Ships and Stars

I find a hood helps even in very dark conditions if chasing the faint stuff. Might add more detail to brighter DSOs as well. Even under 21.9 skies, once fully adapted, I can see the general surroundings and hills and move around carefully without a torch, part of that might be central belt LP, but I reckon a lot is simply from the Milky Way! Iain - I bought some glow in the dark tape - would be ideal for your chair! Peter - there was a small company in the states that made a Monk's hood vest thingy just for astronomy, had large pockets for eyepieces and an absolutely massive hood, haha, function over fashion!

Excellent photos! I'm a visual astronomer but admire all the astropics, the processes behind it are amazing. You'll be able to get some really good advice here on SGL.

Great comparison between focal lengths, a lot of times it's a toss up between FOV and brightness/detail on larger targets. I think of Mel Bartels and some of his faster/shorter focal length scopes (his DIY 6" f2.8 and 10.5" f2.7 in particular). Sounds like you had great conditions, hope the snow isn't too deep! Been quite a mild winter here, temp wise. Cheers!

Thanks Gerry! I feel like I achieved something here. Not to constantly butter everyone up with tons of accolades 🤣, but I only managed this with the help of you and Scarp and everyone else who has replied to my many and varied posts here on SGL. I've learned a lot and am still learning by leaps and bounds. I will have to take another keen astronomer with me next time to verify that one can binoview the HH under the right conditions/aperture. Someone may well have already done this, but I've never found any online accounts of people binoviewing the HH (someone in the states saw it through a pair of large observation binoculars and then there's the particularly interesting account of the fellow down in the Florida Keys who saw it (or detected it) with 12x70s binos/Hb filters apparently!). I'm sure someone out in Nevada or Texas or Western Australia with a giant 30-32"+ has seen B33 with binoviewers, but haven't read about it. This particular dark sky site is about as good as it gets in my neck of the woods, I reckon it's the darkest place within reasonable driving distance of home, even for a weekend. The only disconcerting thing is some obvious skyglow on the horizon from the central belt of Scotland starting about 50-60 miles away (which happens to be right below Orion), but I guess that shows how dark it is there. By 2am when the LP on the horizon was down a bit it was just amazing, and I'm not even sure seeing and transparency were close to optimal (the wind was one clue). Besides a thunderous Milky Way, the sky was ink black and the stars were just intense points of light. Anything much darker in a Bortle 1/22.00SQM environment would require a trip to a few select places on the West Coast of Scotland, or even a ferry trip to the Outer Hebrides for the ultimate conditions here. Exit pupil was never something I paid much attention to until everyone kept bringing it up, haha. I think it made all the difference viewing the HH with the 40mm EPs - I wouldn't have known about the false exit pupil dynamic until you pointed me to the CN post (last time I'll mention this, I promise!) Next time out there I want to try the 32mm EPs - I ended up ordering 3 sets of plossls (40/32/25) and a 42mm 70deg 'finder' eyepiece for not much money from Telescope House on discount, so that's quenched my binoviewer madness for the immediate future 👍 Maybe you can give the HH a whirl sometime with the 24" and the binotrons/Hb/UHC/NPB! I'm also sold on using a large hood to seal out all extraneous light and getting in the most comfortable position I can and relaxing. My ladder (a freebie, was left by previous homeowner!) has a small platform and a handle on top so I can lean against it in relative comfort. PS the binoviewers on M31 & Co was a treat, really good - need to do a direct comparison with single EP viewing next time. I'll have to go for the Leo Triplet next time and the Virgo Galaxy Cluster, been wanting to chase these. I await your next post - my 'grab and go' dob is on the way after selling my smaller Newt/EQ mount yesterday, so waiting in anticipation for that as well. Hopefully that's me sorted on the scope/EP frontier for a good long while! Cheers!

Check out mooncalc.org, very helpful for planning this sort of thing, I use it frequently.

Just had a look at the analogsky website Peter, these designs look very interesting and I dare say, possibly affordable!

I have a Lumicon UHC, supposed to be one of the best and mine also presents stars as green blobs with a tiny red dot in the bottom right, I call it the 'Christmas tree effect' I think it's fairly common with UHC filters, probably because different colours in the light spectrum aren't converging fully or something to that effect. I use my OIII mostly, so it doesn't bother me a lot but can get annoying if viewing with it for a long period. I've seen this green/red phenomenon discussed on one of the forums in more detail. My next filters will be the DGM NPB set hopefully.

Ah yes I probably had a FOV of something like 38-40deg max, haha, not the greatest. I bought the cheapest EPs I could find for this test, they aren't too bad actually, fully coated and blackened where it counts, but the Morpheus and TV stuff is noticeably more contrasty. The WO binoviewers have the standard 20 or 21mm fieldstop, so any EP over 25mm I believe vignettes. The bigger BVs like TV and Denk, Baader maxbright have 25mm on up to 27mm I think. I now get eye strain really easily in my right eye (my main viewing eye) so keep flipping back and forth but need to refocus slightly each time, so the binocular view is something I will probably be doing more and more of. Must check out these links, thanks for sending those along. Thanks Peter!

I usually leave my step ladder or finderscope at home, must be some kind of record 🤣 That ate into a lot of time last night managing without that. The skyglow was a bit alarming and I'm fairly certain now it was distant LP as it seemed to dim markedly late into the evening and wee hours. There are lots of interesting sights around IC 405, I could spend a while just on that area. Doubt binoviewers will replace my single eyepiece collection, but was happy with how they turned out last night, if I have the money someday and a pair of Denks/Earthwins or maybe Sieberts pops up for sale, I may have to try that. Moving the van around was a necessity, it got a bit bad for a while last night with the wind, thought it would be a show stopper! That caught me a bit off guard. Next time out I want to try for more galaxies, I was using Dubhe as one of my alignment stars last night, and kept sweeping past tiny galaxies trying to find Dubhe without the finderscope! I was all over the place, haha. Got there eventually. Hope there are more clear nights for everyone soon!

Thanks Lee, that's at least the second time I've left the finderscope at home, argh! I have a telrad but there's no place to mount the base so that's going on my smaller 'grab and go' dob (when I get one). Just the 12x70s bins were amazing, star cluster after star cluster out there! I'm definitely keeping the 500p but will be looking soon for a 10"-14" dob to play around with after my 200p newt on EQ5 is sold. Looking for one that's scratched and generally beat up but optically ok, preferably a flex-tube. The 500p can be a handful to set up just for quick sessions (e.g. under an hour or two). Cheers!

Hi all, a bit of a long-winded one here but hopefully interesting. Clear moonless skies yesterday, so set off late afternoon for my dark sky site, somewhere between 21.90 and 21.92 supposedly (Note: would like to obtain SQM-L for actual at-the-time readings, seemed to be a bit more early evening LP on the horizon this time, but still exceptionally dark). I always forget to bring something. Well… this time it was nothing less than my finderscope, I had it with all my gear going out the door, but left it tucked against the sofa… needless to say, this made alignment with a 2m tall, 2000mm focal length 500p an absolute nightmare in windy conditions, and it took ages to find my alignment stars in the EP (21E is the widest I currently have) and I really struggled to achieve a proper alignment for much of the evening which greatly curtailed the number of stops I made, but on the upside, I spent more time studying the targets I did acquire. Anyway, soldering on, I had 25-30mph gusts for the first few hours so I moved my van to act as a windblock but the wind kept veering north until it finally died down. Thought scope was going over a few times, and that weighs a good 75kg. If I unlocked the clutches, it would freely weathervane around! ----------- First stop – IC 405 Flaming Star nebula, 21E & Astronomik OIII – excellent – nebulosity just seemed to keep going out out out, away from the central area. Blue Snowball NGC 7662– Leica Zoom and TV 2X Powermate – got to around 300-350x before view came apart, but nice to pay a visit. Bubble Nebula & M52/NGC 7510 – 21E again, very nice. M1 Crab Nebula – I understand this is a lot fainter than when it was first catalogued, still, an easy one to spot and good nebulosity under these conditions. M31,32,33, M110 (M31 naked eye) – binoviewers! Awesome. Can only recommend. Please see notes on slightly unusual 40mm eyepiece choices below. M36,38, NGC 1893 – lovely star clusters in the neighbourhood of IC 405 M42 – always a must see. Tried the Trapezium Cluster at 350x to 450x, got the four stars sharply at lower mag, couldn’t get more at higher mag, sky wasn’t having it. The nebulosity around M42 just kept going and going and going… best views with 21E and no filter, OIII was good to excellent, but in the end, preferred without filter. Double Cluster (naked eye & 12x70 binos). ----------- Horsehead B33, IC 434, NGC 2023, Flame Nebula NGC 2024 – I spent a lot of time last night doing a few eyepiece experiments on the famous B33 Horse Head and Flame Nebula – the Flame I sort of forgot last time in my obsessive quest for the HH, so gave NGC 2024 due admiration this time. This is only the second time I have seen B33, but the views were even better last night. I finally slewed on target with the 21E and OIII. Right after Alnitak came in the FOV, I noticed the Flame was immediately visible with direct vision, so I figured this was a good sign. I then swapped to a 27mm Orion (fittingly) ‘Flat Edge’ EP with Astronomik Hb filter and moved down to B33. It was immediately apparent with direct vision, just a huge dark bulge jutting out into IC434. Excellent! ---------- Crazily enough, I’ve wanted to try B33 for some time through binoviewers (or a binoviewer). I assumed that in a 20” dob, splitting the light still roughly equals using a 14” binoscope, plenty of aperture under these dark skies. I imagine someone out there has tried binoviewers on the Horsehead, but I haven’t read any reports or comments about binoviewing the HH online, so gave it a shot - I broke out the WO with 1.6GPC which goes in a Baader clicklock 2” to 1.25” adapter straight into the focuser to get the BV as close as possible to the secondary to reach focus. BV eyepiece choice – this is where it gets kind of interesting. I used 40mm 1.25” Revelation plossls that cost me a whopping £22 each from Telescope House on special. Why 40mm EPs in an f4 scope, especially for very faint DSOs? A fellow SGL member (thank you again @jetstream!) pointed out before there is a ‘false exit pupil’ dynamic whereby the BV splits the light and reduces the exit pupil area by 50%, if I understood correctly. With 40mm EPs at 1.6x in a 508mm f4 dob with 2000mm focal length, this gives me 80x mag and twin exit pupils of 4.49mm, not the usual 6.35mm that a single 40mm ep (with 1.6x GPC) would normally provide. By the way, the 40mm would give 10.6mm exit pupil with no barlow on its own. I realise the FOV is probably only around 40deg but it gives a low 80x magnification which is close to what the bbastrodesigns visual detection calculator recommends for some of the fainter DSOs (85x) in my scope. FOV doesn’t matter for the HH in my opinion anyway, as I want Alnitak well out of the picture, so to speak. Here’s what I came up with: Binoviewer ‘false’ exit pupil: (508x508)/2 = 129032 Squrt129032= 359.2102448427661 Therefore, a pair of 40mm eyepieces with a 1.6 barlow in a binoviewer is not an individual 6.35mm exit pupil (508mm/80x mag = 6.35mm), it is actually 359.21/80 when split, which equals a 4.49mm exit pupil for each eye. Roughly calculated… 40mm EP with 1.6x barlow = 80x = 4.49mm exit pupil. 40mm EP with 2.0x barlow = 100x = 3.592mm exit pupil 32mm EP with 1.6x barlow = 100x = 3.592mm exit pupil 32mm EP with 2.0x barlow = 125x = 2.874mm exit pupil 25mm EP with 1.6x barlow = 128x = 2.806mm exit pupil 20mm EP with 1.6x barlow = 160x = 2.245 mm exit pupil ----------- So did binoviewers work on the Horsehead? Absolutely 100% yes! I saw the Horsehead with both direct and averted vision through binoviewers with as Hb filter on the nosepiece, no maybes or buts, a definite hit, and could see IC434 running along the dark dust cloud. I couldn’t quite make out the small notch for the nose, but was really close. The windy conditions actually made it a little easier to see at times as it shook the scope during the gentler gusts, kicking in some averted vision, but I'd still prefer it calm. The only drawback is the massive amount of eye-relief from the 1.6x barlowed 40mm EPs, which must be huge as I had to hold my head well back from the eyepieces. This meant eye placement was critical and extremely limited. I want to try 32mm EPs next, those are in the post along with some 25mm EPs and a solitary 42mm 70 deg finder EP. One thing I found a necessity for the best views of the really faint stuff - a hood or towel over your head, even under starlight. The huge increase in contrast and ease of viewing seems to far outstrip most other factors such as particular make of eyepiece, coatings, etc. The boost in contrast was substantial. I have a down parka with a big hood that has an integral wire brim which I gently fold around the EP or binoviewers. The more incoming light you can block out completely, even reflected from the ground below, the better. The stars were bright enough I could see my feet and walk around easily once dark adapted. Those small but annoying LEDs from the GOTO unit, dew controller etc etc were all covered up with a raincoat. Total darkness is the goal, aside from what’s coming out of the eyepiece. That makes a big difference in my book and really lets me focus on what's in the glass. I later tried the UHC filter in the BVs and managed to see the HH with direct and averted vision. Here, averted vision was definitely better and things were quite washed out and really lacking a lot of contrast at this stage in comparison to the Hb filter. Next trick was dropping in the 20mm WO eyepieces, but too much mag (160x I think) for binoviewers and things just turned inky black with the Hb, perhaps I should have tried the UHC here. Which was better – a single EP or BVs? Both! Really interesting, both have pros and cons. I later switched to a single 17.5mm Morpheus and got a really contrasty view of the HH with Hb filter. It loomed large in the eyepiece and was immediately unmistakable. I didn’t quite get the nose detail, but the huge lump projecting out into IC434 at 114x was near impossible to miss. Considering I only have bog standard binoviewers with ultra-low end eyepieces and a small 1.25” nosepiece which projects well into the large light cone coming out of an f4 dob, I was really impressed. It had reduced contrast and a slight reduction in overall brightness in comparison to using a single EP, but was this was largely countered by greatly reduced eye-strain and the benefits of binocular vision. I would say there was no more detail with either set-up, maybe a slight edge to the 17.5 Morpheus or 27mm Flat Edge, but being able to see the HH directly with both eyes was a genuine pleasure I will remember for a very long time. I think with some large bore Denks/powerswitch or some crazy Siebert binoviewers, higher-contrast EPs and the 45mm OCA for fast dobs, this would match or exceed the solitary Morpheus views. By the way, I wish Baader made 2” wide-field Morpheus EPs! Flame nebula was wonderful with the binoviewers, not as contrasty as the single Morpheus, but great to scan across. Hb filter worked better than OIII here. The Hb on the Morpheus was also excellent, probably the best view there of the lot. I really like the Flame Nebula, especially with the dark lane in the middle, a nice one to admire. One thing I note – I don’t think Orion ever gets very high in the sky here at my latitude (57-ish). Viewing from very dark/excellent skies further south (La Palma! Morocco? Alps?) must be excellent. The site I use in the Cairngorms is very dark indeed and supposedly 21.90 to 21.92SQM according to the LP map. However, I noticed considerable skyglow on the horizon, right under Orion as a matter of fact, so not sure where this is coming from, perhaps from the Central Belt starting some 70-80 miles away. Not sure some of this wasn’t zodiacal glow either, but not 100% on that. Either way, it was definitely excellent overall sky darkness, winds and turbulence in the atmosphere aside which limited magnification and seeing, but if Orion was another 10deg up, it would make a noticeable difference. Once the scope was packed around 2am, I spent about 20 minutes with my trusty 12x70 Cometrons just taking everything in. Any trace LP visible on the horizon had dimmed a fair bit and the sky was just absolutely incredible. I started at one end of the Milky Way with the binos and did transects across until I had rapidly covered all it. I lost count of how many star clusters and double stars, etc I saw, an excellent way to end the night, despite the self-inflicted finderscope problems and strong gusts which swept through for much of the early evening. Thanks for reading and feedback welcome…👍

Excellent stuff Iain! I am lacking widefield EPs at the moment, tried for California last night but might have been looking right through it. Good tip on the coma corrector reducing exit pupil by the way. I am intrigued by Barnard's Loop now, should have given that and the Witch Head more attention when wandering around Alnitak Estates, lol Hoping we get more of these nights before long, there is so much I want to see up there.

Thanks all! Lots to digest here. I do have tracking on the dob, it seems pretty good once on target, I can walk away for a bit and come back and the object is still in the the EP, but it might not be AP-level tracking. The NV tube route appeals to me, but would have to wait until a real bargain came along. I think I've seen the French fellow's website before. In the meantime, I might just go the second-hand Watec route for a play to see how that works, can always sell it on if I don't get on with it. Sorry for the short reply, looking after the children this morning as the wife's price of getting away tonight for some astronomy! Cheers all!

Hi all, Sorry to be running in circles here on SGL. My goal, like the vast majority of visual astronomers, is to see faint nebula and various DSOs in 'real-time' or near-real time. I am under widely varying LP conditions ranging from some horrible urban floodlights near home, down to Bortle 2/3 at my dark sky spots. After buying and selling a Mullard 1332XX Gen 2 tube earlier this year (it was way too heavy), I simply looked at getting my hands on a larger scope with more aperture to do this. I already have a 20" dob, so anything bigger is going to cost an absolute ton and push the limits of what I can transport. I've heard EEVA results will far outstrip any increases in aperture us mere mortals can afford, unless you happen to own a 40" dob in the Nevada desert. Some of the NV tube phone images I've seen here on SGL are amazing as well. I've read a small bit on what EEVA is and basically I gather there are two avenues - one is using a low light video camera to view through a monitor or laptop, and the other is using an NV tube attached to an EP like a 55mm TV plossl. I'd prefer to keep things light and simple without cables, don't want to do any live stacking or drag a laptop around, and want to look through an eyepiece, not at a monitor. However, I do have a budget, so understand I may have to go the camera route. What EEVA set-up would you choose for around £500-£1000, and if you could, what higher end set-up for around £1000-1500+? I buy most of my gear used, so I'd keep an eye out for any bargains. I'm looking at: 1.) old school like a Watec 910HX (how do you even view the image, analogue to digital then on a laptop? Is it a disappointing low-res view? Can you run a Watec off a 12v leisure battery in the field?) 2.) something like an Atik, ZWO or Starlight Xpress viewed through a laptop 3.) a proper NV tube that attaches to an eyepiece or prime focus (probably the most expensive, but most effective option). 4.) Are thermal cameras something you can use, and are they crazy expensive? To make a simplistic eyepiece analogy, I'm looking for the Baader Morpheus of the EEVA world, great quality, but not Ethos expensive. Ideas?

Excellent advice really! I've decided to stick with the 20" and try the EEVA route. If I can view the fainter objects from home when the businesses turn off their lights in the evening, I'd be delighted and would get more use out of the 20", plus I'd always be able to take it to my dark site when time and conditions allow.

Yes indeed, I think a lot of the motivation is simply the desire to build something impressive (to me anyway) and do something astro-related in the summer. I'm increasingly intrigued by the EEVA route, a decent video camera in the 20" dob should produce some good results, and allow me to see things that I'd struggle to find or observe on visual alone even with a monster mirror. Plus the 20" already has goto and decent tracking. Think I'm going to give that a try. Thanks everyone for the advice!

Hi Peter, what type of EAA would you suggest? Video? Andrew above mentions the Watec video camera, reasonably affordable. I will look into this route to allay my aperture fever! Yes, I've been know to start a few projects, get about halfway into it and... I reckoned a few years grinding and polishing a large mirror with no promises it will have decent quality is naturally a real gamble. Finished mirror sets in that range on up are decent used car money and thus out of my league. The EAA route certainly has appeal when looking at it like that, but I've always been a dreamer. Sometimes it works, sometimes it doesn't! I thought mirror making would be a good summer hobby when it's too bright here between c. mid-April to mid-August.

This is interesting! I must confess I know nothing about this area. Does it use the dob as a prime lens, or does it attach to say a 55mm plossl or 2X powermate? With the right filter(s) would I be able to see Hb areas like the Cocoon or HH? £500 is certainly reasonable in comparison to my other options, besides doing some single 10sec AP subs.

Hi @GavStar, I was just discussing large mirror making here on SGL when someone correctly pointed out that rather than spend years of effort grinding and figuring a monster scope, (I already have a 20" dob) just go for EEVA in near-real time. May I ask what set-up you are using and what magnifications you can go to? I had a 55mm plossl to try something similar but ended up stalling and sold it. Welcome to send a PM, any info appreciated. Best regards, S&S.

Hi everyone! The EEVA route is appealing I must say. Recently saw images of someone using a relatively small refractor from a suburban/urban LP zone - the results were simply astonishing. Was that you @Cosmic Geoff? I originally bought a 55mm TV plossl to adapt to an intensifier tube, but never got that far and sold the plossl. Can you even get Gen 3 or 3+ in the UK? I think that's the top end of the spectrum as far as I know. I'm guessing £3k if I'm lucky?

That's not a bad idea actually. I would ideally like to buy a finished mirror set already coated but work will need to pick up considerably! If I can learn to figure and test a few smaller mirrors first then I'll look at going large. I'm not in a hurry, but a project like that would need some pace or I'd just get tired of looking at it! Like you, I'll see how I get on with the basics first. This would be a summer project when the nights are too bright for astro.

Wow! Love the stainless steel. I've just had a quick look at your build thread bit will definitely have a closer look. I do a little bit of MIG on mild steel, haven't tried stainless yet, but have been meaning to. Great to hear someone built a big dob from scratch like that, I'm a lot more comfortable working with metal than wood myself. Good stuff!

I would if I could! That's a huge amount of money. I'd go for a Star Structure dob with Lochwood optics. Make it a 32" f3 please! Oooh I think it will take me a lot longer than 50 hours to get anywhere. I'll start with an 8" or 10" then do a 16" then see if I can go bigger. I've read that over 16" things start to get really difficult in a hurry, even some professional mirror makers struggle with figuring large mirrors, the bigger the trickier. Before I start working on one, I want to learn how to test them first. Still lots of reading to do, just picked up this book below. I love thinking about it though! I think 25-28" is perfect for what I'm looking for. Larger than 28" and I will need a trailer behind by van or park it at a friend's farm. I'd be thrilled with something in the 24"-28" range someday.

Cool! I'll have a look. I think I'm determined to try and figure a huge mirror someday, but will do a few smaller ones first to see if it's something I can get right. Thanks! Really good prices by the way.

Thanks Gerry! Extended forecast here isn't looking too bad, err, other than the 65 mph winds predicted tomorrow! Storm Brendan apparently. That's fine, I'm working inside!