2nd video - Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF30

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Re: space filler- Lunt 60PT f/8.3 to meade LX70 5" f8.3 & B

Post by marktownley » Sun Dec 27, 2015 9:34 pm

Welcome back old friend, we've missed you. Glad you have the solar fire back in your belly.

Yes, this mod will work like a dream, I look forward to the pictures as it develops :)
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Re: space filler- Lunt 60PT f/8.3 to meade LX70 5" f8.3 & B

Post by marktownley » Sat Jan 02, 2016 9:20 pm

Will that crud clean off? Looks to be on the outer surface. I agree, it is darn annoying when things come like this...
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Re: space filler- Lunt 60PT f/8.3 to meade LX70 5" f8.3 & B

Post by Kvak » Sun Jan 03, 2016 3:42 pm

Infested by fungus ? It is very very rare on old lenses. The fungus is very different and can damage the coating.
http://www.zeiss.com/camera-lenses/en_d ... enses.html

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Re: space filler- Lunt 60PT f/8.3 to meade LX70 5" f8.3 & B

Post by edobosz » Mon Jan 04, 2016 1:09 am

I assume this is the blue filter in the blocking filter that faces towards the telescope. This blue filter has had some problems in Lunt BFs. I believe these are chemical residues that react over time and then become visible as a milky haze. I received a replacement from Lunt. After which I decided to see if I could clean the old filter.

I found Isopropyl and acetone had no effect at all. I found vinegar to slightly reduce marks. I then suspected that something with acid base would be effective. I managed to remove it using CLR see here: http://www.walmart.com/ip/CLR-Calcium-L ... r/14574716. This product contains phosphoric and glycolic acid.

I simply soaked it for two minutes then gently rubbed with cotton pad soaked in CLR. If your problem is the same residue, it will come off easily leaving no marks behind. I would however speak with Lunt first about a replacement.

Ted

PS I have now included some examples of the problem.
Attachments
BF Problem Image 2.jpg
BF Problem Image 1.jpg
Lunt LS80THa DSII Quark Prominence ES127mm refractor

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Re: space filler- Lunt 60PT f/8.3 to meade LX70 5" f8.3 & B

Post by [whrudey] » Tue Jan 05, 2016 1:56 am

Regarding "crud" on the IR blocking filter of Lunt scopes, I had this experience a year or two ago when my H1a images were steadily being degraded. Tried everything until, after removing the diagonal, the "crud" was apparent. Talked with Rikki at Lunt who noted that this was not an uncommon problem and, they would send out replacement IR filters. Meanwhile, whilst awaiting delivery, I attempted to clean the filter without effect until, I tried Naval Jelly rust remover. Since the filter is homogeneous glass, rather than coated or a sandwich, the process worked great. Rinse thoroughly in water after though. Replaced the filter and was instantly back to normal imaging with a pair of replacements on their way. The following image shows the "cruddy" filter before cleaning - after cleaning, looked like new:
IR Filter.jpg
IR Filter.jpg (47.28 KiB) Viewed 4262 times
The filter has performed well since and, is periodically checked for "crud" return.

Cheers,

Bill

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Re: preliminary- Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF

Post by _Zakalwe » Sun Jan 31, 2016 5:31 pm

Watching this with interest. Ive got a similar OTA kicking about that I started to mod but then ran out of enthusiasm and ability.

Would you mind letting me know the distance from the objective to the Lunt? Thanks in advance.

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Re: preliminary- Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF

Post by _Zakalwe » Tue Mar 01, 2016 10:40 am

<bump>

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Re: preliminary- Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF

Post by _Zakalwe » Thu Mar 03, 2016 8:34 am

Ghost-Fire wrote:
_Zakalwe wrote:Watching this with interest. Ive got a similar OTA kicking about that I started to mod but then ran out of enthusiasm and ability.

Would you mind letting me know the distance from the objective to the Lunt? Thanks in advance.
Distance from the front of the objective to the front of the pressure tuner ERF is exactly
32-inches

Thank you! :bow2
Food for thought......time to get the measuring tape out for me :D

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Re: 1st video - Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF3

Post by marktownley » Fri Mar 04, 2016 7:59 pm

Are you going to black the lucite tubes for better contrast Apollo?
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Re: 1st video - Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF3

Post by marktownley » Fri Mar 04, 2016 8:34 pm

Just put some flocking on the inner surface I guess?
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Re: 1st video - Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF3

Post by marktownley » Sat Mar 05, 2016 3:20 am

Looks like British skies!
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Re: 1st video - Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF3

Post by marktownley » Sun Mar 06, 2016 8:29 pm

Oh yes, those are British skies. It's frustrating isn't it :roll:
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Re: 2nd video - Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF3

Post by marktownley » Sat Mar 12, 2016 7:33 am

These are pretty good! Use ImPPG it's free, lots of people using this now instead of photoshop...
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Re: 2nd video - Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF3

Post by marktownley » Wed Mar 23, 2016 6:38 am

Is that Lucite tube light tight now, if not it will reduce contrast which wont help with your proms...
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Re: 2nd video - Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF3

Post by marktownley » Sat Mar 26, 2016 10:39 am

Looking good fella! A flat should sort the gradient.
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Re: 2nd video - Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF3

Post by marktownley » Wed Mar 30, 2016 9:58 pm

Enjoying following the development of this scope!
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Re: 2nd video - Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF3

Post by _Zakalwe » Thu Mar 31, 2016 7:42 am

Looking good!

Personally I wouldn't bother with anodising....anodised aluminium is highly reflective in IR. Prime the inside and paint with chalkboard paint, or stick some flocking paper to it.

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Re: 2nd video - Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF3

Post by marktownley » Tue Apr 05, 2016 6:38 pm

Cool looking setup!
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Converting a Lunt PT 60 mm H-alpha to larger objective

Post by solarmax2016 » Fri Jul 29, 2016 7:11 pm

I need some help!
I tried converting a 60 mm Lunt Pressure-tuned Etalon assembly (the red hub and focuser behind it) into a 4" objective Refractor. In fact it was my Meade 102ED which has an enormous back-focus (11 inches) that I used as an OTA. My Meade 102 ED has a Moonlight focuser that comes with a slip-on
extender. Its bore was exactly 3 -1/2" (by chance) which takes Lunt's G25 pitch thread (same as on the back of the PT 60 white optical tube). All
went well in the threading process. the Lunt PT assembly fit on the Meade 102ED perfectly and was easily removed. PROBLEM IS - it will not focus.
I know that all Etalon assemblies require collimating lenses, but LUNT would not tell me what they use in their PT60 mm. I guessed it would be about
the same as the Coronado PST (-200 mm). Was I wrong!. First of all, has any of you tried using a Lunt PT,H-alpha module in a scope with a larger
objective?. The neat thing about my process was the Moonlight Adapter which made it possible. I'm not going to progressively cut the Meade
OTA off until I reach the exact focal point to make it possible. In fact I also tried it on a converted ORION 80 mm tube with 400 mm focal length (same
focal length as Lunt's objective for the 60 mm PT instrument) and I could not get it to focus either. It should be a snap to do this but LUNT holds the secret to the negative measurement required by that collimating lens. The tough thing about the pressure-tuned modules is the Pressure-tuning control on the side of the OTA which forbids you from testing the focus point by inserting the whole module up the body of your desired optical tube., You can only get this measurement by trial and error. Have any of you ever tried converting the 60 mm PT instrument to a larger aperture?

John - New Forest Observatory Ontario

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Modding a Lunt 6mm PT Etalon to a Meade 102ED Donor Refractor

Post by solarmax2016 » Sat Jul 30, 2016 4:09 pm

I got a part answer from Solar-Cologne in "And now the H-alpha Killer, a Lunt-Mod", but the Meade 102ED has only a 4-1/2" bore and is further restricted
by its tailpiece flange having less than a 3-1/2" aperture - so the Lunt PT 60 mm white OTA tube will not pass through into it. It means making some
sort of temporary frankenscope support to fool around with finding a focus. The part of all of this I do not understand is "why is the etalon is not placed
up into the regular optical path like the PST Etalon (-200 mm)" ? It must have a collimating lens on its nose, and if so, why does the etalon have to be PAST the point of focus of its donor scope as Solar-Cologne found out? This tube arrangement is so long that its sure to swing the tailpiece and 60 Mod
downward, and at least stress your drive into slipping. I think a whole new OTA tube with the donor Objective and tailpiece connection is a much better
idea, eliminating the frankenscope look and encumberance to the drive. I still want to know what anyone has discovered as far as finding the focal point
or "interception point" for the 60 mm PT Etalon in a Meade 102ED tube before I start making a new OTA. I cannot arrange a "bench-test" like Solar-Cologne did anyway, since I cannot pass the 60 mm PT optical tube into the Meade Refractor to find its exact focal point. I have machined and threaded the Meade tailpiece adapter, so I'm ready to just slip in a short extension tube to the 60 mm PT Red Etalon Housing. Its simply a matter of how long the tubing should be! Help!This Mod should really be a good test for modding the Pressure-tuned Etalons from Lunt. Just think of this...buying a Lunt PT 60 mm and adding a donor Objective of your choice instantly converts your scope into a fabulous, up to $10,000 retail instrument. Since Lunt Corp. will not cooperate with you if you ask them what the focal point set-up is for their 60 mm Pressure-tuned model, you are stuck with experimentation and
frustration. Since we have the capability - lets get the ball rolling and make superior H-alpha scopes at less than 1/4 the retail price. The whole "mystery" around H-alpha filter technology needs exposing so we are not limited by a profuse amount of differing gadgets requiring frankescopes and costing an arm and a leg! Its not nuclear science. To convert my Meade 102ED has cost me $125 for machining so far, a short 3-1/2" tube plus
threading, possibly $150 more. The result is a !00 mm Objective $10,000 solar telescope - a dream.

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Re: 2nd video - Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF30

Post by marktownley » Sun Jul 31, 2016 9:05 am

It's a simple matter to work out the collimating lens spec. What ever the focal ratio of the Lunt scope is will be the focal ratio of the collimating lens. All you have to do is measure the free diameter of the Lunt collimating lens and you have the spec for their collimator.
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Re: 2nd video - Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF30

Post by solarmax2016 » Sun Jul 31, 2016 2:34 pm

Thank you Mark

Lens theory is not one of my realms of knowledge (I'm just an Architect and Writer). It makes perfect sense to take the Lunt's Scope f/ratio and reverse it to the collimating lens, using the collimating lenses diameter in the famous equation Focal length = Diameter of Objective (lens) x Focal Ratio =
Focal length. Its going to work out to about (f/6.8 x 2" = 13.6 inches for the 60 mm Pressure=tuned instrument, and f/9 x 2" = 18" (for the Meade 102).
Its no wonder I could not reach focus at the end of the retail tube at 32"!!! Trying to make a frankenscope jig to find that focus is a nightmare - if you have the focal length accurately you might only have to saw off another inch from your prototype tube to get exact focus. Imagine starting from the
donor scope length and sawing backward until you reach a suitable focus. Frustrating.

Now to find a faster 4" Achromat (i.e. f/7)- I'm not going to cut up that Meade 102ED with its nice Moonlight focuser. That means I will now have 5 refractors and the best one is sitting in a wooden case - the Televue NP 101 - what a shame.

Thanks again,

John

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Re: 2nd video - Lunt 60PT f/8.3 to meade LX70 5" f8.3 & BF30

Post by solarmax2016 » Sun Jul 31, 2016 6:21 pm

Mark;

Before I order a new tube I'm curious about Solar-Cologne's approach to this Mod by ADDING length to his Donor Refractor. Could he possibly reply to
us on how far beyond or within (or at) the focal length of his Donor Refractor he placed the collimator lens on front of the 60 mm PT Etalon? He shows
his experimental rig in the photo (probably permanent rig) but if he gets an even-illuminated field and good definition his Mod might be a better answer.
The Etalon-Up-the-tube solution may not be the best arrangement after all. Consider that the cone of light from a 4" objective spills over the etalon and
you get what you see in the PST MOD - uneven band width and uneven resolution. At the tailpiece end however, if the MOD is placed correctly, you could
imntercept the whole field and get crisp resolution like the PST. Could Solar-Cogne provide an answer? The only problem is overbalance on the tailpiece.

John

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