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New DS for Lunt 100

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#1 bigdob24

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Posted 04 January 2020 - 05:44 PM

I’ve got a DS II ordered for my 100.

Been reading some forums and see some concerns about “red glow” and “ ghosting” 

Seems like rotating the DS units mounting position may or may not help?

Is there a filter that Lunt sells to reduce the red glow?

Any info on these problems and solutions? Are they overwhelming or easy to deal with?

Thanks

BD



#2 Gregory Gross

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Posted 04 January 2020 - 06:20 PM

I know that Lunt has a high resolution filter available for the 80mm internal double-stack modules. The filter reduces the glare that adding the DS module creates. But I don't know if they have the same thing available for the DS module paired with the 100mm Lunt. You may want to call them up and discuss options.


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#3 GUS.K

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Posted 04 January 2020 - 06:58 PM

The glare and ghosting is very noticeable, and rotating the tuner to different locations didn't help in my case. What did was placing a circular polarizer between the two etalons, eliminates all the ghosting, but darkens the image. Most CPL's will work but the BW Kasseaman ones are optically better than most others. I've tried a few different ones from camera stores and most seem okay( image quality seems good even at 200x magnification. Lunts anti glare filters just seem to be ERF filters, all they do is darken the image and ghosting but the glare is still very noticeable. 



#4 bigdob24

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Posted 04 January 2020 - 07:05 PM

I’ve got several questions for Lunt on the 100 DS II. 
Im strictly a visual observer and strive for a good image , nothing to distract from that.

I know there are some guys out there with DS 100 that can commit on this. 
Thanks

BD



#5 GUS.K

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Posted 04 January 2020 - 07:20 PM

https://www.cloudyni...lunt-dsii-glow/My solution for the CPL on my LS100 DSll is in this thread.



#6 bigdob24

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Posted 04 January 2020 - 07:43 PM

Has Lunt addressed on there new DSII if it’s been happening ?

BD



#7 bigdob24

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Posted 06 January 2020 - 01:48 PM

I spoke with Faye at Lunt today and asked about the “red glow and ghosting “ issues with the DSII for the 100.

Lunt has a HRG filter that can be purchased and it addresses the red glow.

While not eliminating it 100% it gives some relief. It’s kinda a personal choice I guess and I’m going to see how it looks and decide then.

The ghosting is an artifact that means something is wrong / misaligned and should be corrected by rotating the DS to different positions until it’s removed. If that doesn’t work then send it back in for repair/ adjustment.

She explained that they visually test each unit before shipping and my scope hasn’t been out of there hands for too long so maybe it will all work.

I explained that I’m strictly a visual observer and don’t want anything distracting in my field of view.
‘My unit could be shipped tomorrow and I’ll report back with what I find , I’m hoping for a knock your socks off detailed ,contrasty view.

BD



#8 dscarpa

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Posted 06 January 2020 - 02:56 PM

 I like my had since early June SM 90 III a lot with one etalon. Tuning is easy, prom performance is excellent and surface contrast good. Yesterday was able to use 280X that way. So far I don't care for it DSs. Prom performance is no where near as good, I can't use as much power, tuning much more complicated, there're more ghosts than a haunted house and I don't care for through the glass darkly look of the image. Surface features are easier to see but so far I've not seen anything with two etalons I couldn't see with one. I've used the DS unit at most 2% of the time. When activity picks up I may change  my mind. Also given the complexity of having 3 tuners when DSs it's entirely  possible I've not yet been able tune it optimally. David


Edited by dscarpa, 06 January 2020 - 03:20 PM.


#9 George9

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Posted 06 January 2020 - 11:46 PM

I mistakenly thought the DSII for the LS100 came with the HRG ("high resolution glass") attached. Glad to hear the true answer.

 

For my LS80, I aligned the two etalons dead-on using a shim, which to my eye minimized the glow. The HRG filter dimmed it but reduced the glow by 90%. I later switched to a circular polarizing filter, which pretty much eliminated the glow for only a barely detectable difference in brightness compared to the HRG. The problem is that you have to figure out your own mounting, and you have to align it, for example, if you use a binoviewer.

 

The LS100 is generally brighter than the LS80, so the dimming of the filter has less effect.

 

Even with no filter and with glow around the outside, my LS80 DSII produces a wonderful high-contrast disk view. The glow only affects the prominences.

 

George



#10 bigdob24

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Posted 07 January 2020 - 09:19 AM

It sounds like these artifacts can be fixed to obtain an acceptable view.

Im going to see what I have for first light and go from there.

I do want to tone down the red glow as I do like to observe proms .

I asked Lunt why they just don’t address this in the build and while no direct answer I’m sure it comes down to cost.

More to come

BD



#11 BYoesle

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Posted 07 January 2020 - 12:36 PM

 

I’m sure it comes down to cost.

You are correct. A true optically polished quality CP filter would likely double the cost of the entire telescope system... the B+W Kaesemann CP filters are the best alternative, and on sale here.


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#12 bigdob24

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Posted 07 January 2020 - 01:05 PM

I’m wondering how the B+W Kaesemann CP filter you mention compares to the HRG filter Lunt sells in eliminating the glow?

The HRG filter screws on easy from the factory , seems like the B+W Kaesemann CP filter has to be adapted for installation. 
The HRG I’m told does not eliminate the glow but reduces it to an acceptable level.

Will the B+W Kaesemann CP filter eliminate the glow 100%

 

BD



#13 BYoesle

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Posted 07 January 2020 - 02:10 PM

See George's comment above.



#14 bigdob24

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Posted 07 January 2020 - 03:08 PM

Sorry , I did read that.

More after I receive it and test to see what I find

BD



#15 Eddgie

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Posted 07 January 2020 - 05:17 PM

 I like my had since early June SM 90 III a lot with one etalon. Tuning is easy, prom performance is excellent and surface contrast good. Yesterday was able to use 280X that way. So far I don't care for it DSs. Prom performance is no where near as good, I can't use as much power, tuning much more complicated, there're more ghosts than a haunted house and I don't care for through the glass darkly look of the image. Surface features are easier to see but so far I've not seen anything with two etalons I couldn't see with one. I've used the DS unit at most 2% of the time. When activity picks up I may change  my mind. Also given the complexity of having 3 tuners when DSs it's entirely  possible I've not yet been able tune it optimally. David

Like you, I find the views with single stack more than good enough.  I have owned two double stack scopes, but my main compliant is that they do dim the image considerably and this makes high power study difficult. I also use binoviewers and that further dims the image.

 

I had the Lunt DSII on my Lunt 8 and there iwhile it did slightly increase surface contrast,  the reflections washed out prominence detail and the dimming make powers over about 80x just too dim for me. 

 

Someone posted on how this could be reduced by removing a filter (which I am not so keen on doing) but the DSII also made the scope weigh far more and kind of overwhelmed my mount and that is a bad thing.  My mount sits outside on the patio 24/7 in the elements.  It is a light and cheap mount but it works well up to 120x with the Lunt 80 and with the DS, it was very shaky. 

 

I know the surface contrast is a bit better with DS, but I just like the brigness, lightness, and simplicty of single stack.  With the binoviewers, the surface detail is much improved over the single eyepiece view and I feel like it is stack and a half level detail vs my 60mm Double Stack. 

 

I have learned that best for everyone else is not always best for me.   SS is fine for me.  I look at the sun almost every day and I see amazing things.   I am content. 


Edited by Eddgie, 07 January 2020 - 05:18 PM.

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#16 bigdob24

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Posted 07 January 2020 - 08:39 PM

Eddgie you must be in Florida or Arizona to get to observe everyday.

Today was clear here in Central IL but we go for days a not see the sun

Call you lucky

BD



#17 MalVeauX

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Posted 07 January 2020 - 09:16 PM

must be in Florida....... to get to observe everyday.

 

Pssshhhh.... Florida has been a dirty cloudy sky most of this year! The idea of "sunny Florida" I think really only pertains to like... West Palm and around that area with as little land as possible. The rest of Florida is a cloud magnet lately between hurricane bands....  undecided.gif

 

Very best,


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#18 dscarpa

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Posted 11 January 2020 - 02:06 PM

When you double stack you never go back certainly doesn't apply to me at least so far.  Here daytime seeing can be quite good. Using  my sngle tilt etalon Lunt 60 which also has good  surface contrast I rarely go below 90X and with the SM 90 III 115X using one etalon. The SM 90 III bests the Lunt 60 for surface contrast but this may be because of the considerable size difference . I could see DSing being more appealing if your seeing limits you to lower power anyway.  David



#19 bigdob24

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Posted 11 January 2020 - 03:17 PM

Seeing here in the Midwest is all over the place . It’s worse in the winter and better in the summer and fall.

My DS is on the way and of coarse the weather looks pretty grim at best.

Im sure I’ll get a chance to test the DS and BF Heater soon

BD



#20 bobhen

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Posted 12 January 2020 - 07:48 AM

Seeing here in PA is about the same. On days of poor to mediocre seeing, if there is disk activity, I usually stop my Lunt 100 SS down to 70-75mm and that has the benefits of:

 

1. Shallower light path for the filter
2. Less bright image overall
3. Less smearing due to seeing
4. And of course no red glow

 

The above increases disk contrast.

 

I never stop down to observe proms or if the seeing is above average.

 

Bob



#21 bigdob24

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Posted 12 January 2020 - 09:01 AM

Seeing here in PA is about the same. On days of poor to mediocre seeing, if there is disk activity, I usually stop my Lunt 100 SS down to 70-75mm and that has the benefits of:

 

1. Shallower light path for the filter
2. Less bright image overall
3. Less smearing due to seeing
4. And of course no red glow

 

The above increases disk contrast.

 

I never stop down to observe proms or if the seeing is above average.

 

Bob

Bob

I have experimented with stopping mine down and have settled on 75mm as the best choice.

Ive got an old discolored end cap for my scope and I’m going to cut a 75mm hole in it and have a nice aperture stop. 

I did not realize stopping down would eliminate the red glow. 
‘I’ve got a lot of things to test and play with, hoping for a warm sunny winter.

BD



#22 bobhen

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Posted 12 January 2020 - 09:37 AM

Bob

I have experimented with stopping mine down and have settled on 75mm as the best choice.

Ive got an old discolored end cap for my scope and I’m going to cut a 75mm hole in it and have a nice aperture stop. 

I did not realize stopping down would eliminate the red glow. 
‘I’ve got a lot of things to test and play with, hoping for a warm sunny winter.

BD

I meant no red glow on the SS (single stack).

 

I thought about double stacking but I have to say that stopping down the scope has kept the disk contrast high on the many days of poor/mediocre seeing here, at least  to “my” satisfaction.

 

Lets us know how things work out.

 

Bob



#23 bigdob24

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Posted 13 January 2020 - 07:02 PM

 Christmas came early

The UPS man showed up a day early with my new DS unit along with the new style BF heater, a new smaller diameter o ring for the pressure tuner and a bit of grease to lube it up.

Of coarse weather is cold and cloudy so the the plan is on the next sunny day setup have a look and tune the primary and then add the DS unit and tune it and prepare to be amazed.

Its going to be cold but I hope to report back in the near future

BD


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#24 dscarpa

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Posted 14 January 2020 - 05:35 PM

 There's some nice proms and good sized filaments today but no ARs. The next decent sized AR that shows up I'm putting the SM 90 III's  DS etalon on.  Having the single tilt etalon Lunt 60 out at the same time as the SM 90 III DSs worked out well given it's very good prom performance . David 



#25 bigdob24

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Posted 14 January 2020 - 08:35 PM

I was able to assemble the DS to the scope to get the feel of how it all goes together.
‘Cut out the foam in the case so it will fit with the DS on. Have to take the BF off “to long”

and it fits on the side now. 
Something to do on a day I can’t observe.

Put the heater on the BF , will turn it on tomorrow to see what temp it operates at.’

Waiting for the sun

BD


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