New to solar

[FrankPorter]

Given spending about the same amount of money, perhaps this week, $3000-3500, which is the best way to go? A Lunt LS 60 DS with 1200 BF & Feather Touch focuser or a Lunt LS 80 SS with a 1200 or 1800 BF and Feather Touch foucuer? I plan to use it for visual observing until next year. Then I will get into imaging.
Interested in the difference between a Lunt zoom EO and a Baader Hyperion zoom EP for about $140 more. I plan to mount it all on a Celestron AVX mount. Comments are greatly appreciated.

[Bruce Girrell]

Greetings Frank,

I too, am new to this, having bought my gear just prior to the Aug 21 eclipse. I was weighing the very same options as you. Based on my reading, I went with the LS80T, but single stacked to keep the cost down. Lunt makes it easy to add a second etalon later. Although I have not had the opportunity to look through a LS60, I can make the following observations:

1) I have worked with cameras and lenses, including microscopes, for close to half a century, so I have some idea of what to expect from optics. I was absolutely delighted with the images that the LS80 produces. The sharpness of this little refractor easily matches, and I believe exceeds, what I am getting from an 8" SCT.

2) I wouldn't want the image to be much smaller. I'm already lusting after the LS152. I'm starting to extract some fairly decent images from the processing (get ready for a bit of a learning curve on the cameras and software) and can see that I'm right at the edge of being able to get the detail I want. So if you can afford that LS80, I would lean toward that, based on your desire to do imaging. Of course, the suggestions that you get from others with more experience than I should generally carry more weight than mine.

3) I took the standard Crayford focuser with my scope. I find it completely satisfactory for my imaging. I wrote to Lunt and asked them about the differences between the Crayford and the Feather Touch. Their response was that the Crayford can't deal with as much weight as the FT. So, if you are mounting a heavy camera system, you will probably want the FT focuser. But I have had no problems holding focus with my cameras and the Crayford.

4) The blocking filter is a function of the image sensor size that you plan to use. Large images sensors with lots of pixels potentially given you more pixels for the processing software to work with, but slow down the image transfer rate to your computer and slow down the processing. I have a camera with a 4/3" sensor with 4656 x 3522 pixels and the 1200 BF does just fine for me. Chances are, you'll do fine with the 1200. Call or write to Lunt and ask them which BF would be best for your imaging setup (you didn't think you were going to have to start looking at camera gear this soon, did you?)

5) Being unfamiliar with various eyepieces, I went with the Lunt zoom. As far as I'm concerned, it's all I need for visual observations. You definitely do not need any fancy APO eyepieces, as hydrogen alpha is essentially one color. Hence, good color correction is not an issue at all. The LS60T and LS80T cannot be used for anything but Ha observation. The LS152, on the other hand, can be used for white light and Ca K. An eyepiece with better color correction may be warranted there.

6) I bought a TeleView 2.5x Powermate to get the image of the solar disk large enough to fill the frame of my camera's image sensor. I found that the use of the barlow gave me a bad case of Newton's rings. The effect was much less on a camera with a global shutter (as opposed to rolling shutter), but the effect was still clearly there. I allow the telescope tracking to drift some during acquisition and the large image sensor makes for slow image transfer speeds, so it it can take more than a minute to acquire an image. This seems to mitigate the rings pretty well during the stacking process.


That's all I can think of at the moment. Hopefully others with more experience will be able to provide more insight.

Welcome to the addiction

Bruce G


This (false color) image was produced with my Lunt LS80T Ha single stack

12_53_51_g4_ap2316Colored1.jpg (2.24 MiB) Viewed 2194 times

[Derek Klepp]

Frank go for the feather touch and the B1800 will be better for imaging.

[Bruce Girrell]

Derek, Could you expand a bit on why you prefer those options? There are a lot of details for people new to this arcane science to learn. Why do you prefer the FT focuser and if the 1200 BF is big enough for your camera's image sensor, what benefit does the 1800 give you? What are you getting for your money in each of these cases?

Thanks

Bruce G

[FrankPorter]

Derek I see why you would rather have a B1800 with a Lunt 80 but I am going to buy a 60 DS so as I understand it, a B1200 is all I need instead of a B600 that would be better if I only wanted visual. I will get into imaging so why not go with the B1200 out of the box?
With cameras in the $500-800 range, are they too heavy for a Crayford?

[Derek Klepp]

Frank the B1200 will be fine .I have a CaK version for imaging.As for the focuses the Feather Touch is much more precise especially when imaging

[FrankPorter]

Thank you all. I am ready to drop the cash now. Watch it will rain for the next 2 weeks. I am pleased with the quality or responce I got. I will order the Lunt 60DS with the Celestron AVX mount and Lunt Zoom, a Sol Ranger and dove tail bar. Since I too want to remain married, I will stop there after trying to squeeze a bit of astronomy club discount out of Optcorp. They agreed to 2% but Lunt said they would go 7% so I will try to get Optcorp to match them. If I can I may spting for the Baader zoom.

[Merlin66]

Frank,
The DS60 is a good starting point.... I had the Coronado SM60 double stack and a BF15 for a few years - great views.
Bruce, Re the newton rings - you should try with a T2 Tilter adaptor on the camera - works well for me ( I use the ASI 174MM)

[Bruce Girrell]

> Bruce, Re the newton rings - you should try with a T2 Tilter adaptor on the camera - works well for me ( I use the ASI 174MM)

Thanks. I have read about the tilt solution, but I have apprehensions about doing it that way. With a 4/3 image sensor, a tilt of 1 degree would introduce a positional difference of 0.3 mm from one side to the other of the image chip at the focal plane. I don't understand why this doesn't make it impossible to achieve uniform focus. Perhaps I don't understand how they work correctly. But right now, the rings are not the worst of my issues. I still have a lot to learn in the processing. I know that, in one manner or another, I will be able to suppress the rings when they become the largest thorn on my side so I haven't yet spent too much time on them.

You do add another interesting data point for me though. One other means to address the rings that I have seen come up in discussion is the use of a global shutter rather than a rolling shutter. The ASI 174MM has a global shutter, yet you apparently still have rings appearing in your images. Tests that I have done indicate to me that a global shutter is not the answer and your experience appears to support that conclusion.

[Frank Porter]

What do you think about my choice of solar scope on a iOptron AZ Cube Pro. Its more expensive than the Celestron AVX, at $1299, good idea ir not.

[Marcello]

Hi Frank,
that's an excellent choice! I had the Lunt 60 DS for some years and had a lot of fun, enjoy it!

I would just suggest you some ortho or plossl eyepiece rather than a zoom, they should have a better contrast

cheers
Marcello