RobertI

25 minutes ago, Louis D said:

Here's an Ed Ting comparison between a reflector, a refractor, and a Maskutov to see which yielded the best images.

Nice comparison, although admittedly on premium scopes. So basically (spoiler alert) the 5” apo refractor and the 7” premium Newtonian gave similar performance overall, beating the Intes 6” compound scope. Kind of backs up the traditional wisdom about 4” fracs and 6” Newts being similar performance. But the article also makes the point that you can enjoy whatever scope you happen to possess!

37 minutes ago, Roog said:

Interesting, I have not heard this one before, is this generally accepted and if so why does this come about? Do lenses transmit more light than mirrors for a given aperture or is there another characteristic in action here ? 

I’m sure this question will generate a lot of answers! My understanding is that unobstructed aperture of the refractor allows for greater contrast and cleaner images which can make up for its lack of aperture and potentially provide better views certain objects such as planets. I would have thought greater resolution of a 6” Newtonian will always give better views of objects such as globular clusters and should reveal fainter DSOs. So as a very general statement it is probably true but depends a lot on what you enjoy looking at. 

Just to add another perspective to this thread (and hopefully not confuse the the OP!) it is possible to do basic astrophotography with a lightweight altaz mount. Below is a recent EEVA (Electronically Enhanced Visual Astronomy) session with my 66mm refractor on a SkyProdigy mount - very similar to the AZ-GTI or Virtuoso class mount I would think in terms of accuracy and load capacity. Exposures are typically 20 seconds. So you can do basic Astro Photography (AP) with modest altaz setups and get results which are better than eyeballing through a much larger visual scope. So as an alternative, how about a 150P Virtuoso for visual and then add a 60mm frac for basic AP?

And just a quick plug for EEVA, it's so quick and simple compared to traditional AP and shows you much more than visual. It's quite addictive....and cheap!  

Had a brief session to see how wide a view I could get with my Zenithstar 66 and binoviewers. The result was a respectable 1.7 degrees at 39x. Stars were beautiful pinpoints and I had some nice views of the clusters in Cassiopeia and Cygnus and some doubles. Jupiter and Saturn looked good even at this low magnification - low power views of Jupiter really highlight the Jovian system with its satellites.   

21 hours ago, Ags said:

Saturn has been duly observed at 125x, or 0.528 mm exit pupil, using a Speers WALER 4.9 mm with 1.6x extension tube. The ZS66 blows away (not that phrase!) the C6 on Saturn. Clearly visible in the little frac: Cassini Division, the ring passing in front of planet, traces of surface detail, planet's shadow on the rings. I must say I am happier looking through a telescope that I feel is overperforming rather than one that seems to be doing the opposite. Also, absolutely no traces of floaters in the frac - I am sure they were there but indistinguishable from the seeing ripples.

Two hacks I am using to boost the refractor's performance: a celestron prism diagonal to reduce the residual CA of the scope (it really does work - on the right scope!) and a Wratten #8 to tame the atmospheric dispersion.

Interesting to see the ZS66 outperforming the C6 so much on Saturn. I also use a prism diagonal on my ZS66 and I haven't noticed any CA at all - it might be there if I were to look really hard, but if it's not obvious and is not interfering with the observing, then it's effectively absent for me! I find orange and red stars stand out really nicely with this scope, perhaps the 'semi-apo' glass helps there.

Great report Stu, it must have been good for the soul to observe pre-dawn and then watch the sky brightening. Good tip about the bright light stimulating the cones - I will try this. 👍

9 hours ago, Ags said:

I had a good long look at Jupiter and Saturn last night with my Zenithstar 66, and the difference to the past few nights of observing with my C6 was quite striking. 

Firstly seeing seemed much more stable with the ZS66, a well known effect of small apertures. I will need to prove this with a side-by-side comparison of the two scopes on another clear night.

Secondly the contrast and color was much stronger in the refractor. For example, the SEB is faint in the C6 but plain as day in the ZS66. The GRS was visible last night but I  think the smaller scale in the refractor worked against it.

Thirdly I'm not sure the C6 has revealed much more detail. On Saturn, the ZS66 seemed to show better definition of the rings including shadows on the rings. I guess on a night of excellent seeing the C6 would pull ahead, but I don't exactly live on a mountain-top.

Finally, even when I pushed magnification to 0.5 mm exit pupil, floaters were less of an issue in the refractor than the C6. I wonder if this comes down to what photographers call bokeh - the smoothness of out of focus objects. Mirror lenses for cameras are plagued by very rough and intrusive bokeh because of their central obstruction while a good refractive camera lens can have much smoother bokeh. So maybe what troubles me with the C6 isn't just the floaters  but the noisy bokeh of the floaters?

I won't get rid of my C6 - it excels at deep sky and some kinds of doubles - but I am definitely saving up for a bigger refractor.

Fascinating report! I found similar when comparing my 102ED refractor and my C8 on Mars a couple of years ago, although the smaller scope had binoviewers. The full report is here for your interest. I also tried my ZS66 with binoviewers on Jupiter and was suitably amazed at the detail it showed. 🙂

On 25/08/2022 at 10:01, Stu said:

I know I can be a bit of a grumpy old man about this, but I would love to see more of these posts as individual reports in the observing section. I find myself skimming through the thread, with some really great observations and it would be good to comment on them rather than just like. One good idea which I think PeterC65 does is to post in the observing forum (or whichever is appropriate), then link to a short summary post here. That works well 👍

That’s a great idea, think I might do that next time I have a decent session to report on in detail. 

Hi and welcome. Great choice of scope, you’ll see some wonderful sights with that. 🙂

9 hours ago, Alan White said:

Not the post person, but me taking a drive to collect.

A nice original Vixen GP mount, weights, pillar and a bonus Astro Systems 6” f6 scope as well.

All is good for Lunar going forwards as well as planet season.

 

it has an original polar scope as well

Vintage Vixen heaven in matching hammered green livery. Lovely stuff,  should be a joy to use 🙂

Lovely report. SVBony do seem to be producing some nice products, this scope sounds great. I too have struggled with the Crescen over the years. The best I have managed is seeing the upper part of the crescent, with my C8 and a UHC filter I think. I did also see an oval smudge in the right place in my 130P, this time with an OIII,  but no crescent shape. But I’ve never felt like I’ve really ‘nailed’ the view, and I feel that you need the right combination of aperture, magnification, filter and dark sky to really get it. One day……

Well, hey, that’s more reaction than I’ve ever got from my wife! You sure that’s not the headphones nebula?  

38 minutes ago, steppenwolf said:

For the first time in months, last night I was outside just to observe and not a camera in sight (reviewing a beginner's telescope) and I can't tell you just how therapeutic and fun it was too. Because it was for a review, I observed a wide range of objects from double stars, clusters, globs, planetary nebulae and galaxies through to Jupiter and Saturn and I was reminded of what it was like when I first started out in astronomy - the pure delight of a clear sky, a swathe of Milky Way ribbon across the heavens, Saturn's rings, Jupiter's bands and the attendant pin-prick moons. What a great hobby this is!

Totally agree, I love simple, tech free observing. Sometimes I re-live the excitement that I felt when I first viewed objects like the Ring nebula, Orion nebula, Hercules cluster and Jupiter and Saturn, over forty years ago. It’s also good for your mental health! 

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.

1 hour ago, Pete Presland said:

you can certainly see the Seeliger effect on Saturn's ring system. 

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

4 hours ago, Alan White said:

So have you pondered and come up with a plan yet Rob?

Curious to which way you will go, I have a feeling I can guess, but you never know.

 

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! 

On 17/07/2022 at 15:08, iapa said:

+1 for Telegizmos 365

My CGX-L has been unused and under one of these since May 2020. Minimum temperatures -9C, max 26C

All i did today was demolish some arachnid housing just under the top plate.

all knobs move freely. One hex head bolts has slight rust, and there is a small flake of paint missing.

A second mount was also under a Telegizmos, it also survived well.

 

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

8 hours ago, Jimboscotland said:

I like studying stellar evolution

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.