120 replies to this topic

[saguaro]

Thanks Rich!

[saguaro]

Just received the LS50c double-stack module yesterday! Screwed it on to the front of my LS 50 THa. The disk features really stand out now, and the views of the proms are enhanced as well. There isn't any negative impact on the quality or brightness of the image; it's simply enhanced, (like adding polarized sunglasses to the view). I'll probably leave it on all the time.

 

You first pressure tune the scope, then screw in the double-stack module. Then you tune the double-stack module by turning the small tuning wheel on the module until the sun's "reflection disk" moves out of the field of view. No time for imaging yet due to some cloudy weather, but here are some photos of the LS50 with the double-stack module.

 

Scope with double-stack module screwed into the front:

 

 

Close-up of ds module (tuning wheel is at the bottom in this photo, just behind the larger Lunt label):

 

[GUS.K]

Nice new Toy.  Hope to see more images from this setup.

[bill1234]

Looks sweet..... looking forward to images

[Rich (RLTYS)]

Nice looking scope.

 

Rich (RLTYS)

[bandazar]

I have scope envy, despite the fact that I have a double stacked 90...

[swsantos]

I have the same scope yet the focuser is different. Yours has a scale on it mine does not. What serial number did you get? Also do you feel 7.2mm high power setting that that Lunt zoom gives is the most you can push it? I've been trying the ES 6.7 which works well and so does the. Nagler 3-6 zoom.

[saguaro]

Steve,

 

When I picked up my scope at ASAE, I was not completely happy with the helical focuser. It had a wobble in it whenever the focus ring was turned in either direction. The next day when I went back to ASAE, I mentioned the issue to one of Lunt's engineers who was at the show (and who had been very helpful when I was evaluating the scope before purchasing it the day before). He offered to take a look at it if I brought it to the Lunt office in Tucson. Since I live in Tucson, this was no problem. When I visited him at Lunt a few days later, he swapped the helical focuser on my scope for another one, and gave me the choice of one with the scale on it, so I chose the one you see in the photo. After using it for a few days, the wobble is less, but it is still there. I emailed Lunt to ask about possibly upgrading to a better focuser (crayford). I was told that they don't offer another focuser option for the LS50. The helical focuser is OK and is certainly usable, but it is the only part of the scope I'm not completely happy with. Otherwise it's a wonderful scope and I'm having alot of fun with it.

 

Regarding magnification, if you are getting good views with 6.7 and 3-6 zoom eyepieces, then by all means use them. But I find the Lunt zoom gives great views and is very convenient to use. If I already had other eyepieces offering higher magnification, I would use them too.

Edited by saguaro, 28 December 2014 - 09:46 AM.

[swsantos]

Interesting my focuser also has a wobble perhaps it's inherent in the design and as you said it's OK but something I am unaccustomed to. They offered to send me another focuser I guess they are easy to swap in the field or for me to send it back to them but I wonder if the wobble in my focuser is what you had before swapping it or if I have the less wobble like you have now. Also this is my first pressure tuned unit, should the pressure setting hold from session to session or does it have to be reset each time? Do you have to remove it all the way releasing the pressure and rethread it on sometimes to reapply the pressure? It takes a few tries to reattach the pressure piston and there's always the worry of cross threading it.

 

I think I will call them again about the focuser wobble and ask if the scaled one is an improved design.

 

Thanks,

[saguaro]

Steve,

 

I don't think the "scaled" helical focuser is any different in design, but you should definitely follow up with Lunt if you're not happy with your focuser. Perhaps they may eventually improve the design they currently offer based on enough customer feedback.

 

Regarding the pressure tuner, it's also my first one. What I do is partially unscrew it and then rack it back in to find the best tuning. I don't think you need to unscrew it all the way (I found it very hard to put back on so wouldn't do it again unless absolutely necessary). I do set the scope out in advance to let it equalize with the ambient temps before using it. Enjoy!

 

-Robin

[saguaro]

Thanks for the kind words from Cloudy Nights members on this post! I have benefited so much from Cloudy Nights in the past that I feel it's important to give back by sharing my learning experiences in hopes others will benefit too.

 

Here's an update on my imaging efforts with the double-stack setup on my LS50: I first tuned up the disk with the single pressure tuner to center the tuning sweet spot over the center of the disk. I then threaded the double-stack module onto the front of the scope. I had read elsewhere on Cloudy Nights that you want to keep the tilt-tuning of the double-stack to a minimum. I noticed that as I turned the tilt-tune knob, disk detail gradually diminished, as I had expected. So I started with the premise that I didn't want to tilt-tune at all, if possible. I realize that this means the sun's reflection disk would overlap the "real" disk, but when I looked at the live camera view on my laptop, I couldn't see the reflection disk, so I determined it wouldn't be an issue for imaging. (Only when I turned the gain way up did I see the reflection disk.) Perhaps this is a wrong assumption, but it seemed to be working for me so I went with it.

 

Now, in order to achieve proper tuning of the disk with the double-stack, I had to center the tuning sweet spot over the center of the disk by moving the scope in RA and Dec. I turned up gain and centered the sweet spot over the disk by moving the disk around the field of view. I then very carefully rotated the double-stack module (carefully unthreading it) about a 1/4 turn. I had read elsewhere on Cloudy Nights that this technique (called "clocking") was effective in tuning. I also knew that I had about 4 1/2 turns on the threads before the filter completely unscrewed, so I knew I wasn't in danger of having the filter fall off! I found that by slowly turning the double-stack filter, I could get the tuning sweet spot to reduce in size and get more or less centered over the disk. Ultimately I found that the best tuning was achieved with about 100 degrees of rotation (a little more than half a turn of the threads). I am still not completely happy with the tuning but this method definitely appears to help.

 

Just to clarify: I only used the "clocking" method for imaging; for visual use, I leave the double-stack completely screwed on and just use the tilt-tuning knob to move the sun's reflection disk away from the "real" solar disk. But again, I found the less tilt-tuning you do, the better the darker detail on the solar disk appears.

 

Here is my best effort so far, with the double-stack, taken yesterday (Dec 27). Seeing wasn't great, only average:

 

 

I'm not completely happy with the tuning in the above image, and I hope to improve on the above results. Any advice or comments?

 

 

-Robin

Edited by saguaro, 28 December 2014 - 01:01 PM.

[saguaro]

Here is another image from >earlier< in the same session, just to show how the seeing was better, but I wasn't happy with the tuning in this one. You'll notice the dark features on the disk really "pop". Now I finally have some proof that seeing makes a big difference!

 

 

I'd really appreciate your comments, suggestions, etc. Thanks!

 

-Robin

[bill1234]

Steve,

I almost never equalize pressure.

Also never release pressure after using. It's almost  always right on band the next time I use it , be it a week or a month or longer. Rikki at Lunt said it is ok to store this way

I equalize when I notice my range shift. Here at sea level, my 80 is right on with about 4 threads showing.

[GUS.K]

Hi Robin, looks like you've got a winning combo there. Regards removing the PT piston, I unscrew it and as it comes off, I hold it in that exact position for a sec or two and then screw it on with no problems. As long as you don't twist the piston as it comes off the last thread, you should have no problem getting it back on, I do this every couple of days and have never had a problem getting it to re engage the threads. The only time I have a problem getting it back on is when I completely remove it for re greasing.

[saguaro]

Gus, thanks for your comments; removing/reinstalling the PT is something that I'll probably try again at some point if I feel it's necessary. Since I use the scope in the same location all the time, I don't think the ambient air pressure varies enough to do it on a regular basis (but maybe I'm wrong about this?)

 

For my next imaging session, I plan to image the sun in both single-stack and double-stack configuration, so that I can compare images to see what the differences are. The differences are pretty dramatic for visual observing, so I'm curious to see how they differ for imaging.

 

I'm also hoping some other folks will start posting images with their newly acquired LS50's! Looking forward to seeing some images from others!

 

-Robin

[saguaro]

Here are my latest LS50mm images in both double-stack and single-stack, taken during the same imaging session yesterday, December 29. The double-stack image is much more challenging to get evenly illuminated than the single-stack image. I still haven't mastered it but I think this is pretty close.

 

 

For this double-stack image, I tilt-tuned just enough to move the sun's reflection disk off the real solar image. Also, I didn't have to use any clocking of the double-stack filter in this instance, although it's another "tool" in the "toolbox". I find that I have to do alot of "mucking around", adjusting tilt, then filter rotation, then adjusting the position of the sun in the frame, etc. But I think the results are worth the effort.

 

For comparison, here is a single-stack image from the same imaging session.

 

The differences between the single-stack and double-stack images is pretty dramatic (echoing the differences I see when observing the sun visually with the single stack and then adding the double-stack), so I'm pleased that my "budget" camera (Skyris 132m) seems to be performing beyond my expectations.

 

Wishing everyone a Happy New Year!

 

-Robin

[Koen Dierckens]

Robin,

 

Count me among the people who appreciate this post and the efforts you made in showing what to expect from the Lunt 50.

 

For over 2 years, I have that itchy feeling that only can be cured by buying a solar telescope, but the price of these contraptions was a quite strong antidote against the purchase... Now with this new scope and your report... the antidote is losing some of its effectiveness.

 

Cheers!

 

Koen.

[Lee.S]

I just keep reading and learning from this post .I have one on order ,shipment expected around March,so that's more time for gathering information on what to expect .

 

Thanks to all, keep feeding,  I'm hungry

[Chich]

Thanks for the info Robin. Just ordered one and it should be here in a week or two. Single stack for now.  

 

We'll see just how far down this rabbit hole I get in a year or two

 

Chich

[saguaro]

Thanks, Koen, Lee, and Chich!

 

A couple more things I've learned when imaging with the double-stack:  you do always want to apply a bit of tilt to move the sun's reflection disk away from the "real" solar image. Also, with the double-stack you will always have some uneven illumination in the solar disk image. The cure for that is to create a flat field video while imaging, and then use AutoStakkert to apply a master flat using the flat field video you created. I don't know exactly how this works, but it is supposed to result in a more evenly illuminated disk produced by AutoStakkert.There is probably info on this in Cloudy Nights if you search around for it. That's the next thing I'm going to tackle.

 

For those who get the double-stack at the same time they get the scope, you may want to start imaging without the double-stack just to get some experience at producing evenly illuminated solar disks (since it is much easier to do this with the single-stack pressure tuner). 

 

Another great resource is SolarChat! I have a discussion going in SolarChat! which pretty much covers the experiences I've described here, but there are also some tips offered by SolarChat! members which have been very helpful to me. That thread (called "First image with my Lunt LS50mm") is located here: http://solarchat.nat...php?f=4&t=13780. I have the same username over at SolarChat! (saguaro). There are a couple folks there who also have just received LS50's so hopefully we'll see more folks start to share their experiences and images.

 

-Robin

Edited by saguaro, 31 December 2014 - 02:53 PM.

[Chich]

My LS50 arrived today   SS with the 600 filter

 

 Initially had a problem with the PT housing not threading back on but a quick call to the super nice folks at LUNT solved it.

 

 With the the PT handle removed from the scope, you disassemble it (there is a 2.5mm allen screw under the top cap) and remove the plunger. Same as if you were replacing the O ring.  On the end of the plunger are two recesses for holding the O ring. Move the O ring to the top recess and reassemble.  Easy peasy now.  On the lower recess it just did not give much of a purchase on the threads, at least with this one.   

 

And of course being north of 60, the sun is now down so no more playing for me today.

 

Before fiddling with the PT 'fix', we set it up on my SE mount with a 32mm EP in the living room (-30C today) and had a look through the window . I was not expecting much as A) its through the glass and B) they are not the cleanest but we could see a surprising amount of details.  My wife had a look and although she is not a big astronomy fan she has now claimed it as her scope.

 

Chich

Edited by Chich, 06 January 2015 - 05:46 PM.

[saguaro]

Congratulations Chich! Look forward to hearing more once you have better viewing conditions!

 

Time for an update on my solar image processing. I've been learning how to create and apply a master flat in Autostakkert to remove the inherent uneven illumination in the solar disk images taken with my double-stacked LS50.

After imaging the solar disk, I put a bag over the front of the scope, adjusted gain and exposure to create an even histogram and then I took a 200-frame video for use in Autostakkert. Here is the bag on the scope:

 

I had tried a bag from the produce section of the grocery store first, but found that it was too transparent. The bag in the above picture is just a bit more opaque and gave me a better result.

To create a master flat in Autostakkert, I loaded my 200-frame video and then used the "Create Master Frame" command on the Image Calibration menu. Here is the resulting master flat:

 

I then used the "Load Master Flat" command to apply the master flat to my solar disk videos. The first thing I noticed was that Autostakkert was producing solar disks that were much brighter than my original images. Luckily I found a post on SolarChat! that describes just such a bug with earlier versions of Autostakkert. I had been using Autostakkert version 2.1.0.5 which had this bug with master flats. Once I installed the latest version of Autostakkert (version 2.3.0.21), the results were much better (plus this newer version of Autostakkert runs way faster).

 

More to come in my next post.

 

-Robin

 

[saguaro]

Here is the solar disk with NO master flat applied. Notice the uneven illumination on the disk and notice all those pesky dust motes:

 

 

Here is the same disk image after applying the master flat in Autostakkert:

 

 

Not only is the illumination in the above image more even, but the dust motes are removed too!

 

Final image in my next post.

 

-Robin

[saguaro]

Here is the final image after sharpening and colorizing in Photoshop and compositing with the proms:

 

 

Looking forward to hearing from others on their experiences with the LS50.
 

-Robin

[dennisjames1]

Hello Robin

 

 

I have just ordered the LS50THa today, no double stack as yet as the supplier in Australia has only just received his batch of scopes and the double stack is a special order which i will get.

Just enjoyed reading your progress with the scope. I will be single stack for a while a 2 to 4 month order turn around here and i think i am the first buyer he has had for that model so far.

 

The single stack pics also looked impressive, I have a Canon 700d  DLSR which i would think would take some great shots,depending on the mount, but i think that Celestron Camera you have works wonders and probably much lighter.

 

Just thought i would let you know where i am at

 

Dennis