A Glimpse of Saturn

It has been a long and cloudy week, the forecast became glum right after I ordered an auto-guider. The kind folks at the Telesscopes subreddit (reddit.com/r/telescopes) confirmed that my choices were adequate or fine. Listed in that post are the mounting bar by ADM - a few pieces of machined aluminum with a black anodizing coat along with alignment rings. From there we have an 80mm guide scope. Someone recommended I get an ST80 but I could only find a CT80. If I was more patient, I could have gotten a used ST80 - it was a nice enough scope with more metal than plastic. While shopping around I did stumble into a 120mm scope that was a bit more than double the price, but the sample images showed that it excelled for beginner astrophotography.


Further investigation will be warranted, it migth make a good "light configuration" main imaging scope for nights when I don't want to deal with the long focal length of the SCT. It could also make for a decent guide scope, although it would be considerably heavier. So many options to consider.. so much to defer thinking about.



For today's post, I have one photo to share. Perhaps later I shall share the predecessor images which lead me to this final image of Saturn.

Saturn after heave post-processing.

The image was captured though a "Celestron 8" Schmidt-Cassegrain telescope on a Sky-Watcher EQ6-R Pro mount. It was captured on an Olympus Pen E-PL1 mirrorless camera body at prime focus. It started out as a two minute MP4 with an AVI extension and was then processed through registax. The key was the "wavelet" processing feature or filter. I only did two passes with most of the aggressive effort happening on the first pass. It was actually done by adapting a method which some guy used for processing Jupiter.

After having minor success processing Jupiter, I decided to do the same thing to the moon.

 Lunar surface seen through 2x barlow lens with Olympus Pen EPL-1 at prime focus.

At the level of magnification seen above, the waves were big. The image was far too dull to share with the world, but after a two pass wavelet process.. it's pretty acceptable. There is some blurriness at the left edge of the field, most of it was cropped out.

In short, the "lucky shot" method through which video is processed to get a still image works pretty well. In the near future I shall further detail how both of these images were accomplished. For weeks prior, my photos of Saturn and Jupiter had flat homogenized colors and were a bit blurry along the edges although still distinct. They lacked detail mainly because the I had not yet turned off digital noise reduction. Only after turning the noise reduction off was it possible to process that picture of Saturn. I was surprised that any detail from the rings showed up, but there is a thin line between the inner and outer set of rings. Thus, with improved image acquisition we should see further improvements after processing.

An Ode to an Awesome Couple / Thoughts on Temperature

These folks are so cool, they gave me a very helpful head start in the hobby of astronomy and astrophotography. They are the reason that I was able to obtain the Sky-Watcher EQ6-R Pro equatorial mount. During that time I used the telescope in table-top configuration. On the second night I took it outside, it was less than twenty degrees outside and I was using my BBQ's flat surfaces. The steel flexed a lot and the high gusts of wind were not helpful.


Naturally, I did not get clear images of the moon during that eclipse. It was too cold to play with the settings but I still got off a few shots at different ISO exposure settings as well as shutter speeds. It was some of the longer shutter speeds which enabled me to see the pinkish hue of the eclipsed moon. Anyway, from there I took the OTA out on every clear night I could and did a bit of star hopping. In fact, my first use of the OTA was through a window and it taught me some interesting things.


One would expect a window to be a factor in diminishing image quality, and it is but not the biggest factor. The greatest factor in my opinion is that of temperature, on the OTA, in the room and outside. For example, if it is 20-degrees outside and 74-degrees degrees inside, you will not be able to achieve the sharpest focus. For example, while observing the moon you'll get it to a point where it doesn't get any sharper and you can turn the nob a few degrees and see no change. Whereas, if you take the telescope outside and let it cool down, you will be able to achieve sharper focus.


One idea was to simply open the window. Surely this would eliminate the effects of having a window in front of me. I don't think my window is gold plated or super-coated which means it is indeed possible to view through it, while more well tinted/plated windows are increasingly difficult to look through with a telescope. So, I opened the window and it got worse. The image was distorted and got blurrier, at first I thought it was dew/fog on the lens but nope, it was not.

"...I opened the window and it got worse."

My theories were as follows:

* The corrector plate is being incongruously cooled, thereby changing shape by contracting/shrinking ever so slightly. This, while the primary mirror at the rear of the OTA remains at room temperature.

* The scondary mirror getting cooled incongruously. Less likely, it's kinda buried under stuff and I believe it would take longer than a few seconds of exposure for it to be effected.

Then a third one which was proposed by a coworker and auto-buff is that this was the result of "heat waves." I'm not sure about this, but I'm not sure about eliminating this as a possibility just yet either.


Bottom line, once you bring the OTA outside and it normalizes or equalizes to the ambient outdoor temperature, it does indeed perform better.

In the Beginning...

In the beginning, I just wanted a decent newtonian telescope - something for under $500. Maybe around $349. Many advised me to get such a telescope, and to "get the biggest mirror you can afford." During my pre-Christmas research I was talking to a couple about printers. After having recommended a printer, I randomly asked "so, do you know anything about telescopes?" The husband said, "I got this big one in my garage.." No idea on much else about it but he kindly offered to send me a photo of the telescope as he was willing to part with it.


Later that day I received a photo of an orange tubed Clestron from the late 1970s. Right off the bat, I recognized that it was indeed a Schmidt-Cassegrain telescope. The close-up of the placard on the base confirmed it, a "Clestron 8". With some details about aperture and a diagram to indicate that this was indeed a catadioptric telescope. If you don't know what that means, it basically means that there is a hole in the primary mirror at the rear of the tube. This lines up with where the eyepiece or a camera is mounted. The secondary mirror is still in the front, but no longer does it direct the light diagonally to an eyepiece in the front like on Newtonian or Dobsonian design.




What jumped out at me first was the fact that it's fork mount looked like it was taken from a tank, or some other heavy metal machination. It would be fair to consider the current iteration of NexStar 8SE telescopes to be direct descendants of this unit right here. I did not expect there to be anything "electric" but there was a "clock drive" which basically allows the right-ascension (left and right movement) to follow the stars by countering the rotation of the Earth. I've read it's not perfect, some have built or bought control units which reduce or increase the input voltage in order to affect the speed of the drive. I found the AC port to be in a weird place when using it in table-top configuration so I never bothered to test the clock-drive outside. If I had to wait another two weeks for my mount, I would have drilled a hole in the plank of plywood which I've been using as a surface for the base of the fork. Just to see if such a clock drive would allow me to multi-second time exposures.



As I played around with this telescope and learned some of the ropes, people were advising me that a Newtonian or Dobsonian telescope was the way to go. If my only option was a current day SCT, it would have ran me just under one grand. The used C8 that the kind gentleman was "really trying to get rid of" was offered for $250. I felt extremely fortunate, this gave me a head start. I knew that even if I spent a thousand bucks on the OTA that the mount would have still likely costed me more. Was it a fair price for both parties concerned? I think so, it certainly got me to "jump" at buying and stop vacillating over the decision.



Was the telescope ready to be used immediately after? Well, yes and no. Yes it was immediately equipped to get rather stupendous lunar views. Maybe could be better by some other people's standards but it had a lot more zoom than any of my SLR lenses and greater clarity than my camcorders which are capable of rather high levels of magnification. Many years ago I even managed to spot Jovian moons with a Sony HandyCam TR-818. At some point soon I may try a few of my camcorders out, perhaps afocal through the eyepiece. Perhaps this will allow me to do that thing where you extract the good frames or let software filter out the noise. Haven't even looked into that too much yet.


As I've been doing already, I shall perform imaging through an Olympus EPL-1 mirrorless body with the sensor at prime focus. Tonight's plan, weather permitting. First we'll try for tracking the moon. After I've achieved approximate polar alignment. Maybe I'll be lazy and just start in Alt-Az mode. Depends if I can see the constellations around Polaris. Then again, maybe I can use another means to align. Well anyway, first I'll get the mount properly oriented -- whatever that entails. Next I will set my "circles" or whatever you call the various rings with the numbers on them. Setting circles? Well, those. I really think I should buy a real compass. I don't trust my phone although it does a more admirable job than all of my prior devices which claim to have a "compass", compass my... never mind.


Presumably one simply needs to identify where north is and align the mount and the RA ring accordingly. Then once the mount is level to the ground, to do the same for the declination ring. After that, I would power up and use the SynScan keypad to tell the mount where I am, and what time it is. Oh snap, before I even do that I have to probably adjust something based on my latitude. I think that's the only detail that I am aware of not being clear on at this time.


Aside from alighning it right and tracking the moon, tonight's third goal is to point the mounted telescope at the Orion Nebula. To take pictures as I already have without any tracking, except this time with tracking. It is my hope that I can take time exposures that are longer than one second without encountering trails. My goal is to get up to 15-20 seconds. At a 2.5th  second I can resolve the gaseous nature of the nebula, with more time I presume that I'll see more. Of course the ligh pollution will become more troublesome but I'm in a south facing (SSW) backyard, Manhattan is north-east of my position. I fear that finding Polaris can be challenging but at least it's a number of degrees left and away from the graduated dome of light which emanates from the heart of of this metropolis.

In The Beginning: Indoor Observation and Attempts at Imaging

With wind gusts in excess of 30 MPH and my having to get to bed, it was justifiable not to be outside with my telescope but the moon was in direct  line of sight through my window, so I had to try and capture it. Something new is learned every day; since I've started shopping for a telescope and after receiving one delivery of the "Clestron 8" OTA with stock fork mount. Ready for use in "table-top" configuration.

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General observations since starting;


Focus can be fairly sharp but it only gets so sharp "sharp" before it can't be made any sharper when used from my indoor sky spotting corner. First few times I used it inside my room I was worried but once I took it outside on a cool night it became evident that far sharper focus was achievable.

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One thing I didn't really expect to learn but am not surprised by is the effect of atmospheric  conditions. Of course I was aware of diffraction and how humidity, clouds and random particles in the air could collude to reduce the image quality, whether it be visual or an image sensor at prime focus.

Most interestingly, if the atmospheric conditions outside are radically different than inside, you will find it hard to get sharp focus from inside.

Specifically, if it's 30 degrees outside and 74 degrees inside - it will be difficult or impossible to achieve sharp focus. The focus will always be sharper when the OTA cools down outside, perhaps becoming a uniform temperature as well.

If it is warmer outside, the telescope will perform better inside.

For those who think the window is the culprit, I tried opening the window to compare but the results of those test show something else but not particularly surprising. The image gets blurrier and distorted. It seems that the cold air has an affect on the corrector plate and because of the incongruous temperature -- essentially the existence of a sharp thermal gradient. Now, I suspect if I could cool the primary mirror down that things might behave a bit better.. but what of the secondary? Will vents do the trick? I've seen this fan-vent mod which makes the consumer grade 8" SCTs gain vents which resemble those found on some of the higher priced astrographs. 

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Inversely, when it is warmer outside -- even in the mid 50s (Fahrenheit) the gap between the indoor and outdoor temperatures is sufficiently narrow to allow sharper focus. Opening the window still has the potential of causing distortion although this is less of a problem as the outdoor temperature increases. Thus when possible, it is preferable to have the window out of the way. Naturally, the best way to do that is to take the telescope outside. The only time I really ever want to view from inside is when it's just too cold for my sensibilities on a given day.

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For a few weeks, while waiting for a back ordered mount, I've been using the BBQ as a sort of table-top surface for my fork. Shook a lot but it was preferable to putting the fork on the ground. The simplest short-term solution is a plank of plywood. I don't even need to bolt the OTA to it, although I do have the appropriate bolts so I'm ready. I was thinking about doing this if I needed more stability than the what the combination plywood and patio chair can provide. Also got an idea or two in order to make a cheap EQ wedge although I wouldn't count on it. I think I would use it more for convenience, for when the camera is too big for a 90-degree declination. Pointing straight up would cause the SLR to bump into the bottom of the fork in some configurations. As there is no motor for the dec, it's not a big deal but I'd imagine there might be a night or an object on a given night that requires me to be able to point straight up.


In short, the attempts at photography still come out like crap, except for the moon and the un-detailed disc of the sun. There is an obvious need for a few accessories like a Barlow and eyepieces which can work for me in eyepiece projection or other afocal methods but I have not pulled the trigger on it all because I don't want to waste money on things I come to not need soon after buying.

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I keep saying I can do without thhe JMI Motofocus add-on but I'm starting to get the sense that it would go beyond just being convenient to have. We'll see, or perhaps not, since I do not yet have a motorized focuser.