First light with my new CPC 8" and Ethoses.

[luminary (Ben)]

After a week, I suddenly had an opportunity to use the scope properly for the first time. I had had one or two opportunities to familiarise myself with the alignment process on clouded nights by using the moon and another visible star using two star auto align. Had also allowed it to get the GPS ephemeris etc by leaving it on for half an hour etc.

Today after a week of cloudy nights, took the scope out to the yard at 18:00 where there is unfortunately much light pollution from a neighbours "security lights" and a street light but not much I could do about that.

Got myself ready and covered in aerogard. Waited till about 18:30 and started the alignment process with the two star auto align. Started with a-Centauri and let it slew automatically to Canopus and it was way off. Found the alignment through the finder scope difficult at this angle as Canopus was almost at the zenith at that point. So restarted by aligning first on Canopus - I released the clutches and aligned by hand first. Then allowed it to auto slew to a-Centauri - again miles off but I used the motor to get it in the finder scope and pressed align. Everything went through OK.

I had the 21mm Ethos in the diagonal. Alignment was made easier by defocussing so the star airy disc becomes large and centering this in the eyepiece is alot easier than a small pinpoint in the 100 degree field.

The defocussing gives a nice impression of collimation too. Practically perfect in this case from the factory. Very impressive.

Focussed back on the star again - a-Centauri easily separated as a double. The 100 degree expanse of the Ethos is very very nice. It definitely requires the eye to be placed carefully and close but I had no difficulty seeing the field stop with my peripheral vision when I wanted to concentrate on it. Other times the central vision takes over and one feels immersed in the field.

OK so I decided to try out NGC104 or Tuc 47. This is in a very bad spot for me since the streetlight is in the same rough direction. Slight tweak of the focus and I see a nebulous patch - faint. Individual stars are just visible but at the limits of direct vision. AVerted vision gives slightly more but its not very impressive from my location.

Saturn had just cleared the roof of the next door neighbour by now so I did the GOTO to it.

A slight amount of recentering (due to my alignment imprecision initially) and I had the cute disc of Saturn and its rings edge on. I tweaked the focus somewhat and the viewing was very steady. After a little time i could make out very slight banding. After a further period I could resolve two moons. Both Westward - the rings were running vertically and the moons were superior or Westward as I looked at it in a laterally reversed view through the SCT. One moon, the easier to see was about a rings width away outside the rings and the other was observed just below or Southward and within the span of the rings.

At this point I changed over to the 13mm Ethos and refocussed. The viewing was again steady and the two moons were much easier to resolve. wished I had a higher power eyepiece at this point but the view was superb. The wide field of the 13mm is also immersive and very easy to use.

Noticed here that the focussing knob on my CPC is very slightly notchy in that it seems to move in little bursts at times and very occasionally I see the image jump somewhat. Not sure if this is normal for an SCT.

After about 3-5 minutes of observing Saturn - with only very occasional slow turbulence in the view which I put down to some heat off the neighbours roof and not atmosphere since the viewing was very nice tonight; I decided to look at a few other easy targets.

First eta Carinae nebula. Back to the 21mm Ethos. And here I was just stunned. Even with the light pollution, the nebulosity was evident. I could make out in the dark lanes the "emu's head" and neck of the emu. The 100 degree field was simply amazing. I spent 5 or more minutes just looking here with direct and averted vision.

Then to the jewel box. Again stunning. Greeted with groups of three and four almost collinear stars like mini Orion's belts. Surprisingly geometrical and I could see the orange of one of the stars easily.

Finally to omega centauri nebula (NGC 5139) and again a bit of a disappointment in the light pollution, like Tuc 47 but I could just see the faint cluster of stars filling the entire central field of the Ethos. I didn't bother going to the 13mm as doing that on NGC 104 had resulted in a less than stellar view - pun intended.


Had to cut the session there as I had prior commitments and really took the scope out to get my first real views. About an hour of viewing and despite the tropical strength Aerogard roll on.. the mozzies had gotten me on the fingers.

I was very impressed at what I could see despite the light pollution and now can't wait till I use this in real dark sky conditions.

[MikeyB (Michael)]

Thanks for that interesting observation report, Ben and congratulations on your new scope. You've got two great eyepieces there too and when you can get to some darker skies, I'm sure you'll be thrilled with what you see.

On the somewhat jerky focusing you mention, can I suggest you try turning the focus knob all the way from one extreme to the other a couple of times (many, many turns!). That should ensure that the initial manufacturing grease is more evenly distributed along the internal moving parts than perhaps it is at present.

[telecasterguru (Frank)]

Ben,

Thanks for the first light report. Enjoy your new scope.

Frank

[kustard (Simon)]

With the two star auto align on my CPC 925 I find that the accuracy is not that great. I've tried a few combinations of stars with varying successes. I'm assuming your CPC is the CPC 800 GPS and has the SkyAlign feature which lets you align on 3 bright objects. I have found this method of alignment to be the best and most accurate.

The thing to remember with the SkyAlign feature is that when you point to the third object that this object is not on the same line as the first two objects. I found that if you can make the biggest triangle in the sky with the three objects then you get the best alignment and accuracy.

Remember to only use the manual alignment with the first object, if you release the clutches with the subsequent objects it will affect the alignment process (i.e. use the controller to slew to the other two objects).

As Michael pointed out, moving the mirror from one extreme to the other a couple of times will help with the mirror shift problem. I've done it with mine but have noticed it's still quite jerky (though my old C8 was nice and still) so I've gone and put a Crayford focuser on the scope which improves focussing no end (though not really required, I just happened to have the money to get it).

Other than that, nice report and good to hear you had a good experience with the eyepieces.

NB: I can recommend grabbing a Telrad or RedDot (zero magnification) finder to help with the initial alignment of the scope. Once you're aligned you can turn it off but I find them (I've used both) really useful if the scope is at an awkward angle.

[luminary (Ben)]

Originally Posted by MikeyB

Thanks for that interesting observation report, Ben and congratulations on your new scope. You've got two great eyepieces there too and when you can get to some darker skies, I'm sure you'll be thrilled with what you see.

On the somewhat jerky focusing you mention, can I suggest you try turning the focus knob all the way from one extreme to the other a couple of times (many, many turns!). That should ensure that the initial manufacturing grease is more evenly distributed along the internal moving parts than perhaps it is at present.

Thanks for this tip... I did it a few times today but now understand that the phenomenon - image shift or mirror shift/flop - is a common issue with SCTs.

The manual makes a very small mention about it in terms of saying that final focussing should be anticlockwise which moves the mirror against gravity. So overshoot clockwise and then move anticlockwise to sharpen up.

[luminary (Ben)]

Originally Posted by kustard

With the two star auto align on my CPC 925 I find that the accuracy is not that great. I've tried a few combinations of stars with varying successes. I'm assuming your CPC is the CPC 800 GPS and has the SkyAlign feature which lets you align on 3 bright objects. I have found this method of alignment to be the best and most accurate.

The thing to remember with the SkyAlign feature is that when you point to the third object that this object is not on the same line as the first two objects. I found that if you can make the biggest triangle in the sky with the three objects then you get the best alignment and accuracy.

Remember to only use the manual alignment with the first object, if you release the clutches with the subsequent objects it will affect the alignment process (i.e. use the controller to slew to the other two objects).

As Michael pointed out, moving the mirror from one extreme to the other a couple of times will help with the mirror shift problem. I've done it with mine but have noticed it's still quite jerky (though my old C8 was nice and still) so I've gone and put a Crayford focuser on the scope which improves focussing no end (though not really required, I just happened to have the money to get it).

Other than that, nice report and good to hear you had a good experience with the eyepieces.

NB: I can recommend grabbing a Telrad or RedDot (zero magnification) finder to help with the initial alignment of the scope. Once you're aligned you can turn it off but I find them (I've used both) really useful if the scope is at an awkward angle.

Wow thanks for the pointers. I did try a 3 point skyalign on the first time I took the scope out and found that the identified three objects were way out - including Regulus which I can't even get due to Northward trees. I'll have to try it again as I think it really requires like you say a triangle of stars. Having said that the misalignment with the two star auto was not great. I mean Saturn was about halfway between the centre and field stop on GOTO.

The included finderscope is abysmal. I'm definitely going to get something like you point out. Telrad probably.

I'm not sure about the Feathertouch focussers yet. Quite a bit of money and I was considering the knob modification but I see the benefit of perhaps using the Crayford type instead.

[kustard (Simon)]

Originally Posted by luminary

Wow thanks for the pointers. I did try a 3 point skyalign on the first time I took the scope out and found that the identified three objects were way out - including Regulus which I can't even get due to Northward trees. I'll have to try it again as I think it really requires like you say a triangle of stars. Having said that the misalignment with the two star auto was not great. I mean Saturn was about halfway between the centre and field stop on GOTO.

The included finderscope is abysmal. I'm definitely going to get something like you point out. Telrad probably.

I'm not sure about the Feathertouch focussers yet. Quite a bit of money and I was considering the knob modification but I see the benefit of perhaps using the Crayford type instead.

No probs, happy to help

The first time I did a SkyAlign it was rubbish and I had no end of troubles, then using a triangle of stars it was much much better. Something else to check is that you are on the right setting for DLS (daylight savings). The first few times I didn't have it selected properly and objects were not right, though now we are back to normal time so it might not be an issue for you.

I have the stock finder and at times wish it had a right angle viewer but it's good enough for initial set up and any subsequent re-aligns.

Give the focuser a few limit to limit turns a few times first and see how it pans out.

The biggest issue I have is remembering to turn off cordwrap and having the scope do a 300 degree turn instead of a 60 degree turn...

[mozzie (Peter)]

great work aligning your scope!!it usually takes a few sessions to get the fell of the scope and its workings.try and come to astrofest in august great people,camping and plenty of scopes