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vineyard

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About vineyard

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  1. Hi Nigella, I finally had time to write it up. I hope it doesn't sound too mad. Cheers.
  2. Hello, I'm not sure whether this is the right category to put this in on SGL but it seems the closest. Anyway, I think I have managed to make a mod that allows me to put the etalon of my Lunt 50THa on the back end of my 102mm refractor, and hey presto I think I have a 4" solar scope? I'll break this post into two sections - the first is the mod itself, and the second is the journey that got me there (which was very interesting, and also entailed seeing first hand some pretty scary stuff!). This way, if anyone is only interested in the mod, they don't need to bother reading the rest . I should preface this by saying that I’m not an optics expert (so some of the reasoning below may be wrong, although it seems to have led to a place that works?) and of course the standard disclaimer: this is not a recommendation, I am not an expert, modify at your own peril! THE MOD Basically, if you unscrew the tube on a Lunt 50, you see the back bit (which has the ERF and behind that the etalon, the diagonal with the blocking filter etc). The back bit has a male M68 thread. So I cobbled together various adapters to create a combined adapter that threads on to that male M68 and then steps down to a 2" nose with a female thread. Into that I put a UV-IR filter, and the nose can then be inserted into my 4" tube (like a normal 2” diagonal would). And that's it. So the final configuration has a 2" UV-IR filter, and then behind that the ERF that comes fitted on the Lunt 50 (and behind that the etalon, and then the blocking filter in the Lunt diagonal). And the advantage is that I can use the better focuser on the 4” rather than the horrible helical on the Lunt. Photos are attached. I don't think it will work with every 4" tube - in particular I think this mod may need tubes that are designed for BV'ing (see the next bit for more on this). THE JOURNEY I got my hands on a barely used Lunt 50THa last year. And after I managed to figure out how to see the Ha features ("burping" & greasing the tuner, putting a t-shirt over my head ) and also how to find focus with an ASI camera (on which there is a separate thread elsewhere on SGL - @Rusted @Nigella Bryant @Pete Presland were particularly patient & helpful, thank you again!) I was so taken by what I saw that the 50mm aperture left me wanting more. So the topic of PST mods came up, and @Peter Drew & @Merlin66 kindly picked up my open posted Q and were v helpful in sharing how those work, and the things to keep in mind (thank you both!). While looking into that, and looking at the mounting cost involved with a donor scope, an ERF, a used PST etc, the Q came up in my head of whether my Lunt could be used instead of a PST. Clearly I wasn’t the only one thinking of that b/c google then took me to this v useful thread on Solarchat. Looking at that thread, and the f-ratios and the distances involved from the focal point to the sweet spot, started to get me cautiously excited. Mostly b/c my 4” refractor is an old & now discontinued TV102iis. This was designed for BV’ing and so the tube is actually shorter than a normal TV102 (to use it for monocular viewing, you have to attach an extension into which the diagonal is then inserted). And the amount of travel on the focuser meant that I reckoned just using it as the stubby tube in BV configuration might allow the etalon unit to still find the sweet spot without having to physically change anything (since I am not going to take a hacksaw to my TV!). So I knew I would have to make a “nose” that could thread on to the Lunt back-end (with its white tube removed) and then be inserted as if it was a diagonal into my refractor. While I suspected that I would be able to find focus, the next big thing was energy rejection. My ideal situation would be a front-mounted ERF. But they are so expensive (of course its worth it when its your eyesight you’re talking about, so while I was prepared to go down that route, I kept looking to see if there were alternatives). There was the possibility of internally mounted (ie smaller & cheaper) ERFs but I didn’t want to have to physically delve into the innards of my OTA every time I wanted to use it (I wouldn’t trust myself with the inside of my scope!). And then I realised that the Lunt 50 has an ERF already in front of it. However, I wasn’t prepared to just rely on that. With 4x aperture area, and therefore at least 4x energy being brought to focus on the ERF (actually I think well in excess of that given the longer optical train and hence more convergent beam?), I wasn’t sure what the comfort margin in the Lunt ERFs energy density tolerance might be – and also I wasn’t sure whether that might degrade them faster. This thread about the energy levels was also v helpful – and salutary about the need to be v careful (not only did opinion seem divided but the energy levels could also be quite high!). And then I found this post which talks about adding a UV-IR filter in front for apertures above 80mm (obviously not to be used just by itself). That got me thinking about adding a UV-IR filter to the nose I was already thinking about. I chatted w Simon @ Widescreen Centre (since they sell Lunt ERFs and I wanted to see if I could find out specs of their transmission rates & energy tolerances). When he realised why I was asking, he suggested I chat w Gerd Neumann at Astronomik. So I called him up and described what I was thinking. He was v helpful & approachable (this hobby is so great for that btw) and reckoned that that double combination of a UV-IR and the ERF ought to be sufficient (although it was of course on me what I did). We also chatted about ideally what size image should be falling on the filter (since if it was too small, the intensity on the filter would be higher with all the Qs that raises, and if it was too broad, then the actual nose would start heating). Interestingly the ideal size he independently recommended was about what the image would be if the focuser was completely in (ie the risk of the nose being heated was not there). So I thought, ok I will try that and test it (worst case, I can use the filter for my night-time viewing!). So once all the adapters & filters arrived, it was just a case of waiting for a sunny day and then – with a meat probe thermometer from the kitchen drawer also at hand – getting started. First off, I just used the Lunt 50 as it is – took the diagonal out and used a sheet of paper placed at the focus of the image. Measured the temperature of that image – a reasonably steady low 20s C. Then I pointed the 4” at the sun (with all its back end taken out) and did the same thing. Making v-e-r-y sure that I was not anywhere near looking through the tube! The image on the paper was so intensely bright that it hurt even looking at it. And the temperature readings were s-c-a-r-y. Within 2-3 seconds, the temperature was in the high 70s C and still rising fast. The thought of that happening to a retina just does not bear thinking about. Those warnings about never looking at the sun through a scope are not idle! Then I put the nose in with the UV-IR filter mounted. And did the same thing w temperature reading. It rose more slowly but was still getting to the low 50s C. So those warnings about how these UV-IR filters should not be used by themselves to look at the sun are also not idle! Then I threaded the nose on to the back bit of the Lunt and put that into the refractor. With the diagonal out, I found that I could get an image to focus on the paper (yes!) and when I measured the temperature, it was stable and in the low 20s (yes!). So the next thing was the moment of truth, of putting the diagonal on it, and looking through it (gingerly) myself. It was lovely. You could only see part of the disk (not the whole disk as with the Lunt 50 OTA). I was running out of time before having to go to work, so I took some quick photos w/o any barlows etc (I also hadn't seen @MalVeauX handy tutorial video at that time, so I didn't capture all the right data on the prominences, and my processing is also clumsy - it was about 70 lights (not even a movie) stacked with AS!3 and then played around v-e-r-y clumsily w Registax, GIMP and Lightroom). Anyway, sorry for what has turned into a v long post. I will defer to the expertise of others on whether I’m doing something stupid or insane (or things to be careful about with regards to regular use). There are some tweaks I plan on doing, but I’m feeling pretty comfortable about the setup – there’s a UV-IR filter followed by the Lunt ERF and then also the blocking filter in the diagonal (which I guess is an aperture stop rather than an energy rejector so I'm not relying on that), and the temperature readings were also reassuring. I’d like to say a huge thank you to everyone who helped patiently with all my various questions on this rather unexpected journey. What I like about where this has led to is that I can use the Lunt as a travel solar scope or for whole disk viewing, and then swap it in to the larger 4” for closeups (and more resolution?), while also being able to use the same 4” for night-time viewing. A bit like the modular scopes that Lunt are now marketing for the price of a used car Cheers all, Vin
  3. Be careful what you offer up Nicos...I may well be diving in Cyprus in April! Are you near Larnaca? That does look an amazing scope, and I've never looked through a Tak (I went the TV route). Cheers, Vin
  4. So this just got weirder. I'd saved a JPG of a GIMP'ed version of the TIF file. Today I reopened that JPG in GIMP and 3 colour channels were there? But if I go back to the TIF it only shows greyscale channel. <Scratching head, but if this the workflow that works then hey ho!>
  5. That's stunning. If you move the slider from left to right quickly its like going to warp speed must be like (if it existed!). Thanks for the patience to do that & for sharing it!
  6. Hello, Here's M36 that I took & processed last night. 30 lights of 30 sec (w darks & biases applied). ASI178MC. Its not great but I'm just getting started so I'm quite happy enough with it for now. Esp as the main objective last night was to test the Mount Model capability of my kit with EKOS (it worked ). Q1. Does M36 have some colour in it in real life. I could have sworn that when looking at the lights as they were being taken there were some colour stars? Yet this image insists on coming out as grey scale. I've made the FITS setting adjustment in DSS multiple times to Generic RGGB (and also Generic GBRG) and saved it a a 16bit TIF file, but every time in GIMP it only shows greyscale (even the linear stretch previewed in DSS only shows grey scale, no RGB). Am I doing something wrong, or is there really no colour in M36? Q2. I tried stacking with SiriL and it came up as saying it could not find any stars in the image! As did PI. So I then used DSS (I knew quality may be variable across all the lights b/c clouds were passing through, neighbours lights were going on & off etc). DSS did find enough stars to stack although it didn't pick many images to stack. Is it common for different stacking software to return different responses like this? Q3. This is probably a Q for the mounting section, but I'll include it here for completeness. I did rough polar alignment, did the Mount Model alignment (3 stars), and it plate solves and slews to target correctly. So far all good. But then as the lights are being taken I can see the image is moving in the FITS viewer. So is this the mount not quite tracking right, is it a periodic correction error (I'm not sure what that means tbh!), or is it inevitable with tracking (its an old GP2 with an EQStar EQ5 go-to modification) - is this what would be improved with a guide camera also set up? Thank you for any pointers! Vin
  7. I remember once having some problems where the image when exported out was v dark (and colourless). Not sure if that's the same problem as you're having. From memory, I went back and clicked on debayer on the first step, and re-stacked and then it was fine. (But this is a while ago so I may be misremembering!). Good luck!
  8. I have to write it up to share - will do v soon (esp as the weather is rubbish)...has been on my to-do list since Dec but life's been a bit mad (how is it already almost the end of Feb?).
  9. If you get a binoview-compatible refractor, you can do all sorts. I've managed to set up a way of removing my Lunt 50 etalon from its OTA and putting it into the 102mm OTA and voila...!
  10. I'll defer to others with much more experience. But maybe swap the 12inch for a smaller refractor that you could use with EEA kit (ie, set up to come on automatically, image & shut down automatically - if you trust the weather, then EKOS is pretty good for that)? You might also use it more often just of an evening (should also be fine for lunar & planetary?)? I'm of the school of if it's not being used, then why keep it (just something else to look after!). Given the quality of your solar images, definitely do not give that up though! Cheers.
  11. Hi, do you mean something like this? https://astro-gadget.net/pdfs/EQStarEQ5.pdf If so, I can highly recommend it - I modded my old Vixen GP2 with those, and control it with EKOS. It's a lovely piece of kit - stepper motors & belts. Was pointed towards it by some folks on CN & would happily buy it again! Cheers, Vin
  12. Hello, A relative newcomer to AP here. And a Mac-based one too. So, I was just wondering what would people recommend for registering & stacking solar images on a Mac? I've seen ImPPG generate some amazing images here on SGL - @Rustedhas been v kind and even worked his ImPPG magic on some v clumsy shots of mine of the sun & moon in other threads. But ImPPG doesn't work on Mac OS and I don't want to run the Windows emulator on my Mac. So, is there another software that does that? I use SiriL for my newbie deep sky attempts, but I've found that SiriL can't seem to register & stack the pre-processed images sharply (it cleans them up fine, but because the sun has moved across the FOV - I use alt-az for solar - the final registered & stacked image is a blur). I tried Pixinsight but that didn't work either (which may have been operator error tbh as I couldn't even get PI to stack some M42 images that SiriL did stack fine). I'm hoping that someone somewhere knows of a piece of software that allows for registering & stacking a solar disk on a Mac OS? Otherwise there's a real gap for Mac-based users...or maybe I'm just not using SiriL right for solar? (While I'm by no means an expert, I suspect the problem may be one of registering b/c SiriL offers Lucy-Richardson deconvolution just as ImPPG does - the blurring of the stacked images suggests to me that the processed individual lights are not being lined up correctly?). Thank you for any help, Vin
  13. Goodness, I got v excited and looked at the website. And stopped when I saw the list price of $5,785 for the Lunt 100MT Luckily have managed to mod my little Lunt 50 to work with my 102mm refractor for about 5% of that cost - will stick to that (and its modular too as I can swap the Lunt out for night-time viewing) Cheers!
  14. I figured out what the problem was. Because I had installed astropy, I had to change the location in the Align Options to point the software in the right location. This thread was a useful pointer: https://indilib.org/forum/ekos/5400-python-3-mac-osx/40883.html b/c when I used Terminal and pip/pip3 it came up with a message saying that astropy was already installed, with the location handily specified. So I just cut & paste that location into the EKOS Align Options box for python's path and hey presto it worked. Used it offline last night, and it worked a TREAT (and fast too!). Replying to myself (a) in case anyone else has any similar problems, and also (b) so when I inevitably forget in the future, I can come back & look here
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