy advertised back in the early 80's. It was one of two dream scopes of mine back then. The other was the Coulter Optics Odyssey II (the 17.5" model, and guess who's got one too? :D ).
As I already have a Celestron C5 of the 1990's vintage, I was able to compare the optics and tracking capabilities of both as the two use mains power clock drives: no fancy electronics here!
This C8 also doesn't have the "special high transmission coating". Celestron offered this coating as an optional extra back then.
After a rough north/south alignment, I first checked the collimation with Sirius. I was most impressed with the out of focus image I saw- perfect cocentric airy discs with not a hint of skewing! Most impressive, particulary considering it's probably been many years since the optics had been collimated.
As viewing conditions wheren't great, I just did a quick tour of some old fav's, trying different eyepieces and filter combinations. M42 was already in my western, and worst sky. The background skyglow washed out a lot of detail, but the faint filagree was certainly there. A lovely soft green "eagle".
Eta Carina was next. Having a fork mount, objects near the south pole tend to be tricky to manuover to. Some mental gymnastics are needed to work out the best positon of the diagonal. Here my 20 years experience with the C5 came in handy. Eta was a better location than M42, and the view was just splendid. Billowing gas clouds, dark pillars, masses of star clusters, and the Homunculus, all there, not just hinting at, but ALL THERE! Tack sharp and inviting more time to be spent on it. I'm sure I uttered a "WOW".
By now the Sombrero was up over the garage's roof. Not an ideal situation, but you take what you get. M104 was a soft streak with a definite dark lane spliting the two halves.
Omega Centauri is always special. With so many tiny stars, it needs a moments pause to one side of it for its full magic to take hold. An intense ball of stars, much brighter than in the smaller C5.
The Jewel Box was a must. It was the first DSO I saw through the C5. Just a stunning scattering of diamonds with a lovely bright red ruby smack bang in the middle.
Then, Old-Man Saturn. This showed some interesting quirks in this old C8. Taking the magnification to 333X with a TMB Planetary Type II 6mm (way more than the atmosphere allowed that night) showed up something that the C5 doesn't have- image shift when focusing. I had heard much about this curse of SCT's and Maks, but Celestron had solved this problem by the time my C5 was produced. A recent viewing of a brand spanking new 7" Skywatcher Mak showed me image shift for the first time (obviously something that still needs fine tuning in these scopes). The image shift in the C8 was only a little more than this new Mak.
This is a brilliant planetary scope. Its slow focal ratio easily accomodates high power viewing without needing a barlow. This C8's optics are so sharp, that the fleeting moments of clarity showed not only Cassini's division, but striations in cloud formations. Like I said, Saturn was rising over my garage roof, so less than ideal conditions, but the image quality was still outstanding.
I've added a couple of single frame pics of Saturn using the webcam-come-astrocam I made following the instructions in the Articles and Projects heading. I really don't have too much of a thing for imaging, but these little cameras are still a wonderful tool at least at star parties in urban areas. The smaller image is neat through the scope (2000mm focal length), the second is using a 2X barlow (effective f.l. 4000mm). I'm pretty chuffed with these two modest little pics, :) .
Many thanks for taking the time to read this. I just had to share my thoughts on this beautiful scope whose optics many people consider have rarely been matched or surpassed.
This is the C8 that Leonard Nimoy advertised back in the early 80's. It was one of two dream scopes of mine back then. The other was the Coulter Optics Odyssey II (the 17.5" model, and guess who's got one too? :D ).
As I already have a Celestron C5 of the 1990's vintage, I was able to compare the optics and tracking capabilities of both as the two use mains power clock drives: no fancy electronics here!
This C8 also doesn't have the "special high transmission coating". Celestron offered this coating as an optional extra back then.
After a rough north/south alignment, I first checked the collimation with Sirius. I was most impressed with the out of focus image I saw- perfect cocentric airy discs with not a hint of skewing! Most impressive, particulary considering it's probably been many years since the optics had been collimated.
As viewing conditions wheren't great, I just did a quick tour of some old fav's, trying different eyepieces and filter combinations. M42 was already in my western, and worst sky. The background skyglow washed out a lot of detail, but the faint filagree was certainly there. A lovely soft green "eagle".
Eta Carina was next. Having a fork mount, objects near the south pole tend to be tricky to manuover to. Some mental gymnastics are needed to work out the best positon of the diagonal. Here my 20 years experience with the C5 came in handy. Eta was a better location than M42, and the view was just splendid. Billowing gas clouds, dark pillars, masses of star clusters, and the Homunculus, all there, not just hinting at, but ALL THERE! Tack sharp and inviting more time to be spent on it. I'm sure I uttered a "WOW".
By now the Sombrero was up over the garage's roof. Not an ideal situation, but you take what you get. M104 was a soft streak with a definite dark lane spliting the two halves.
Omega Centauri is always special. With so many tiny stars, it needs a moments pause to one side of it for its full magic to take hold. An intense ball of stars, much brighter than in the smaller C5.
The Jewel Box was a must. It was the first DSO I saw through the C5. Just a stunning scattering of diamonds with a lovely bright red ruby smack bang in the middle.
Then, Old-Man Saturn. This showed some interesting quirks in this old C8. Taking the magnification to 333X with a TMB Planetary Type II 6mm (way more than the atmosphere allowed that night) showed up something that the C5 doesn't have- image shift when focusing. I had heard much about this curse of SCT's and Maks, but Celestron had solved this problem by the time my C5 was produced. A recent viewing of a brand spanking new 7" Skywatcher Mak showed me image shift for the first time (obviously something that still needs fine tuning in these scopes). The image shift in the C8 was only a little more than this new Mak.
This is a brilliant planetary scope. Its slow focal ratio easily accomodates high power viewing without needing a barlow. This C8's optics are so sharp, that the fleeting moments of clarity showed not only Cassini's division, but striations in cloud formations. Like I said, Saturn was rising over my garage roof, so less than ideal conditions, but the image quality was still outstanding.
I've added a couple of single frame pics of Saturn using the webcam-come-astrocam I made following the instructions in the Articles and Projects heading. I really don't have too much of a thing for imaging, but these little cameras are still a wonderful tool at least at star parties in urban areas. The smaller image is neat through the scope (2000mm focal length), the second is using a 2X barlow (effective f.l. 4000mm). I'm pretty chuffed with these two modest little pics, :) .
Many thanks for taking the time to read this. I just had to share my thoughts on this beautiful scope whose optics many people consider have rarely been matched or surpassed.