There has been a changing of the guard recently, on a couple fronts, at Little Piney Observatory.
Those of you that have been following my progress know that the 800mm focal length AT8IN was sold some time ago, and I have since been saving up and looking for a nice apo to replace it. I liked the field of view I got with that scope using the DSLR. The STF-8300M has a smaller chip than the DSLR, so I was looking for a triplet in the 600-700mm focal length range that would produce a similar FOV.
After much research, I decided to purchase the TS Photoline 107mm f/6.5 Super-Apo with 3" CNC focuser and modular carbon fiber tube, from Teleskop Service in Germany. APM offers this exact scope in a metal tube version.
The optics in the scope are said to be very close to the famous LZOS. It is an air-spaced triplet with an FPL-53 element. The interior of the scope and dew shield is lined with a black felt and seems to provide very high contrast views and images.
The first night out with it was a quick eye test to check collimation and do some observing. As expected, the color correction was excellent and viewing with an Explore Scientific 82 degree 8.8mm eyepiece provided extremely high contrast views even when pointed towards a rather large and bright Moon. It can best be described as the often stated, "shimmering diamonds on a black velvet background." I am very impressed with the views this scope provides, and look forward to pushing the magnification for some planetary observing soon.
The scope did not arrive without some anxious moments. The big box it came in was leaking shipping peanuts as I carried it into the house. It was obviously not treated very well by UPS.
Fortunately, it was packed very well and had a smaller box with a nice case inside that protected the scope.
Now the worst part of the whole ordeal. I pulled the scope out of the case and removed the dust cap. When I pulled out the dew shield I saw something that horrified me. I immediately thought that these two screws had been bouncing off the lens during its travel across the Atlantic!! Thankfully, when the dew shield is closed it seals off everything from the optics.
These are two of the three screws that hold the lens cell to the optical tube. Not really something you want to see when you pull out a dew shield. I removed the dew shield and put the screws back on. After getting all three screws snugged up fairly tight everything seemed to be fine.
It was a while before the clouds allowed me to get in some imaging with the scope, but the first night out with it gave me the results I was looking for. The only thing is the carbon fiber tube does not behave like my carbon fiber RC, in that it does not keep its focus as well when the temps drop off at night. I suspect this is because the tube has two 60mm long extensions that have metal threads. These threads will expand in the heat and contract in the cold which changes focus. My FWHM (Full Width Half Maximum) started out in the low 4's and as each frame clicked off the stars grew to a FWHM in the mid 7's after eight 20 min subs. I refocused and frames 9-13 remained in the 4.01 to 4.28 range. Last night I captured some RGB of IC 405, the Flaming Star nebula, and the FWHM was as low as 3.80 and was never higher than 4.61 for the entire night. Since the 3" focuser appears to be pretty stout, I think I will keep it and remedy this problem by getting a Rigel nStep stepper motor with temp sensor and automate my focusing for this scope.
Here's what I managed with the camera the first night out with it. This includes all thirteen of the 20 minute hydrogen alpha subs. Soon I will be getting some new H-alpha data and will get rid of frames 3-8 which should make for a better looking image. I'll be adding RGB and possibly some OIII soon.
The other new addition is the Stellarvue SV60EDS. I decided to sell my trusty Levenhuk 80mm f/6 and try out this very small 60mm f/5.5 scope. The 330mm focal length gives me a much wider FOV compared to the 480mm focal length of the 80mm scope. TS even makes a 0.79X reducer/flattener that would work for me and reduce the focal length to 260mm and focal ratio to f/4.3 for an ultra wide fov.
I have yet to find the sweet spot for this scope using the TSFlat2 field flattener. I am not at all happy with my corners, but the color correction seems good and I love the field of view. This is a test shot of the Rosette nebula, two 30 minute subs with no darks, no flats, and no bias frames.
Hopefully I can get the spacing figured out for this scope and get some nice widefield shots. If I cant get the spacing right for the TSFlat2, I might purchase the TS 4-element 0.79X reducer/flattener. This corrector says the spacing needs to be 70mm for up to 350mm focal length. It should be very close with the 330mm fl Stellarvue.
I'm looking forward to using these two scopes a lot more in the near future. Hopefully the weather here will allow this. Although I'm not completely sold yet on the SV60, I plan on keeping the TS 107mm for years to come.