Lunt 60mm

[pragmatist]

Well i will be ordering my Lunt 60mm next week but just need some advice from some of the more experienced solar observers on this forum.

I am going for the 60mm with B1200 blocking filter (would like to image at some point) and would like to know if the pressure tuner makes much of a difference. I can afford it so that is not the issue, just would like to know if it's worth the extra outlay?

Thanks in advance,

Matt

[DrRobin]

Hi Matt,

I bought a Lunt 60 pressure tuner about 18 months ago and asked a very similar question. The answer was not much difference, but the PTs give a finer control over the tuning so went for one based on using it for imaging. I am glad I did as I double stacked it about a year ago with a front mounted tilt Etalon and the tuning is much finer on the PT than it is on the tilt.

Instinctively the PT should produce a more even image as the plates of the Etalon don't tilt, it is the air pressure in the chamber that changes to tune the Etalon so it should give a more even image over a wider field of view, but whether it does or not I couldn't say. Even if you got two side by side, one a PT and one a tilt you still might not draw any conclusions as there is some variance between Etalon to Etalon of the same design as they are quite tricky to make, hence the price.

The other thing about the PTs is that they are slightly more bulky, will definitely weigh more and the tuning adjustment needs a little bit of force to compress the air so on my light weight tripod, the PT sends the image all over the place, much more than the front mounted tilt Etalon.

What made me go for a PT, like you I could afford the PT and it was the finer control it offered, plus the suggestion of been slightly better for imaging. I knew if I saved a few quid and went for the tilt I would regret it later as there is no upgrade path. I didn't consider the Feather Touch focus for exactly the opposite reason, it is easy to upgrade later and I have been perfectly happy with the stock focuser.

I hope this helps, check out my pics in the solar imaging section taken with a Lunt 60 double stack and DMK41 for proof of what you can do with these great Ha scopes.

Robin

[pragmatist]

Hi Robin,

Many many thanks for your detailed description ref pressure tuners and i think based on your thoughts i will probably get one. It seems that for imaging alone a PT will probably be a good thing especially as i do intend to double stack later on as my experience with solar observing grows.

I was quite impressed by the build quality of the Lunt and am sure it will give me many years of enjoyable viewing/imaging.

Regards,

Matt

[allcart]

I can only echo Robins words. I went for the PT and Feathertouch and have never regretted it. It was expensive, but I did not want to end up having niggling doubts as to whether The PT would have been better than the tilt tuned version. I wanted the best that Lunt could offer.

I also double stack, and can say that tuning both etalons to get the best image is very easy.

[pragmatist]

Thanks Allcart, just need to clarify the difference and benefits of the B1200. There is the B1200D which i assume is the blocking filter in the diagonal and the B1200S. Can anyone describe the differences?

I know this will be a silly question with an obvious answer.

Matt

[DrRobin]

Hi Matt,

I have been very pleased with my Lunt and my experience is that the build quality is good, the design is right in that everything works as it should. The tilt Lunts don't have a central obstruction like the Coronado Ha scopes so it does give you very slightly more aperture and as far as I know they are the only supplier of pressure tuned Etalons at least among the suppliers offering products to amateur astronomers.

I don't think you will be disappointed either visually or whilst imaging. I reckon to get 5x the use out of my Lunt than I do any of my night time scopes, mind I do take it work most days in the hope of getting 30 minutes at lunch time.

Robin

[DrRobin]

Hi,

I didn't know they did two blocking filters but it turns out the B1200D is in a diagonal and the B1200S is in a straight through tube. If you want to use it for visual get the D variant, you don't want to be bending down to look straight towards the sun apart from risking damage to your eyes, your view will be impared by the bright sun shining in to the other eye.

If it was only for imaging then the straight through would get rid of the mirror and any errors in the mirror and I presume some cost?

I have the diagonal and guess that most people will want this, they seem pretty good quality, certainly good enough for a 60mm scope.

Robin

[Zakalwe]

I was in a similar situation and also opted for the PT version.

Stephen Ramsden's site is a gold mine of information, if you haven't already viewed it?

http://www.solarscopereviews.com/

[pragmatist]

Great stuff, many thanks. Think i will put my order in tomorrow, getting itchy fingers now to get hold of one.

Kind regards,

Matt

ps Robin i would probably do the same as you, take it to work and hope for a lunch time session while out of office.

[brantuk]

DS, PT, B1200 is the way to go. I too used Stephen Ramsden's web info - I think he must've used just about every solar scope on the planet. One word of advice - if it seems appealing to get a 50mm DS with the 60mm scope (cos it's cheaper) then don't. I tried it and it's an ill match that just doesn't work.

[allcart]

Yes the B1200D is what I have and is great for visual and no problem using ccd cams. The B1200S would be better for imaging only as it would give a direct lightpath to the ccd chip. I certainly would not want to use one for visual observing. Looking directly at the sun, would be awkward unless it was very low in the sky, and you would need to shield your face from the sun.

I agree with brantuk, if you want to double stack at a later date, save up for the 60mm DS filter. Its worth it.

[Zakalwe]

There's a massive difference in price between the 50mm and 60mm Etalons though. £1100 for the 50mm, £1700 for the 60mm. Expensive toys these.

I managed to find a virtually new 50mm for £500. That was too good not to snap up at the time!

[jonathan]

Good choice of scope, I have been very pleased with my PT B1200 Lunt 60mm.  I purchased on the advice of that solar observing website mentioned and some from here.  Although the choice of solar scopes is relatively small, choosing the right one for you can be quite hard - you could go for the cheaper coronado, but by the time you start double-stacking and all the rest of the things they do it can work out to be at least as expensive as the Lunt and for very little or no actual gain.  The Lunt and Pressure Tuner are a joy to use, they look and feel expensive and well-built, and they come in a nice custom fit flight case.  The dual-speed focuser is perfectly adequate for visual use.

I use mine on an Omni CG-4 mount, very solid and with motor drive tracks pretty well.  You can use it on a photo tripod but I find the accuracy of tracking is gone and unless you have a very good tripod there's just too much slop.

You might like to invest in a zoom eyepiece, I use the Baader Hyperion 8-24mm Zoom, it's easy to switch between magnifications and effectively gives me about 5 eyepieces in one (plus all the space in between click stops) and has a matching barlow available (which I have yet to try, but by all accounts sounds like it should be good).  I tend not to bother with other eyepieces as this one Zoom eyepiece provides everything I need, the quality is as good as my other individual eyepieces in my seeing conditions through the Lunt.

Oh, and turning the pressure tuner feels like you're revving a motorbike!

[pragmatist]

Great, will check out the Baader Hyperion today. Should be placing my orders tomorrow. Will do a first light once I have had a day to play, guess that means cloudy times ahead.

[brantuk]

I'll second that as well - the Baader Zoom is perfect for it - like Johnathan it tends to be the only eyepiece I use with my solar scope. The only trouble is - so many folks like to drop by and have a look, that I end up cleaning the zoom as much as the missus wipes dust off the mantlepiece lol.

[jonathan]

Another thing you will require if you intend to use the scope with a typical astronomy mount is a vixen dovetail bar, there is now one specifically available for the Lunt LS60 although I can't vouch for how easy it would be to balance the scope on such a short bar if you have an heavy eyepiece fitted (I may well try it myself as I could do with one that fits in the Lunt case); I would also highly recommend getting a solar finder, I have the Televue Sol Searcher which does the job brilliantly.

[trazor]

 if it seems appealing to get a 50mm DS with the 60mm scope (cos it's cheaper) then don't. I tried it and it's an ill match that just doesn't work.

That may be true for photographic purposes, I would not know.

But for visual I find the addition of the  LS50F raises a 60 mm Lunt to another level entirely.

I would not be without mine.............

[Zakalwe]

That may be true for photographic purposes, I would not know.

But for visual I find the addition of the  LS50F raises a 60 mm Lunt to another level entirely.

I would not be without mine.............

I agree with this. Visually the 50mm DS makes the disc so much more contrasty (is that a word?) and brings out features that you wouldn't see in the SS. For imaging you need to work a lot harder. Tuning both Etalons and getting the rotation correct is a faff, but it doe work.

Kim, Are you "clocking" the front Etalon? You have to rotate it to get in into the correct spot as well as tuning it. I think that it was Dr. Robin that pointed me in the direction of this doobry (esoteric, technical term) ....expensive for what it is but perfect for the job.

https://www.teleskop-express.de/shop/product_info.php/info/p4295_TS-360--Rotation-with-M90-thread.html

[trazor]

I agree with this. Visually the 50mm DS makes the disc so much more contrasty (is that a word?) and brings out features that you wouldn't see in the SS. For imaging you need to work a lot harder. Tuning both Etalons and getting the rotation correct is a faff, but it doe work.

Kim, Are you "clocking" the front Etalon? You have to rotate it to get in into the correct spot as well as tuning it. I think that it was Dr. Robin that pointed me in the direction of this doobry (esoteric, technical term) ....expensive for what it is but perfect for the job.

https://www.teleskop-express.de/shop/product_info.php/info/p4295_TS-360--Rotation-with-M90-thread.html

Would this ring give any benefit for visual use, do you think?

[DrRobin]

Hi,

It was me who suggested one of these rings, I bought one last year after spending several hours designing one on the 3D CAD intending to get it printed on a 3D printer only to find that the printing costs were going to be £160 and then it might not work. I found this and they work great.

For visual as imaging it helps you fix the front mounted Etalon in the optimum position and I leave mine on all of the time, that way I only need to adjust the pressure tuner and a quick tweak on the front mounted Etalon. I used to mark the position of the front mounted Etalon, but just hanging on the treads it seldom went back in the same place.

I also bought one of the Lunt dovetails to reduce the weight over the Vixen one I was using when going travelling. I had to drill a couple of extra holes in it to get the perfect balance when using the double stack as long it is not. Ideally, they want to be about twice the length to get the balance point for single, double stack and then a range of eyepieces or barlows and a camera.

Still no one said solar Ha was cheap. In comparison to the cost of the scope the accessories are at least manageable.

Robin

[Zakalwe]

Would this ring give any benefit for visual use, do you think?

Yes, absolutely. When you mount the front Etalon you have to "clock" it...rotate it on the thread until you get the best spot, and then tune it. It'd be highly unlikely that the best spot is just where the thread gets tight, so you end up with the front Etalon loose on the threads. Which means that it can shift a little which knocks it off-band. With this dovetail you can tighten everything up and then rotate the Etalon in the dovetail to the best spot. Lock the dovetail off and Bob is your mother's brother.

Still no one said solar Ha was cheap. In comparison to the cost of the scope the accessories are at least manageable.

Oh man, this is so true. Still, the views are spectacular. And these scopes have only really been available to the amateur for the last 10-15 years.

[trazor]

Yes, absolutely. When you mount the front Etalon you have to "clock" it...rotate it on the thread until you get the best spot, and then tune it. It'd be highly unlikely that the best spot is just where the thread gets tight, so you end up with the front Etalon loose on the threads. Which means that it can shift a little which knocks it off-band. With this dovetail you can tighten everything up and then rotate the Etalon in the dovetail to the best spot. Lock the dovetail off and Bob is your mother's brother.

Never realised that rotating all of  the second etalon could improve the view.

Will try with some low tack tape, if it works I will purchase the adapter.

Thanks for the knowledge..................

[Zakalwe]

Never realised that rotating all of  the second etalon could improve the view.

Will try with some low tack tape, if it works I will purchase the adapter.

Thanks for the knowledge..................

Clocking the front Etalon is essential IMHO. Tune the main Etalon first, then stick the front one one. Clock it to get the best view and then tune it. You'll probably have to tweak thins back and forth as the atmospherics change.

[DrRobin]

Yes, absolutely. When you mount the front Etalon you have to "clock" it...rotate it on the thread until you get the best spot, and then tune it. It'd be highly unlikely that the best spot is just where the thread gets tight, so you end up with the front Etalon loose on the threads. Which means that it can shift a little which knocks it off-band. With this dovetail you can tighten everything up and then rotate the Etalon in the dovetail to the best spot. Lock the dovetail off and Bob is your mother's brother.

Oh man, this is so true. Still, the views are spectacular. And these scopes have only really been available to the amateur for the last 10-15 years.

Oh, what a time to be alive. We might not be at the cutting edge, but it nice to be in the slip stream of the [technology] blade.

Robin

[trazor]

Would anyone know the thread size of the grub screws in this 90 mm adapter?

I would like to use nylon grub screws instead, to prevent damage.