RobertI

A beautifully transparent night last night, so I thought I’d make use of the the C8 for a change. Randomly starting with M51 and a single zoom eyepiece, I was pleased to easily see both cores, and as I upped the magnification, the view just got better and better. Which made me think….perhaps binoviewers would work tonight….. I’m really not sure of the exact magnifications I get with the BV in the C8 but I estimate I was getting around 200x with the GPC. So first BV view was M13 the great globular cluster in Hercules. What a beautiful sight in BV, and at 200x so may stars resolved, with that 3D look and the propellor easy to see. I popped the observing hood on and just soaked up the view for a good 10 minutes - thanks to the comfort of BVs. Next was M57, the ring nebula, another old favourite but a good candidate for high power viewing. And I wasn’t disappointed - the ring looked so clear, with the outer edges of the short axis showing brighter and the central hole slightly glowing. No sign of the central star but the nearby 13th magnitude star was clearly visible, confirming the nice conditions. Next was Saturn. Conditions were pretty steady and some lovely detail was visible, the bright equatorial band and a darker band above and a darker pole. The Cassini division and ring shadow easily seen. Quick sketch of the moons, and later checking revealed they were Titan (8th mag), Rhea (9th mag), Dione (10th mag) and Tethys (10th mag). I had noted a field star of similar brightness to Titan, but apparently that’s where Iapetus should have been - I know it varied in brightness but didn’t think it got THAT bright? Finally Jupiter. Although low on the horizon it was pretty good. Wonderful colours. The GRS should have been visible but I was struggling to see anything, then a few moments of stillness and WOW, there it was clear as day, salmon pink and embedded in a cloud band that seemed to be flowing round it with a clear gap. I watched for a good 15 minutes and got some lovely views in those still moments, but nothing quite as good as the WOW moment! 🙂

Lovely shots Reggie. I had to look it up, but can now see the rings are definitely looking brighter than the planet. 👍

Hi Alan, thanks for asking! I think a pier is definitely the way to go, and I think it is the EAA that would really benefit, rather than visual. For visual, I think it will always be really useful to be able to move around the garden to find the best location (one corner is best for planets/moon, one side is best for viewing east, etc) so will probably stick with a portable setup for visual. There was an interesting development in July though. I suddenly realised that for EAA, I already have the makings of a super-quick ‘plonk and play’ setup. I attached my EAA cam to my 66mm frac and popped it on my little SkyProdigy mount, plonked the whole thing in the middle of the garden, switched on and bingo, it self-aligned, did reasonably good gotos, tracked well and gave some lovely ‘live’ views. No faffing with polar-alignment, 3-star alignment, calibration, etc. See results here. I think it’s scratched an EAA itch and given me a way of doing some EAA with limited time and without the need for a pier. Although, I should add that since that good session, my camera has started playing up, and last time out I had some issues with the mount, so EAA will end up stealing your time, one way or the other! At some point I will want to use my ‘serious’ EAA kit which is double the focal length of the above - I think this is the setup that will really benefit from a pier - unless I am willing to spend £££ on a heavy duty ‘plonk and play’ setup using an AZ-EQ5/6 with Starsense…. which I’m not! 🙂 So a pier is on the cards, but ironically, it will probably have to wait until a time when I have MORE free time, so I can make make the most of it!

Impressive. It’s amazing to see how well these mounts survive under these protective covers. 👍

This looks decent value… https://www.altairastro.com/starwave-ascent-80ed-f7-refractor-telescope-geared-focuser-469-p.asp

You’d probably enjoy carbons stars too then? Quite a few of those around, which increases the number of interesting objects available to a smaller scope. If stars are your thing, it’s hard to beat a refractor for aesthetic pleasure. So for doubles and carbon stars, would I choose my 100mm F10 achro or my previously owned 72mm ED refractor? The achro has better resolving power but introduces a yellow cast and is pretty unwieldy at 1000mm FL and therefore not always fun to use. However the purple halo typical of achros is only visible on really bright stars. The yellow cast can be annoying in some situations, but actually it can highlight the colours of orange and red stars, even if not totally accurate. The 72mm gave lovely pinpoint views, superb contrast and was just so easy to use. If you can get a used 80mm ED perhaps that’s the best of both worlds?

Not sure what the impact would be apart from not being able order from that website? Higher prices I guess!

Although another kilogram and I could take the Zenithstar 66 …. 😬

Off to Turkey in a week and determined to take something to observe with. I’ve put together a super lightweight setup, 60mm scope plus eyepiece weighs 1.06kg and the tripod plus head weighs 2.21kg, total weight is 3.27kg! Shouldn’t ruin my baggage allowance. 🙂 I’ll also take my Baader zoom and some narrow band filters. Might get some nice views of the low southern horizon.

Great stuff Victor, glad the BVs are working for you! 🙂 I don’t know if you found this but objects seem bigger when viewing with two eyes, so the moon at 70x through BVs is more like 100x with cyclops in terms of image scale (I realise it’s an optical illusion). And as you rightly point out, BVs encourage you to view for longer…. much longer. The biggest revelation for me is planetary viewing at around 170x - Mars and Jupiter are awesome with BVs and the 102ED. Fortunately I can get 170x just by screwing the lens of my Classic Baader Barlow to the nosepiece of my WO BVs with the standard 20mm eyepieces. The Baader VIP Barlow gives about 150x. Looking forward to comparing notes when Jupiter gets higher. 👍

Very nice report, love to see the ‘story’ unfold as you increase the magnification. Enjoyed some of your other reports too, some amazing observations, especially M57 . 👍

Nice report, quite a haul! It’s lucky we have doubles to look at when the moon is high enough to spoil the darkness, but too low to be observed. Your 12 inches of aperture must really help to cut through the murk.

Interesting point, I've never had a dob larger than table top, so never really experienced that convenience. I'd probably have an 8" dob if I didn't already have the C8. I do have a 12" dob on my "one day" list though. You're right about the tripod and mount - the Skytee is heavy and a pain to move, although I recently bought an AZ4 with 1.75" tripod - much much lighter.

Nice report. 👍 Having two scopes definitely adds an extra dimension to the night’s observing. I sometimes have my refractor and C8 side by side on the same mount. As you say each has its strengths and it’s nice to have options, and is fun to compare, the frac is great for doubles and wide field, the C8 brilliant on globs and fainter DSOs. Having said that, most of the time of the time these days I just use the frac as it’s so quick and simple.

At the moment I’m getting 1.2 degrees with the WO BV, and looks like I’d be getting 1.8 with the SL BVs which is a pretty decent improvement.

I think a hacksaw would certainly be a permanent solution one way or the other! I have an old Tal 100 RS which is probably a good candidate for shortening - trouble is with a FL of 1000mm I’d still be at 50x which isn’t exactly wide field!

Well something surprising happened last night. I tried the BV with the 1.6x GPC in the ‘proper’ place (attached to BV nosepiece) to see how many mm short of focus I was, and was amazed to find that it came to focus with about 4 or 5mm to spare. I don’t think my slimline 2” to 1.25” adapter was what solved the problem, so perhaps I cocked up when I first tried it. Anyway that’s great news as I can now observe at 57x and that is giving some really nice views of open clusters and Milky Way. I will try it on a dark night (sans moon) and try some other types of DSO, and compare to cyclops viewing to see how I get on. Thanks @Victor Boesen and @Franklin for the heads up on the adaptor. I did try unscrewing the BV nosepiece and e/p holder on the diagonal, and held the BV directly against the diagonal prism to see if I might be able to get focus with the adapter and without the GPC - sadly as always seems to be the case, I was a few mm short , so I don’t think the adaptor will work without a GPC.

Thanks globular. My 1.25" prism diagonal has T2 connectors, but unfortunately I think the problem lies on the BV side - the BV thread into which the nosepiece goes is very small and non-standard (at least none of my numerous adaptors fitted!) so I can't see how I could connect the BV directly to the T2 connector of the diagonal. Great review and very informative. Sounds like the SL BVs might not be the way forward, although FLO make it safe to try with their excellent returns policy. Interesting. I had been investigating the Baader MBs anyway and they would probably attach nicely to my existing T2 diagonal. Interestingly, in that thread I said I could get 56x with my BVs, but I think that was theory, when I tried I believe I could not reach focus. I have managed to eek out another couple of mm on my existing setup by changing the 2" to 1.25" converter - I'll give it a go later to see if that helps.

Thanks all for the really helpful comments @globular @Space Hopper @Louis D @Stu. To answer a couple of questions, from memory I think I literally only need a few more mm to get to focus with the 1.6x GPC but I just can’t see a way of doing it - I am already using a 1.25” prism diagonal with a short light path and I have screwed down the eyepiece holders on the BV. I’ll double check though as there might be another way to get a few more mm, although even if I could manage it, it will probably still only get me down to 57x. I was hoping for more like 40x. Interesting that the mirror BVs only have 17mm aperture. Even so, I think l the absence of a GPC would still mean that a 16 mm eyepiece is getting me down to 45x which is more like was I was hoping for assuming the eyepiece has an decent FOV. Is that right? @Stu It’s entirely possible I may also end up preferring the cyclops wide field views, I just wish there was an inexpensive way to find out! 😆 Perhaps I should do some more critical comparisons of cyclops v bv at my current 70x setup, to see whether the bino experience outweighs any downsides. From memory I don’t think stars are quite as pinpoint and the background is darker implying poorer transmission, but the BV experience is SO comfortable. The mirror BVs might have better transmission too?

I am trying to work out what is the widest field I could get with a binoviewer and my 4” F7 refractor. I currently have a William Optics BV and the lowest magnification I can get with the 4” frac is around 70x using the supplied 20mm 66 degree eyepieces (the 1.6x GPC won’t reach focus, unless I put it before the diagonal which results in roughly 2x). I believe the supplied eyepieces are about as low power as you can get as the field stop of the BVs is quite narrow at about 20mm. So I don’t think I can go any lower mag or wider field with those BVs. But is there another BV setup I could use which goes wider? I understand the Baader Maxbrights have a 27mm aperture but they still have prisms which means glass path correctors which increases focal length? There are also the mirror BVs which don’t appear to need a GPC/barlow (as sold by Bresser and under various other brands) and therefore any 1.25” eyepiece could be used, so in theory I could use 24mm 68 degree eyepieces and get the full 2.3 degree field at 30x? Is that correct? Are the mirror BVs the best ones to use for low power binoviewing?

Nice report. Glad you’re enjoying the scope. I was also out observing with my 102ED last night and saw some of the same targets as you. Really enjoyed the low power views of Cygnus and Cassiopeia with my 21mm Hyperion (34x), lots to discover just by sweeping the Milky Way. My favourite jewel of the evening - the carbon star WZ Cassiopeiae - very pretty.

That’s rough, never been so hot here at night that I can’t observe, hope it’s just a one off for you. Yes it’s been exceptionally hot and dry for many weeks where I live in UK, all my grass is yellow and crunchy underfoot, and it’s like a dust bowl. Still no sign of rain. 🙁 Good news is we’ve had lots of clear nights, but I’d prefer a bit of rain TBH.

I would definitely do a collimation using your collimation cap - it could be way off. Collimation can be simple, the most difficult bit for me is with a longer scope, you cannot look through the collimation cap and twiddle the primary mirror adjuster knobs at the same time unless you have very long arms, so there is a bit of back and forth. I’ll see if I can find a simple guide. As for atmosphere distortions, it best to do some trial and error, the higher the object the better it will look, and sometimes the atmosphere is just wobbly anyway (known as poor ‘seeing’). Also rooftops and concrete will give off heat haze as they cool down over night so best to avoid. The best observing sites are in the middle of a grassy field with clear horizons, but not many of us have back gardens like that!

Hi there and welcome to SGL. Your 8” Dobson Ian is capable of giving superb views of Jupiter, Mars and Saturn, so don’t worry about that. I guess the first question is have you collimated your telescope? Collimation is the first step with a Newtonian telescope and good collimation is essential for making out details on the planets. The other point is that the planets need to be reasonably high in the sky - if they are too close to the horizon you will get too much distortion from the atmosphere. Might explain why Jupiter looked better?

Superb, you have a lot to look forward to, and I look forward to the reports! Congratulations. How about a daytime tour of your observing site?