New Scope and Moon

We finally had a nice weekend with clear skies. I have just added a Celestron Classic C8 to my telescope “collection.” I’ve used this particular telescope several times in the past and always admired it. Apparently, I’m the only one that has used it over the last few years because I no longer have to borrow it, it’s mine now.

So, of course I’m antsy and want to get it outside and check it out to make sure everything’s in place and doesn’t need adjusting. With last Friday being nice and clear that’s exactly what I did.

The feature I was most curious about and eager to test is the ability to attach my camera to the telescope. It came with the T-back and I had the T-ring for my camera. I was hoping not to need to use a Barlow or my T-adapter. In theory I shouldn’t need it, but I just didn’t know.

With the night so clear and nice, I quickly assembled the telescope and had it ready to go. The Pentax attached just fine to the tube and it was a mere 5 minutes to attach the wedge to the tripod and the telescope to the wedge. This night I elected not to use the clock drive but rather to direct it manually. I also did not align the scope on Polaris. The goal, after all, was to just check things out.

Image of the viewing end of a Celestron orange Schmidt-Cassegrain 8" telescope with a Pentax K-10D DSLR mounted where the eyepiece would normally be.

My Pentax K-10D installed on the Celestron Classic C8 using a T-ring and the telescope’s T-Back.

I’d forgotten that my Pentax K-10 only records up to a 800mm lens in the EXIF data. So, the pictures I took all say the focal length is 800mm and don’t show the f-stop. In this setup, the C8 becomes a 2000mm f/10 prime telephoto.

The first target was the most obvious: Luna, Queen of the Night.

It was immediately noticeable that the finder scope was off to one side. With the moon centered in the crosshairs, She was not visible in the viewfinder of the camera. There was an apparent faint glow off to one side, so I moved the telescope that way. Almost immediately, the viewfinder filled with a soft white light, obviously the moon. For a couple of seconds I was disappointed before I remembered I had yet to focus the image in the main tube. It didn’t take much adjustment to bring the moon into focus, and it was a beauty. I just enjoyed the sight for a while, almost forgetting that I had the camera attached and not an eyepiece.

I played with the focus a little, trying for the best possible view. The camera was already on manual mode, so I checked the ISO, set the shutter to a 2 second delay, and adjusted the shutter speed. Setting the shutter to a 2 second delay gave the system two seconds after the shutter was released to let any vibrations die out before actually recording the image. I had hoped to set the f-stop manually but was unable to, which actually is normal for a fully manual lens on this camera. The camera has no way to tell what the aperture is, so it refuses to let you set anything there. Adjustments to update the EXIF will have to be done after the fact, which is easy enough to do.

With everything set to my satisfaction, I began taking pictures, adjusting the shutter speed for each shot and checking in the display. For each shot I would move the telescope to lead the moon slightly, then press the remote shutter.

Image of a half-moon taken through the C8 telescope with the Pentax K-10D

The moon taken through the Celestron Classic C8. I love how it fills the entire viewfinder.

This worked well because there was enough reflected light from the moon that I could utilize high enough shutter speeds to freeze the moon’s motion. No tracking was necessary.

So far, everything was working well. There were only two issues that I could see. The first was the misaligned spotter scope. An easy enough fix and one I’ll take care of soon. The other is more a use issue than real problem. Even then, it’s only an astrophotography problem and not a viewing issue since when simply observing I can use the right angle adapter for the eyepiece. That night, the moon was up high, almost overhead, and that makes it a little hard to get a good view through the camera. That’s one reason the spotter scope has got to be aligned.

Satisfied with all this, I turned my eyes to M42, the Great Nebula in Orion.

It was just visible, even with all the light pollution in my driveway. I decided to try some camera shots just to see what would come out.

I’ve taken shots of the night sky before, and even have images with a fairly decent Milky Way and very little star trails. I even got this nice shot of M42 with just an 11mm lens on the camera. I’d forgotten, though, just how narrow the field of view for a 2000mm would be. Even though I used the least possible amount of shutter speed, I could not avoid very noticeable star trails. That, of course, made the nebula itself impossible to see in the resulting photos. It was also a good reminder how little of the sky would actually be in the image.

Happily, I also have the piggyback mount so I can attach my camera to the top of the telescope and hopefully use my 200mm and 400mm prime lenses for some deep space photos. For this type of astrophotography I’m going to need the telescope tracking and that is actually one of the reasons I’m so happy to have this scope. I look forward to seeing how this turns out.

Yes, my Celestron 102GT does have NexStar guidance, but it does not yet have an easy way to mount the camera on it. However, given all the control I have for it, as indicated in this blog post, it may be that I will mount the camera on the tripod in place of the telescope and use the NexStar guidance/Stellarium control to do my astrophotography tracking while I use the C8 to enjoy the night skies at the same time. I just have to build a camera bracket first.

All in all, I am every bit as pleased with the Celestron Classic C8 as I expected to be. Before I use it again, you can bet I’ll have the spotter scope zeroed in and the piggyback mount installed.


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